Space Heat Pumps

[tom in maine]

I had posted a while ago that we were getting in air source heat pumps that are for space heating.
They are here and we are finishing testing in our lovely Maine winter.
They are being manufactured for us to our specs.
They produce heated antifreeze, so no refrigerant plumbing is required. The refrigerant side work is done in the factory. You just plumb it in with copper or PEX.
Here is a link: (broken link removed to http://www.americansolartechnics.com/products/space-heat-pumps/)
They can produce hot antifreeze up to 150F.

We are also stocking low water temperature fan convectors that tie in with these units.
The system is reversible so it can heat and cool.
These are inverter units and we are currently testing them and will be offering more info online.
There will be more lines to come as the year progresses.

 

[peakbagger]

Great news that its coming to fruition.

Now if I could find my dream unit which would allow me to plumb glycol from a water source into a HX on the refrigerant circuit so I could use groundwater in place of outdoor air at subzero temps it would be perfect. I have spare well with supply and return line on it so I could easily hook up a heat exchanger and plumb glycol through the loop to use ground temp instead of air temp.

 

[iamlucky13]

This is good to see. I've got good hopes for the flexibility of this type of system. I hope these perform well for you.

 

[semipro]

I had posted a while ago that we were getting in air source heat pumps that are for space heating.
They are here and we are finishing testing in our lovely Maine winter.
They are being manufactured for us to our specs.
They produce heated antifreeze, so no refrigerant plumbing is required. The refrigerant side work is done in the factory. You just plumb it in with copper or PEX.
Here is a link: (broken link removed to http://www.americansolartechnics.com/products/space-heat-pumps/)
They can produce hot antifreeze up to 150F.

We are also stocking low water temperature fan convectors that tie in with these units.
The system is reversible so it can heat and cool.
These are inverter units and we are currently testing them and will be offering more info online.
There will be more lines to come as the year progresses.

Where are they manufactured?

 

[woodgeek]

Do you have COP numbers for your system versus lift temps? Can you estimate a HSPF?

 

[georgepds]

Do you have COP numbers for your system versus lift temps? Can you estimate a HSPF?

He has cop numbers on the link

~2at -5
~3 at 25 f

 

[woodgeek]

Thanks. One supposes that that does not include defrost losses, typically 10%

 

[tom in maine]

The units are made in China. The build quality is good. We are putting together the manual for the unit. If you have ever read anything prepared by folks from other countries, there is usually some information that tends to be a bit confusing. We want to make sure this is sorted out.
The weather has slowed down our initial test unit installations. We have two installed and working well. They are tied to the fan coil convectors that we offer to use with these units. The fan coils and heat pumps are reversible, so they can cool and heat.
The fan coils are also great for other heat sources. I am using one in my shop with our pellet boiler. It is very quiet and throws a lot of heat out.
And functions well with low temp water (~90-130F).

We have worked with several companies in this country and have not been happy with the results. One unit, that will go un-named, just gave a refund to the customer. It has been a big ball of ice all winter. The company just gave up on it.
The units we are working with have been running perfectly through a lot of weather that would be considered challenging.
Time will tell, but these are the same inverter technology used on mini-splits that we all like. And they use the same name brand components.

 

[maple1]

Could one use more than one fan convector unit per heat pump unit?

How far could they be away from each other?

 

[tom in maine]

Could one use more than one fan convector unit per heat pump unit?

How far could they be away from each other?

You can use more than one. The HP puts out 34k btus. The smallest convector delivers 9400 btus at the highest setting.
We currently have three sizes.

 

[maple1]

How about the distance between (inside/outside) units?

Just when I have myself almost decided on a mini-split, the water changes on the beans, tech-wise. (Which I guess I was hoping for anyway, really).

Seems I could perhaps do shoulder season heat, summer a/c, and DHW (using a plate exchanger) with one of these units?

 

[iamlucky13]

Are these for heating only or cooling also? If the latter, have they been tested much for cooling combined with the fan convectors, and does that require condensate drains?

 

[georgepds]

How about the distance between (inside/outside) units?

Just when I have myself almost decided on a mini-split, the water changes on the beans, tech-wise. (Which I guess I was hoping for anyway, really).

Seems I could perhaps do shoulder season heat, summer a/c, and DHW (using a plate exchanger) with one of these units?

Remember..this is a new technology

Air to air Minisplits have been studied for a while and are a proven item,by many different testers

For me to choose it over a minisplit there would have to be a very compelling reason

 

[Highbeam]

One compelling reason is the lack of an ugly indoor unit hanging on the wall blowing heated air.

 

[peakbagger]

For someone who has storage and low temperature radiation, this is nice option for shoulder season.

