Apologies for my lack of technical knowledge but this question arises from one asked on alt.hvac regarding the Danfoss 12/24volt compressors BD35 running on R134a.

These comps use capillary lines for off cycle equalization and the compressor can be speed changed in 500rpm steps from 2000rpm to 3500rpm.

My knowledge of speed/pressure square laws provide me with some thoughts on what might happen to the suction and discharge pressures but my understanding of the effects on refrigerants is incomplete.

If the machine is set up to provide a -15°C evaporating pressure at 2000rpm but we needed a quick pull down would the pressures changes cause much effect on the evaporator temperature or will the increased gas flow counteract these?

The scenario I am thinking about is using one of these comps for a vehicle based cold box which could be 'fast' cooled before use.