Measures to save energy throughout the life of refrigerating systems are increasingly acquiring significance. In this regard, natural refrigerants offer a double incentive, as they cut back on costs and help protect the environment, postulates Monika Witt.

The decision as to which refrigerant should be used in a refrigerating or air conditioning system is based on the major criteria of safety, costs and protection of the environment. But against the scenario of constantly increasing energy prices, the energy consumption of a system also plays an increasingly important role. Ideally, the chosen refrigerant should have excellent thermodynamic properties, high chemical stability and good physical characteristics. Furthermore, it should have no or only a negligible impact on the environment, while also being inexpensive and available worldwide.

However, there is no one refrigerant that fulfils all these requirements. And so, in practice, zeroing down on the most suitable refrigerant depends on a series of different factors. Here, the operating area and the operator’s requirements need to be factored in, together with the installation site and environmental aspects. But above all, it is the actual rating of the overall refrigerating system, while taking into account part-load conditions, which has a crucial influence on energy consumption. This is because it is the overall concept of a refrigerating system, which has a greater influence on efficiency than the choice of refrigerant. However, a number of current projects show that systems operating with natural refrigerants are particularly efficient and environment-friendly.

AMMONIA REFRIGERATION SCORES ON ENERGY EFFICIENCY

Ammonia is the refrigerant with demonstrably the best thermodynamic properties. It is the only natural refrigerant which the industry never wanted to dispense with, on account of its high efficiency. Ammonia is also unbeatable in ecological terms: it has no ozone-depletion potential and no global warming potential (ODP and GWP = 0), with a favourable TEWI balance, thanks to the high COP of ammonia systems.

In industrial systems with capacities exceeding 500kW, ammonia is simply unsurpassed in terms of energy and cost efficiency. Also, it is finding increasing use on a smaller scale, for example, in systems with a capacity of less than 500kW, where the quantity of ammonia can be reduced when choosing a suitable secondary refrigerant.

At present, intensive research is in progress in Europe, in particular, in the range of small-capacity systems, with the objective, among others, of developing small, semi-hermetic and hermetic compressors, with output below 100kW. Reduced quantity heat exchangers are also being developed along the same lines. Furthermore, various research projects are also looking at simplified oil management with soluble oils to facilitate DX systems, as well.

Moreover, today, ammonia is also being used increasingly in areas that used to be dominated by synthetic refrigerants. For example, all large exhibition buildings in Germany have been equipped with ammonia liquid chillers for air conditioning. Banks, insurance companies and office buildings, too, increasingly use ammonia liquid chillers for energy-saving air conditioning. Even modern airports make increasing use of ammonia systems, in the light of risk-analysis results, indicating that ammonia does not pose greater hazard potential for the general public or airport employees than systems using synthetic refrigerants.

Ammonia systems, therefore, have been installed not only in Düsseldorf’s refurbished airport, but also in London Heathrow’s new Terminal 5 and in Zurich Airport. The freight hub in New Zealand’s Christchurch Airport also saves energy by using ammonia for cooling systems.

CARBON DIOXIDE – ENERGY EFFICIENT AND ECONOMICAL

The last 10 years have witnessed increase in the interest shown in CO2 refrigerating systems. This is due, for example, to the fact that the global player Nestlé has constantly forged ahead with the development of NH3/CO2 cascade refrigeration plants, demonstrating their energy efficiency, with installations in Europe, United States and Japan. Other companies have followed suit. In addition, this trend has been encouraged by state incentives in some countries.

For instance, the Netherlands grants considerable tax relief for CO2 systems, while taxation on synthetic refrigerants has been increased in Scandinavia. CO2 is also particularly suitable for heat recovery or heat pump systems. Applications of this kind are already widespread in Asia, and other countries can be expected to follow.

How much energy can actually be saved by using CO2 as refrigerant, depends, above all, on the ambient temperature. The efficiency of a CO2 system is clearly superior to a plant operating with synthetic refrigerants when used in the subcritical range. But success is also being achieved in optimising system efficiency even in the supercritical range. This has been confirmed – among others – by the Coca Cola Company, which uses both CO2 and R134a for its 550-litre refrigerators, with the result that the systems operating with CO2 consume 20% to 30% less energy.

In the trans or supercritical mode (temperatures > 31.2°C), CO2 systems are, in principle, less efficient than those using synthetic refrigerants. Even so, when viewed over the whole year, CO2 refrigerating systems are frequently more energy-efficient than those with synthetic refrigerants, as most systems operate in the subcritical range most of the time, particularly in latitudes with moderate weather.

CLIMATE-NEUTRAL COOLING WITH HYDROCARBONS

Hydrocarbons, such as butane, propane and propene are ideal refrigerants. Butane, for example, is very successful in more than 300 million domestic refrigerators currently being used. Furthermore, butane can also be increasingly found in smaller commercial refrigerating systems. The beverages company, Pepsi, for example, compared the efficiency of small drinks chillers with up to 150g coolant and found that units operating with butane consumed up to 27% less energy than those using R134a. Since then, the beverages manufacturer has given preference to butane in these chillers, and it is not the only one. Ben & Jerry used butane for its ice-cream freezers for the first time in the United States, with most satisfactory results.

Propane has very similar thermodynamic properties to R22. Some Asian countries have, therefore, replaced R22 with propane in their central air conditioning systems. They report cutbacks in energy consumption between 10% and 30%, with the systems needing only minimum modifications. Unilever is another company that has recognised the advantages of propane as a refrigerant. During the 2000 Olympic Games in Brisbane and Sydney, the company performed a field study with 360-litre ice-cream freezers, comparing operation with propane to operation with R404A. On an average, the propane freezers permitted energy savings of about nine percent.

Hydrocarbons have excellent thermodynamic properties, which is why refrigerating and air conditioning systems operating with these substances are particularly energy-efficient. They are well miscible with conventional refrigerating oils, and have a relatively high critical temperature. While the flammability of hydrocarbons requires hermetically sealed systems with explosion protection for electrical components, all components are easily available and the current technology copes well with the demands of safe operation. Given the high energy saving potential of systems with hydrocarbons, a number of companies have announced their intentions of operating new refrigerating systems with hydrocarbons.

Up to now, Europe has imposed a 150-gramme filling restriction of hydrocarbons. However, this value was determined arbitrarily, so that it would be preferable to make the filling restriction dependent on the prevailing conditions in each case. Recommendations for such site-dependent limit values could be compiled and developed, for example, in the framework of a scientific research project. Larger filling quantities could probably be permitted if the propane filling is located up high on the roof of a building, or in large, well- ventilated rooms.

In the USA, there seems to be a willingness to rethink the situation. While the use of hydrocarbons hitherto was restricted to industrial applications, this restriction may possibly be lifted in future. For the first time, the US Environmental Protection Agency (EPA), with its highly critical stance on substances that pose a safety risk on account of the product liability laws, has approved of a field study that will test up to 2000 chest freezers operating with flammable refrigerants. This could lead to a real breakthrough.

