Quote Originally Posted by coldwine View Post
Mf, for the condition you describe, rather low COP as out of the sweet spot for these units with a low TD on hot side. As you know, the CO2 heat pump can achieve an 80 to 90 F rise across the gas cooler in only one pass, so the lower the TD, the lower the performance. We might get 1.6 to 2.0 for cooling and a little more for heating depending on flow rates at those conditions. In addition, the cold side temperatures you gave are also out of the sweet spot a little, best performance at heat recovery temperatures down to chilled water temperatures at 42 to 48 F or so. In our wineries here, we usually operate at these temperatures most of the year, then for a short time for cold stabilization, we go down to those lower temperatures of 26 F.
At higher cold side temperatures and with a large TD across hot side, these units really can achieve high COP's up to 7 or more and this has been field proven.
Please remember to all that these units are really designed to address replacment issues with boilers and other polluting fuel burning devices, and not take the place of other heat pump systems, products etc...In California, tighter regulations are being placed (for some good cause too) on gas buring devices such as old boilers, electric water heaters etc...as well as a new Refrigerant Management plan just now adopted requiring much stricter reporting and record keeping of HCFC, HFC etc... based refrigerants. There is also a lot of solar PV here, so many interested in "offgrid" central systems, so electric heat pumps fit well for those. This product is only one solution, but it is available to address these needs. We find it best to not wait for another man made chemical refrigerant to "replace" the existing systems and be a cure all. We have been doing that for long enough and it is time to put the HVACR platform to front and center, to show how an Industry can work together and really make a fast and forward thinking solution to energy issues. Whether one believes in Global Warming or not, it is a fact that we cannot go on polluting the environment and creating new gases and chemicals, when we already have the best refrigerants available known to man kind, ammonia, CO2, water, air and nitrogen. Let's all move forward!
Thank you for reply and giving the correct honest answers. Of course i knew what the answers would be (but was hoping to be suprised), but is a fairly typical of many sitiuations, down here.
As an engineer ???????????, I some times get frustrated by sales techniquies, where client expectations can not reached, which in the long term damages the industry not improves it. Most of us know very little about industries that we are not associated with, we tend to us major bullet points given by experts to help our decision making process.
In your original comments you stated upto 194F (in most minds that means 194F) using both heating and cooling for maximium COP (8 stated earlier by others). As a uniformed client I would expect close to these results (or do i give not enough cridit to clients) For this reason did i start with a negative comment. "why bother"
I have had a look at your web site, "very nice",
In these feilds, fundementals do not change, tweeks can be made, to increase performance, the art is in application.