Variable vantage points

One of the highlights of the 3rd Annual Middle East Variable Refrigerant Flow Conference was the interaction between consultants and the manufacturers of VRF systems. We bring you the blow-by-blow, verbatim account of the consultant community’s views on VRF systems and the response from the manufacturer community…

By Content Team |
Published: May 10, 2015

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George Berbari, the CEO of DC PRO Engineering (speaking on Day 1 of the conference):
“For the last five years, I have been asking for the validation of the super performance of VRFs. And we have no doubt that Eurovent has done certifications at a single point, and are confident that a single-point performance may be accurate as we want it to be. However, Eurovent has not tested at 46 degrees C ambient temperatures; and we shared the point about the complexity involved in validating VRFs and the sensitivity of the piping on the overall performance.

“Two years ago, I started having doubts. I used a friend’s townhouse [for measuring energy efficiency], which had a new insulated VRF system, and [compared its energy efficiency to] my villa, which has a ducted split system of the same brand. His villa was consuming slightly more [energy] in winter than my villa. The summer performance of my villa was much better.

“There was a study done at the ASHRAE headquarters that measured the energy efficiency of a VRF system and a water-cooled, water-sourced heat pump system in their living lab. They did an actual two-year measurement: what was claimed to have an EER of 20 had an EER of 8.5 when measured. Now, this translates to 1.4 kW per tonne of seasonal efficiency, which under the UAE weather will translate to 1.8 kW per tonne.

“Engineering is about science. It is not about claims and perception. We have a condemning report from the highest authority in the world saying that VRF is not as efficient as they [manufacturers] claim. I still design VRFs for bedrooms and for villas; I am not against it. The biggest selling point is that it saves space on the roof, it has low noise, it has high quality, but I don’t sell it for high efficiency. And this condemning report requires response. The industry is coming with a response. The response is the VRW… that instead of pumping refrigerants, they are pumping water and that they are measuring by a BTU meter, and this can be validated. In my opinion, by 2020, VRFs will be phased out in favour of VRW.

“The only way to convince me [about the efficiency of VRFs] is to have field data. The only field data we have is ASHRAE’s, and we don’t have any counter field data that says otherwise.

“For my 500-square-metre villa, with an installed connected load of 144 watts per square metre, the actual average performance from February to September, you will be surprised to learn, was 13.3 watts per square metre. In winter, it was around four watts, and in February, it was 11.9. (See Image 1)

“When I went to my friend’s townhouse, which was insulated at least from one side, and which was 320 square metres in size and had more occupants, the winter data was about 5.4. And in February, it reached around 17.4, with a marginal increase of over six months of 13.2 watts per metre square, which is good for engineers to know; the difference between the actual average consumption was mainly 10% of the connected load. This always shocks electrical engineers more than mechanical engineers. (See Image 2)

Kandasamy Anbalagan, the Managing Director of Proleed Consultants, speaking on Day 2, in his capacity as the Moderator:
“One of the points that was raised yesterday (Day 1) was for the manufacturers to come out with operational data and to introduce transparency. And we have been struggling to obtain this operational data. Though most of the manufacturers claim they have sub metering BTU facilities within their control philosophy, it is not being done on the field. They need to provide the data to the consultants and end-users, so as to understand whether it [VRF system] really has the claimed seasonal efficiency. Also, one of the points that was brought up, which we as designers look forward to, is to have a consistency in the manufacturers’ claims, at least the kW per tonne at peak loads; some people claim 1 kW per tonne for the system, and some claim 1.38 kW per tonne, which sounds more reasonable [than the former].

“As a starting point for the discussions, we shall talk about George Berbari’s data, presented yesterday, which indicates there is no difference between VRF systems and independent standalone systems. I would like to hear from the manufacturers.

Prasath Sivakaminathan, Area Manager of AHI Carrier, presenting real-time operational data from a field installation, to substantiate his points:
“George said yesterday, ‘If you can measure it, then do it accurately. If you have measured it, then report it.’ So, here we have recorded it and we are presenting it. We will give you the exact results obtained from our Toshiba VRF SMMSi system, installed at our AHI Carrier office. This recorded data is up to yesterday – that is, from last April 2014 to March 30, 2015. This system has been supplied by a 14 HP machine outdoor unit. And there are seven indoor units, most of which are compact cassettes and standard cassettes.