WATER REFRIGERATION – UP TO 25% POTENTIAL SAVINGS

The evaporation of water has always been used as a means of cooling. But this method that functions quite naturally in the human body through perspiration, presents a challenge when considered on an industrial scale. A huge flow of water vapour is needed to achieve an adequate cooling effect, which in turn, requires the use of turbo-compressors. Suitable machines here consist either of axial compressors with a relatively small base area and many stages, or radial compressors connected in series. However, these are sensitive to load fluctuations and need the operation to be as constant as possible. The situation is further complicated by the fact that the operation takes place in a deep vacuum, which requires a system that is absolutely tight. Even so, these stringent technical requirements are offset by huge energy-saving potential of about 25%, compared to the currently available R134a liquid chilling units. This is why research is in progress in France and in Dresden, Germany, on prototypes for both radial and axial compressors.

AIR – RAPID REFRIGERATION AT LOW ENERGY COSTS

Air is interesting as a refrigerant for temperatures below -50°C. Systems with a closed air circuit are convincing, above all, on account of their particularly rapid cooling at low energy costs. But air has not become widely accepted as a refrigerant because of the comparatively high costs for the overall system. To achieve the necessary mass flow density, expensive turbo-compressor/expander systems are necessary, together with special shaft seals to minimise leakage. However, at the same time, air-cooled systems are also very compact. This is why, at present, they are primarily used for gas liquefaction on tankers, where the high costs are justified in view of the confined space available.

BALANCING THE ENVIRONMENT AND THE BALANCE SHEETS

Natural refrigerants are inexpensive, available in abundance, and can cover nearly every refrigeration application presently in use. Furthermore, they have a very low global warming potential (GWP) compared to synthetic refrigerants. This alone is reason enough to recommend their use. However, it is just as important to make sure that they are highly energy-efficient. After all, more than 80% of the global warming potential posed by refrigerating and air conditioning systems results from system energy consumption and not from refrigerant leaks. At present, around 15% of global electricity consumption is used to generate refrigeration, resulting in huge savings potential. Measures to save energy throughout the entire service life of refrigerating systems are, therefore, acquiring increasing significance, and can help considerably in relieving the burden on the environment. This is where the use of natural refrigerants comes into play, as they offer a double incentive for companies – by reducing energy consumption, they not only cut back on costs, but also help protect the environment. Everything, therefore, points towards the use of natural refrigerants in both ecological and economical terms, in order to safeguard both capital expenditure and the environment in the long run.

The writer is the chairperson of Eurammon, the European initiative for natural refrigerants. recruitment

As the person who played a crucial role in the OMD building at Dubai Media City being awarded the LEED Silver certification, Sougata Nandi of TECOM shares his experience of the process. En route, he demonstrates that the certification is an achievable goal.

By the time we started the LEED certification programme for the OMD building at Dubai Media City, we had already delivered two LEED-certified projects at TECOM, and the LEED Gold Metito HQ complex (in 2007). We had, therefore, grown in confidence and, perhaps prematurely, thought that we should be able to deliver LEED Gold projects incessantly. But surprises were in store, and at the end of the LEED certification of the OMD project, for the first time in my career, I was able to empathise with Sir Isaac Newton’s humility, when he stated, “I do not know what I may appear to the world, but to myself, I seem to have been only like a boy playing on the seashore, and diverting myself in now and then, finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.”

DUBAI MEDIA CITY – A THRIVING HUB

In order to contextualise its LEED-certification process, it would not be inappropriate here to describe in brief, the backdrop against which the OMD Building project was undertaken. TECOM Investments launched Dubai Media City (DMC) – its second brand – in 2000, to support and develop a cluster for the media industry.

Ideally located on Sheikh Zayed Road, both from the commercial as well as sustainability points of view, it is not close to any water body and is accessible through RTA bus lines. It complies with development density guidelines, has all support services required for commercial offices within the zone, and several other green building features.

As originally envisaged, the cluster has grown tremendously as a thriving media hub. Many global media giants and promising entrepreneurial ventures have joined DMC’s vibrant community. The City provides advanced infrastructure for media-related businesses to operate globally. DMC is the place where activities, such as media consultancy, publishing, music, film, new media, leisure and entertainment, broadcasting, media and marketing services, and business and news agencies flourish. Companies based in DMC include CNN, Leo Burnett, Thomson Reuters, AFP, The Neilson Company and Dow Jones International Limited.

Figure 1: A three-year utility cost savings at Dubai Media City

Since April 2007, TECOM Investments, through its Sustainable Energy & Environment Division (SEED) has also implemented an Energy and Water Conservation Programme at DMC, in line with the Sustainable Development Policy of TECOM Investments. This conservation programme has achieved significant results for DMC, as summarised in Figure 1.

On a cumulative basis, the Energy and Water Conservation Programme at DMC has generated a net utility cost savings of Dh4.85 million during a period of 33 months – from April 2007 to December 2010. Of these savings, Dh3.86 million was achieved from electricity savings, which was a result of good housekeeping practices for MEP equipment. The remaining Dh0.99 million was saved in water costs. The overall conservation programme required an investment of Dh118,000 (approximately), which has paid back in 70 days, at the present rate of annual savings.

These initiatives are not only in line with the energy and water-saving goals laid out in the sustainable development policy of TECOM Investments but also support the LEED certification of the existing buildings at DMC.

DMC, in collaboration with SEED, has also been pro-active in engaging several tenants in the ongoing energy conservation programme, whereby the tenants are guided on no-cost conservation measures and good housekeeping practices.

It is, thus, evident that DMC already had a favourable ethos when the OMD Building project was initiated – an existing free zone in a well-established, pro-sustainable site with most of its buildings developed.

LEED FEATRURES OF THE OMD BUILDING

The project:

The OMD building was designed to be a commercial building intended to be occupied by OMD as a single long-term tenant. With a built-up area of 55,715 square feet, the building will house offices, meeting rooms, restaurant, basement and surface parking. The ground floor will be occupied by a food outlet, and the offices will be located on the remaining floors.

The chillers, chilled water pumps and FAHUs are located on the roof. Most of the car parking area is underground, and is in the form of three levels of basements. Although the building has only 55,715 square feet of built-up area, it has three basements, ground and six floors. As it happened, this turned out to be a crucial factor during the LEED certification process.

Site sustainability:

Site sustainability plays an important role, as it is through this section of the LEED rating system that a building becomes part of a community, and holistic sustainable development is achieved. Given the location of the project within the precincts of DMC, it was able to perform quite well in this segment, securing nine points of the possible 15.

The site had other additional advantages:

The ‘Average Neighbourhood Development Density’ worked out to approximately 104,000 square feet/acre, given that the project was constructed on the only empty plot available in the middle of several buildings. The ‘Project Development Density’ worked out to 256,000 square feet/acre. The building footprint being small on both the project as well as the neighbourhood levels, the project was in compliance with the LEED requirements. The project, thus, exploited the advantages of being located in a previously developed community.

