End of ground source with R290 monoblocks?

[Zwy]

Ran across this video this morning and I know R290 has been mentioned a few times in the forums by our friends overseas in Europe. I do think ground source may just be on the way out using R290 monoblock air to water heat pumps with some thermal storage/buffer tanks. My eventual plan with the gasification wood boiler is to also add an air to water heat pump for part of the heating season or dump load.

 

[S Davis]

One draw back is you are running water/glycol mix running your heating fluid to the outside, this can be a lot of glycol if using buffer tanks.
You can install a heat exchanger and smaller glycol loop but you will lower your max system temperature and lose some efficiency. I can’t count the number of systems I have seen that were eaten up from the inside by acidic glycol, you need to monitor water quality. I have one of each system going right now, a SpacePak monoblock and a NorAire split unit.

 

[Partimewages]

Ground source has a market place and will. It's a proven technology.
I've seen all types of systems come and go. We will see.

 

[S Davis]

I will not install anything that doesn’t have at least a five year track record, and positive feedback from other contractors/service providers. And most important is how engaged is the manufacture, what is their tech support like, does it take weeks or months to get repair parts?

I am a Mitsubishi dealer because of the above reasons, the units when sized properly just work and the occasional problems are solved quickly. Mitsubishi is in process of making a HyperHeat air to water, can’t wait.

 

[S Davis]

Double post

 

[Zwy]

Ground source has a market place and will. It's a proven technology.
I've seen all types of systems come and go. We will see.

I own a hoe and could install ground source if I wanted to, but I'm really not interested. Some of it is cost, some of it is tearing up my yard and a few other factors. My opinion is the majority of the market will leave ground source for air source heating and cooling, probably within the next 5 years.

As you have seen all types of systems come and go, it should be no surprise if ground source came and then went.

 

[Zwy]

One draw back is you are running water/glycol mix running your heating fluid to the outside, this can be a lot of glycol if using buffer tanks.
You can install a heat exchanger and smaller glycol loop but you will lower your max system temperature and lose some efficiency. I can’t count the number of systems I have seen that were eaten up from the inside by acidic glycol, you need to monitor water quality. I have one of each system going right now, a SpacePak monoblock and a NorAire split unit.

Many causes of corrosion. https://www.boydcorp.com/blog/avoiding-galvanic-corrosion.html

 

[Zwy]

I will not install anything that doesn’t have at least a five year track record,

Shouldn't be a problem then as R290 is in the second decade of use in Europe.

and positive feedback from other contractors/service providers. And most important is how engaged is the manufacture, what is their tech support like, does it take weeks or months to get repair parts?

Maybe you should read this article from Emerson Copeland? https://www.copeland.com/documents/...refrigeration-proliferation-en-ca-5438748.pdf

I am a Mitsubishi dealer because of the above reasons, the units when sized properly just work and the occasional problems are solved quickly. Mitsubishi is in process of making a HyperHeat air to water, can’t wait.

Maybe it is using R290? Maybe this one? https://www.pv-magazine.com/2023/03...opane-heat-pump-for-residential-applications/ or this one that uses R32? https://www.mhi.com/news/23122501.html

Even with R32, there will be a move towards a refrigerant with less GWP. I'm equipped for YF, rather hesitant on purchasing the recovery/recycling equipment (EPA Section 609) for it but started seeing it more often as vehicles come out of warranty. And yes, I am under Section 608 too as I still work on reefers and buses.

 

[Partimewages]

Ground source has been around since the 70's.
Some of this other stuff not so much.
That's the reason why I think it stays. I want to see with some of the "new" technology. Although a new refrigerant development can change things.

 

[S Davis]

Europe has always had a large head start on equipment and efficiency, I have 35 years in and have seen a lot of great equipment that either got worse when converting to our voltage or just never made it because of not enough market to make it worth the cost of going through the testing.

 

[Zwy]

Ground source has been around since the 70's.
Some of this other stuff not so much.
That's the reason why I think it stays. I want to see with some of the "new" technology. Although a new refrigerant development can change things.

