Seeking an air-to-water heat pump

Hallowell is working on a air-to-water for hydronics.

http://www.gotohallowell.com/development_products.aspx

And I think I remember reading that Mitsubishi might have something ready.

As recommendation, put lots of styrofoam under the slab, at least R20.

Finally, having spent a couple of weeks in March, a couple of years ago, I couldn't help thinking that homes built to the Passive House standard would be pretty easy to achieve there.

Good luck with your project.

Allison,

That should have read "having spent a couple of weeks in Victoria in March".

Also I checked and the Mitsubishi heat pump I was thinking of is an air-to-air.

http://www.mitsubishielectric.ca/en/hvac/zuba-central/

If you are going for LEED you may want to consider how efficiently you distribute the hydronic heat around the house. There are a few really efficient circulators from Europe that are starting to be available here.

The Wilo ECO Stratos is an A rated variable speed circulator that I found made my hydronic system easier to design. It also helps to eliminate some hardware, specifically a differential pressure bypass valve. Which was something I couldn't get my head around!

http://www.wilo-canada.com/cps/rde/xbcr/ca-en/ECO_Brochure.pdf

Here's a little more info on what a system using a EC motor variable speed circulator would look like.

http://www.radiantandhydronics.com/CDA/Articles/Glitch_and_Fix/BNP_GUID_...

Just substitute the air-to-water heat pump you are planning to use for the ground source one in the diagram.

Grundfos also makes an EC motor variable speed circulator, I believe it's called the Alpha.

Cheers,

Andrew

In the US you may also want to check out RC (reverse cycle chiller) units from Unico (Unichiller RC), Aqua Products, and Multiaqua....

In Canada; Aermec (from Italy) is currently being distributed ....

There are a number of manufacturers that could enter the North American market with Asian and European products; Daikin, Hitachi , Mitsubishi, Sanyo, Stiebel Eltron, Veissman etc.... of course pending getting UL/ETL certification for North America...

Look Daikin Altherm. It is specifically made to provide hydronic water heating and domestic water heating for residential. If you find something for commercial I would appreciate some feedback.

http://www.altherma.co.uk/default.jsp

For US and Canadian readers;
http://www.nmdgreen.com/altherma-heat-pumps.shtml

also has a link to Daikin Altherma technical info in “American Units” instead of SI Units;
http://www.nmdgreen.com/pdf/daikinaltherma-brochure.pdf

So glad I found this posting. Thank you all for the info.

Please update this as anyone sees more news.

The Daikin website now has info. on the Altherma. Go to http://www.daikinac.com/residential/altherma.asp?sec=products&page=53

Still looks like October for first ability to purchase?

The Geyser for DHW, maybe more...
http://www.northrdt.com/Geyser/index.html

First Daikin Altherma system installed in Portland looks good, however, I got a quote of $22,000 to install a system in our house, and because it is not yet elegible for the 30% Federal renewables tax credit, it's an expensive way to reduce electric energy use. I have to say I don't understand where the high price comes from, the components are pretty straightforward to install.

I have priced out the Mitsubishi Zuba Central for our 1,110 sqft raised brick bungalow. It came in at about $11,000 including new water heater. Good price and competitive with the FAG systems I was quoted. Now comes the debating... I have searched and only found a couple reviews that were positive but no concrete numbers for what was paid yearly on heating/cooling.

I discussed with Mitsubishi the last 2 years, a air2water heat pump system for hydronic heating and cooling. They have a larger 6 Ton City Multi model for commercial use just introduced. they expect to have a smaller 3 ton air2water unit ready for test instalations by december 2010. I expect the full role out for spring 2011 for the AC season. Efficiency is apparently 378% range. Pricing will be fair as the install labour is easy. wait a bit. I am.

I'm looking for a unit that is about 12000 btu/h ... the geyser is 6000 btu/h (is that an outdoor unit?) ... the altherma is 38000 ... unichiller is 30000 or so ... seems like a gap in the range for all the ones I've seen. Any help or direction? Thanks.

Michael,

6000 Btuh is average for a HPWH. Of course, they all use storage tanks, so a comparison with a tankless is meaningless.

You're right, the Geyser was never designed for space heating, and all air to water heat pumps have issues with ambient temperatures at the evaporator.

For a discussion of the issue, see: http://greenbuildingindenver.blogspot.com/2009/08/heat-pump-hot-water-he...

Follow this link to see why a well-insulated garage could be the best place for a HPWH: http://www.greenbuildingtalk.com/Forums/tabid/53/aff/13/aft/45292/afv/to...

I talked with the people at Geyser and they said someone is trying it out for hydronic radiant heat in a small super well insulated space as well as domestic hot water where they have a marathon electric hot water tank to supplement. I'm planning a similar setup and am pretty convinced that 6000 btu/h would be just enough to meet my needs for my 1000 sq ft well insulated, passive solar house in WA. Plus the thing is only $1000. The killer for me is that it has to be indoors.

I'm talking with the people at CIAT too regarding their Yuna 20H model -

http://www.ciat.com/rubrique/index/eng-catalogue/33/YUNA/1803

That model is about 18,000 btu/h and is due to be ready this month. No word on price yet. This is overkill for me but might be the smallest outdoor model on the market. I don't really want to oversize my heat pump for many reasons ... smaller is quieter, cheaper to buy and cheaper to operate. Wish I could find an option in the 10,000 btu/h range that could be installed outdoors.

