Heat Pumps and Electric Heating - Heat Recovery Units & Heat Pumps

I saw an earlier post that said they use a heat recovery unit(s) on their heat pump in Missouri. I am in the process of buying a dual fuel HP/natural gas unit here in extreme Northwest Arkansas. None of the contractors seem interested in talking HRU's to me. Are they an issue elsewhere? Void warranty? Worth installing on new, high-efficient HP's?

Can anyone suggest any specific units that could be located near my hot water heater and operate on 120 (no 220 due to gas power)? I have little ammunition to encourage a detailed discussion with the contractors

Hi Jerry, I'm surprised they aren't at least discussing the topic, especially in today's energy conscious atmosphere. I would think Google would at least tell you who has the units and what the various applications are. The only one I have read about are the heat pump water heaters, but that is not what you want. I'll be watching the thread to see what others have to say.

Bud

Thanks Bud9051. I have seen some 220 volt units on the web, but the contractors just don't pick up on my request. I figure if I had a specific unit, 120 due to the power at my water heater, they might work with me. One of the moderators (Ed ...) had a post back in 2007 saying that he had them installed up in Missouri which isn't that much different than down here in Northwest Arkansas 30-40 miles below the state line.

I guess everybody is leary of something new if they haven't done it.

PS: I am talking about air-to-air and not geothermal.

Just for reading, have you looked at Acadia Combined Heating and Cooling System. I drive by them but I'm not plugging them, but they advertise one of the highest air to air efficiencies. The prices I have seen aren't cheap, but you mentioned air to air and as you go north that gets less efficient.

Bud

Are you talking about a desuperheater?

Are you talking about a desuperheater?

I know they use that term when talking about geothermal units. I discovered the term "heat recovery unit" in various posts.

Also, I can't for sure say that they are air-to-air. Don't know exactly how they transfer heat from the hot coolant to the water heater water.

You could get various quotes from the major brands such as Lennox, Ruud, Carrier and then contact the manufacturers to see what desuperheaters will mate with that system. Also check over on hvac-talk and ask the pros how to coax another pro.

dac122, I have contacted 3 manufacturer's via email and phone on whether they have this unit or know of any that doesn't void their warranty. Still waiting except the call to Lennox said they have none, know of nobody who does but it doesn't void their warranty if the Lennox is maintained yearly. Not very helpful.

I looked up the name of the poster who said he had heat recovery units installed. It is Ed Inmeduc, who is probably a moderator, but I don't know how to contact him from his post. Thought he might catch my posts but maybe he cruises elsewhere.

You should be able to send a private message to Ed...if you see his name on an old post, just left click on it...one of the options will be "send a private message to....."

Depending on how he has them set (if he has them on), he may get an E-mail telling him, or he will get a notification when he logs in. I just saw a post by him not too long ago.

You can find his old posts by using the advanced search function. Left click on the search tab above this thread.

Thanks, Gunguy45. I tried the message to Ed .... Hope I didn't misinterpret the HRU terminology for that of ventilation exchanger which I do not want.

When trying to decide should I keep the one I have had for 20years when I install my new heat pump, the info I was finding lead me to decide to remove it. What I was seeing is that the newer and more efficient the heat pump, the less "waste heat" there is available to recover. In other words, the higher the SEER rating of the unit, the less savings available from the recovery unit.

P.S. the unit I have is a heat exchanger that runs the hot freon from the compressor on one side and pumps water thru the other side to the water heater, I have heard this type referred to as a "desuperheater" which is an accurate description of how it operates.

You said "What I was seeing is that the newer and more efficient the heat pump, the less "waste heat" there is available to recover"

The domimant source of heat "to be recovered" is the heat you are moving from the inside to the outside and that will remain the same with a new high efficiency unit as it currently is with your older unit. The only reduction in heat available for recovery is the reduction in heat generated by the unit itself. In other words, the unit still has to do the same job, it just uses less electricity in the process.

Does that sound right?
Bud

You said "What I was seeing is that the newer and more efficient the heat pump, the less "waste heat" there is available to recover"

The domimant source of heat "to be recovered" is the heat you are moving from the inside to the outside and that will remain the same with a new high efficiency unit as it currently is with your older unit. The only reduction in heat available for recovery is the reduction in heat generated by the unit itself. In other words, the unit still has to do the same job, it just uses less electricity in the process.

Does that sound right?
Bud

Sounds good to me, what I was reading was that the newer units are more efficient because they operate at lower pressures therefore the temperature of the gas from the compressor is lower, so less heat to transfer to the water (less differential between the high side gas temp and the water temp), which also sounded reasonable. Now I'm really :confused: