The Design Of Air Source Cold/hot All-in-one Machine Bath On DSP

Air source heat pump water heater system is regarded as one of the best equipment in pioneering use of energy in the world today, It is a new generation of hot water device and equipment after the boiler, gas water heaters, electric water heater and solar water heater. In an increasingly tense in the global energy supply situation, air source heat pump water heater with its high efficiency, energy saving, environmental protection, safety, comfort, and many other advantages, quickly recognised by consumers in the market, and develop into a new industry of energy conservation and environmental protection.This paper design a system of air source cold/hot all-in-one machine bath on DSP. The cold/hot all-in-one machine including three working mode, respectively is hot water mode, frozen water mode, frozen water hot water mode. Hot water model working principle is through the high efficiency compressor doing work, from the quantity of heat of the evaporator absorption by cold media to high temperature water condensation released to the heated in the water, so as to achieve the purpose of hot water. Frozen water model work principle is through the capillary will high temperature and pressure liquid refrigerant into low temperature of low pressure steam liquid mixing cold media, again through the condenser pump will enter into the four-way valve of the frozen water, so as to achieve the purpose of frozen. The frozen water and hot water model work principle that the above two models of the combined action of the results, It is to control the working state of the four-way valve change of refrigerant in the energy transmission path, finally realizes the chilled water automatic switching mode and hot water.The controller of air source cold/hot all-in-one machine is a 32-bit floating-point DSP controller—TMS320F28335, through temperature sensor, water level sensor, phase sequence detection sensors will coil temperature, water temperature, water temperature, water tank, phase sequence detection results, such as input to the DSP microcontroller. The output after ULN2003 AN relay driver module driven compressor, blower, hot water circulating pump, frozen water pump, four-way valve actuators such as orderly, successfully completed air source hot and cold water integrated control task. In the simulation of temperature sensor collected data after AD conversion, the median average filtering algorithm is used to remove the white noise in the process of temperature measurement, improve the accuracy of the temperature detection; In fan coil fin the defrosting process, combining the advantages of the traditional defrosting method designs a four-way valve based on time-temperature defrost method, can make the fan coil finned temperature is not lower than 2 ℃, very good to avoid the coil finned frost phenomenon; Finally by the classic PID control algorithm for air source constant temperature control, When they work in the heating mode, the ability to quickly and stable get ideal water temperature 65℃, when they work in the cooling mode, it can quickly and stable get ideal water temperature 5℃.In addition, the hot and cold water machine has adopted the operation mode of the water closed-circuit circulation, through the circulating pump circulation water homework, make the water storage tank in the water cycle through the heat exchanger, keep the water temperature of the ideal, not as a result of long time stay in the water tank water temperature down or up; through backwater homework for water pumps, and the water of the water pipe the water in the tank to keep dynamic flow characteristics, such not only can avoid the water pipe caused by a static water precipitation jam phenomenon, but also can make the water temperature of the water pipe and water tank in the water temperature, make a switch on the water, the water flowing out of ideal temperature, don’t have to wait.