Sanyo is making a CO2 ASHP
 

Might be old news, but it's new to me.. :)

CO2 Water Heater 4.5~9kW - - Ess Aircon

"The Sanyo CO2 hot water heaters offer environmentally friendly and efficient water heating for homes and commercial premises. Now available in 4.5kW and 9kW models, the external air source heat pumps use heat energy recovered from outside to provide highly efficient heating for your water supply. The use of CO2 as a refrigerant enables supply of hot water to the tank up to 65°C.

* Abundantly supply space heating and tap water
* Environmentally friendly with CO2 natural refrigerant
* Low ambient operation down to -20°C
* DC rotary 2 stage compressor
* High reliability
* Expand operation range
* High efficiency C.O.P.s up to 3.8
* Low noise and vibration
"

http://www.essaircon.com/LF307-co2-0...PG&w=550&h=247

is there a price?

It seems like they are in the UK and not over here yet..

Maybe since the USA is so anti-CO2??

I really don't think "anti-CO2" has anything to do with it. It is true that Europeans are much better informed when it come to issues such as global warming. I think it's embarassing to see how many Americans allow themselves to become so dis-informed about an issue of such inescapable importance.

It's much more likely that when corporations have found a sure way to take a large profit, we will see them for sale here.

The price in dollars for their small unit is $9489.491 + VAT. This would supply 15354 BTU/hr.

The price in dollars for their larger unit is $11996.149 + VAT. This would supply 30708 BTU/hr.

Both units have a COP of about 4.

Pretty expensive for a water heater, but pretty reasonable for a hydronic boiler, when you consider that comparing this system to GSHP where COP of 4 is the same, excavation costs are avoided.

Looks like the output temp is 149 degrees F, which is high for a ASHP water heater, but below the low end of the output temperature range of existing fossil fueled boilers.

This would suggest that the standard hydronic radiator deployment would be insufficient, and that more and/or bigger radiators would be needed.

However, hydronic floor heating, especially PEX-in-concrete (AKA: wet systems) would be dandy.

But then a properly designed wet system does the job using lower feed temperature of existing compressors.

Regards,

-AC_Hacker

co2 ashp..
 

So what are the advantages of CO2?

Is it just that it is ozone friendly?

I had heard that there are co2 systems in Japan and I guess this is the first of them to go outside of that market.

But the prices are very high..my two 100m boreholes were only 8000 us dollars. Granted if you haven't got the space for the groundworks then air source is the way ahead.

Any other thoughts?

I'm not sure that a CO2 ASHP would be any more efficient than my Sanyo R410A ASHP..
http://ecorenovator.org/forum/projec...l-project.html

When it was working, the Sanyo was so efficient, I can' believe that there
any ASHP that can be very much better. I'm hoping to get it back on line this month.

The Sanyo 24,000 BTU ASHP might be just as cash efficient as any
off-the-shelf 2 ton GSHP when you factor in total cost over time.


But, perhaps using cheaper CO2 is easier because it's not ruined by exposure to small amounts of air.?.

My guess is, the higher pressures of CO2 means a CO2 HP needs to handle
higher pressures than R410A.. Making the hardware a bit more costly.