Air conditioning units with blocked or poorly maintained condensate drain lines damage property and affect indoor air quality. Installing traps, overflow switches and switches with integral pumps, coupled with a regular maintenance regimen will prove economical in the long run, says Gerry Spanger.

Some building maintenance departments do not realise the importance of air conditioning unit condensate maintenance until it is too late, and the property they are supposed to be maintaining incurs thousands of dollars worth of water damage or, worse yet, significant mould or mildew problems.

All air conditioning systems condense humidity from the airstream which gets collected in the drain pan. When a blockage prevents a drain pan from properly draining, it overflows into its surrounding area. While property damage is visually evident, the hidden danger of mould, mildew and other indoor air quality problems can lurk for months in air conditioning systems with blocked, partially blocked or poorly maintained condensate drain lines.

All this can cause substantial damage. However, many maintenance departments overlook the potential of overflowing external units on rooftops because they think the roof pitch will drain away the condensate. Unfortunately, many air conditioning units sit on a kerb and use bottom air discharge, a design where condensate can overflow the drain pan and drop into the building.

In my opinion, all air conditioners should include an adequately sized and pitched drain line to transport the condensate away from the unit. Drain lines are a necessity. However, biological or inorganic particulate matter in the unit’s airstream invariably washes down into the condensate, and eventually clogs the drain line. Units in high pollen areas are the most susceptible to biological growth. Therefore, air conditioner condensate drain lines should be checked by maintenance departments a minimum of every three months or simultaneously, when air filters are checked and changed.

Luckily, technology has developed solutions such as cleanable and transparent P-traps, overflow switches, overflow switches with integral evacuation pumps and other air conditioner condensate overflow prevention devices to minimise these problems.

BASIC P-TRAPS

Condensate traps are available in many varieties, but the best maintenance solutions are the transparent and cleanable models. The see-through feature allows easy blockage detection. The cleanable aspect offers up to three accessible cleaning ports on the trap for a brush, which is not included with most trap brands.

Generally, condensate traps are mandated by the International Mechanical Code and the Uniform Mechanical Code, as well as the air conditioner manufacturers. However, this does not necessarily mean the installer of an air conditioning unit has actually complied with, or was aware of, these code requirements.

Traps are easy to install and should be fitted to every unit, regardless of size, or whether the unit is under positive or negative pressure.

Good practice dictates that the first fitting off the drain pan should always be a capped cross, which provides permanent access into the drain line or trap. This also permits access into the drain pan itself without the necessity of opening the unit or removing access panels.

The mechanical codes mandate the use of rigid pipe, which may be PVC, CPVC, abs, copper or other metals. Coiled pipe is specifically prohibited, because it can develop sags which create secondary traps and inhibit water flow. The pitch of the condensate drain pipe is also mandated by mechanical codes and must not be less than ¼ inch per foot.

To check an air conditioning unit’s draining integrity, water is poured into the condensate pan to ensure proper drainage.

Condensate traps also offer an IAQ benefit that is not always appreciated. In negative pressure systems, the trap prevents the introduction of unconditioned ambient air into the airstream, which reduces efficiency as well as prevents dirty air, insects and small rodents from entering occupied spaces through the drain line and air handler.

In positive pressure systems, the trap prevents energy loss by eliminating an open drain line from which conditioned air can escape.

Another anti-microbial strategy is condensate tablets that dissolve in the drain pan over the course of several months. However, this method introduces unnecessary chemicals into the environment and, therefore, should be used only in locations with histories of extreme biological growths.

SIZING TRAPS

Maintenance departments planning a trap installation should know that there are different trap sizes and specifications to consider:

Diameter: The standard diameter is 3/4-inch for up to 15 tonnes; one inch for approximately up to 25 tonnes, and can vary from 1/¼ inch to two inches for larger tonnage units

Depth: Trap depth is critical as it is a direct function of negative or positive pressure in the unit usually expressed in inches of water (wg). Rule of thumb is that trap depth must be at least equal to inches of water plus 30% margin of error to allow for surges in pressure in the AC unit

WG capacity: Traps come in pre-engineered ratings ranging from ½ inch to six inches wg to match the static pressure of the AC unit

It is, therefore, important to choose the right trap as per the air conditioning unit manufacturer’s specifications. It is equally important to see that the unit is sufficiently elevated to a minimum height of six inches to insure there is room for a trap and adequate pitch in the drain line.

WATERLESS TRAPS

Conventional P-traps depend on residual water level for a seal. This usually dries up when the cooling season is over, creating what is known as ‘dry trap’. A dry trap will allow insect ingress and air infiltration, retard drainage on a negative pressure system and increase energy costs on a positive pressure system. A good solution to these problems is a waterless trap, which relies on a float (which may be spring-loaded) to act as a check valve and create a seal. Waterless traps are freeze-resistant, require no priming, do not allow air to flow in either direction and permit the free flow of water at all times. Waterless traps are available in ¾, 1 and 1¼-inch diameters.

OVERFLOW CUT-OFF SWITCHES

An overflow float switch is useful because it deactivates the unit during an overflow event. The switch is typically mounted to the top of the cross fitting above the trap. During a trap blockage, water rises up into the cross and lifts the switch’s mechanical float, which cuts power to the 24-volt circuit that is wired in-line with the air conditioning unit. While there are many overflow switches on the market, it is important to note that switches with a capacity of less than four amps may not perform properly on many units, because they may not be able to handle the higher currents associated with modern air conditioning systems.

Overflow switches are invaluable, but not a cure. They should not be used as a substitute for the regular maintenance of traps and/or drain lines. An overflow switch is a second line of defense that only treats the symptoms of a blockage by cutting power to the unit. Once the water recedes, as in the case of a partial blockage, the unit activates and the cycle perpetuates until the drain line blockage is physically removed. There are many varieties of switches, of which some have visual or audible warning alarms.

While an overflow cut-off switch prevents the unit from operating during blockages, there is one disadvantage. Iced evaporator coils will continue to thaw and feed the slow receding or blocked drain pan even though the unit is deactivated.

OVERFLOW SWITCH WITH A SELF-EVACUATING PUMP

For units up to five tonnes of capacity, the ultimate in overflow protection is an overflow switch with a self-evacuating pump. Regardless of thawing ice, which may form on evaporator coils, the pump will continue to pump out the drain pan and prevent an overflow, even through the switch has deactivated the air conditioning unit. Blocked drain pans are evacuated in under three minutes by the integral pump.

As previously mentioned, a simple overflow switch only momentarily deactivates the air conditioning unit in situations of partially blocked drains. Conversely, a combination switch and pump uses stainless steel electronic probes to sense rising condensate levels. It deactivates the unit while the integral mini-pump evacuates the excess condensate into a ¼-inch vinyl tubing drain line. The pump remains live, while the unit stays deactivated until maintenance removes the blockage and manually presses the integral pump’s reset button.

Traps, overflow switches and switches with integral pumps are inexpensive to purchase and install in-house when compared to the costs of replacing damaged property. These devices are invaluable when applied along with a periodic maintenance schedule. A maintenance crew well-versed in controlling condensate will save tenants and building managers a significant amount of money long-term, while also improving indoor air quality.

The author is Vice President of  Airtec Products, Fall River, Massachusetts, USA. He can be reached at gspanger@airtecproducts.com.

This is the second in a multi-part series on air filtration [read the first part here].

Clean air is not only a right but also a necessity. Absolute air filtration is the main channel through which clean air can be obtained. But it cannot be achieved without making a conscious effort to understand, and put in place, the equipment and the necessary process involved.

The complexity of the process highlights the factors that affect its performance. Earlier, though this aspect had not been given the importance and the attention it deserved, fortunately, there is a recent shift in emphasis towards air filtration. There is, at last, a realisation that indoor clean air is critically important to the well-being of human beings, gas turbine air intakes, and HVAC equipment.

TYPES OF FILTRATION PROCESSES

The first step in the general understanding of the air filtration process is distinguishing between the two types of filtration processes, namely depth, and surface filtration. Fabric and membrane filters are considered surface filters, while fibrous and granular filters fall under the depth filtration category.

Surface filtration:

In surface filtration, large particles are expected to get deposited on the surface of the filtration medium by a sieving mechanism so as to form the so-called dust cake. Thus, surface filters rely on the formation of the dust cake to do most of the filtration action, and therefore, have high pressure drop. (Pressure drop is the measure of airflow resistance through a filter.) In this process, the dust cake layer itself becomes the main filtration segment of the entire filtration process. A detailed knowledge of the properties of the local atmospheric dust is needed to better evaluate the surface filtration process. Pulse filters are a good example of surface filters, and are generally used in gas turbines.

Depth filtration:

Depth filtration relies on capturing the particles within the filter medium. This method of non-cake filtration requires an understanding of the media properties. Depth filtration process allows fibrous filters to have the same or better degree of purification and minimal resistance as that of surface filters.