Again, for the same reasons, the project has the advantage of being accessible via two RTA bus lines, as part of alternative transportation credit requirements.

Given the fact that a significantly large multi-storey car park building already exists right in front of the project, we were able to limit the number of car parking slots to only the minimum required by zoning guidelines. This is a further demonstration of the advantages a green building can enjoy, if constructed in a previously developed urban setting with readily available infrastructure.

As part of the LEED requirements, and also in the TECOM spirit of transforming the built environment towards becoming more sustainable, SEED prepares a ‘Tenant Design and Construction Guideline’ for every project undergoing a LEED certification. This guideline is now for use by OMD, the intended tenant for this project.

Being located in an urban setup, we were definitely mindful of the heat island effect that buildings typically create. Therefore, both credits on heat island – non-roof and roof – were aggressively pursued and successfully achieved. Except for the mechanical equipment area, the entire roof surface is covered with SRI-compliant white terrazzo tiles to reduce solar heat gain.

Water efficiency:

The intention of this credit is to “maximise water efficiency within tenant spaces to reduce the burden on municipal water supply and wastewater systems”. (Source: USGBC). SEED’s Water Conservation Programme at Site A (DIC, DMC & DKV) has secured the 2009 Emirates Energy Award. Being a project located at DMC, water conservation, therefore, was a prime objective on this project, too, and it performed extremely well on this count, securing four points out of the available five in the Water Efficiency category. An additional innovation point was also secured due to exemplary performance in water use reduction.

The project did not pursue the ‘Innovative Wastewater Technologies’, as it is located in an urban setting with connection to the Dubai Municipality’s sewerage network. Onsite sewage treatment was, therefore, consciously avoided.

Here, it must be stated that the project’s water savings performance has been benchmarked against both US EPA standards as well as local practices (See Figure 4).

In addition, the following water-saving measures have been adopted:

• The toilets are being fitted out with ultra low-flow restrictors on wash basins.
• For all male toilets, waterless urinals have been made a standard in this building.
• All flush tanks are of the dual-flush variety.

While LEED requires that the water savings are calculated against US EPA standards, we also do a consumption comparison against ‘standard’ consumptions in TECOM buildings (flow rates in water fixtures prior to implementation of the Water Conservation Programme), in order to put the extent of savings into perspective. Therefore, while the project achieved water saving of 50.5% against US EPA standards, when compared to a standard building, the project is 61.5% more water efficient.

Water-efficient landscaping:

The project has achieved a 100% savings in potable water requirement for landscaping through a two-pronged approach. The irrigation water requirement has been minimised by utilising native plants with low water consuming properties. For the first time in a TECOM project, the AC condensate from the building’s HVAC system has been connected to the irrigation tank located in the basement (See figures 5a and 5b).

Energy efficiency:

The intention of this credit is to achieve increasing levels of energy conservation beyond the referenced standard to reduce environmental impacts associated with excessive energy use (Source: USGBC). This was one of the two key elements of the LEED certification process that we were surprised with. Energy conservation being our primary thrust area, the most attention was paid to this segment of the LEED certification. Based on past experience of LEED certification projects, a standard set of energy conservation measures are always applied to all our projects. These include:

• Improved insulation for walls and glass
• Heat recovery wheels
• Demand controlled ventilation using CO2 sensors
• Energy efficient light bulbs and significantly low lighting power densities
• Occupancy sensors in common areas
• Appropriate metering to monitor energy end-use

Although these measures would typically allow the project to achieve an energy savings of around 20%, the project experienced a couple of constraints: 1) The architectural design of the project resulted in the building envelope having more than 60% glazed area. This is significantly higher than the 40% prescribed by ASHRAE 90.1-2004 for the base building, and 2) Since building is higher than five floors, ASHRAE 90.1-2004 requires the base building to be modelled using water cooled chillers, which have lower KW/TR compared to air-cooled chillers. However, for a project having a built-up area of only 55,000 square feet, the HVAC tonnage required is in the range of only 150 TR. Water-cooled chillers will rarely be used for such small capacities, and the project uses air-cooled chillers as standard practice.

Due to these two severe constraints to the base building energy use, the Visual DOE energy model identified an energy-saving potential of only 11%, which is equivalent to Dh50,090 of energy cost savings per year, in spite of the adoption of the energy conservation measures. This meant that the project was able to secure only one point in the ‘Optimise Energy Performance’ category, and also missed the Gold level of certification by two points.

Indoor Environmental Quality:

The intention of this credit is to “provide optimal indoor air quality to tenants” (Source: USGBC). This is another LEED segment where the project performed very well, scoring eight points out of a possible 11 points. The facility is designed to enjoy 30% more fresh air, compared to ANSI/ASHRAE 62.1-2004: Ventilation for Acceptable Indoor Air Quality standard requirements, making the building very healthy for its occupants. Also, the HVAC system design complies with ANSI/ ASHRAE 55-2004: Thermal Environmental Conditions for Human Occupancy standard, and thus, provides a comfortable thermal environment for the building occupants.

The project utilises operable windows in lieu of individual controls, in order to achieve the ‘Controllability of Systems’ credit. The windows of this building are positioned in such a way that 74% of the occupied area complies with the requirement of being within 20 feet from the external wall and within 10 feet from either side of the window. Of course, thanks to the high percentage of glazing and the shallow nature of the building, the project easily complied with the requirements of ‘Daylight and Views’.

PROJECT PERFORMANCE

This project secured 32 points to qualify for the LEED Silver certification level. The project was able to secure all 32 points that it applied for.

KEY PROJECT FINANCIALS

At this juncture, it is important to share the financial cost-benefit of LEED projects, in order to dispel the popular myth about green buildings costing more. In fact, after the energy- modelling challenges, this was the second key lesson learnt from this project – if an organisation can make green design mainstream, then the concept of green premium does not arise, subject to the level of certification desired. It is interesting to note that, on this project, it was a struggle to identify the additional cost for going green. In fact, other than the administrative costs for the certification and fees paid for the energy modelling, the project did not incur any additional financial burden to achieve the LEED certification.

In effect, the project has incurred a ‘Green Premium’ of only 0.11%. Figures 11 and 12 further demonstrate the point.

LESSONS LEARNT

Although a small project in terms of its size, it taught us two very unique lessons:

1. The energy-modelling exercise can be very tricky. Although the ASHRAE 90.1-2004 energy-modelling guidelines require the use of water-cooled chillers for a building that is higher than five floors, if the building’s HVAC tonnage requirement is small, it will almost invariably be designed with air-cooled chillers. The project will then significantly lose points on this count.

2. If green becomes mainstream, no additional costs need to be incurred for a project to secure a LEED certification, unless the project aims to secure a very high rating level.

EPILOGUE

At the time of writing this article, we have delivered two more LEED certified buildings, bringing TECOM’s tally to five LEED certified projects in 10 months – between April 2009 and January 2010. This achievement consolidates TECOM’s leadership position in sustainable development further, considering that there are only eight other LEED-certified projects in the entire GCC, as of January 2010 tally (see figure 13).

