COP and Superheat - does is it help?

[desA]

RefSim feedback

This process simulator allows a designer to tweak various system parameters & see how others change. I've found it very useful over the years.

RefSim package relies on the evap program DXC, which fixes SH at a normative value of 7.5K. It cannot be adjusted further.

There is no way to adjust suction line heat addition, or removal. I was hoping to coerce RefSim via this route. Didn't work.

RefSim can export to a Mollier chart program, with a snapshot of the last system balance. In Mollier, the SH can be adjusted, See an earlier reference in post #77. The problem with this is that Mollier takes, as given, the values of Te,sat / Tc,sat / SH / SC - it does not re-balance via RefSim to compute the new system balance point - if SH varied within Mollier itself.

Basically, I expect Te,sat to lower as SH is raised off a fixed operating condition. For the condenser, I expect the increased SH to raise Tcomp,disch. For single condenser, this would then take up a little more of the condenser surface area with de-superheating, displacing some condensing area. With reduced condensing area, Tc,sat would also rise a little to compensate. This assumes that the reduction in refrigerant mass-flow around the system (with increased SH achieved by throttling TXV a tad), does not auto-compensate in the condenser, so re-balancing available condensing area.

Haven't thought through the compressor efficiency implications yet.

So, if my logic is correct, with unchanged compressor efficiency, a rise in SH leads to Te,sat reduction / Tc,sat rise / COP reduction. (Please holler folks if I'm missed something obvious).

COP reduction can be compensated for in the condenser by oversizing the surface area, forcing a reduction in Tc,sat. Alternatively, use a de-superheater/condenser combination.

These logic twists, assumptions & guessing, is why I honestly advocate performing some runs on a real system.