In this process, glass fibre media is used extensively due to its low pressure drop and better performance at high temperatures. The structure of fibre glass media is delicate, and may not be regenerated either by washing with water and/or through the use of compressed air. Attempting to regenerate a fibrous filter by ejecting the dust out of it will lead to the destruction of the structure of the media, and the dust particles may not be removed completely.

The structure of fibrous filters is illustrated in Figure 1. The porosity of fibrous filters is around 90%, which indicates that the sieving mechanism plays no significant role in the process. This type of filtration is widely used in the HVAC industry.

OPERATING CHARACTERISTICS

When evaluating any of type of air filter, there are three main performance characteristics that should be of primary interest: efficiency, the ability of the cleaner to remove particulates from the airstream and pressure drop. Pressure drop is dependent upon fluid properties, filtration media properties, and the properties of the collected dust. In fact, pressure drop across an air filter varies with its thickness, fibre radius and filter packing density, air velocity and viscosity. The third performance characteristic is the filter life time, which depends upon pressure drop and efficiency.

LEARNING LESSONS FROM DISASTERS

Though air filters are necessary, it appears that we always need an unpleasant event to remind us of the critical role they play. To cite examples from the recent past, the impact of SARS, Anthrax, and H1N1 are engraved in our collective memories, and we are not likely to forget the 2010 volcanic eruptions of Eyjafjallajökull at Eyjafjöll in Iceland. The catastrophic eruption caused massive disruption of air travel across Europe. However, the great lesson learnt from it was that suspended high particle concentrations in the atmosphere affect nearly all human and industrial activities. Had appropriate filter selection been made and proper maintenance measures exercised throughout the year to the required professional degree, air filters would have played a pivotal role in particle removal in protecting human beings and industrial applications during the havoc caused by the volcanic ash.

Frequent sand storms in the Arabian Peninsula are another example of high dust concentration, where they can negatively influence air conditioning equipment and gas turbine performance. Figure 2 illustrates how dust particles settled on the cooling coils of air handling units can reduce their effectiveness.

AIR CONTAMINANTS

The two major classes of air contaminants are particulate and gaseous. The particulate class covers a wide range of particle sizes from dust, which are large enough to be seen by the naked eye, to the sub-microscopic particles that escape most filters. These particulates may originate from natural processes, such as wind erosion, sea spray evaporation, volcanic eruption and metabolism or decay of organic matter.

Figure 3 shows various contaminants that may exist in the atmospheric air. A filter’s effectiveness in removing different sizes of particulates depends upon its filter class.

In the case of power generation, the prime function of air filters is to provide clean air to gas turbines. This can be done by means of high-efficiency filters installed at the air intake. Obviously, the problem begins when particles collide with the turbine blades and cause impediments like corrosion, fouling, and erosion, which are responsible for altering the performance of gas turbines. Erosion, for example, occurs when a particle strikes the blades at a high velocity. This causes a change in the blades’ mass, leading to rotation imbalance in the turbine assembly.

The presence of salt in the air is another factor to be taken into consideration, as it not only corrodes the turbine blade but also the particles settled on the cooling perforations will lead to overheating. Clearly, in such instances, a strong case can be made for installing air filters. They defend gas turbine assembly and help minimise annual shut times for maintenance and, thus, reduce loss in energy output.

It is evident from the examples cited that fine filters are necessary to remove particles from the air stream and lower their concentrations. However, what is really needed is the use of High Efficiency Particulate Air (HEPA) as a final stage of filtration to guard against air contamination. Although there is a great push in the gas turbine market for this, and the industry is aiming to use HEPA class filtration on the air intake of gas turbines, designers might still be reluctant to use them due to concerns about the pressure drop and associated loss in energy output. However, with the launch of the latest intelligent designs of new ultra-low pressure drop HEPA filters, the use of absolute filtration is gaining momentum, as it can provide the higher efficiency desired, at the required pressure drop.

NEED FOR APPROACH RE-ALIGNMENT

It is indeed ironic that a great deal of money is invested in purchasing the most efficient HVAC equipment, but the same degree of emphasis is not placed on investing in high-efficiency filters. There are a few serious questions that need to be asked and answered: Do HVAC designers pay equal attention to the filtration stage of AHUs as they do to the rest of the components? What stops us from installing the highest efficiency of filtration at home, at work and for industrial applications? The climate is changing; shouldn’t our approach to it?

The writer is Regional Director, Middle East, and International Consultant, EMW Filtertechnik, Germany. He can be contacted at iyad.al-attar@emw.de

The two-day Kuwait District Cooling Summit, held on January 25 and 26, had a sense of urgency and purpose to it. Organised by the Ministry of Electricity and Water, under the patronage of H.E. Dr Bader Al-Shuraiaan, Minister of Electricity and Water, the event was indicative of the fact that district cooling was high on the country’s energy-conservation agenda.

The oft-repeated statistics is now common knowledge: Kuwait holds around 10% of global oil reserves but faces domestic power concerns. It has one of the world’s highest per capita consumption rates of electricity. Official figures estimate that around 70% of energy is consumed by air conditioning units, placing a heavy burden on the country’s electricity supply. The country is planning five mega cities to accommodate a growing population, which will make further demands on energy.

The rationale behind the event, therefore, was not difficult to ascertain. Apparently, Kuwait is now ready to place its faith in district cooling, which at least theoretically, comes with a list of advantages: lower cost, lower maintenance, enhanced efficiency and reliability, space saving, flexibility of air conditioning load and longer plant life.

Though Kuwait pioneered water-cooled chillers in the 1960s, it is a relatively new and a late entrant to the DC club in the region. Therefore, though the country has a strategic plan to invest in district cooling in a big way, it has been experiencing teething trouble. As both the cause and effect of it, the sector is still unregulated, and needs a well-defined structure and legislation in place before ushering in a regime of district cooling as a viable investment model. Raising awareness among decision makers and end-users are other main challenges.

It was under the shadow of these challenges that the Kuwait District Cooling Summit was held. However, it was evident from the papers presented that the Summit had inscribed for itself a wider arc. Its scope extended beyond Kuwait’s district cooling sector and its challenges, and included the region and the world, as it also sought to learn from global case studies. As events like these generally tend to be, it was also a forum for senior-level decision makers, engineers, project managers and regional and international experts to discuss the latest technologies, best practices and cost and sustainability dividends of district cooling.

Though the dividing line was blurred, the presentations roughly fell under two rubrics: conceptual/ideological and technical, one overlapping the other. Benefits and challenges of the sector were the recurrent undercurrents of the presentations.

This was reflected in the presentation by Abdulhamid Al Mansour, CEO, Saudi Tabreed. It was titled, ‘Challenges facing the district cooling industry in the Arabian Gulf countries’. Mansour compared the generation of electricity in the six GCC countries and enumerated the following concerns, which were, by and large, echoed by other presenters:

• Meeting air conditioning demand
• Escalated electricity peak demand – summer/winter power fluctuation
• Low electricity tariff
• Cooling water shortage
• Environmental concerns
• Lack of air conditioning legislations
• Poor management of existing systems
• New civic structure expansions
• Increasing local fuel demand

At the crux of Al Mansour’s presentation was the question: How can district cooling mitigate these challenges? His gaze was also on optimisation of benefits of district cooling – increasing energy efficiency and reducing environmental emissions, including air pollution, greenhouse gas (GHG), carbon dioxide (CO2) and ozone‐destroying refrigerants.

He highlighted the fact that most Middle Eastern governments are parties to the United Nations Framework Convention on Climate Change. With most countries in the region having extremely high GHG emissions per capita, he argued that the issue would become increasingly important in the context of government policy making. Affirming that district cooling could reduce annual CO2 emissions by about one tonne for every tonne of district cooling refrigeration demand served, he listed a few of the provider responsibilities:

• Investment in capital to build plant and infrastructure
• Managing design construction of facilities
• Looking into customers’ requirements
• Providing specialised operators and technicians to monitor and maintain equipment and ensuring 24-hour service
• Back‐up system that allows uninterrupted routine upkeep and repair
• Assuming all risks
• Illustrating a proven track record

To sum up, Al Mansour’s presentation explained why district cooling was environmentally friendly and how its benefits could be optimised.

In his presentation, titled ‘Prospective of district cooling for residential sector in Kuwait’, Prof Abdullatif Ben-Nakhi, Department of Power and Refrigeration, College of Technological Studies, Kuwait, focused on the current status of district cooling in Kuwait. Apart from highlighting the benefits of district cooling, his presentation touched upon the HVAC market for residential buildings in Kuwait. But the main thrust of his argument was the need for district cooling in residential suburbs in Kuwait (RSK). He examined its feasibility, barriers in implementing it and suggestions to overcome them.

Ben-Nakhi pointed out that no district cooling system had been installed as a public utility system in Kuwait. This was because it required community support and political backup. Saying that those involved in district cooling could be grouped into building owners, the municipality, and the society at large, he cited resistance and ignorance as the main obstacles for implementing it on a large scale. He listed other barriers under the following categories:

Barriers related to non-governmental district cooling investors for RSK:

• Starting district cooling for RSK is risky
• Long payback period – exceeding 10 years
• No political support
• No legislation for the district cooling market (for example, protecting the investor)
• Overall billing and collection of several and different types of customers
• Requires access to municipal property
• Resistance from unitary AC (installation and maintenance) companies

Barriers related to the government:

• Absence of political support
• No formal district cooling -related strategy
• No policy supporting the district cooling industry

Barriers related to the community:

• Fear of inefficiency due to misuse by other linked users
• Lack of trust in the charging and billing processes
• Ignorance of service quality control mechanisms
• Fear of monopoly in an essential service sector

Ben-Nakhi suggested the following solutions:

The government should initiate:

• District cooling boost in RSK
• District cooling-supportive policies
• Incentives for district cooling users
• Reduced financing costs for district cooling investors
• Cheap rental for district cooling plant rooms
• Introduction of off-peak electricity rates
• Legislate the district cooling market:
• Protect participants
• Control cost and quality
• Design and build district cooling piping network and infrastructure free for the community
• Sponsor further application-oriented studies

Ben-Nakhi’s final appeal was, “Let’s take this chance! Let’s start now!”

Anand K Rohatgi of Synergy Consulting, in his presentation, ‘Why district cooling under BOT/BOO structure may not be for private sector off-takers: learning from Dhahran district cooling project (a case study)’, examined the subject from a financial angle.

Delineating on the economic motivational factors of a district cooling scheme, he listed the following:

• Highly profitable from a national economy perspective
• Lower initial and recurrent operating costs for the district cooling plant operator
• Smart energy technology and economically efficient utility service
• Reliability in excess of 99.7%
• Improvement in carbon footprint for the economy
• Smooth load distribution – lower cumulative capacity requirements
• Presents attractive value propositions to building owners in terms of space
• Lower cooling costs to end-users

Rohatgi identified bankable transaction as the key factor for the success of a district cooling project. He believed that it provided a sense of comfort to lenders that debt obligations would be met within schedule, and ensured balanced recovery of all project costs, appropriate equity returns and proper risk allocation.

Rohatgi argued that district cooling was a viable solution in the long run due to better efficiency, which could be observed by comparing consumption charges and also the fact that its viability would increase with the availability of longer-term debt.

Fadhel Al Kazemi, CEO, Kazema Global Holding’s presentation went into both the generalities of the GCC context and the specifics of the ground reality in Kuwait. Titled ‘GCC countries or state-by-state draft district cooling utility acts and regulations setting fair business relations among the state, customers, developers and utility providers’, it stressed that the technicalities of district cooling as a concept needed to be co-opted by and subsumed into the larger ideological concept of Kuwait’s avowed “National Destiny and Purpose”, which would ultimately reflect the shared aspirations of the GCC countries. He believed that creating a “National Will” through a national-level initiative was important in order to implement district cooling, as part of the larger agenda.

Under the header of National Destiny and Purpose set by the leaders of the GCC countries, Al Kazemi listed some of its salient objectives:

• To reduce electrical power demand
• To reduce CO2 emission and domestic fossil fuel consumption
• To increase use of alternative renewable energy in both demand side and supply side
• To effect mass transit through trains and underground transportation to reduce the use of private vehicles
• To transform the GCC region into one of the world’s financial centres and global hub for passenger airlines, freight airlines and marine logistics

With the above as the unified ambition, and a reminder that all GCC countries have ratified the Kyoto Protocol and signed the Montreal and Copenhagen Protocols, Al Kazemi believed that a common agenda agreed upon by ministries within each GCC state would make district cooling a more viable proposition.

Mohammad Abusaa of ADC Energy Systems made a presentation on behalf of Fadi Hashem, Engineering Manager and Co-founder, DC PRO Engineering, on the topic, ‘District cooling in Kuwait – environmental footprint comparison (IEA)’, which highlighted the electric power stations and power demand data in Kuwait vis-à-vis the impact of district cooling on overall government infrastructure costs, on carbon emissions and elaborated on the benefits of implementing district cooling in Kuwait.

Reiterating that the GCC countries have one of the highest environmental footprints per capita in the world in terms of peak electric load/capita, carbon emissions/capita and annual power consumption/capita, Abusaa said that with the global move to reduce carbon emissions and preserve the environment, and with the power failures and crises in Kuwait occurring since the summer of 2006, it was essential to adopt energy-efficient and environmentally friendly solutions, like district cooling, to meet the future expected growth in the country.

Emphasising on the fact that 60 to 70% of building peak electricity load and over 50% of the building annual energy in the GCC is consumed by air conditioning equipment, Abusaa, articulating Hashem’s presentation, said that district cooling, along with better building designs, could play a vital role in curbing power consumption related to air conditioning, and could offer numerous technical, commercial and environmental benefits to the government and end-users.

Armed with key data about district cooling and sustainability in the GCC countries and in Kuwait, he claimed that switching to district cooling would give Kuwait an additional estimated peak cooling load growth of 1,200,000 TR in the next three years, with an estimated actual load of ~890,000 tonnes. Highlighting the advantage of Thermal Energy Storage (TES), he stressed that the electric demand for 1,200,000 TR was 919 MW for district cooling with TES tank, as compared to 2,233 MW with traditional air-cooled systems. The inference, Abusaa said, was that district cooling and thermal storage would yield rich dividends in the long run.

Georges Hoeterickx of Evapco Europe, in his technical paper, ‘Cooling towers for district cooling design considerations’, looked at the issue of cooling tower size versus approach, the difference between cooling tower water outlet temperature and design entering wet bulb temperature and the difference between cooling tower water inlet and cooling tower outlet temperature. He advised against recirculation, as the bypass of warm discharge air into the cooling tower air inlet would cause capacity losses.

Taking the issue further, Jeevan Joy from Spig and Hisham Hajaj, Project Principal, Stanley Consultant Group, examined the implications of using sea water for cooling towers. Joy’s presentation was titled, ‘Application of field-erected cooling towers in district cooling’, while Hajaj spoke about utilising sea water cooling towers for district cooling.

Joy argued that using sea water in cooling towers was technically and economically feasible, and cited its merits:

• Sea water cooling towers can satisfy cooling needs of petrochemical industries
• No significant O&M complications with seawater cooling towers have been reported
• Economics are favourable compared with the once-through system

Hajaj cited other added advantages: Durability, easy maintenance and control, energy conservation, obviating scarcity of water resources, heat rejection from industries dissipating back into the sea, plume forming far away from the ground level, low emissions in case of salt water, no restrictions for tower sitting within the site, unbiased to wind direction, thus no issue of tower orientation, and less piping, as there is a short distance to the process plant.

That it was suitable only for low-rise buildings, had limitations of geographical location and delivery system and issue of discharge seawater temperature were the disadvantages Hajaj listed. His presentation concluded with the case study of sea water cooling towers of Jubail Industrial City, Saudi Arabia.

Jarmo J Heikkinen, General Manager, Kamstrup Middle East, in his presentation, ‘Cooling energy (BTU) metering’, made a case for individual metering. Despite resistance to it in some pockets of the sector, he believed that the following merits overrode the concerns:

• Saves money and energy – 30% less energy consumption, according to experience in Europe
• Enables effective meter reading with minimum personnel
• Enables fair billing
• Exact monthly reading provides accurate statistics
• Detects failures in the cooling system – leakages of water, energy or low delta T indication

Based on studies in the UAE of end-users, Heikkinen claimed that they preferred individual metering, as it increased consumer confidence. Also, actual consumption data would provide valuable feedback, which could be used for design recommendations.

Magdi Rashad, General Manager, S&T Cool (Sorouh & Tabreed District Cooling Company), gave Tabreed’s perspective on district cooling in his presentation and touched upon challenges facing Kuwait and how to overcome them, reiterating points raised by others.

While Roger Baroudi of SSHI, in his presentation, ‘District cooling designing for life power and cost saving’, dealt mainly with case studies like the Kuwait University Cooling Towers, Soren Kjaer of Perma Pipe focused on understanding international standards for pre-insulated piping for district cooling piping networks.

Tim Burbury, Partner, King & Spalding LLP, in his presentation, drew attention to an area that has not received much attention: ‘District cooling projects: legal and commercial issues and their solutions’. Asking what legal structures were being used in the sector, he looked at commercial and legal issues, like regulation, stakeholder concerns, billing and collection, project phasing – phasing of capacity and temporary chilling/heating construction, reticulation network/centralised plant interconnection, O&M, bankability, water source, end-user demand and off-take guarantees.