“We have a Smart Manager system. Through our Smart Manager system, our VRF outdoor unit communicates all the recorded data (gathered in a day); all this data is stored in our computer systems. That’s why we were able to generate the data within the stipulated time of 24 hours.

As you can see (see Slide 1), the kWh seems to be less. We need to multiply by 10 to get the actual result. The value [for Board Room 2] has been shown as 2,120 kWh per year, but actually it is 21,200 kWh recorded for the year. You can see from April to March what the power consumption is (see Slide 2).

“If you see the temperature profile and the power consumption, the relation is directly proportional.

Anbalagan: How easy is it for you to submit such operational data?

Moan Abraham, General Manager (Air-Conditioners), Hisense Middle East: I think most of the VRF manufacturers have IT-based control systems, which are very up-to-date; and they have software to record the data on a real-time basis. We have a sample installation in a villa in Jumeirah Village. It was installed around six months ago. And we have been tracking that [data] on a weekly basis and sharing with our factory. This is part of the field test we are conducting. As far as I know, manufacturers are not going to hesitate in sharing such data, because it also helps in terms of troubleshooting to see if there are going to be any concerns when it comes to pressure or operational reliability.

As I mentioned earlier, we at Hisense are still in the data-collection process. We have one project test site operational right now. We are recording the data not only for our internal verification and validation but also to share with our customers. The main performance criterion we are trying to look at is to measure during the summer months, so the next three to six months are going to be crucial. It is not only the ambient condition in the Middle East but also the environment, which includes dust and humidity. So there are a lot of factors we want to evaluate. I am hoping to present the data during the next conference.

Faizan Ahmad, Manager – HVAC Solutions, NIA Limited (Gree): He (Berbari) compared a fixed-speed standalone system with a VRF system, and he concluded that a VRF system consumes more energy. That is totally not possible! I say this, because your connected load itself is 30% less than your standalone system. We have installed a VRF system in a villa in Victory Heights [in Dubai]. We have all the data for that, which we would be willing to share on request. The client is enjoying 30% savings on energy.

Vishal Ate, Consulting Sales Manager, Daikin Middle East: I think we have been very transparent right from the beginning. The first installation was way back in 1999. It was a hotel in Saudi. Although the field performance data was not taken, because it’s difficult to do so, what we did was to ask for the field results from the owners. The owner had two different hotels, both of which had 120 rooms, one with chiller installations and one with VRV. We have electricity bills, and we have been circulating those bills to a lot of clients, who were initially not ready to understand how 30% [savings in energy] can be the difference between chiller and VRV systems. We can circulate the data to you as well as to Climate Control Middle East.

Secondly, much like the metering systems that AHI Carrier has shown, clients can install their own Smart Managers; all manufacturers have those kinds of devices. Clients can see how much [energy] they are consuming on their work stations. They can monitor the performance, record it and question the manufacturer. There is a new and advanced software, called Energy Navigator; with it, you can pinpoint a particular FCU that is consuming more power in your entire installation.

In terms of transparency, we have a very big installation that is five towers (G+12). It is a tenant billing system installed for staff accommodation. We have had DM [Dubai Municipality] and DEWA [Dubai Electricity and Water Authority] people visiting the site. They have checked how the electricity billing happens and how the owner is billing it to the tenant, as well. If required, we don’t mind consultants visiting, as well. This was way back in 2011, when we were trying to persuade the utility companies to accept our data as a billing system.

Syed Jafar Imam, Senior General Manager (RLC), AHI Carrier: Let me cut to the chase. None of the data shown here [referring to the slides shown earlier] is confidential or proprietary. Every one of you sitting here can have access to this data. You just need to purchase the system – the so-called Smart Manager, which records the data. And you can sit and do the analysis, as and when you like, in the comfort of your home, on the Internet. You can record and check what has happened throughout the year. Everything is recorded. Nothing should be left to doubt. This is not confidential data.

Editor’s note:

In an attempt to convey the tone as well as the substance of the discussions to you, we took a decision to present them in verbatim format. The results are depth, detail and nuances, which perhaps we might not have been able to capture through employing a narrative style, containing a paraphrased account interspersed with quotes.