Development Of The Comprehensive Testing Instrument Of Water Source Heat Pump Unit

The environmental pollution and energy crisis have become the foremost endangering human's survival problems, how to settle these problems has been the topic for the whole world. Green building and correspondent air-conditioning system characterized by environmental protection and energy saving come into being.The water source heat pump system is a new central air-conditioning system which satisfies the above requirements.With the gradual rapture and wide use of the water source heat pump technology in recent years, the testing system of water source heat pump unit obviously cannot meet the needs of the production test and quality investigation of water source heat pump unit because of its low intelligence, low efficiency, poor precision, heavy consumption and large size.Based on the deep analysis of water source heat pump principles and actual operations, the thesis proposes a general design of water source heat pump testing system following the energy conservation principle. The instrument adopts two water containers, with one simulates circulating water system of heat source side and the other simulates circulating water system of using side. Only if the water temperature of the two water containers keeps at a certain range, can we test the parameters of the measured water source heat pump unit. However, there are nonlinear and uncertain factors in the water temperature as well as external interference, so the subject puts forward higher requirements on control method. This thesis designs a Fuzzy-PID control method, realizes reasoning and decision-making by fuzzy rules according to practical water temperature and setting temperature, on-line adjusts three parameters of PID controller, and thus controls the water temperature of the two water container.For the hardware, the project adopts Modular design. The touchscreen is used as a human-machine interface for data display and parameter setting of the whole system; PLC is used as the main controller for controls system running, input collection and output module of the system; regulates pump and rotation speed of compressor in frequency conversion unit with inverter to control temperature and flow; adopts industrial control module with standard RS-485 communication interface in data collection of temperature, flow and power energy, and transfers back to PLC to form closed loop control system. All collection, control module and main controller form an overall layout by networking technology. On software, the project also adopted Modular design. It has designed PLC ladder-chart program and touch screen used to human-machine display. Anti-interference measures are also taken to ensure the system steadiness.