I think the market will determine the outcome once the EPA changes regs on R290. That has been the holdup, once that happens the manufacturers will offer R290 systems in the US market.

 

[Zwy]

Europe has always had a large head start on equipment and efficiency, I have 35 years in and have seen a lot of great equipment that either got worse when converting to our voltage or just never made it because of not enough market to make it worth the cost of going through the testing.

I've seen the same, fixed my first AC unit for pay 28 years ago. Back then I did residential alongside my primary specialty just due to customer requests. When the state formed a HVAC licensing board with continuing education requirements for lead, asbestos, etc, I decided I didn't want to give the state another form of "taxes" and quit residential for the public. I had enough to do working 100 hour weeks during the spring, summer and fall.

It's not that state licensing wasn't needed, I had seen enough hacks working out there that some minimum requirements were needed. Residential just wasn't where the big money was for me.

I commonly see some of the stupid things tried concerning HVAC and controls, then the engineers realize it doesn't work well or stand the test of time and they go back to proven concepts. Then those engineers must retire and a new crop fresh out of college come along and make the same mistakes.

I think the market will provide the push needed on changes coming to residential HVAC due to increasing utility rates, the public moving towards more renewables as energy costs rise plus wanting efficiency along with lower installation costs and government forcing adoption of lower GWP refrigerants. Current refrigerants do not seem to work well in very cold climates.

I've run across enough propane in systems over the years and I know it did work well but the systems were not designed for it. I saw plenty of it back when R12 retrofitting was the biggest market.
A local Mennonite family decided to build their own ground source heat pumps and as none of them were 608 certified they purchased refrigerant off the internet. I had been called to look at a tractor they had installed it in one day that had blown the head off the compressor, the identifier flagged the hydrocarbons immediately. I packed up the service truck and left. About a month later there was an explosion in the basement of one of the houses and the fire department was called. They found what looked like a 20 lb propane tank hooked to the heat pump, story was there was a small leak and so the husband who was in PA at the time, had been just adding refrigerant now and then.

The chair of the state licensing board showed up and it was quite the show from what I heard.

 

[S Davis]

I hear you I have seen some stuff you would not believe, including deaths by carbon monoxide from people not doing their jobs.

 

[JohnEBoy]

That there R290 sounds good but I haven't seen it said that it can be reversing for cooling. I also wonder how it compares efficiency wise to CO2 (same question about reversing).
Any insite?

John

 

[Zwy]

That there R290 sounds good but I haven't seen it said that it can be reversing for cooling.

No different than any other heat pump.

I also wonder how it compares efficiency wise to CO2 (same question about reversing).
Any insite?

John

R290 is very efficient, way more efficient than CO2 (R744) which tends to suffer at higher temps.

I was involved with some of the feedback discussions back a few years when the Section 609 for MVAC systems had proposals for a new refrigerant to replace R134a. At the time the main proposal was R152a and not R1234yf and some like Mercedes wanted CO2. The issue was high flammability with R152a and with MVAC there is some difficulty in designing something along the monoblock design mentioned in the original post. Any of the very flammable refrigerants are extremely efficient due to low vapor pressure.

If you are interested in reading more about R290 and R744, here is a pair of articles on the subject.

Fun With Hydrocarbons

I was going to call this post "Playing With Fire" but didn't for obvious reasons. Anyways, in my last post we saw how CO2 (R744) can be used in both a traditional sub-critical as well as in trans-critical cycles which operate almost backwards to each other.

www.linkedin.com

Subcooling Part I

Subcooling is defined as the process of cooling something below it's saturation temperature. Hot water out of the tap at 140F is subcooled 212-140 = 72 degrees.

www.linkedin.com

 

[JohnEBoy]

No different than any other heat pump.

R290 is very efficient, way more efficient than CO2 (R744) which tends to suffer at higher temps.

I was involved with some of the feedback discussions back a few years when the Section 609 for MVAC systems had proposals for a new refrigerant to replace R134a. At the time the main proposal was R152a and not R1234yf and some like Mercedes wanted CO2. The issue was high flammability with R152a and with MVAC there is some difficulty in designing something along the monoblock design mentioned in the original post. Any of the very flammable refrigerants are extremely efficient due to low vapor pressure.

