Refrigeration, air-conditioning and cooling technology - 2007.pdf

PLH_KKK_32_85.QXP 25.05.2007 10:11 Uhr Seite 44C OLD-WATER LOADTemperature controlFlow rate control is not always favourable.The admix circuit can be used for controlleddehumidification and to prevent falling underthe dew point. The feed temperature can beadjusted to the room load and the limits can bekept by measuring the actual value at the criticalpoint of the system. The volume flow in the loadcircuit remains constant.Temperature control with admix valveMThe pump is to be designed according to the capacityand frictional resistances in the load circuit.There should be a differential pressure ofzero on the input side of the control loop. Thiscannot always be achieved in practice, even withcontrolled feeder pumps. For this reason, a differentialpressure controller is to be put in theconnection line of the load circuit without auxiliarypower. In order to retain good load circuitcontrollability and to protect the pump fromdamaging thrust forces, a differential pressure of