Eco Cute CO2 heatpump

[desA]

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.

Could you perhaps tell us what your sweet spot is, then? We could use this as a means of comparison. May I suggest, for illustrative purposes, that we base our calculations around CoolPack 1.48?

As you know, the CO2 heat pump can achieve an 80 to 90 F (44.4 to 50 K) 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.

When you say 1.6-2.0 for cooling & a 'little more' for heating, can you please expand on this?

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 (5.6 to 8.9 'C) 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 (-3.3 'C).

Can you select your ideal 'sweet spot' & then compute the COP,r & COP,hp accordingly?

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.

Can you perhaps state your required TD, for these sweet spots?

I'd also like to suggest, in fairness, that others then be allowed the same courteousy of evaluating equivalent HFC, or alternative heat-pump circuits for a true comparison of operating issues, costs, & so forth. This could be an interesting exercise all round.