If you are interested in reading more about R290 and R744, here is a pair of articles on the subject.

Fun With Hydrocarbons

I was going to call this post "Playing With Fire" but didn't for obvious reasons. Anyways, in my last post we saw how CO2 (R744) can be used in both a traditional sub-critical as well as in trans-critical cycles which operate almost backwards to each other.

www.linkedin.com

Subcooling Part I

Subcooling is defined as the process of cooling something below it's saturation temperature. Hot water out of the tap at 140F is subcooled 212-140 = 72 degrees.

www.linkedin.com

Thanks Mr. Wizard,
I'll review articles. But if they don't mention it...
Do you have knowledge of commercially available home reversing monoblock units even if European or???

John

 

[timselectric]

I don't know why any manufacturer would only build a cooling only unit these days.
Losing half of your sales over $10 worth of parts is not a good business model.

 

[Zwy]

Thanks Mr. Wizard,
I'll review articles. But if they don't mention it...
Do you have knowledge of commercially available home reversing monoblock units even if European or???

As for R290 units, can't say, I haven't approached that part of my 2 year project.

Any monoblock unit will require a buffer tank for heating/cooling. When cooling the tank is chilled and the chilled water will run thru an air handler or fan coil. Heating can be be radiant or thru the air handler however a high temp emitter such as an air handler will require higher buffer tank temperature than radiant when used for heating. For best efficiency, the lower temp emitters are preferred for heating purposes. Radiant cooling would not work here due to high summer time humidity and the floors would sweat.

My 2 year plan or longer, is to use an air to water heat pump to heat/cool thermal storage using PV energy to power the heat pump. The thermal storage can carry us thru times of lean PV power. Just another battery but in a different form. During extremely cold weather, the thermal storage will be heated by a gasification wood boiler. For air conditioning, I'll probably still rely on the mini split heat pumps already installed which we do use for some heating spring and fall now. I prefer options.

 

[ruralsolar]

As for R290 units, can't say, I haven't approached that part of my 2 year project.

Any monoblock unit will require a buffer tank for heating/cooling. When cooling the tank is chilled and the chilled water will run thru an air handler or fan coil. Heating can be be radiant or thru the air handler however a high temp emitter such as an air handler will require higher buffer tank temperature than radiant when used for heating. For best efficiency, the lower temp emitters are preferred for heating purposes. Radiant cooling would not work here due to high summer time humidity and the floors would sweat.

My 2 year plan or longer, is to use an air to water heat pump to heat/cool thermal storage using PV energy to power the heat pump. The thermal storage can carry us thru times of lean PV power. Just another battery but in a different form. During extremely cold weather, the thermal storage will be heated by a gasification wood boiler. For air conditioning, I'll probably still rely on the mini split heat pumps already installed which we do use for some heating spring and fall now. I prefer options.

Lookup john siegenthaler, he's been pushing low temp hydronics for decades, lot of webinars on YouTube.

You can go no buffer tank but the system needs to be sized exactly for the space with a J-Load calculation. I do not have a buffer tank for my setup, cooling or heating each zone allows for the heat pump to run at it's minimum output, bufferless is ONLY possible with inverter based system (not aware of a A2W that is not inverter...).

I chill my basement floor slab in summer, to avoid the condensation thing, I have a floor slab temp sensor and only bring the floor down to 64F. Chances of that condensating are beyond slim inside the home.

 

[ruralsolar]

Ran across this video this morning and I know R290 has been mentioned a few times in the forums by our friends overseas in Europe. I do think ground source may just be on the way out using R290 monoblock air to water heat pumps with some thermal storage/buffer tanks. My eventual plan with the gasification wood boiler is to also add an air to water heat pump for part of the heating season or dump load.

Ground source in the northern states will always be an option if someone has the funding to do so. Air Source works well but the ground argument will always win since it's 50ish down there all the time. I went air source since the number of days where a air source heat pump wouldn't keep up are so few and far between, I'll "save" money by using a 3kw resistive heater on those cold nights/days versus the amount I would have spent on ground loops.