The growing number of certified green projects clearly removes any ambiguity about whether or not external rating systems work in this region. Of the 13 certified projects in the GCC, three are LEED Platinum, six LEED Gold, three LEED Silver and one LEED certified. A majority of the projects being LEED Gold or above, clearly demonstrates that LEED not only works in this region, but actually works quite well. TECOM Investments, through (SEED), is committed to creating a sustainable development industry in the region. As an offshoot of this, the dissemination of technical and financial information from its projects is helping create local case studies – so vitally important for green building practitioners.

Ref 1: Memoirs of the Life, Writings, and Discoveries of Sir Isaac Newton (1855) by Sir David Brewster (Volume II. Ch. 27)

Sougata Nandi, B Tech, M Tech, LEED AP, PMP, is the Director, Sustainable Energy & Environment Division (SEED), TECOM. He can be contacted at: Sougata.nandi@tecom.ae/ Sougatan@eim.ae

Fires cause loss of life, damage property and harm the environment. HVAC fire protection issues inside buildings are, therefore, important. Now, thanks to a positive fire code and a regulatory framework in place, the UAE is better prepared to combat the menace, writes Alexandre Benoit.

Fires in the UAE

Fire hazards within buildings are still a global concern, especially in the UAE, where more than 2,000 fires occur annually. The fires are caused essentially by accidental human factors (60%) and technical failures (40%). They result in deaths, injuries and/or damages, which form a threat to residents and tourists in the UAE. For this reason, preventive safety against fire hazards and disasters has become a major strategic objective in the Dubai Civil Defence Strategic Plan 2009-2015.

Need for fire protection – preventive safety

Safety is a key subject that needs to be addressed, not only by the UAE authorities (civil defence), but also by developers, consultants and contractors, in order to ensure a maximum level of safety for all buildings presently under construction or already built.

If sustainability can be considered as a positive trend taking shape slowly in the UAE to promote efficient green buildings (via effective water and waste management, energy consumption ratings and indoor environmental quality), quality and safety need to be further prioritised by the different construction bodies in the UAE. The quality and safety standards of building construction are still quite low in the UAE. This is due to various factors, such as cost reduction, lack of regulations, minimum specification requirements by consultants, poor labour skills, and disregard towards specifications by actual contractors. As a direct result, the UAE has faced structural collapses affecting some buildings or car parks under construction. But if these collapses constitute tangible and visible proof of bad quality of structural construction, a low level of quality and safety is also affecting the thermal insulation, the HVAC systems, and, indeed, the fire-protection systems, which are really critical, in the event of a fire.

What actually is a fire?

Fire is the combination of flame and smoke caused by the combustion of gases occurring at high temperatures. The flame is the visible part of the fire which attacks and burns materials. Smoke is made of combustion gases. The resulting toxic and opaque fumes prevent people from breathing and affect the visibility required to escape a building. This creates panic. At high temperatures, the large volume of smoke generated by fire creates high pressures with convection movement. As a direct result of this, fire can spread quickly and unpredictably throughout the surrounding areas, if there is a lack of efficient compartmentation and if no smoke-management system is in place.

Alexandre Benoit

To effectively deal with the possible dangers caused by fire, the European Committee has developed different standards based on the following nomenclature for “the resistance to fire performance of construction products, construction works” (for example, fire dampers, smoke dampers and ventilation ducts in HVAC):

• E: Integrity
• I: Insulation (no heat transfer)
• S: Smoke leakage (no smoke leakage)

Victims – people, buildings and the environment

The first issue is that fire can pose a real danger for a country by endangering its people (family, children, people with disabilities, tourists and fire fighters), with deaths and injuries being often the result. As life is priceless, there should be no cost issues in bringing the best level of safety to a building. The key danger for people caught in a fire comes mainly from smoke inhalation, which can be managed efficiently through proper compartmentation of structural areas, plus an efficient smoke-management system.

The second issue resulting from a fire can be the destruction of a building or parts of a building, if effective compartmentalisation has not been implemented. The destruction implies a tangible cost for insurance companies, developers and even owners/tenants. This being the case, it is essential to limit the spread of flame, smoke and heat via efficient compartmentation, with “EIS” fire dampers, and to fight the fire with water (sprinkler systems) to notably reduce its intensity and spread.

A fire can also cause damage to the environment, given the large amount of combustion gases emitted into the atmosphere during a blaze.

Impact on MEP/HVAC systems

There are four key priorities in protecting people, buildings and the environment during a fire:

1. Limit the spread of the fire (flame, smoke, heat)
2. Let people escape the building safely
3. Fight the fire safely to avoid damage
4. Limit the impact on the environment

Compartmentation:

An efficient compartmentalisation is fundamental to ensure a minimum level of safety inside a building. The main objective is to subdivide a building into fire compartments to isolate a fire as soon as it starts and to limit the spread of flames, smoke and heat throughout the existing AC ductwork.

It’s critical that there be no smoke leakage and no heat transfer for two hours through any fire dampers. This means an efficient sealing system, for example, intumescent seal, use of sealant, and quality refractory blade material (for example, calcium silicate) should be in place. These fire dampers should be motorised to ensure instantaneous operation via a fire alarm panel connected to smoke detectors.

The key objective is to avoid any leakage of cold fumes through the blades of the fire damper, before the potential activation of a mandatory thermal trip or fusible link at 72°C. In the European EN 13501-3 classification, these fire dampers are classified EIS 120.

Moreover, to ensure energy savings and achieve a better sustainability, motorised fire dampers should be operated under an electric signal emission and not by a power cut.

Far too many curtain fire dampers (CFD) are still used in the UAE, even though their performance is really poor: smoke leakage through openings, heat transfer and late activation (only when the temperature reaches 72°C). The authorities, developers, consultants and even contractors should be more concerned about these issues, especially on large projects, such as the Masdar Institute of Sciences and Technology, where so much emphasis is placed on sustainability. Safety should come first. After all, a building on fire is not sustainable at all!

Curtain fire dampers should be replaced by the more efficient fire dampers, described above, in new building, and especially in sensitive buildings – for example, high-rise buildings, hotels, schools, hospitals, which have occupancy, accompanied by potential sleeping risks.

Smoke-management systems:

The management of smoke is best done by controlling the high pressure of smoke generated directly by the fire. This allows people to escape safely via fire exits. The way smoke spreads is by moving from areas of high pressure to areas of lower pressure, in an attempt to find a balance. Consequently, there are two main ways to manage smoke:

1) Pressurisation:

The objective is to create a higher pressure in opposing areas – for example, staircases and corridors – of the fire compartment to avoid any smoke passageways, even if a door is opened (see figure 2).

2) Natural/mechanical smoke extraction – corridor smoke control):

The objective is to create a low pressure point in a corridor – opening through a smoke exhaust damper – to create a controlled smoke passageway. The goal is to extract the most smoke and combustion gases in the early stages of a fire in order to keep the escape and access routes free from smoke and gases (see figure 3).

