Are air source heat pump boilers even avaible in the US?  Everything I find on the net is in Europe.  Are we that far behind?

we have a Daikin Altherma installed in our shop right now, but it's new. There are a couple of others out there in america, one by Robur (gas absorption) and one by a company called Alternate heating systems, LLC, though the only reports I've heard from that one were less than stellar.

we are that far behind. some of the units in japan blow away anything we're even talking about over here.

Posted By NRT.Rob on 07 May 2010 04:15 PM

we are that far behind. some of the units in japan blow away anything we're even talking about over here.

Thanks, I knew the answer to that question before I even asked it!

Sanyo is selling their co2 heat pump in the UK now.  Sanyo US doesn't even list it on their web page.

I wonder what UPS shipping would be from England..........

Posted By NRT.Rob on 07 May 2010 04:15 PM
we have a Daikin Altherma installed in our shop right now, but it's new. There are a couple of others out there in america, one by Robur (gas absorption) and one by a company called Alternate heating systems, LLC, though the only reports I've heard from that one were less than stellar.

we are that far behind. some of the units in japan blow away anything we're even talking about over here.

About how much would a Dakin unit cost?  I'm looking at a project with 2500 sqft heated/cooled? 

 How do you like yours so far?

would depend heavily on final heating/cooling loads and your design temps. Per unit you could probably expect to pay something like $15k+ installed. However if you are doing heating and cooling, replacing both a boiler and a chiller makes that look not bad.

there are some design considerations. for instance, my heating design temp is -4 which is the min operating temperature of the heat pump. the big one (054) only gives about 18kBTUs/hr at that temp, which is about half of my design heat load (calculated, not accounting for people, lights or computers). So the 6kw backup will definitely have work to do unless I wanted to buy two units... which I didn't. modelling indicates backup will be a fairly small amount of time though and seasonal COP *should* be good. we're hooking up monitors now so we can measure its performance this summer during cooling and beyond. They claim a heating season overall COP of 3 in a climate similar to maine though.

So far I like it, but it's only been installed since mid march. so it hasn't exactly had to work very hard, and I don't have any monitors installed yet to quantify performance. it is working and quiet though. I should start having cooling demands in about a month and it should get fairly serious in july... 10 computers and 6 people build up some real heat gain internally I need to nix.

Daikin mentioned a CO2 model as well but apparently no one will test it in the US because of the pressures involved. Ridiculous, of course, but that's the american hydronic powers that be for you.... after hearing what the CO2 models can do though it makes me sick with envy. That said I'd avoid importing foreign units. pretty hard to service and get replacement parts, lots of unexpected headaches too. Never mind if you have any codes issues...

Okay, at the risk of asking a really dumb question, why not use a reversible air to air unit and swap one of the fan coils out for a shell and tube heat exchanger, plumb to hydronic system and proceed?

That's what a desuperheater is (just smaller).

But in this case it would be running as a condenser, no? I'm about ready to build one for my friend's shop, any reason it won't work?

Posted By dbollermann on 19 May 2010 01:55 PM
Okay, at the risk of asking a really dumb question, why not use a reversible air to air unit and swap one of the fan coils out for a shell and tube heat exchanger, plumb to hydronic system and proceed?

Warranty and mfr support.

When I was discussing the planned installation of the Daikin air/air system (~$13k for equipment) for my house I wanted to add an exchanger for domestic hot water. The Daikin is a multi-indoor unit system. Pretty straight forward trade out of fan coil unit with an exchange coil. Daikin even has a refrigerant flow controller that connects to a non-Daikin coil unit! No dice. Daikin USA reviews every installation, I believe, and said the installation conforms to their designs, or they won't sell the units. Considering how complicated the control system is on a Daikin there was no way the local distributor was going to circumvent Daikin rules. My dealer/installer was quite willing to consider doing what I wanted, but he couldn't afford to stick his neck out without factory technical support or warranty.

If you are planning on using a heat pump with a fairly limited control system, willing to live without warranty support, and are buying components that are pretty much commodity, i.e., are willing to wing it entirely on your own and at your own risk, do it. The compressor doesn't care what's taking the heat out of the line, or adding heat to the line. It can't tell the difference between water or air. Now maybe the control system can. I don't know.

Air-source heat pumps air-water heat pumps are ideal alternatives for traditional boilers.This manufacturer "Wave Heat Pump" supply water heating solutions with heat pumps. Go to this site for your information: http://www.waveheatpump.com

Commerical / Industrial air to water and water source CO2 refrigerant heat pumps are available in USA now. We have installed several water source units this year and they are working very well. The issue has been the certification of UL/CSA due to the high pressure involved with CO2 and the test required to meet UL/CSA which can take some time to pass. The unit now available is a 80 to 100 kW heating capacity and is only available now in 480/3/60.
The water source unit is great for applications requiring hot water to 194 F while chilling water/glycol for air conditioning. This results in a high COP.
You can visit www.novustherm.com for sales information for these units.

ok, this is a marketing piece i am excited to see.

any plans for residential units in the future?

Posted By NRT.Rob on 16 Nov 2010 12:42 PM
ok, this is a marketing piece i am excited to see.

any plans for residential units in the future?

With 80-100kw of heating capacity you could skip the house, buy the heat pump, and be comfortable living in a  large tent! 

