This type of control will allow chilled water temperature to climb when less load is present. Table 2 summarizes the effect of reducing head pressure or increasing suction pressure to the COP of the compressor. Utilize heat recovery for absorber concentration. As seen from Table 1, double-effect units have a much higher efficiency. Compressor efficiency depends on the type of compressor being utilized, and will effect the efficiency of engine-driven systems.
Some compressors operate better than others when only partly loaded.
Reciprocating compressors generally operate better when partly loaded while screw compressors operate better under fully-loaded conditions.