Heat Pump Boiler manufactuers?

Chuck_17

I was watching a youtube video by a guy in Australia (I think) talking about the merits of heat pumps replacements for boilers. The way I understood it, it was for infloor heating (so relatively low temp) and had a buffer tank but was more or less a replacement for boilers. Residential.
Do you know some manufacturers marketing this in the USA?

I am familiar with several heat pump manufactures (air to air).
I am not talking about domestic hot water (but for bonus points - any information on a large commercial domestic water heaters that work in cold climate ....)

EBEBRATT-Ed

Everyone make heat pumps for hot water heating. Do your want air to water or water to water?

Jamie Hall

One wouldn't use the term "heat pump boiler". That said, there are, I believe, several manufacturers who make heat pump equipment which can be used for low temperature hydronic heating, either as air source to water or as ground source to water. Daikin is one, but there are others.

Air to water heat pumps have, at least to date, not been suitable for use in colder climates -- say with design temperatures below about 10 Fahrenheit. Nor am I aware of any which are suitable for higher temperature hot water heating say about 130 or so), never mind steam. Ground source heat pumps, however, if properly sized, do function well in lower outdoor temperatures -- since they are largely independent of the outdoor air temperature. Again, however, they are so far as I am aware not suitable in systems requiring higher water temperatures or steam.

I do know of one installation in a large academic setting in a cold climate, using ground source heat pumps and low temperature hot water. It was very expensive, as it required the complete removal and replacement of the heating in most of the older buildings, which had been steam or high temperature (180) hot water.

I'm not sure what the largest air source heat pump hot water heaters are. I do know of at least one installation, using several commercially available units, which is in use in a resort hotel with about 200 rooms for domestic hot water. That particular installation does use gas fired hot water boosters, however, for the hot water for cleaning and dish washing and other sanitation needs.

All that said, from the standpoint of the engineering and physics, is it possible to create such a system? Yes it is, although it may have two or more stages. It's purely a matter of choosing appropriate refrigerants and pressures and pressure ratios. Is it economically attractive? At this time, no.

Larry Weingarten

Hi @Chuck_17 , Perhaps the attached will have something of interest.

Yours, Larry

hot_rod

air to water heat pumps are becoming a viable option. They certainly can work in cold climates. Efficiency will drop some at lower outdoor conditions. Low temperature heat emitters will be a better choice. It's all in the numbers.
https://idronics.caleffi.com/magazine/27-air-water-heat-pump-systems

Steamhead

Larry Weingarten said:

Hi @Chuck_17 , Perhaps the attached will have something of interest.

Yours, Larry

A brief glance through that uncovers some Code issues- like, hooking up all that electrical equipment to a 100-amp electrical service? That wouldn't fly in a lot of places...................

Jamie Hall

Steamhead said:

Larry Weingarten said:

Hi @Chuck_17 , Perhaps the attached will have something of interest.

Yours, Larry

A brief glance through that uncovers some Code issues- like, hooking up all that electrical equipment to a 100-amp electrical service? That wouldn't fly in a lot of places...................

That is one of the minor problems...

Chuck_17

Thanks for the replies.
Still looking for a manufacturer - air to water for heating.

I am familiar with ECO2 and am looking at it for a large central hot water system.
I am not in love with sending the water outside to the heat pump. (Not sure why the CO2 heat pump can't be split system. I have an idea why but haven't confirmed it yet.)

Jamie Hall

I am always in favour of folks who are willing to push the state of the art -- provided that a) they know exactly what they are doing, b) know what the potential difficulties are, and c) are willing to take the risk. So -- presumably you fit a, b, and c.

That said, however, so far you have not provided information on design outdoor temperatures, no defined "large" nor "hot water". Without which information I am unable to either comment on how far you are pushing the state of the art, nor provide further advice beyond generalities.

leonz

The issue with heat pumps is how much is enough and do I have enough for the coldest weather.

A family member has Mitsubishi air to air heat pumps in the apartments he has and well you can forget heating well with seasonal low temperatures and severe low temperature periods which we are having more of.
The very cold periods freeze the ground and help kill the ticks and other bad bugs in the soil but its not conducive to heating so they need to add supplemental heating.

The Water furnace folks have water to water geothermal heating systems and I am not up to snuff on the efficiency of them these days,

For a drilled well geothermal system you need 100 foot of drilled well per ton of cooling and heating to make heat or cooling power.
As a NYSDEC certified well driller and pump installer I absolutely barf when these folks talk about the geothermally enhanced grout used to improve the heating or cooling in a drilled well system as its nothing but a clay grout that traps heat.
If you take the system installed at the Auburn NY municipal building as an example these multi well geothermal systems that have two pipe systems in each well bore connected with each other in series in shallow wells and its a waste of good money. If they used a deep well bore hole using concrete sand instead of the geothermal grout it would have been more beneficial.
They could have drilled fewer wells and had a more efficient system using the 100 foot of bore hole per ton of heating and cooling.
The closest the number one Silurian salt seam is to the surface is 1100 feet and they could have mud drilled a 1,000 foot bore hole, lined it with 50 twenty foot joints of steel casing and then installed the drop pipes and then pumped the well full of concrete sand using a tremie pipe to fill the bore hole slowly to let the wet sand and water fill the bore hole all the way to the surface.