After further discussions with CIAT I found out that their heat pump is designed for 50Hz ... which is the European standard.

Why is there no small sized air to water heat pump available on the US market? I don't need air conditioning - just heating and I live in a climate where the temp rarely drops below 30 F and never drops below 0 F.

Someone must be making such a product ...

I have found and air to water heat pump from Techwell industries in Hong Kong, China. It is a DC inverter heat pump. It is a split system, an outdoor unit and an indoor unit. It will supply hot water for radiant floor heat and domestic hot water. The unit I want to purchase is $2100 plus shipping to Vancouver, Ca ($200) . It is a 3 ton unit (36000 btu/hr). I don't have experience with this product yet, but believe it is the way to go for my project. Purchasing a product from a Chinese company may be offensive to some, but I have yet to find an affordable product produced in the U.S ($6000 and up). There are several products produced by toshiba, mitsubishi etc. that are I am sure are great products that have been built for the European market and not yet available for the US and the ones that are availble such as Daikin are cost prohibitive (over $10000). Aqua products in South Carolina builds an air to water heat pump in conjunction with York but I found their customer service to be very unresponsive to my email inqiries and I finally found out the price of their product ($8000) from a dealer. Since I am looking for a DC inverter heat pump that is more efficient one is forced to look outside the US for a product.

There are two distinct categories of systems available for air to water applications. The first are for domestic hot water generation - either integrated with a tank - GE,Rheem - or separate units tied in with an existing electric tank - Geyser, Air Trap. The second category of systems is for heaitng and cooling via radiant floor or fan coil on the heating side, or fan coil on the chilled water (cooling side). The latter category ranges in sizes from 3 tons up to 5 or 6 ton capacity. As mentioend Daiken, Unichiller and Aermec are currrently in the developing market stage. However, there is an entirely US made system - NorAire - out of Minnesota (Electro Industries). The NorAire system has incorporated some significant advantages over the other market palyers especially on the back up heating side, and the defrost cycle which is very important in colder climates. NorAire has a design manual which I have attached.
The air to water systems are especially adept at radiant floor heating, as they produce a lower supply water temperature - 105 to 110 F. They can also be used to pre-heat a domestic hot water tank in the same way that a ground source heat pump does. In fact, it may be reasonable to think of an air to water heat pump as a poor mans geothermal system. Same result, but with slighty lower performance (dependant on ambient temperature conditions). However, installed cost is going to be about 1/5 th that of a geothermal system.
There are currently no third party ratings for air to water systems - AHRI - who rate air to air and other HVAC equipment, so be careful of claimed COPs by some air to water manufacturers. However, it is likely the performace is going to be in the range of 1.5 to 2 - better than a gas boiler at 95% AFUE, plus you get cooling.

Nice to see the last two posts. I bet there is a sizable market for low cost heat pumps that are reliable and that a suitable for colder climates too.

Murray, page 4 of your PDF looks like a nice system that would cost $35,000 is my guess. Am I close?

Ted, I hope you update us, nice post, great cost for the HP part of your HVAC system.

More details on the NorAire system have been added to thier web site at http://www.electromn.com/gen/noraire.htm
Since there are a myriad of system configurations, the pricing will range significantly from a basic single zone heat only radiant system to a multizone heating and cooling application. While the air to water was primarily targeted for radint floor, the chilled water capability opens up some options on the cooling side - central fan coil or individual room units (buffer tank required). A basic system with heat only one zone of in-floor will have an equipment cost about the same as an air to air heat pump.
Where the air to water systems will shine, will be in areas with moderate winter temps - Pacific Northwest, etc and as a miuch cheaper alternative to ground source equipment - no field loops, pumping eqpt, well drilling, etc and producing exaclty the same water temperature.
As far as inexpensive offshore equipment goes, buyer beware. Two of the major offshore players in the market right now are nowhere near the cost that one of the previous contributors quoted. There are hundreds of Chinese, Taiwanese and Korean system out there, but if you buy one, who is going to support it after sales? Unless you are a refrigeration mechanic that can trouble shoot your purchase if need be, good luck.

Hi all,
I did the post on purchasing an air to water heat pump from a Chinese manufacturer. I continued to research this option after my posting. Even though I felt the Chinese product was the answer for my radiant floor system, I decided not to purchase the equipment for the reasons stated by another person on this post, which was what would I do when it came time to service or replace parts. I felt my options would be very limited, if any. I ended up buying a used 3 Ton Unichiller RC (3 years old) that I found on Craigs list for around a 1/4 or less of the cost of a new one. The Unichiller design does not require a refrigeration tech to install since the refridgeration cycle is contained in the unit itself. All I had to do was plumb the water from the unit to my radiant floor and hook up the power. My Taco zone controller has an end switch that starts the Unichiller whenever heat is called for. The Unichiller is providing 115 to 120 degree water, which is fine for my radiant floor. I also plumbed a heat exchanger in the the radiant loop that preheats the water going into my domestic hot water tank which should also reduce the cost of my domestic hot water needs. The only other thing I am going to do is obtain a thermostat switch that will turn the water pump on in the unichiller whenever the outside air temp gets to 35 degrees or lower to prevent my water loop from freezing. I am now waiting for my next electric bill to see what the savings will be . All is well in Bellingham.

Ted, greetings from Friday Harbor and thanks for the update. I would be very interested in how this performs and what the operating costs are, as you move forward.