Design Of Energy-saving Control System For Modular Air-cooled Heat Pump

Modular air-cooled heat pump system is easy to operate,secure to run and convenient for installation or maintenance.And it is widely used in various public places and different industry areas.Traditional modular air-cooled heat pump systems use constant water temperature and water volume control,load or unload compressor capacity control according to a fixed water temperature set-point,rotate the pump in power frequency,and there is no any data exchange between indoor fan coil units and outdoor chillers.When outdoor ambient temperature or indoor side load changes,system can’t adaptively adjust chilled water temperature or water volume,resulting in high energy consumption and low efficiency of central air conditioning system.According to the characteristics of the modular air-cooled heat pump system,a primary pump variant water volume system is designed,and the differential pressure is used to control the water pump frequency.At the same time this paper designed a control framework for communication network between indoor fan coil units and outdoor chillers,and put forward an energy saving control strategy of variant water temperature set point according to outdoor ambient temperature and indoor side actual load demand.For the modular air-cooled heat pump control system design,this paper describes in detail the outdoor chiller controller design which hardware is based on ARM Cortex M3 processor and software is based on uC/OS-II operating system,as well as the indoor thermostat controller design which hardware and software is based on Microchip PIC16 processor.And Modbus protocol based RS485 communication bus is used for network between indoor thermostat and outdoor chiller.In view of the nonlinearity and hysteresis of variable water temperature control,PID algorithm is proposed based on the BP neural network,at the same time both hysteresis control and sequence control are complementarily to control the compressor capacity load and unload to meet the demand of water temperature set point.For the control of variable frequency regulation of water pump,expert inference machine is used to intelligently switch forward control and PI control,realizing the variant water volume of the primary pump system.Finally,good control effect is obtained from the actual modular air cooled heat pump system testing and verification.