I have to go for now and I will add more.

kcopp

spacepak... https://www.spacepak.com/hydronic-heating-and-cooling

Chuck_17

Spacepak - hmmm
Toshiba is marketing one in Australia

Jamie Hall

At some risk of pointing out the obvious... Australia might be a fine place for heat pumps. There is nowhere on the entire continent -- nowhere -- which gets colder than the odd frosty night, except for some high ground in the aptly names Snowy Range... where it does snow. Now and then.

hot_rod

Nordic and Arctic are Canadian brands Enertech, Chiltrix, Aermec, and SpacePak Soltice are a few others. Viessmann has a nice looking unit, the VitoCal, but not available in the US yet. It uses R-290 , propane refrigerant. Mitsubishi has some in the works, I imagine most heat pump manufacturers are watching th growing A2WHP market.

mikeg2015

I’’m waiting for a heat pump that can make steam for my primary heating plant. I think Mitsubishi made a R718 (water) compressor at one time. It requires high mass flow, and I assume you need magnetic bearings and High temp seals. But it would be interesting to mechanically produce steam instead of using heat. I suspect you have to cascade it with a regular 410A heat pump and COP would therefore be pretty poor. Probably something like 1.5 at best.

Jamie Hall

mikeg2015 said:

I’’m waiting for a heat pump that can make steam for my primary heating plant. I think Mitsubishi made a R718 (water) compressor at one time. It requires high mass flow, and I assume you need magnetic bearings and High temp seals. But it would be interesting to mechanically produce steam instead of using heat. I suspect you have to cascade it with a regular 410A heat pump and COP would therefore be pretty poor. Probably something like 1.5 at best.

Funny you should suggest that. I mentioned just such a possibility a few months ago on here. Nothing wrong with the concept theoretically. The two problems are first, you have to get the COP up. Until all the electric power is generated by rainbow powered panels and unicorn farts you need a COP of over 3 to beat the fuel (carbon) efficiency of direct oil or gas boilers. Second, you need enough electric power. Consider Cedric, a somewhat larger than average but still no uncommon residential boiler. With a COP of 1 you would need 500 amperes at 240. If we suppose on the coldest day that the COP was 2, you'd only need 250 amperes. You have that much power? Most houses don't even come close.

mikeg2015

Keep in mind you may not need to run it like a conventional gas boiler. You can add TRVs and reduce pickup factor to a minimum. Or do a hybrid with a smaller gas boiler combined with a heat pump one. Gas boiler just for startup, then heat pump carries the load until the call ends. If you slow the venting down or come up with newer, slower vents, I think many system will run with minimal pickup, or even with output below EDR and closer to actual heat loss.

But you bring a mother good point, you need a LOT of electric backup during a defrost call for steam. OR use gas for that as well. However, you’d probably find that with 2 cycles per hour, the system could defrost during standby if it was smart enough to recognize that.

Jamie Hall

mikeg2015 said:

Keep in mind you may not need to run it like a conventional gas boiler. You can add TRVs and reduce pickup factor to a minimum. Or do a hybrid with a smaller gas boiler combined with a heat pump one. Gas boiler just for startup, then heat pump carries the load until the call ends. If you slow the venting down or come up with newer, slower vents, I think many system will run with minimal pickup, or even with output below EDR and closer to actual heat loss.

But you bring a mother good point, you need a LOT of electric backup during a defrost call for steam. OR use gas for that as well. However, you’d probably find that with 2 cycles per hour, the system could defrost during standby if it was smart enough to recognize that.

The numbers quoted for Cedric's power consumption are steady state, not pickup, and are, in fact, more or less the actual heat loss for the building on many winter days (on really cold windy days, he never shuts down). It would be nice to think that tweaks to the system of one kind or another could reduce that, but... a BTU is a BTU. Sorry about that. This is not an uncommon situation.

Nor is it an isolated instance. On the main highway on which Cedric is located, there are about 40 houses in a 5 mile stretch of 23KV power line. At the moment most of them are 100 amp services (Cedric is in a farm -- 200 amps). That feeder is loaded to about what it can take. Now... multiply that load by 5 more or less to handle electric heat, even with heat pumps, and... blackout. So. You now need all new feeder...

Dreams are lovely. Reality is tough.

ratio

Eh, nothing a good panic, some misguided legislation, & a large dose of pork bellies can't fix.