It was Yaqoub Almatouq, Head of Refrigeration Team, Ministry of Social Affairs & Labour, Kuwait, who finally gave a comprehensive perspective on the subject, viewed through a technical, environmental and ideological prism, in his presentation: ‘District cooling: environmentally strategic option’. He not only outlined the advantages and potential role of district cooling, but also squarely addressed implementation-related concerns, such as:

• Costs: initial and running
• Durability: longevity components compared to conventional AC systems
• Reliability: capability to provide the required cooling capacity
• Serviceability: repair period in case of malfunctions
• Expandability: cost of more cooling due to building expansion – for example, plant and piping network, capacity improvement
• Technical support: professionalism of district cooling operators and technicians
• Validity of design: sizing, selection, integration of the components with the buildings they will serve
• Monopoly of district cooling service: can the end-user select/change between different providers of district cooling?
• How and who will control the cost of service?

Despite all the misgivings, quoting Alan Kay, Almatouq concluded: “The only way you can predict the future is to build it.” This, perhaps, signalled that the time had come for Kuwait and the region to sidestep interminable debates and discussions about the pros and cons of district cooling, and give it a fair chance. However, who will bear the moral onus and cost, if it does not live up to its promise, is not exactly a rhetoric question.

Peddling of counterfeit refrigerant is nothing new, but following a high profile case in the Middle East, Honeywell continues to raise awareness of the dangers of fake coolant. Paul Collett talks to Paul Sanders, MD, Honeywell Fluorine Products.

The trade in counterfeit goods is an on-going battle to raise awareness with buyers and end-users as to the public health and environmental dangers. In the refrigerants’ sector, the impact of non-regulated replacement products finding their way into air conditioning, chiller and plant cooling systems can be, literally, poisonous.

To counter the trade, Honeywell has been waging an on-going campaign to prevent infringement on its intellectual property portfolio for a number of years. Unlicensed products at trade shows have been seized and, notably, in the Middle East a warehouse was raided in Deira, Dubai, last November.

In the following question and answer, Climate Control Middle East brings you the lowdown on counterfeit refrigerant.

Which products specifically should the HVACR sector be on the lookout for?

HVCAR professionals will be well aware of our Genetron 134(a) refrigerant cylinders, used throughout fridge systems as well as air conditioning. This product is a single component HFC refrigerant that replaced CFC-12 in many cooling applications. Refrigerant R-134a holds an A1 ASHRAE safety classification, and can be used to replace CFC-12 in existing HVAC systems, or to service R-134a systems.

Honeywell also invented and patented R-410A and its use in air conditioning and other applications. This technological innovation has since become the globally accepted standard for use in new residential and light-commercial air conditioning systems.

In addition to R-410A, Honeywell has patents relating to the following refrigerants: R-404A, R-408A, R-507, R-236fa and 245fa.

So what’s in the counterfeit products, and what’s the health and environmental upshot?

Generally, substandard components are used which have not been tested or certificated. This means performance is below par – very damaging for chillers and refrigeration plants and, of course, industrial, domestic and tower air conditioning systems.

We breath the air these systems pump out, and facility and operations managers can be looking at costly repair or replacement as the gases are not fit for purpose and, in some cases, highly flammable and toxic. You, then, have to factor in downtime, costs and the potential for spoiled goods. Not forgetting the impact on the environment from CFCs and their negative impact. The major issues really are safety, performance and the environment.

How do you differentiate between counterfeit and genuine products?

We carry out tests in two stages: the first is to check the cylinders themselves in terms of packaging, the cylinder and security markings; the second is to test the chemical contents at our laboratory.

Counterfeit goods carrying the Honeywell brand can’t be good for business…

Honeywell quite rightly wants to protect its trading name. We have invested substantial resources to develop and commercialise our refrigerant technology. We have demonstrated we will take the necessary action to ensure that others respect our intellectual property, and we’ll continue to do so.

How does Honeywell take the fight to the fakers?

Working closely with our distributors, partners and representatives we gain market intelligence and engage with relevant local authorities. In partnership, we identify the target and arrange a sting operation. This takes time and costs money, but we enjoy strong cooperation with local enforcement agencies, which is critical to successful operations.

What is the future of counterfeit busting?

Counterfeiters are becoming more sophisticated all the time. But we have the resources and the desire to continue our fight, take the goods off the streets and out of harm’s way. We also have the experience, intelligence and support of the authorities, and are confident we can keep up the pressure on the fakers. In fact, that is our mission.

9-10 May 2011, Dubai, UAE

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Being organised by Climate Control Middle East, Food Chain (the event) is a natural extension of a bi-annual supplement on food safety by the same name. Food Chain will examine key issues involving food safety from farm to fork. The emphasis will clearly be on the end-users of refrigeration, filtration, insulation and other equipment and refrigerated transport services (logistics) in the food business, be they supermarkets, hypermarkets, cold storage facilities, dairy farms, restaurants, hotels or hospitals. Issues for discussion include installation practices, O&M and training.

The seminar will include a round-table, with end-users as participants. Key issues for discussion include reliability and energy efficiency. Manufacturers, suppliers and service providers will, then, have an opportunity to present their side of the business.

The event will be of interest and relevance to farming cooperative societies, supermarket and hypermarket chains, hotels, restaurants, hospitals, supply chain and logistics providers, equipment manufacturers, suppliers, service providers (including O&M companies), government regulators on food safety issues and policy makers.

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Contact: B Surendar
Editorial Director & Associate Publisher
CPI Industry
T: +971 4 375 68 31
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E: surendar@cpi-industry.com

Salah Nezar, a sustainability design specialist, is Sustainability Services Leader for Qatar Project Management (QPM). With a wide range of experience in designing and managing projects involving cutting-edge green technologies and forward looking design practices, he dreams of designing high performance buildings at the frontier of zero energy in the region, and finding solutions to solar cooling related challenges.

MY BACKGROUND

With Theodore Monod

I am almost 47. I was born in Batna, in Eastern Algeria. After obtaining my Baccalaureate degree, I learnt Italian and was about to join the Carlos Scarpa School in Italy and become an architect. It didn’t work, so I moved to building services, instead. I earned a degree in Genie Climatique from the University of Constantine, one of the few schools in the world of its kind, devoted to a five-year degree course on HVAC and refrigeration.

The course was, therefore, in a very narrow discipline, with a focus on air conditioning and building services. What I mean is, 90% of the people in the HVAC industry study the subject as part of their Mechanical Engineering degree, but we were capable of offering a wide array of choices in computing HVAC load calculations by the end of the third year of the curriculum.

I completed my degree in 1989 and went on to graduate school while working as an HVAC engineer for a local engineering office. I got a Master’s degree in Bioclimatique – a combination of passive design and intelligent active AC systems. It was specific for hot and arid areas. The research topic was sponsored by the Government of Algeria, in collaboration with the EU. I had to undergo a number of very specialised training programmes with ADEME (L’Agence de l’Environnement et de la Maîtrise de l’Energie) and l’Université Catholique de Louvain. They have one of the most advanced labs for Bioclimatique research.

During this phase, I had the chance to meet a number of top-notch sustainability specialists at the University of La Rochelle, and L’ecole des Mine de Paris. My discussions with the scholar, Theodore Monod are engraved in my memories on how to embrace sustainability as a mode of life and not as a buzzword.

At the end of the research work, I wrote a technical paper, which was selected by the World Energy Council in 1998 as the best of its kind, proving a rethinking approach in integrating passive and active energy conservation strategies in a single thermal model. I didn’t expect it to, but the paper changed my career and my life.

The year was 1998. I took the paper to the United States for a presentation in Texas. My plan was to be in the US for a few days, but I stayed on for years!

Subsequent to the presentation, in Texas, the University of New Orleans contacted me to join their energy conservation programme. I was in charge of the energy simulation lab and taught students numerical tools to conduct energy simulation and energy auditing, and discussed real case studies with them on intelligence buildings. It was a 4,000 level course.

FROM COLLEGE CAMPUS TO RETROFITTING

In 2001, I moved from the world of academics to the world of industry – to Dome Tech Engineering, in New Jersey. The firm specialised in commissioning and retrofitting, with a focus on pharmaceutical and medical facilities in hospitals. During my time there, I completed assignments for Pfizer, Johnson & Johnson, Merck, Baxter, in addition to a number of hospitals in the New York metro area, like NYU, Mount Sinai and Winthrop. It was an enriching experience, as the level of cleanliness involved was very high, and the designs had to be very stringent and specific. The assignment also involved trouble-shooting.

Speaking of trouble-shooting, let me cite an interesting anecdote from this period. In the pharmaceutical business, each product has a production line. One of these lines was serving a branded and well known medicine. From its starting day, generally, in summer, every year, the production line would go down, owing to humidity and high temperature.

The system, therefore, had to be shut down. This obviously had cost implications.

Speaking at a sustainability event in Dubai

Pfizer, in New York, called several companies to solve the problem. They all thought it had to do with air-balancing. But it was fortuitous that I looked at the data and decided to do water and air tests. When I looked at the test results, I noticed a shortage of chilled water. But that was not the crux of the matter. I asked for as-built drawings, and after doing some mathematical calculations, I concluded that the problem could be in the cooling coil. When we opened the AHU, we found that the coil was facing the reverse direction. Once it was flipped to the right direction, the system was able to achieve the design conditions despite a slight shortage in chilled water flow.

