Air-to-Water Heat Pumps for hydronic radiant concrete slab (4"x1500sq ft) in Zone 6.

lofine

Thanks for the input on my last thread, I thought I'd make this discussion more targeted to avoid confusion as to what I am asking for.

Please tell me what ATW heat pumps you have first-hand experience with, in Northern climate zones, in concrete slab floors only, and how they performed.
How did they do below 20deg F? Below zero F?
Interior

Extra thanks if anyone has info on one installed totally in the interior (a basement or mechanicals room etc). That is what I am hoping to work out, since I am going to be dealing with below zero temperatures.

Thanks!
-Kevin

Hot_water_fan

https://www.greenbuildingadvisor.com/article/air-to-water-heat-pump-retrofit

Here’s a case study: it’s a mix of in-floor and panel radiators in Vermont. In-floor, using cooler temperatures, will be more efficient than a mixture. Frankly, it doesn’t matter much how well they do below 0 in VT if you have some sort of backup, as that’s a small portion of annual usage. 

Extra thanks if anyone has info on one installed totally in the interior (a basement or mechanicals room etc).

What do you mean by this? An air to water heat pump must have an outdoor portion (that’s where the heat comes from), but some keep more hardware indoors than others. 

lofine

Hwf:
Interior air-to-water heat pumps have no equipment on the exterior except for the grates for the intake and exhaust via short ducting. Air from outside, equipment inside.
What you're describing is a split-system ATWHP.

Hot_water_fan

Excellent, afraid you were trying to heat the space with a DHW heat pump (a frequently asked question). 

hot_rod

There are monobloc and split system type of A2WHP. I have seen some Euro versions that use two large grills in an exterior wall for the air in and out
SpacePak has plenty of systems installed around upstate NY and and New England, 10 years or more of operation, try their website for case studies

More info on various types of HPs and a few upstate NY installations


https://www.caleffi.com/sites/default/files/file/idronics_27_na.pdf

TAG

hot_rod said:

There are monobloc and split system type of A2WHP. I have seen some Euro versions that use two large grills in an exterior wall for the air in and out
SpacePak has plenty of systems installed around upstate NY and and New England, 10 years or more of operation, try their website for case studies

More info on various types of HPs and a few upstate NY installations


https://www.caleffi.com/sites/default/files/file/idronics_27_na.pdf

Who makes the SpacePak unit? Interesting that they have been using them that long -- I got the wrong information a few years back.

A self contained unit with an internal heat exchanger inside would be perfect for my new studio building in PA ... no NG gas available

lofine

Hey TAG,
SpacePak looks to be a division of Mestek, Inc, who bought SpacePak in 1991 when they were known as "the original" small duct central air distribution system.
I guess Mestek is a local-to-me (45 minutes away, in Westfield, Mass.) residential/commercial HVAC manufacturer started in the late 40's. They also own some top brands like Argo and SlantFin (both known for quality and good warranty etc).
I'm currently asking around about them. Some other top names I see in my searches are Nordic and Arctic, which are located in New Brunswick and Manitoba, respectively. I guess all three companies (especially the Canadian ones) are evidence that Heat Pump tech has progressed enough to be useful in really cold climates. I'll probably buy a small electric (resistance) boiler as a backup running in parallel, just in case.