 

[tom in maine]

I will try to answer all the comments.
Air source heat pumps that heat water are sold overseas in Asia and Europe. Of course, the European units are of interest since they have similar climates to us.
There has been one unit sold in the US for a while. It is the Dakin Altherma. It is not cheap. Wholesale for a 34k unit similar to the one we are offering is about $9k. But, they were first in the US and they work well.
These are and can be year-round systems, except in the extreme northern areas.
It has always been my thought that this is part of an integrated system that uses some storage, PV's with grid tie in and a small wood or pellet boiler for the bad times when it is really cold out.
These are heating and cooling units. The convectors have a condensate drain. This is imperative for most regions when cooling.

We will have some videos as soon as the weather allows us. We got dumped on yesterday and more to come tomorrow.

 

[georgepds]

One compelling reason is the lack of an ugly indoor unit hanging on the wall blowing heated air.

Eyes of the beholder and all that. Air ducts, air vents, steam radiators, electric baseboard heaters, wood stoves, these things all belong in the Louvre just behind winged victory? Whereas the modest reliable ultra quiet heat transfer unit of the mini split is relegated to a roadside mechanical freak stand just outside Toledo Ohio? Personally, I'm all for new technology that performs better/differently, but not at the cost of reliability(*)

That said I wish the vendor good luck, it's nice to see new technology described here. I appreciate the info on how the heat transfer is attained ( water storage, see above)


(*) It took a Chevy volt to pry me away from Toyotas (questionable reliability compared to Toyota's record, but clear performance/ functional improvement)

 

[Highbeam]

So, I'm still left scratching my head at the application. How exactly does the water coil of this device transfer heat to the room efficiently without being visible (not that I consider visibility a drawback)?

By circulating hot water through traditional and often existing hot water heat emitters. Most folks will not use this in a ducted forced air system since traditional split systems work fine for that. This new water heater can also heat domestic water, or maybe ONLY heating domestic water.

 

[tom in maine]

These units perform with the same COP's that mini splits offer.
The big difference for me is no refrigerant plumbing. And the ability to use it as a central unit, if you desire, and also integrate it seamlessly with
other systems such as wood, solar or fossil fuels.

I find the convectors to be of particular interest because of their ability to use low temperature water for space heating from storage.
And the fact they are relatively quiet compared to something like a kickspace heater.

There is no one solution for everyone. This is just another piece of a puzzle that will fit in some places.

 

[georgepds]

These units perform with the same COP's that mini splits offer.
The big difference for me is no refrigerant plumbing. And the ability to use it as a central unit, if you desire, and also integrate it seamlessly with
other systems such as wood, solar or fossil fuels.

I find the convectors to be of particular interest because of their ability to use low temperature water for space heating from storage.
And the fact they are relatively quiet compared to something like a kickspace heater.

There is no one solution for everyone. This is just another piece of a puzzle that will fit in some places.

Thank you

I get the idea of how the circulating hot water integrates with the existing HW systems

Can you comment on the air conditioning part? Do you just circulate cold water (anti freeze) or is there another heat transfer unit

 

[semipro]

These units perform with the same COP's that mini splits offer.
The big difference for me is no refrigerant plumbing. And the ability to use it as a central unit, if you desire, and also integrate it seamlessly with
other systems such as wood, solar or fossil fuels.

I find the convectors to be of particular interest because of their ability to use low temperature water for space heating from storage.
And the fact they are relatively quiet compared to something like a kickspace heater.

There is no one solution for everyone. This is just another piece of a puzzle that will fit in some places.

And its easier to run liquid lines rather than ducting. Probably less thermal losses also (e.g. leaking ductwork).

 

[maple1]

Max distance between indoor & outdoor units?

 

[Highbeam]

Max distance between indoor & outdoor units?

Why would it not be just like any other hot water line? It can go forever until head loss starts chewing at flow rates.

We don't even know if this thing has an internal circ pump. It might just be a water heater and it's up to you to design the pump circuits.

 

[tom in maine]

Current units have an external pump that can be controlled from the HP.
The unit has 1" fittings. It can be run a reasonably long distance and I would suggest a Primary/Secondary system.
Heat loss and friction loss is going to determine the run length limit.

 

[iamlucky13]

Can you comment on the air conditioning part? Do you just circulate cold water (anti freeze) or is there another heat transfer unit

Yes, you'd just circulate cold water through the same heat transfer units.

I suspect with cooling it's more important to use forced convection (eg - fan convector) rather than the old-style passive radiators. Passive heat convection of a floor-level unit will cause warm air to rise and circulate around the whole room. Cold air when in cooling mode, however, will tend to just settle down near the floor.