The basic smoke extraction system is made by one vertical riser supplying outdoor air through an air inlet located close to the floor, and another vertical riser that extracts smoke via a smoke fan through a smoke exhaust damper located close to the ceiling. The goal is to create a smoke-free area (stratification) in the bottom area of a corridor to allow a safe escape, and to keep smoke in the upper area of the corridor before being discharged outside (see figure 4).

These two systems have two different strategies. Whereas the pressurisation system is fighting (with the support of a sprinkler system) against the high pressure of smoke generated by the fire, by creating a higher pressure, the advantage of the smoke-extraction system is to control the amount of smoke and heat not by fighting against it but rather by working together with its flow and leading the spread of smoke and heat towards safe exhaust openings.

This is a key advantage for a smoke-extraction system, considering that fire behaviour is nearly always unpredictable and uncontrollable. By supplying fresh air and exhausting smoke and heat close to the fire location, a smoke-extraction system reduces the danger for fire-fighters due to an under-ventilated fire (for example, flashover, backdraft). In turn, this dramatically eases the fire-fighters’ operations by reducing the temperature and increasing the visibility within the building.

Even if the burning rate increases due to the supply of fresh air, the smoke-extraction system creates a safer environment by controlling the fire-spread and intensity. This benefits both the victims and the fire fighters during the early stages of a fire.

Conclusion

In the UAE, Dubai Civil Defence, with the support of the Government of Dubai, is heading in the right direction by implementing a fire code in the near future. This fire code will address all the main fire-protection issues, to give a tangible framework for all the consultants and contractors in the UAE. Both compartmentation and smoke-extraction issues will be dealt with, in accordance to the American and European standards. The publication of the code will be a great step forward in creating a better city for a better life.

As the UAE is participating in the Shanghai World Expo 2010, whose motto is Better City, Better Life, the UAE and the Government of Dubai are demonstrating once again with the new fire code that they are fully dedicated to improving the quality, sustainability and safety of buildings to bring to all locals, residents and tourists safe living conditions.

There is obviously a big gap that needs to be bridged between the new and positive regulatory framework and existing construction sites. An efficient training programme, helpful support to consultants and contractors from the authorities and intensification of site inspections, should enforce the right implementation in the UAE market, and considerably upgrade the level of safety in the UAE.

The writer is the Marketing Manager for Aldes, ME. He may be contacted at: contactus@aldesme.com

Transporting foodstuff from field to fork makes big business, but several issues remain unresolved, say suppliers and service providers. Jose Franco has the story…

Companies engaged in refrigerated transport may not have been adversely affected by the recent economic downturn but many challenges remain for the sector to contend with. And it’s about time it did something to remedy the situation, as the cold-chain involves more than just transporting foodstuff from field to fork.

Think of legislative bodies, which should change and modernise the rules and guidelines, and enforce these where temperature-sensitive foodstuff is concerned. Yes, it’s not only the FMCG, or fast-moving consumer goods, group and the general public that need to be aware of the dangers of incorrect storage and transportation of foodstuff.

Food safety controls, in matters of the Gulf market, are “light years” away compared to, say, the Western world, remarks Paul McGarrigle, Key Accounts Manager of Transport Solutions for the Middle East and Africa at Thermo King. “But I believe the region is a victim of its own success where the trend tends to be ‘reactive’ rather than ‘proactive’ of late,” he adds.

The situation may be attributed to the rapid economic expansion which the Arab Gulf countries have all been a part of in the past number of years, he says. Whilst he believes that the region, particularly the UAE, has the right intentions, reforms can be slow at times. And this is something for the industry to think about, considering the threat of pandemics, like swine flu, avian flu and mad cow disease.

“The region needs to understand that food safety controls are put in place to protect consumers, and the Western world has learned from its mistakes,” McGarrigle stresses. “The Gulf region should not have to make the same mistakes before the changes occur!”

The managing director of Güntner Middle East, Adel Kamel, also laments the lack of regulations on the quality of the refrigeration industry, such as the manufacture of equipment and the impact of the materials on the environment. He says internationally recognised organisations, such as Germany’s DKV, or Deutscher Kaelte-und Klimatechnischer Verein, could help set up universal standards for all suppliers to ensure product quality and the protection of consumers.

Another problem, he adds, is that most major refrigeration consultancies operating here are based abroad. “That means there often is not enough experience with the regional market and its challenges – which sometimes makes it difficult for us to offer the optimal and most efficient design,” says Kamel, whose Germany-based company manufactures condensers, evaporators and other components for the HVAC&R industry.

Amitesh Singh

Some industry manufacturers, whose 80% of customers are in the food and beverage industry, also find it difficult to persuade end-users of refrigerated transportation vehicles to opt for energy-saving products, which command a higher price. But Amitesh Singh, Manager for Business Development at Emerson Climate Technologies, is optimistic. “We believe that energy efficiency is gaining momentum in the region, and very soon we expect to see energy regulations in the region,” he says, stressing that Saudi Arabia has already defined its rules on air conditioning and smaller refrigeration equipment.

Dubai-based Anupam Dewan, Director of Sales and Marketing, Refrigeration & Air-Conditioning Division, Danfoss, describes customer awareness in the Gulf as “still limited” when it comes to energy-efficient products, perhaps because energy prices are low. He also decries the “generally limited” level of technical skills, delaying the introduction of new technologies.

“Refrigeration consultants are almost non-existent in this part of the world – which is a shortcoming when we need to convince a customer to go in for energy-saving products,” he says. Noting that end-users always want to have a cheaper product regardless if they get to pay more for electricity, Dewan warns: “Any malfunctioning in comfort cooling leads to discomfort, but any malfunctioning in the refrigeration industry means direct loss of money.”

This sort of forces companies like the European-based Danfoss, which mostly deals in energy-saving products, to change priorities with regard to their operations across the Gulf region. That focusing more on product reliability and lower pricing, rather than energy-efficiency, may be good for them. But Danfoss also has high hopes for its business, as it sees a growing demand for green products in Saudi Arabia, Kuwait and Qatar.

This is not to say that reliability is a lesser issue, inasmuch as the industry is rife with poor installation practices, improper handling of the equipment by operators and inadequate training of personnel and technical staff. Even some of the vehicles and equipment used in the transport of foodstuff have seen better days, says McGarrigle.

Paul McGarrigle

All one needs to do, he says, is take a trip to the Fruit & Vegetable Market in Dubai at 3am of any given day, to see the equipment being used to import and export farm produce to and from countries like Syria, Turkey, Saudi Arabia, Jordan, Iran and Iraq, among others. Besides the amount of spoilage being dumped at the end of trading activity each morning, he says, small operators of vehicles being used to transport goods may have been running and using the same refrigeration components for the past 15-20 years.

