Comments on: Waste Heat Recovery From Air Conditioners

By: Mike

Mike — Sat, 28 Sep 2013 17:02:00 +0000

Not really, a refrigerator has nowhere near the same capacity as a home air conditioner. No one does it because its there is not much heat to be gained.

By: Mike

Mike — Sat, 28 Sep 2013 16:59:00 +0000

Jean, based on your statement it appears that you have no idea how neither an air conditioner nor a waste heat recovery system works. An air conditioner works by removing heat from inside a house to outside the house. Don’t believe me? Put your hand where the air exits the outdoor unit, that is the heat that is being removed from the house. That heat is just dumped into the outside air by the air conditioning unit (now keep in mind that it took a lot of energy to move that heat[running the blower, and the AC]). What this device does is takes this otherwise wasted heat and uses it to heat your water. Its free heat, or i should say heat that you have already paid for and putting it to use. This reduces the amount of energy you have to use for your water heater to heat up the water.

By: Chilled Water Cools MIT Physics Department – CleanTechnica: Cleantech innovation news and views

Fri, 19 Nov 2010 13:25:58 +0000

[…] Recycling waste heat from air conditioners […]

By: Susan Kraemer

Susan Kraemer — Sun, 14 Feb 2010 15:57:39 +0000

Great idea. It would be easy to incorporate the savings upfront. One company that does, though is PVT Solar that combines solar pv (electricity) with solar thermal for heat by Vinod Khosla

By: Susan Kraemer

Susan Kraemer — Sun, 14 Feb 2010 15:57:00 +0000

Great idea. It would be easy to incorporate the savings upfront. One company that does, though is PVT Solar that combines solar pv (electricity) with solar thermal for heat by Vinod Khosla

By: Thomas H. Hebert

Thomas H. Hebert — Thu, 10 Sep 2009 14:12:43 +0000

With regard to previous comments, first, when an A/C system has additional condenser coil surface added, the efficiency goes up not down (if the friction related pressure loss is low), secondly, refigerators do not have enough compressor horsepower to provide significant amounts of recoverable heat, thirdly there is a waste heat recovery unit that produces more hot water over a years period of time than a pumped heat recovery unit, that has no pump or electrical input whatsoever (go to http://www.olivetreeenergy.com , to see). Finally, the maintenance costs alone, make this system more cost efffective than solar (or pumped heat recovery).

By: Thomas H. Hebert

Thomas H. Hebert — Thu, 10 Sep 2009 14:12:00 +0000

By: Dave Kay

Dave Kay — Thu, 03 Sep 2009 19:07:21 +0000

The thermodynamics support the claim of improving compressor efficiency. As long as the rate of heat removal to the 55-degree water is greater than the rate of heat removal to, say, the 90-degree air the AC was designed to dump to(which should be the case, given the relative temperatures and heat capacities of the air and water), the refrigerant will return just as cool if not cooler. It really does reclaim “waste” heat.

But I agree that solar hot water heating seems a lot simpler than intercepting the refrigerant on a central AC — and the units might also keep your roof cooler if mounted on the roof!

By: Dave Kay

Dave Kay — Thu, 03 Sep 2009 19:07:00 +0000

But I agree that solar hot water heating seems a lot simpler than intercepting the refrigerant on a central AC — and the units might also keep your roof cooler if mounted on the roof!

By: russ

russ — Wed, 02 Sep 2009 09:06:43 +0000

The water heater connection is available from some AC models now.

Problem is that it only works when the AC is on and in the heating mode the AC (heat pump) has to run additional time.

Better to just have solar hot water panels. I turned off the electric connection to the hot water tank on 1 April and will turn it on again in November. Zero power except for a very small recirc pump.

By: russ

russ — Wed, 02 Sep 2009 09:06:00 +0000

The water heater connection is available from some AC models now.

Problem is that it only works when the AC is on and in the heating mode the AC (heat pump) has to run additional time.

By: MD

MD — Tue, 01 Sep 2009 15:40:56 +0000

Same could be said for a refrigerator too, yet no one does it for the same reason Jean explained…

By: MD

MD — Tue, 01 Sep 2009 15:40:00 +0000

Same could be said for a refrigerator too, yet no one does it for the same reason Jean explained…

By: Jean

Jean — Mon, 31 Aug 2009 00:27:30 +0000

Recovering ‘waste’ heat from an air conditioning unit would decrease its efficiency, make the unit under-perform when most needed and eventually require more energy to compensate for the losses than recovered.

This is another one of these greats ideas that recover energy by wasting more energy than recovered.

By: Jean

Jean — Mon, 31 Aug 2009 00:27:00 +0000

This is another one of these greats ideas that recover energy by wasting more energy than recovered.