After Dome Tech, I moved to Kallen & Lemelson, in New York City. During this period, the firm bagged a contract from New York State Energy Research Development Authority (NYSERDA). I was fortunate enough to be in charge of managing the energy and sustainability segment of iconic projects in New York State. In all, I was in charge of 20 projects to recommend energy conservation measures and ensure their implementation in the design document in order to be eligible for the state incentives. The amount of incentives depends on the level of energy saved, generally quantified through a full year energy model.

My job was to run the energy conservation side of the projects, from the kick-off meeting to the completion of the design document.

I had to come up with forward looking ideas for energy conservation and generation. The measures concerned finding ways of using smart integrated systems for high performance buildings, using VAV instead of constant volume, use of advance controls in optimising the efficiency of the air delivery system such as demand ventilation control and static pressure reset, and finding ways to have smart chilled water delivery system, including the cooling plant sequencing optimisation. This gave me a lot of experience, because I was dealing with top engineering firms not only in New York but also worldwide, such as, JB&B, Cosentini, and Flack & Kurtz We worked on iconic hospitals, schools and green residential towers.

Besides the NYSERDA contract, I was heavily involved in the project of renovating the 100 year old lion shouse for the Bronx Zoo. It was the first landmark building in New York City to obtain the LEED Gold rating from the USGBC.

You see, the challenge in a landmark building project is that you can’t change the outside and you have to work around it. The zoo project was complex, because it posed other unique challenges. For example, in the exhibition area housing the Nile Crocodiles, Lemurs and other animals from Madagascar, we had to create a specific environment for the animals and plants. We used advanced techniques in providing optimal indoor environment, like dynamic skylight composed of three layers to optimise daylight harvesting and minimise sun load in summer. It was the first time in the US that dynamic skylights were deployed.

At the plant level, we succeeded in integrating the existing zoo cogeneration system and absorption chiller with a new 200 KW fuel cell unit, and a skid of ground source heat pumps. The amount of energy saved was just outstanding for a historical building.

It was soon time to move again, as I got an offer from Syska Hennessey in New York, for the post of Supervisor Engineer. It was a whirlwind time.

While there, one of the first projects was designing the cooling system for a data centre in downtown New York. It was a challenge, because in New York City, space is at a premium, and there was no space to add new cooling towers. To overcome the problem, we took part of a floor and removed the window frames. This allowed for the air recirculation for the purpose of heat rejection. All the units had to be custom made.

During my tenure with Syska, I worked on retrofit projects and many LEED buildings. I was also involved in the commissioning of 1, Bryant Park, which is the Bank of America building. It was the first LEED Platinum high-rise building in the United States. So, straddling between a zoo and a high-rise building was quite an experience.

I was also involved in the retrofitting of the headquarters of the Bank of America building in Charlotte, North Carolina. The proposed design, to achieve a LEED Gold rating, needed a smart air delivery system using passive chilled beams, combined with an underfloor air distribution (UFAD) system. But we ended up with smart VAV systems! The construction cost of the smart system of the first system was $42/square feet, while the classic VAV system was $17/square feet. The difference was quite large, and the bank decided to go for the second solution.

For Vachovia, again in North Carolina, I worked on all the preliminary LEED scoring sheets and recommended a strategy based on a variety of solutions to get LEED Gold for the entire complex. We worked with an engineering firm in Georgia and helped them develop an execution plan for the sustainability strategy.

FROM THE BIG APPLE TO GUANGZHOU

John & me, Bryant Park, NYC

After the Vachovia project, SOM in Chicago contacted me. They had just got a project to design the first zero energy, high rise building in the world – the Pearl River Tower, in Guangzhou. It was designated to be the most energy efficient, super tall structure in the world. I accepted the challenge, because it was one of the most complex projects I have undertaken in my life. It had all the advanced technology and design practices for high- performance buildings (HPBs). There were four cavities in the building structure to house vertical wind turbines. This integration allows the turbine to generate electricity 18 times higher than if they were installed at the ground level. The top of the building was covered with PV cells to generate electricity and reduce the cooling loads. A double-skin (ventilated façade) was used to minimise the space-cooling loads. Blinds within the cavity were covered with PV cells to energise the shading control system. Daylighting harvesting was optimised with the use of efficient lighting to reduce electrical consumption.

Understanding the building loads and using psychometrics encouraged us to opt for a separation between sensible and latent loads. We used chilled ceiling with an underfloor air system for the interior spaces. The load with the perimeter zones was high to a point we had to use passive chilled beams instead of chilled ceiling.

The main challenge was defining a common understanding about the design intent within the design team and lay down a platform able to integrate successfully a set of energy conservation measures, acting at different systems level, and energy generation opportunities from sun and wind. There were moments where we felt lost between divergent inputs from the parties involved in the project. During the closing phase, the stress was at the apogee for the entire team, particularly for me as the lead HVAC engineer.

The project was a huge success. More important, it succeeded in convincing the international panel, which was doing the design review.

Another prestigious project was the assignment involving the new international terminal at Mumbai’s Chhatrapati Shivaji International Airport – a 2.5-million square foot project. It was 12 times the size of a football field. The challenge was to design the new one in phases and integrate it with the existing one. All this had to be done in 20 weeks. We updated cooling load calculation 15 times during those 20 weeks. We had to take into account constant architectural modification, interior design adaptations, life safety, IT and security concerns. We aimed for a high-efficiency building. The clients were pushing for reliable and efficient systems that could also achieve LEED rating.

To suit the air delivery path, as imposed by the architectural team, we had to provide design a special air column. We designed it in-house and sent it to the manufacturer to make it to suit the load requirements of the airport. The project gave me a great sense of satisfaction, as the architectural team (based in New York) and the client were very happy with our work.

UAE-BOUND

After the airport project was completed, I joined KEO International Consultants, Abu Dhabi, as Head of the Mechanical Department. I had to start the department from scratch. I worked on numerous project, like the design of the Dar Al Dhabi in Abu Dhabi.

As a team leader and manager, the big challenge was in understating the energy flow of a team and act as a regulating point to keep the flow going, regardless of the situation. In the beginning, the mechanical team had a heterogeneous pattern in providing engineering solutions. Our design document did clearly reflect this issue, and we worked extremely hard to make our deliverables consistent, useful and in-line with the international norms. I was successful in involving every member of the team in the process of updating CAD standards, several standards and specification without disturbing the production or missing any deadlines.

During my stint in the UAE, I also became the Vice President of ASHRAE’s Falcon Chapter, and the Chair of its Sustainability Committee, where we were involved in a number of activities with Masdar and Estidama. I made some contributions to the work involving the Pearl rating system with the pioneering team, right from the initial stages.

QATAR BECKONS …

From Abu Dhabi, I moved to Qatar. The peninsula needed experts in elevating the level of design and management to help in design reviews and value engineering. Today, my assignment involves activities similar to the ones I was involved in while in New York.

In my opinion, the leadership in QPM has the vision to create a worldwide leading project management firm. The strategic business models are under continuous change to meet the market transformation. Helping host the 2022 games is one of the challenges we are taking very seriously, indeed, at QPM. I’m happy that I’m providing the leadership needed to actualise the company goals. I believe I’m bringing something unique to the initiative. Here, I’m not talking about sustainability in marketing terms but about specific, defined, measurable goals in sustainability.

THE HUMAN ELEMENT

Pearl River Tower under construction

The question often asked is, why should we focus on IEQ and human productivity? The answer is, because it brings thermal comfort, acoustic comfort, visual comfort, olfactory comfort and, not to forget, the ergonomic aspect. If, by putting these together, you get optimal IEQ, you will enhance productivity by five per cent. Do consider $2 per square feet on energy, $3 per square feet on rent, $500/year per square feet on wages, $2/square feet in taxes in midtown New York. So, if you can save just five per cent of that, imagine how much you are saving! This will automatically change the owner/tenant equation. Instead of high rent, the tenant will pay a lower rent. But the owner will get 35% of benefits from the tenant – base rent plus incremental rent.

A case in point is 1, Bryant Park. The Durst Organisation gave it at $120/square feet rental. But at the end of the day, they got $150, because people now want to move away from sick building syndrome and dark spaces. They are looking for connectivity with Nature and green.

I BELIEVE …

I believe that we should focus on energy efficiency and energy generation. It starts with cooling load optimisation. And in this region, 65% is earmarked for HVAC. Therefore, the best way to have sustainable design is to figure out how to reduce cooling load. My experience is that there are different tiers in energy conservation. Let me explain:

Tier 1: Optimisation of building envelope – reduce glazing, shading, orientation and ventilated façade.

Tier 2: Reduce the internal load – lighting load and plug loads–

Tier 3: Smart buildings or advanced control systems

Tier 4: Efficient or enhanced commissioning to match the intent of design with construction practices – you can design the best system but end up having a bad system, depending on the quality of construction. Avoid “You get what we give you” from the project vocabulary.

