A team of North American engineers has managed to develop a refrigeration system called DEVap that uses up to 90% less electrical energy than current air conditioners and is also non-polluting. The DEVap achieves its electrical efficiency thanks to the fact that it combines various elements already present in air conditioning devices, in a new way. It is expected that it can be commercialized in five years.
Scientists from the United States National Renewable Energy Laboratory ( NREL ) have created a novel air conditioning system that could result in energy savings of between 50 and 90% compared to current air conditioners.
As published by the NREL in a statement, the system, dubbed DEVap (Desiccant-Enhanced eVaporative air conditioner), would combine elements typical of air conditioning devices (such as membranes, evaporative cooling or liquid desiccants) in a different way, Until now not applied, giving unique capabilities to the new cooling machines.
Eric Kozubel, co-inventor of the device, says that DEVap could remove a large amount of the gases that contribute to global warming and that air conditioners generate each year.
How does it work.
Kozubal and his colleagues devised an air conditioner that combines evaporative cooling with a material that absorbs water, in order to provide cool, dry air. This evaporative air conditioner has been enhanced with liquid desiccants.
The system eliminates the problem of room humidification caused by certain air conditioners.
As explained in the Technology Review magazine, this has been achieved thanks to the fact that the air generated by the device is divided into two streams separated by a polymer membrane, coated with a substance similar to Teflon, whose objective is to repel liquid water. The water passes through one of these air currents, which becomes, thanks to it, cold and wet.
In turn, the cool air from this stream cools the polymer membrane that separates the two air streams. Lastly, this membrane cools the second air stream, without adding water to it: the air leaves the device fresh and without humidity.
Kozubal says that the novelty of the system is that it manages to combine evaporative cooling and desiccant drying in a single unit.
All in one step.
Desiccants (substances used to remove moisture from the air) in air conditioning systems have been proven for decades.
The desiccants used by NREL engineers are composed of highly concentrated aqueous saline solutions of lithium chloride or calcium chloride. These solutions make the appliances generate very dry air.
On the other hand, the membranes used in the DEVap system are hydrophobic, a property that allows said membranes to “control” the liquid flows inside the cooling device.
With the system created, the air is cooled and dried from its initial humid condition in a single step, which lasts just a fraction of a second. In this way, the device regulates both thermal and humidity levels on the fly.
Help the environment.
DEVap could help protect the environment for a number of reasons. In the first place, the one we mentioned initially: this system requires an energy expenditure between 50 and 90% less than current air conditioners, which use a large amount of electricity to make the refrigeration cycle work.
The device created by NERL engineers replaces this refrigeration cycle with an absorption cycle that is thermally activated and that can be powered by natural gas and even solar energy, requiring very little electricity.
On the other hand, since the DEVap uses saline and non-refrigerant solutions in its air processing, the (CFCs) (derived from saturated hydrocarbons) and the hydrochlorofluorocarbons (HCFCs) that the current refrigeration systems carry would be eliminated from these systems.
Taking into account that half a kilo of CFCs contributes as much to global warming as almost a ton of carbon dioxide, and that an ordinary air conditioner can carry around six kilos of CFCs, it is understood to what extent the DEVap system is suitable, from a ecological point of view.
Marketing in five years.
NREL has already patented the DEVap concept, and Kozubal hopes that smaller and simpler devices will be developed in the next few years that include it.
Perhaps in five years, the system will be ready for commercialization. The idea is that thereafter you start replacing existing systems without much change, with progressive application as people upgrade their old air conditioners.
Seen at: trends21.net.