An often-quoted challenge is the need for balancing good indoor environmental quality (IEQ) with energy efficiency. You say that your products are ideal for building retrofit projects. Have you been able to deliver a sweet spot of good IEQ and energy efficiency?
Tiger Aster: What we do is to split the sensible heat and the latent heat completely differently, and we manage them by independent processes. We use the air heat exchanger, which is a wet plate-type of heat exchanger in a vertical plane. Evaporation takes place, as the air passes over the plate. On the other side, on the horizontal plane, we have the supply air coming in from the outside, passing through the heat exchanger before coming out. We have a change in temperature, which is a temperature drop. But there is no change in the absolute humidity at all. These heat exchangers we typically use two in tandem, getting an efficiency of 85%. And for the remaining 15% of sensible heat and moisture removal, we use a chilled water system or a DX system to cater to the latent load. What in turn happens is that for a 50 TR system, we are able to cut down the compressor usage to about 22-25 TR. That way, we are saving nearly 50% or more of energy.
Are these numbers that you quote based on actual installation or lab trials?
Tiger Aster: They are based on an installation we are currently doing in Dubai. These systems are based on Dubai conditions. The technology we are working on is over 30 years. We are the pioneers of this technology – indirect evaporative cooling. We started with basic units, and then have moved up to a dual-pass technology, which is what I am talking about, where we split the heat and the humidity.
Masood Raza: The main feature of this technology is that it addresses the Low Delta T Syndrome and also aids in the condensate recovery process. The condensate recovery process mostly happens from FAHUs, but you have to pipe it back to some other place. The TORRO FAHUs, on the other hand, have a self-contained condensate recovery system, which means you don’t have to pipe the water to another point. Everything comes there, and the same model is used for indirect evaporative cooling. Secondly, on the coil, we use the chilled water return to cool and dehumidify. That way, we are able to increase the delta T. So you are actually increasing the chiller efficiency. That portion of the savings, we are not even discussing with clients. That is something like an afterthought, like free goodies!
How do the products fit into a retrofit environment? How do you make yourself appealing to the retrofit market in the GCC region?
Masood Raza: We replace the existing AHU in the building with our system. Most of the residential buildings here stop the fresh air supply during summer, because either the chillers don’t function or there is a huge energy bill. If you put this system, you get the benefit of fresh air with very low energy bill, which means nobody will avoid running the system.
And what is the cost involved?
Masood Raza: The recovery period is two years. Within two years, whatever investment you make you get it back in energy savings.
(The writer is the Editor of Climate Control Middle East and the Editorial Director & Associate Publisher of CPI Industry.)