Tiers 5: Solar cooling to shade half of the electrical load.

Tier 6: Ensure enhanced IEQ – human beings should feel this is the right place to be in. Being comfortable doesn’t mean depleting extra natural resources that we should be saving for future generation

HOW I WANT TO CONTRIBUTE TO THE REGION

I would like to contribute to the growth and development of the region by offering my experience to the service of management firms and helping them in achieving high-performance buildings (HPBs) in various ways, be it by way of optimising energy and water consumption or by reducing carbon emissions. I think I can do this by suggesting the best different approaches.

One of my key aims is to contribute to finding solutions for solar-cooling challenges. If we can hit upon a viable solution, we can really reduce specific load by 40%, at least, at the plant level. The focus is on how to find smart alternatives to produce chilled water. We have the highest solar density in the world, and we need to benefit from it. Paradoxically, we also need a lot of water (for the absorption chillers), and we need to find a way to cool the condensing water going to the chiller. I am working on this. Maybe we will find a way to create a prototype in producing the system.

I think I can also help in putting a high efficiency approach in place in building services – some people deploy VFD, but it does not work efficiently, either because the sensors are put in the wrong place or the wrong valves are selected. So, valve authority calculation is important. I think that’s the only way we can know that the system is working in part load. If a building has 40% load, the plant should mimic and have 40% operation. Realistically speaking, if you pay for a system with part load control capability, but your chiller does not see it, what is the use?

MY MENTORS IN LIFE

My mom was my first mentor. She never went to big school, but she had a strong personality and sense for a sustainable way of living. My father encouraged me to have a good education and a passion for work. His words did light my path during critical moments in my life.

Apart from my parents, I had a number of other mentors in Algeria. Every one of them nurtured my talents. In New York, Al Dechiara was my mentor. He had spent 52 years with Syska Hennessy, and was still working at 75. He was a walking reference book. John Maglaiano, the then CEO of Syska, was another mentor. He gave me access to opportunities.

In a way, I consider even the young guys who work with me as my mentors, because I learn something from them when they come asking, “Why do this?”

Theodore Monod, the French environmentalist and scholar and Rafat Girgis, are people I have learnt from. I remember Prof Boudemine Belkhouche of the Tulane University, New Orleans, Michael Thoresen, Rob Bolin and James Regan at Syska Hennessy, as people who have helped me.

I’m particularly grateful to Dr Edwin Russu, Dr Carsie Hall and Belgacem Hizoum at the University of New Orleans, for taking me under their wings. I couldn’t speak English when I went to the United States. I was in Downtown New Orleans with $20 in my pocket and no home or friends. It was a turning point in my life. The question in my mind at the time was, should I go back or stay? I stayed back, because I found friends and the strength to continue. Russo, Hall and Belgacem were there to help and will remain as friends for ever.

Though I had a brief stint at SOM, I consider my experience with them as a very enriching one. People there respected you and your experience. The support provided by Roger Frechette, Russell Gilchrist, Phil Enquist and William Baker have had a considerable impact on my productivity. Unfortunately, I had to move from there, owing to family reasons.

MY FAMILY

My wife’s name is Nadia. She loves trees and green spaces. I have a three-year-old son. His name is Abdel Aziz Sultan.

For us, it’s not about talking sustainability and driving an SUV. We have a social responsibility in our personal life.

MY INTERESTS

I was a university-level soccer player in Algeria. We won the Algerian cup in 1986. I was goalie. My father was a part-time soccer coach in Batna. So I grew up on the soccer field.

I play the game sometimes now. For regular exercise, I go on long walks. For me, walking is a hobby. I think when I walk.

I like reading. Alchemist by Paolo Coelho has had a profound influence on my life.

I also like writing. In fact, I was a part-time journalist and wrote for newspapers like El Massa, Al Atlas and Al Mountakheb in Algeria. I used to write on sports and on environment, since I liked these subjects. I can write in English, French and Arabic. I also participated in a couple of television shows in the early 1990s. I took classes in technical writing. I attended Université de Paris-8 for technical expression.

I also like films and was lucky to be involved in them from the point of view of my profession. I was among the few engineers who previewed the movie, An Inconvenient Truth and met Al Gore personally. I was called in as a preview expert for Chris Paine’s ’s film, Who Killed the Electrical Car? Michael Moore led the Q&A panel, and we had a very long debate that night on real sustainability issue involving a number of celebrities and journalist living in New York Media. I count these among important experiences of my life.

MY PHILOSOPHY

I think we have to give. Life is about giving without expecting. “Don’t create boundaries” is my guiding principle. Every person has a positive side, regardless of roots or religion. I have nurtured my philosophy from those who have been kind to me.

I believe that there should be a spiritual aspect to our life. We need it to balance stress.

What type of cooling tower is better – FRP or concrete towers? Aslan Barazi weighs their comparative merits to facilitate an informed choice.

Since the beginning of the district cooling era in the Gulf region, which began in the UAE over a decade ago, FRP (Fibre Reinforced Polyester) cooling towers have taken the lead. This is because of the material’s ability to withstand harsh climatic conditions of the region, which include factors, such as high ambient temperature, high humidity and high sea air salinity in this area. However, concrete cooling towers are a tried and tested option. There are many concrete cooling towers still in operation in the region that are more than 35 years old, thanks to their inherent efficiency and longevity. This article addresses some of the key features and differences between the two types of cooling towers – concrete and FRP towers.

It is worth mentioning here that each country seems to have its own preference in cooling towers. For example, the UAE appears to be partial to FRP cooling towers, while Kuwait seems to prefer concrete cooling towers. It is interesting to note that there are many examples of old and new towers that use ceramic tile file with a 25 year standard warranty on the fill, for both plant room size projects and small scale projects.

Both concrete and FRP towers have their advantages. An FRP cooling tower comes with a single FRP body, with either a stainless steel construction or an FRP pultruded structure.

On the other hand, a concrete cooling tower is made of 100% corrosion free material. This is because manufacturers take into account the fact that even SS316 in the cooling towers has been shown to oxidise and turn brown, requiring regular cleaning.

An FRP tower is lighter in weight and has a higher stress/strain ratio, especially when made by reputable cooling tower manufacturers, who use an FRP pultruded structure.

Some cooling tower manufacturers offer the option of a double FRP wall, which gives it a life span comparable to a concrete cooling tower, provided it is correctly specified at the time of listing quality specifications. With minimal alterations, it also becomes an FM approved fire rated cooling tower. This is an important factor from a safety point of view. In case of a fire, the fire can be safely contained within the cooling tower cell, without the possibility of it spreading to the neighbouring cell.

Another advantage in the case of the double FRP wall is that it substantially reduces noise levels, since the air medium between the two FRP walls acts as a sound insulator. In addition, a double wall FRP cooling tower looks better.

The point to be noted here is that there is an additional cost for a double FRP cooling tower compared to the single wall corrugated FRP structure – normally in the range of a 1.15 multiplier. It can be argued that the additional cost is justifiable, if we factor in the fire safety aspect, lower noise level, longer life and higher tower stability, compared to a single wall FRP tower. Its visual appeal, of course, is an added advantage.

At this juncture, it is also important to remember that a material density of FRP/glass composite of no less than 12 oz to 16 oz per square foot FRP ingredient is required for the long life and structural integrity of a cooling tower. There are numerous instances of cooling towers either failing or, worse, collapsing, when cooling tower manufacturers have compromised on the quality of material and have supplied cooling towers using material with thickness of lesser density, for example six oz per square foot or eight oz per square foot thickness.

Concrete cooling towers, on the other hand, have a long history, globally, and in the region, thanks to their longevity, compared to FRP cooling towers. Interestingly, what makes them a more economical option in the region is the lower cost of pouring concrete, when compared to Europe or the United States. Having said that, it can be argued that the concrete needs to be competitively priced, when taking into account the overall pricing of the tower. Which means, the total concrete scope of the cooling towers should be part of the civil contractor’s total scope, including procurement and labour cost, for better economies of scale.

When we compare the life cycle cost (LCC) between a concrete and an FRP cooling tower, a concrete cooling tower seems to emerge as the clear winner in the long run, particularly in the region. If they are manufactured by a reputable company, and are properly maintained, concrete cooling towers can be expected to last for about 50 years – the same longevity as that of a building. This criterion could also be applied, in all probability, to the ceramic tile fill (25 years warranty) that comes along with the tower. Comparatively speaking, a standard quality FRP tower has an average life span of about 20 to 25 years by industry standards, and therefore, needs to be replaced twice during the life of a building. Lower in the rung is the tower with a PVC fill, with an average life of seven to nine years, and would, therefore, need to be replaced five to six times over the average life of a project.