Something in the 10-30kw range might be kinda useful for the rest of us though...

just seeing co2 here is exciting. if testing can happen now, that opens the door for the *freaking awesome* heat pump tech the japanese and others have that we haven't even dreamed of here yet...

Posted By NRT.Rob on 16 Nov 2010 02:40 PM
just seeing co2 here is exciting. if testing can happen now, that opens the door for the *freaking awesome* heat pump tech the japanese and others have that we haven't even dreamed of here yet...

Yup!

Just breaking ground on US-code-regulatory stuff concerning the high pressures and issues surrounding CO2 leaks etc. will be enough of the camel's nose under the tent.  Too bad Team-USA is playing "catch up" on all of these efficiency issues though...

Similarly, there is probably 1 or 2 orders of magnitude more (Wisconsin-based)  Marathon EcoPower modulating micro-cogenerators installed in Europe than in the USA-  had they tried to make it on US sales they probably would have gone under.  I'm looking for local product support before installing one in my place- the Takagi placeholder can probably hang in there for a few more years, but the Marathon EcoPower is reasonably-sized for my combined thermal loads, with min-mod thermal output of ~23KBTU/hr, and max ~43K.  Net metered even at wholesale it would cut my annual power bill down substantially for a modest increase in fuel use over the Takagi.  Net-metered at retail the savings on the power bill would exceed my current annual gas bill, here in the land of expensive electricity & moderately priced natural gas.

The post may be older, but nevertheless...

Rob, the 054 actually outputs 25kBTU at -4F on heat pump only, factoring in the reduced output in defrost cycle, not the 18kBTU you had suggested.  Straight from the engineering manual.

We've got the first Canadian install I think of the Altherma, and so far it's been great, and would love to hear of your experience as well, now that there's been at least a good month of cold weather.  In our case we've hooked up a tankless hot water heater as the backup and have programmed it to have the 6kW disabled (except for defrost purposes).

Victor
www.ecobuilthome.ca

Althermas were actually tested for north american up in PEI first, so you're not the first, but you might be one of the first outside of the pilot. I'm basing my output on the output charts Larry Sutton developed and gave to me. I don't have an "engineering" manual though, just install and operation, as there was no engineering manual when we were working with our unit. If you care to share I'd love to see what you've got.

We have backup enabled on our shop as our calc'ed load is about 38kBTUs/hr at -4 so heat pump alone won't, or shouldn't, do it.

Victor,

I'll be installing the Daikin system in the home I'm building now in WA state and I'm wondering about how the Daikin hot water tank is working for you.

Well, actually, I have lots of questions about the whole system, but I'm trying not to ask them all at once. :-)

Posted By ICFHybrid on 04 Jan 2011 11:55 PM
Victor,

I'll be installing the Daikin system in the home I'm building now in WA state and I'm wondering about how the Daikin hot water tank is working for you.

Well, actually, I have lots of questions about the whole system, but I'm trying not to ask them all at once. :-)

Don't be shy about asking questions; fire away at will.  I've learned a ton reading here and the forums here was a major part of my research before we broke ground, and I'm happy to contribute back.

I can't comment much about the hot water yet, as I'm not yet in the house.  I'm probably 3-4 weeks from an occupancy permit.  Everything is hooked up, but obviously we've not been using any hot water.  What I can say is that the the Altherma is heating the water quite nicely.  Currently, the 3 way valve that controls whether to feed the hot water in the loop to the tank or to the space heating is not adjusted correctly, so even though we have the set the control panel not to heat the water, there's enough "leaking" through the 3 way valve that it's heating the domestic hot water tank quite nicely, as the PEX pipe coming off the top of the tube is quite warm to the touch.

We've been learning as we go in terms of how to fine tune the system, especially how we have the natural gas as backup heat.  The two things that I assumed that didn't work out was that we could "supplement" with the natural gas, but instead it's an either/or proposition, triggered by a field-changeable outdoor ambient temperature set point.  In our case, somewhere around -12C to -15C we estimate (we haven't determined exactly because it hasn't gotten that cold yet this winter) we'll switch over from the Altherma to the Navien tankless for space heating.  We've had it down to -11C with no loss in house temperature so far (which would mean we're achieving less than 30kBTU/h heat loss heating 6300sqft of conditioned space).

The other bad assumption we made was that the backup heat can heat the loop for the hot water tank, when in fact it can only heat for space heating.  This is good in the sense that we'll run the heat pump for hot water all the way down to design temp and below (at a COP of 2+), but bad in the sense that we're using electric resistance heat if the heat pump can't output enough, and therefore supplementing at a COP of 1 where electricity rates are 3X of natural gas in our neck of the woods.

The final quirk I can think of is that because you're setting loop temp for both the domestic water and space heating, there's a reliance on electric booster if your set point for the domestic is higher than the space heating loop.  In our case, we have our loop set at 45C/113F, the lower loop temp helping to achieve a slighly higher COP (per engineering manual), and we also have to lower the loop temp because of the low ambient temperatures that we might expect through the winter, but that also means my domestic hot water can only be set to 45C/113F or lower if I am trying to avoid electric booster heat.  I think I'll be setting the domestic hot water to 45C/113F as at my previous house my Bosch tankless for domestic was set at 108F and we were fine with it, and we're trying to stay off the booster heat since we're on-track for probably Canada's largest net-zero energy house, but different folks will have different preferences.

My 2 cents.

Victor
www.ecobuilthome.ca