And even though 99% of the reefers being used in those vehicles are Thermo King’s, McGarrigle says, the company has now evolved to manufacturing products that are more cost-efficient, reliable, traceable and environmentally friendly. These new products will ultimately prolong the shelf-life of fresh fruits and vegetables, and enhance food safety.

He stresses, “I would like to see stricter guidelines regarding the age of equipment being allowed across the borders, carrying food that I may end up eating!”

Whilst the reliability of Danfoss products is not an issue, Dewan stresses, customers will have problems if they opt for cheaper but inferior products. “Limited application knowledge also leads to improper product application, resulting in reliability issues,” he emphasises. “We are investing more and more each year in training customers. We also conduct monthly Web training on our products.”

Other companies are aware of the same need to conduct regular seminars for clients and end-users on the latest products and technologies.

Güntner, for instance, has been offering workshops and symposiums to customers and their staff for the past more than 20 years. “We focus on the installation and maintenance staff,” Kamel says. “The operator should not be affected by the heat exchanger. The refrigerant plant should run unfailingly. Having more than 70 subsidiaries worldwide, Güntner can deliver spare parts at a short notice, and provides two years warranty for them.

At Emerson, Singh says there are more products focused on the efficiency side, as customers and end-users increasingly look for such solutions when planning for their business and financial operations. The company has, in fact, developed multiple solutions to address the reliability of refrigeration components. Emerson’s ZX condensing units, for instance, have scroll compressors designed to weather the region’s harsh climate.

“We also launched a range of scroll compressors for refrigeration applications which are energy-efficient and can provide the large end-users with increased reliability and energy savings,” he says.

And whilst Emerson has experienced a slowdown with regard to new projects, Singh says the existing ones have continued, and those that had been stalled are now beginning to pick up.

At Thermo King, a manufacturer of temperature control systems for mobile applications, business has been favourable even during the worst of the recent economic crisis. Thanks to the region’s ambient temperatures, where refrigerated transport for foodstuff is a major necessity, equipment sales and aftermarket parts and service sales have continued at Thermo King, a unit of the Ingersoll Rand Company Ltd.

“But it’s fair to say that major investment decisions were ‘re-thought’ in 2009 on the back of the very apparent uncertainty that took over the region right through every sector, from tourism to banking,” McGarrigle says. “However, this uncertainty had not caused our customers’ investment and expansion plans to cease; it merely became more difficult since the banks were no longer willing to offer ‘favourable’ interest rates, forcing investors to look for different methods of increasing or replacing existing fleets.”

And this has shifted the trend quite rapidly from customers purchasing their own equipment to end-users leasing additional requirements or outsourcing non-core operations and downscaling fleet sizes, he says, in order to manage their working capital. Which is also something good for Thermo King, whose Truck & Trailer business and aftermarket parts and HVAC sales in the Middle East have registered a total revenue of $100 million for the past two years.

RFID-enabled sensors can be deployed to effectively track ambient parameters, as required by the cold chain, says Soma Sekhar Vedantam.

Well-implemented supply-chain applications provide significant benefits to all organisations involved with increased visibility, tracking and traceability. In the case of cold-chain applications, the ambient parameters are also to be monitored and are important. The emphasis on this issue stems from the social, economic and environmental impact it can have.

RFID technology provides the capability to automate the supply chain. RFID-enabled sensors can track the ambient parameters, as well, as required by the cold chain. RFID-enabled sensors, working with wireless communications infrastructure and providing location and ambience information in real-time, provide the ability to act on adverse conditions and negative events, and prevent products from going bad.

As companies assess their cold-chain practices, RFID-based temperature-monitoring systems offer inherent advantages when compared to standard data loggers/monitors. RFID-enabled data loggers have yet to be widely deployed, yet the need to protect high-value, temperature-sensitive drugs/perishables will focus increasing attention on RFID cold-chain solutions.

Choices of RFID technologies

An RFID system for cold-chain purposes generally encompasses a sensor, a tag and a reader that communicate with one another by means of radio transmission. RFID tags can store an EPC for logistics-management purposes, and if equipped with the appropriate sensor and battery power, a limited number of temperature readings.

RFID tags can be separated into the following categories:

a. Passive RFID tags. These tags rely on the power supplied by the reader. When radio waves from the reader are encountered by a passive RFID tag, the coiled antenna within the tag forms a magnetic field. The tag draws power from it, energising the circuits in the tag. The tag, then, sends the information encoded in the tag’s memory. The lack of an integrated power supply means that passive tags can be very small. Therefore, passive tags can be embedded in stickers and other similarly flat presentations.

b. Active RFID systems (battery-powered). The reliability of active tags is typically higher than that of passive tags due to the ability of active tags to conduct a “session” with a reader. Active tags also transmit at higher power levels than passive tags, allowing them to be more effective in environments commonly found during food distribution. Examples of these situations could be the transmission of information in crowded enclosures (examples: humans and cattle); data transmission from tags attached to boxes, which may be placed in the middle of a tightly packed container of fruit, meat or other products with high moisture content; transmission through metallic walls (examples: shipping containers and trucks) or transmission from long distances (example: containers in transit).

c. Semi-passive tags. These systems are also battery-powered. However, they use the passive RFID interface, thus allowing wireless access to the device without using the internal power source. The battery size is, therefore, smaller than in the active tags.

The preferred RFID embodiments for environmental monitoring of food supply chains are semi-passive or active tags, coupled with sensors. Tags can collect a wide range of information, such as temperature, humidity, shock/vibration, light, radiation and concentration of gases (example: ethylene). The information collected by the tags is “harvested” by a gateway or hub, which then transmits the data to a server, through the use of digital mobile telephony (GSM) or local area networks, which can be wireless (WLAN) or with wired Ethernet connection (LAN). Data collected in the server can, then, be stored and analysed, allowing the automatic generation of notifications and events. A Web portal may display historic temperature data and frequency data and may trigger alerts for the users, transmitted through SMS messages or e-mails. Given that the information is in real-time, or near real-time, sudden situations that endanger the integrity of the goods can be addressed promptly, as opposed to traditional monitoring techniques that only allow analysis of past temperatures and events.

The need for technology for monitoring ambient parameters in real time is not disputed by any party involved. That said, the following limitations and challenges need to be understood:

• Uniformity of global standards across technologies for cold-chain applications
• Cost of technology
• Difficulty of establishing ROI
• Accuracy (sensor accuracy of ±0.5°C and calibrating multiple tags, to be consistent in measurements)
• RFID sensors positioning and representation of spatial variation of entire cargo load temperatures
• Supply chain silos (growers/suppliers/manufacturers, logistics providers, retailers operate without collaboration)

Ongoing research

A heartening feature is that substantial research is taking place in the area of RFID to enhance its usefulness. The areas of study involve:

(a) The combination of RFID technology and time-temperature indicators (TTI). This opens up the possibility of tracking the shelf life of chilled and frozen products remotely.

(b) Wireless technologies that allow gathering of data and exchange of real-time information with supply chain partners.

(c) Multi-sensing RFID nanosensors. The sensor will incorporate ultra-low-power gas sensors along with a thin film battery, allowing data acquisition and storage when no reader is present.

Conclusion

RFID is a promising technology that can provide numerous benefits in temperature monitoring and performance of perishable and pharmaceutical supply chains. The main limitations are a relatively high cost; difficulties in calculating the ROI; accuracy/calibration, which should be further improved.

The writer is Director, TrackIT Solutions, Dubai. He may be contacted at soma@trackitme.com

Bharat Asarpota elaborates on the pain associated with the failure of a compressor in daily operations of a large, multi-chain facility dealing in food and beverages.

The use of refrigeration systems is almost indispensable when it comes to several activities in modern society. Such systems are responsible for everything from providing thermal comfort in office buildings to maintaining low temperatures (-25ºC to 0ºC) in refrigerated chambers, so that food products are preserved. For such systems, one of the main components is the compressor.

The main function of the compressor is to aspirate a certain amount of refrigerant vapour produced by the evaporator and increase its pressure and, consequently, its temperature. 

The lifecycle of a compressor can be divided into four phases: definition and conceptual design, detailed design and development, manufacture and operation. At the onset, considering that compressors have a high rate of failure, I would like to say that efforts to improve reliability must be undertaken during the detailed design and operation phases.

In certain installations in the UAE, it has clearly emerged that failures associated with compressors represent 10% of the total failure of the equipment but nearly 45% of the total cost of maintenance, which reinforces the importance of further studies to minimise the failure of compressors.

A growing concern to those using the compressor is the efficiency of the refrigeration system, which can be achieved through proper maintenance. Indeed, faulty operation and failure of the components causes a high loss of energy. In that context, answering the following questions related to the system or equipment is necessary:

1. How can each component of the system fail, or what are their failure modes? (By answering this question, a failure mode can be understood as a set of factors and demands imposed on a certain piece of equipment during its operation. Those factors and demands will promote the end of the piece of equipment’s life cycle, or they can be the mechanism that provokes that piece of equipment to fail.)
2. What are the effects of such failure on the system?
3. What is the evidence that failure has occurred (or, is there any)?
4. In what way is the failure a threat (if there is any) to safety or to the environment?
5. How does the failure affect the production or the operation of the equipment (if at all)?
6. What is the physical damage caused by the failure (if there is any)?
7. How critical are those effects?
8. How can one detect the failure?
9. What are the actions that should be implemented to avoid, prevent, or minimise the effects of that failure?

At this juncture, it is important to understand the failures, which can be classified into three types:

Early failures: There is a high occurrence of the component failing due to poor application and/or installation errors. The failure rate decreases as time passes.

Random failures: This is characterised by a very low and constant failure rate. Failure is caused by less controllable factors, such as power surges, mechanical impact and vibration. Therefore, the prediction/prevention of such failures is more difficult.

Ageing or wear out: There is an increase in the failure rate at this point due to the natural wearing away (friction and corrosion) that increases as time passes. These failures tend to be dominated by cumulative effects, such as corrosion, fatigue cracking and embrittlement.

Based on the analysis of reports and literature, compressors could produce several modes of failures. This can be inferred, because the equipment is composed of electrical and mechanical components that can fail independently and affect performance. Reliability is determined by analysing, for a predefined period, the amount and type of failures that occur and determining the warranty period for that equipment.

Based on reports analysed, typically the following failures are detected:

1. Liquid refrigerant flood back (includes flooded start)
2. Lubrication problems
3. High superheating
4. Contamination (includes humidity, air impurities, oxide contamination and copper plating)
5. Electrical problems (includes electrical motor overload and breakup of the coiling of the electrical motor)
6. Fabrication defects
7. Other failures (This classification takes electrical failures, mechanical overloads, fatigue and high- and low-aggressive wear into consideration.)

It should be pointed out that most of the compressor failure modes have their origins in problems related to the project and/or the installation of the refrigeration system. Even though these problems are related to the system, their effects directly influence the compressor.

My personal experience has shown that in most cases, designers do no revisit their design to verify whether the design works, as planned. Facilities Management personnel have a big role to play in maintaining the capital investment made. If the design itself is at fault, the FM personnel can do little but wait and watch for the inevitable to happen, which is a premature failure of equipment.

Often, service contracts are given to the lowest bidder, all other things being equal. This may not work with the best results, in most cases. Maintenance providers should have the requisite trained personnel to carry out their tasks. With newer technology being incorporated into equipment, I find that service providers do not invest sufficiently in their personnel to engage new technology.

My specific experience is in multiple locations spread over a wide geographical area, wherein it is logistically and economically implausible to have in-house staff to maintain and service the equipment.

With the state of manpower movement in the Middle East, trained manpower tends to move to better-paying jobs. If service providers depend on certain key personnel for providing reliable service, absence of these personnel causes a huge impact on the end-user’s equipment

To increase the reliability of compressors in the operation phase, it is recommended that the refrigeration system installation be carefully designed, installed and maintained, because a fault in installation can induce failure modes in a compressor.

A detailed study of failures will help to improve the performance of refrigeration compressors, as such studies share information that will help others better understand the failures and provide more qualified information for the maintenance staff.

The writer is Building Maintenance Manager with Emarat (Emirates General Petroleum Corporation). He can be contacted at bharat_asarpota@emarat.ae

The Columbia College, in Illinois, USA, was used as a test case to demonstrate optimisation of the cooling system using CFD analysis. The client was able to reduce both the size of the mechanical systems and recurring energy costs, write Prashant Ojha and R Srihari.

OBJECTIVE

Mechartés Researchers conducted CFD analysis of the Columbia College auditorium, in Chicago, Illinois, with the objective of optimising the mechanical cooling system in a spacious area. The auditorium is used for filmmaking and animation. So, apart from heat seepage through the walls and also due to human involvement, it had 50 big light fixtures of 5,000 watts, which contributed to extra heat gain of 250KW.

THEORETICAL BACKGROUND

Computational fluid dynamics (CFD) is one of the branches of fluid mechanics that uses numerical methods and algorithms to solve and analyse problems that involve fluid flows. Computers are used to perform calculations required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. The crucial elements of computational fluid dynamics are discretisation, grid generation and coordinate transformation, solution of the coupled algebraic equations and turbulence modelling visualisation. The most fundamental consideration in CFD is, how one treats a continuous fluid in a discretised fashion on a computer. One method is to discretise the spatial domain into small cells to form a volume mesh or grid and, then apply a suitable algorithm to solve the equations of motion, like the Navier-Stokes Equation. (See figure 1).

Figure 1: 3-D Image of the auditorium at Columbia College, Chicago

To achieve this end, a 3-D model was created using pre-processing tools, for the auditorium, which is 72 feet in length, 36 feet in width and 22 feet in height. Further, the model was discretised using an appropriate meshing scheme.

It must be noted here that various important parameters needed to be considered for the CFD analysis, categorised as inlet parameters. The analysis served the purpose of figuring out the effectiveness of cooling inside the auditorium.