It needs to be noted that a PVC fill is more efficient and occupies less space than the tile-fill variety. Normally, a tile-fill tower may take15% to 25% more space than an FRP or a PVC-fill tower. A tile-fill tower, however, has the advantage of longer life, and is clog free and maintenance-free, allowing practically any kind of water quality to pass through it, without any worry about the effect of heat transfer on the fill medium, as it happens in the case of the more sensitive PVC-fill tower.

In the case of a PVC-fill tower, a slight nudge or tilt may alter the effect of water trickling over the fill, making the water take the path of least resistance. This would, in turn, reduce the overall cooling tower’s heat transfer performance. Additionally, concrete cooling towers have lower noise levels than conventional FRP (single wall) cooling towers, due to the inherent properties of concrete.

Another feature of concrete cooling towers is that they can be constructed as part of the architectural design and, therefore, have aesthetic appeal. This also makes the cooling towers more flexible, as far as space is concerned. The client or consultant, therefore, can allocate a separate space for the towers, instead of installing them in the plant room. This is an added advantage, especially if space in the plant room is a constraint.

A caveat: though concrete cooling towers offer a wide range of innovative possibilities, clients who want to opt for them need to factor them in at the project’s design stage itself and work in tandem with the architect and the mechanical engineer.

In conclusion, it can be said that both FRP and concrete cooling towers are feasible options for a client to consider. The choice depends upon design factors, LCC cost analysis, available project time scales, space considerations, noise levels, safety, tower fire rating and issues of operation and maintenance.

The writer is the Executive Director of IMEC Electro Mechanical Engineering. IMEC are the Exclusive Representatives of CCS Cooling Towers, USA. He can be contacted at imec@emirates.net.ae

Though VRF systems often prove to be better than air-cooled chillers and traditional ducted splits, they have certain inherent limitations. Dharmesh Sawant demonstrates that connecting fresh air systems and VRF systems will yield greater benefits.

With the recent EHS and ESTIDAMA regulations, stakeholders of most projects are racing against time to earn maximum credits to get the approval from the authorities. This trend has encouraged the real estate and construction sectors to adopt green building practices that are ultimately beneficial to the end-users, who had earlier been sidelined and left out of the value chain.

Given the scenario, quite often, the Variable Refrigerant Flow (VRF) system has been found to be useful, thanks to the high EER (above 12, as per ASHRAE 90.1) and the use of R-410A, which is an eco-friendly refrigerant with zero ODP. Apart from that, the part-load efficiency of VRF systems is also better than that of air-cooled chillers and traditional ducted splits, due to their innovative DC inverter compressor technology and precise control of refrigerant flow to the evaporator coil, with the help of multiple sensors in the refrigerant line.

Earlier, however good the VRF system was, it had an inherent limitation when it had to be used for fresh air systems. Since the VRF system works on the control logic integrated with the evaporator coil, which controls the frequency of the DC inverter compressor, it was, therefore, used only with the factory-tested and designed indoor units.

These indoor units have inbuilt electronic expansion valves, which throttle as per the cooling demand. Also, it has its PCB in the indoor unit, which communicates constantly with the outdoor units at an interval of two seconds. Owing to this limitation of the VRF system in the fresh air system, it is either connected to chilled water, making it difficult to maintain two different systems – VRF for the re-circulating FCU and chilled water for the fresh air system. Or else, the entire system is connected to the chilled water system, increasing capital as well as operating costs.

Looking at the positive side, if it is possible to connect the fresh air system to the VRF system, the benefits compared to chilled water system are as follows:

Reduced capital cost up to 25%

A VRF system needs fewer components – VRF condensing unit, indoor units and connecting copper pipes. The valve packages are all in-built, unlike chillers, which need pumps, chemical dosing plants, valve packages, three-way valves, chillers, chiller manager, makeup water arrangements, etc. This increases the cost of the chiller system. Owing to this characteristic, a VRF system proves less cumbersome for contractors, as they only have to coordinate with fewer vendors.

Chillers are normally kept in remote chiller yards to keep the noise levels away from the main building. This increases the pipe network cost. In the VRF system, however, the condensing units are kepts close to the AHU, thus reducing the pipe cost.

Reduced operating cost by up to 30%

The daily range of temperature in the Middle East is quite high. This translates into a highly variable fresh air load. The DC inverter varies its frequency as per the ambient temperature (fresh air load), thus optimising power consumption. The NPLV figures of the VRF system go as low as 0.58 KW/TR for the horizontal development, with reduced separation between indoor and outdoor units.

Reduced connected electrical load

The VRF system has lower connected electrical load of 1.2 KW/TR, compared to 1.7KW/TR, including pumps at 460C for horizontal development with minimal separation between the indoor and outdoor units. This reduces the size of the transformer, lowering the infrastructure cost.

Ease in commissioning

One of the nightmares of commissioning agents in the chiller system is its hydronic balancing. In the case of the AHU connected to the VRF system, it can be commissioned with the help of a software. As a result, all the important parameters can be viewed on the laptop.

Better control of finances in a phased development

In the case of a VRF system connected to the AHU, the project finance is directly proportional to the development phase. But in case of a chiller system, you need to pay a higher cost than the development phase. For example, in the final stages, if a 50 classroom school is made in two phases of 35 and 15 respectively, within a year’s gap, the capital cost in the case of the VRF will be 70%. But in a chiller system, you need to lay the pipe an install the chiller for the total capacity of 50 classrooms.

All the above benefits are made possible by integrating the AHU and the VRF condensing units with the help of a control kit and an expansion kit. The architecture of the system is as follows below.

A total of eight outdoor units amounting to 700 KW can be connected to a single AHU, giving more flexibility to contractors/consultants. The following options are available with the AHU:

• a) Heat recovery wheel or heat pipe
• b) Temperature/humidity sensors in return and supply air
• c) Damper actuator for fresh air and return air

A total of eight outdoor units amounting to 700 KW can be connected to one AHU, giving more flexibility to the contractors/consultants. The following options are available with the AHU:

• a) Heat recovery wheel or heat pipe
• b) Temperature /humidity sensors in return and supply air
• c) Damper actuator for fresh air and return air
• d) Differential pressure switches across the filters
• e) Valves for the humidifiers
• f) Operation of the motorised damper, as per the CO2 sensors
• g) Operation of the motorised damper, as per the smoke detector

The entire system is BMS-compatible through LONWORK or BACNET gateway. Thus, it offers the benefit of high EER of up to 12~12.5 due to DC inverter scroll compressor, high efficiency DC inverter condenser fan motor, high efficiency sub-cooling heat exchanger and wide louvre condenser fins. Above all, it offers reversible heating cycle.

The condensing unit comes in modular design, with each module having two compressors – one inverter and the other, constant-speed scroll. Therefore, even if one compressor fails, the other compressor comes on automatically, with auto back-up function.

The condensing system is easy to commission with the help of a Monitoring Viewer by hooking the system to the laptop. This provides a real-time view of various important parameters of the air conditioning system, like suction, discharge pressure, sub-cooling temperature, superheat temperature, ambient temperature, and refrigerant inlet and outlet temperature (see Figure1 and Figure2 below).

In addition to this, with the help of the control kit that integrates AHU and VRF system, it is possible to control as well as monitor the AHU parameters using an AHU Viewer.

As shown in the screen shot (Figure 3 below), we can easily check the following:

• Fan and damper condition
  • — Fan ON/OFF, damper opening angle
• AHU condition by sensor installed in each part
  • — Mandatory sensor (RA/SA temperature)
  • — Other sensors (SA/RA humidity/OA/Mixing air, CO2, etc.)
• Control condition
  • — Operation mode (cooling, heating, fan, power saving)
  • — Setting temperature/humidity
  • — Supply and return fan operation

Green fresh air solution with VRF technology has found increasing acceptability in the region, thanks to the enforcement of green building practices by ESTIDAMA, as many stakeholders look for a solution in the design stage to achieve the required credits.

A few of the applications where fresh air units are feasible are schools, mosques, villas, horizontal office buildings (up to 10 storeys), cultural centres and museums.

The writer is Senior Manager, LG Commercial AC. He can be contacted at: dharmesh.sawant@lge.com.

Lack of adequate and efficient ventilation systems with the right airflow rate is a health hazard. Good IAQ is an essential requirement of modern living, says Gaetan Pierrefeu.

Ventilation is a basic need. It is required to ensure proper Indoor Air Quality (IAQ) and level of comfort, and improve the quality of life for people. A system of continuous air renewal is necessary for health, by the process of elimination of pollutants – CO2, Volatile Organic Components or VOCs – as well as odours, spores or germs. It also reduces the humidity rate, and by extension, the development of moulds and acaroids.

A few of the traditional ventilation solutions, such as wind towers or the barajeel system used earlier in the region, ensured basic comfort for residents through a natural system of cool air renewal inside local dwellings, until the 19th century, as can be exemplified by the Bastakya district in Dubai. The need for ventilation is, therefore, old, basic and vital.

