AN OPTIMIZED CONTROL METHOD FOR SECONDARY PUMPS IN HVACSYSTEMS

摘要

The energy consumption of pumps makes up a largeproportion of the total energy consumption in HVACsystems. Recently, the reduction of energyconsumption has been accomplished by controllingthe rotation speed of motors of secondary pumps.The rotation speed of motors is usually controlled bythe pressure in the pipes. A popular method by whichto achieve this control is to maintain constant thesupply water pressure at the outlet of the pumps soas to ensure the flow rates for air conditioners.However, the energy savings is small for this methodbecause the pressure must be maintained too high inthe case of a low flow rate, which occurs at a lowheat load. In the present study, a method to controlmotors assuming a relationship between theresistance of the pipe and the flow rate is proposedand verified. However, chilled and hot water flowrates can be decreased as a result of insufficientpressure being set by the controllers. Consequently,indoor air conditions will deteriorate. Experiments toverify the characteristics of pumps and pipingsystems were conducted at the HVAC experimentalfacility at Chubu University. The energyconsumption for constant pressure control wasexamined.