A lengthwise displacement diffuser was located at eight feet above the ground, with fresh air flowing at 55oF DBT and 60% RH. The outlet grill was located at a height of 15 feet above the ground level. The floor was designed with radiant tubing. The underneath which was maintained at 2oF above the dew point temperature inside the room and the air flow rate was 3,200CFM. Further, the sources of heat gain were identified in consultation with the client and were appropriately modelled numerically in the CFD software. These sources of sensible and latent heat gain inside the auditorium space were through the external walls, which accounted for the thermal resistance of the wall, human occupants and also due to the equipment. This included light fixtures, which were designed for radiation as well convection heat gain. (See figure 2).

RESULTS

Figure 2

The analysis was performed with certain assumptions and boundary conditions. Consequently, a steady state condition was achieved, the materials were homogeneous and there was negligible radiation exchange and contact resistance.

The results clearly showed a thermal stratification, where the temperature was maintained at 75oF at a height up to eight feet. Also, the relative humidity was maintained at 50% to 60%. Effective cooling was done only till the height of 10 feet, thus reducing energy consumption by mechanical devices, and the system as a whole.

Further, it was also observed that depending on the light positions, the effective cooling provided by the radiant floor varied from 10 tonnes to 15 tonnes.

CONCLUSION

The optimisation technique was used to design the cooling system for the Columbia College auditorium applying Computational Fluid Mechanics. It was observed that the client was eventually able to reduce the size of the mechanical systems – chillers, fans, ducts and louvres – by 50%, which yielded a cost-saving of approximately $250,000 in capital expenditure alone. More important, the recurring energy cost was reduced enormously, and the building was granted a LEED- gold rating.

Prashanth Ojha has a Masters degree in CFD from the Moscow State University and B Tech from NIT, India. He is a Design and Analysis Engineer at Mechartes Researchers. He can be contacted at prashant@mechartes.com

Srihari is a Diploma holder in CFD with a Bachelors degree in Mechanical Engineering from Anna University, Chennai, India. He is a CFD Engineer at Mechartes Researchers. He can be contacted at Srihari@mechartes.com

E+E Elektronik

Saying that they provide high quality, wireless measurement of humidity, temperature and CO2, E+E Elektronik has introduced wireless data transmission, Wireless sensor EE240.

The manufacturer claims that up to three intelligent probes can be connected to each transmitter and that each probe operates independently and can be hot swapped.

Explaining the working of the product, E+E Elektronik says that remote probes allow the sensing head to be placed at a distance of up to 10 metres away from the transmitter, making the wireless sensors suited for industrial applications that require sensors to be routinely recalibrated without affecting network operation. The measured values can be read directly off the display on the transmitter or read remotely, using a web browser from any PC in the company network. The integrated web server allows the user to individually configure the wireless sensor network from a PC without installing any software, adds E+E Elektronik.

Product features and advantages:

• E+E wireless sensors conform to protection class IP65, making them suitable for use under demanding operating conditions, as well as in outdoor applications.
• The base station features a digital Ethernet interface to connect to the network and for data analysis.
• The base station comes with four analogue outputs for connection to the user’s system controller.
• A mobile measuring system with up to 500 transmitter stations can be built without having to install any wiring.
• Coded bidirectional communication ensures secure data transmission.
• Wireless routers are available to expand the network and range or to bypass obstacles.

Niagara Blower Company

WSAC at power facility

Saying that the closed-loop, evaporative Wet Surface Air Cooler (WSAC) is a practical solution to a wide range of heat transfer applications for power facilities in simple and combined cycle plants, the Niagara Blower Company, a design-build manufacturer, has introduced the product to the market.

According to the manufacturer, the applications of WSAC include, auxiliary loop cooling, vacuum steam condensing, heat recovery steam generator blowdown cooling, and turbine inlet air cooling.

The company lists the following benefits of the product:

• Simpler system design
• Lower parasitic energy (HP)
• Reduced water use and the ability to use poor quality water as makeup
• Ability to run dry during lower ambient temperatures for more water savings
• Can be used for water management in certain applications
• Competitive installed cost
• Minimal maintenance required

Niagara Blower Company, pointing out that water use and disposal issues have become increasingly important in power plant design, highlight that sources of water that WSAC can handle include cooling tower blowdown, reverse osmosis (RO) discharge, condensate, pond water, gray water and sewage effluent. The manufacturer claims that due to wide tube spacing and use of more durable materials for construction, higher cycles of concentration can be achieved. It further claims that commonly used for adding capacity in ‘thermally challenged’ plants, WSAC coolers and condensers offer additional direct cooling without requiring additional tower capacity or makeup water.

According to the company, WSAC can double up as a first-stage evaporator, because, it says that the more water that can be evaporated in the heat transfer mode, the less needs to be handled in secondary (and costly) water treatment systems. Thus, the product has an advantage for zero discharge facilities, it claims.

Product features:

• Each WSAC system is custom-designed to fit a specific heat transfer application.
• Design parameters are based on customer specifications for input and output temperatures as well as ambient weather conditions.
• Units vary in size from smaller packaged/skidded to large field-erected units.

Eurammon invites like-minded parties to attend lecture series

Eurammon, the European initiative for natural refrigerants, revealed in a press release that it would be providing information about the latest developments in the use of natural refrigerants, at this year’s Chillventa – the international trade fair for refrigeration, air conditioning, ventilation and heat pumps – taking place from October 13 to 15, in Nuremberg. The highlight of the event, said Eurammon, is a series of lectures under the rubrics, Applications with natural refrigerants – country situation and experience, that will be held at the CCN on October 14 from 930am to 1130am.

Extending an invitation to planners, operators and system engineers, Eurammon claimed that international experts in the field would be appraising participants on the current scenario and experience gained in the use of natural refrigerants in countries across the world. The initiative, said Eurammon, was an attempt to bridge the gap between industrialised and emerging and developing nations. The event will be chaired by Monika Witt, Chair of the executive board at Eurammon, it added.

According to Eurammon, the lectures would be followed by a traditional brunch organised for, what it dubbed, ‘Friends of Natural Refrigerants’, which would provide an opportunity, not only for an interactive session with experts, but also to cultivate contacts with the international refrigeration/air conditioning fraternity.

Programme details:

• 920am: Inauguration – Monika Witt
• 930 am: Changes in the industrial refrigeration industry in North America – Bruce Badger, International Institute of Ammonia Refrigeration
• 10am: Natural refrigerants in Denmark – situation and experiences – Svenn Hansen, Danish Technological Institute
• 1030am: Applications with natural refrigerants – the Brazilian situation and experiences – Tomaz Cleto, Yawatz Engenharia
• 11am: Reasons and barriers in switching to natural refrigerants in the developing countries – how to overcome them – Risto Ciconkov, University Ss Cyril & Methodius
• From 1130am: Brunch for ‘Friends of Natural Refrigerant’ at the Eurammon stand, 314, Hall 1