Air conditioning and split-unit technologies came into the region later to cope with high temperatures. But the noise they generate and low thermal comfort they provide are the two main reasons why central AHUs and FCUs have gained popularity in recent times. These systems generally ensure a greater level of cooling due to high cooling loads and lack of proper insulation. This has obviously led to high energy consumption.

The first step in the evolution towards sustainability is, therefore, to work on the envelope of the building to ensure an efficient system of building insulation, air tightness and shade. On the flip side, though these will lead to better energy savings by reducing the cooling load (low heat transfer and low air leakage), they will also increase the need for an efficient ventilation system, bringing outdoor air to cure and improve the IAQ. Indeed, all pollutants and VOCs trapped inside buildings will have to be removed effectively through a continuous ventilation system.

Absence of such an adequate ventilation system with the right airflow rates will increasingly give rise to health issues, especially for the most fragile – children and seniors. In fact, some of the prevailing health disorders can be traced to building-related illnesses.

Indeed, high level of CO2 concentration in a building can often be traced to an occupant’s poor health, a feeling of discomfort and performance degradation. For example, sick-building syndrome reportedly affects the health of employees and reduces work hours. This obviously has a direct bearing on efficiency and productivity. Apart from poor IAQ, the development of new construction and furnishing materials has generated diverse VOCs, which are health hazards.

It is only logical, then, that we direct our collective effort to improving the quality of air inside buildings in which we spend 90% of our time, and where the indoor air is usually two to five times more polluted with formaldehyde, benzene and toluene, than the outdoor air. Here, it must be mentioned that a lot of people are still unaware of the health risks posed by bad indoor air quality.

Many countries in the world have chosen carbon dioxide as an IAQ indicator that reveals the pollution level in the atmosphere, mainly caused due to human activities and materials.

The CO2 threshold value from European standard EN 13779 for non-residential premises is fixed at 800ppm (parts per million) above the outdoor level, which is between 350 and 400 ppm, depending upon the building’s location and the prevailing season. Therefore, in order to ensure the correct level of IAQ, concerned authorities and designers should enforce the common threshold. A daily average air change rate of 0.5-0.6 ach (air change per hour: Vol/hour) for housing is considered sufficient to achieve the CO2 concentration limit of 800ppm above the outdoor level, and a relative humidity of 60% at 18° to 20°C during occupancy.

In the light of this, many types of demand-control ventilation systems have been developed to modulate airflow rates, taking into account the real occupancy inside a building and the working hours. These systems can be timer-controlled. They generally modulate airflow according to optical detection, CO2 or humidity levels, preferably with a minimum airflow for dwellings. Indeed, humidity is also a tracer for a ventilation system, as in every breath cycle, people consume some amount of oxygen and exhale CO2 and H2O in identical quantities.

Other efficient ventilation systems combine the approach of IAQ and demand-control ventilation, with energy-recovery ventilation for further energy consumption control. These systems transfer heat directly to the outdoor air for free pre-cooling, in order to limit cooling from the central AHU or decentralised HRV units, which are used more and more in new designs, especially in schools.

A secondary benefit of good ventilation is that the air can act as an efficient carrier of calories or frigories, naturally present in the outdoor air, which may be warmed by the sun (recovery in the back of a solar cell), or cooled down in the ground (through geothermal ducts), or both, through a heat pump.

As far as countries in the Middle East without any specific ventilation regulations are concerned, in the public interest, it is vital to consider the requirements that define and specify the need for ventilation.

For a healthy IAQ and from the hygiene point of view, dwellings have to benefit from an air renewal and pollutant extraction system, especially from certain areas like the bathroom and kitchen, to avoid health hazards due to high indoor air pollution rates and condensation. As the first step in this direction, CO2 concentrations calculated over one year should not exceed 1,200 ppm for more than two per cent of the year for conventional dwelling occupancy.

It must be remembered that breathing clean air is an inalienable right, as much as the right to drinking water. But, apart from a hygienic environment with high IAQ and low pollutant concentrations, thermal comfort during winter and summer is also a human need.

The writer is Managing Director of Aldes Middle East. He can be contacted at pierrefeu-gaetan@aldes.com

While Qatar 2022 spells good news for the HVACR and related sectors and professionals, it comes with a number of challenges. Pratibha Umashankar highlights them.

Qatar, geographically a mere speck on the world map, successfully marketed itself as a viable venue for the 2022 football World Cup. The event is as much an image-building exercise, as an economic strategy. The authorities believe that their sight is set beyond the World Cup, in terms of financial dividends.

The country is reportedly investing over $30 billion into its infrastructure out of a $40 billion earmarked for the event. The new international airport is slated to be ready by 2013, and reportedly comes with a price tag of $13billion. According to a statement issued by Moody’s Investor Service, on December 5, as reported by Global Arab Network (Banking goals – Qatar gears up to host World Cup), it pegs the government spending to $57 billion over the next decade, for infrastructure development projects and upgrading of existing transportation systems.

With world-class air conditioned stadiums; accommodation and other facilities for visiting teams, officials and spectators, on the cards, Qatar will witness tremendous spurt in all-round growth, which will certainly impact the HVACR sector. Ramiz Gabrial, a consulting engineer, who was ASHRAE Oryx Chapter’s President till January 2011, affirms that the HVACR sector, as a whole, will be positively impacted by the event. “I believe that the positive impact will extend beyond Qatar, as there will be many major projects that will require dedicated research and development programmes to ensure that they meet or exceed expectations of Qatar Football association, FIFA and the world,” he says.

The spill-over effect is likely to be two-fold: benefit for other related sectors and to countries in the region. “The computer and energy simulation fields will get more focused on, as these unique projects will benefit from the available technologies,” says Gabrial. “In return, the same projects will benefit the HVAC profession, as it will create feasible business opportunities for many local, regional and global consulting firms to invest in further developing the technology.”

The volume of work will also give a positive nudge to two other important areas: Project design and construction management. Gabrial believes that the time frames that will be set for various projects and associated challenges will lead to major development in these fields.

“Facility management is another field that will have to get higher focus and get upgraded to required standards,” Gabrial adds. He elaborates: “The volume of work will require large number of HVAC professionals at all levels – senior and junior designers and managers, CAD professionals, energy and other computer simulation professionals and construction managers at all levels. This large and concentrated need will sharpen and shape many professionals who will work from inside or outside Qatar. Accordingly, the whole profession will benefit from the experience.”

Despite rich predicted pickings for the HVACR sector, especially of the low-hanging fruits from mega projects, the situation comes with its attendant challenges. Gabrial lists some of them:

• Procurement of equipment and materials from reputable manufacturers: Due to the volume of work, the industry needs to be careful about the source of equipment and materials they will bring in. Globally, all manufacturers would want to take a share in this market; some may not have the acceptable standards and/or certifications.
• Lack of sufficient design detailing: As the volume of work intensifies, consulting engineers may tend to leave some of the important design detailing for the contractors to take care of and, hence, leave a gap that could create future contract- or facility-management issues.
• Water consumption: Water-cooled systems will be used to serve large projects. This will create an increased water demand to cover the required cooling water volumes.
• Shortages and rising costs of building materials and equipment could be another challenge. This could lead to projects being delayed or, worse still, shoddy workmanship, with mounting deadline pressures. Also, depending heavily on outside skilled workforce, equipment, material and outsourced jobs might prove to be detrimental to the sector, if there are weak links in the other end of the supply chain.

With Qatar, in particular, and the HVACR sector, in general, pushing for green technology, whether the growth is at the cost the environment is another issue that needs to be addressed. “One specific area that will definitely receive major attention is sustainability and green building design,” agrees Gabrial. “Qatar has taken big steps in supporting and implementing sustainable building designs and solutions. Energy and water conservation, reducing carbon footprint of buildings and the use of regional materials, are among the issues that will get major attention as part of the sustainable design effort.” He cites the example of Qatar Foundation as an important player in the effort in the sustainability and sustainable building design movement in Qatar, which is a major element of the design, procurement and construction phases of each coming project.

In this context, the role of the local ASHRAE Chapter gains significance. “ASHRAE Oryx is already focusing on issues that are of interest to the HVAC profession on energy, water and major equipment selection,” Gabrial says.

The January issue of the ASHRAE Oryx Chapter’s journal, in an article titled, FIFA 2022 – The engineering challenges, succinctly sums up both the onus and the rewards: “The amount and type of construction projects that will take place during the coming 12 years will be the dream of any construction professional. However, this excitement and thrill impose added responsibility on us. We are morally responsible to make sure that the hard work that was put to win the FIFA 2022 Bid is translated to bigger success in building world-class facilities that tells the world another great story about what dedication and determination can achieve.

“The mechanical engineers will have their share of the challenge, as these facilities will have to be designed to satisfy specific environmental conditions. Sustainable and Green building designs will be another mission to show our commitment to the environment.”

Calling it an “intense engineering experience that is going to be built in Qatar”, the journal says that the lessons learnt can serve the profession in the long run. The sector, therefore, will certainly be a beneficiary of the World Cup, probably financially, but certainly professionally.