Heat pump comressor discharge pressure

[DickRussell]

Maybe someone who actually works with A/C or heat pump equipment can comment on this. Obviously, the compressor must pump the vaporized refrigerant from the evap side up to a pressure such that the equilibrium temperature of the liquid condensed in the condenser is greater than the temperature of whatever fluid is on the sink side of the condenser (air, water). Also, the heat transfer area of the condenser must be adequate to transfer the required duty at the design sink temperature and compressor maximum discharge pressure. Now the question:

When the temperature of the sink is lower than design maximum, does the typical refrigeration compressor type used in A/C simply put out less pressure (drawing less power), resulting in a lower condensation temperature to correspond to the lower sink temperature? In other words, does the compressor follow a pump curve and sort of "ride" on whatever area/temperature conditions are downstream, delivering whatever pressure is needed to match the ability of the condenser to shrink refrigerant volume by condensation?

 

[imok2]

In a word ...yes The lower the fluid temp the lower the head pressure and the lower the power used as long as the evaperator load remains constant

 

[quark]

Yes, imok2 put it nicely. The keyword is constant evaporator load.