Hybrid thermal-photovoltaics water distillation equipment design and its thermodynamic analysis

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With the rapid development of social economy, the worldwide shortage of water resources is becoming increasingly prominent, especially in the coastal countries and regions of high population density areas. Market demand is driving the development of sea water desalination technology to the direction of large scale, high efficiency, low energy consumption and low cost. The paper uses solar radiation heat — photovoltaic integrated energy, a seawater desalination device was designed based on the two stage heating and cooling system, the water is heated by two stages, by the solar collector and the photovoltaic electric heater respectively, then the condensing heat exchanger is used to process the saturated vapor condensation obtained by two stage heating to obtain fresh water. With the method of thermodynamic energy balance and energy-level balance analysis, the energy efficiency and related parameter variation characteristics are respectively analysis based on energy saving and energy level matching. By calculating the heat loss (heat transfer, heat convection and heat radiation) of seawater desalination device, the optimization equation for calculating the middle control temperature between solar collector and photovoltaic electric heater is established. And, the interactional relationship among initial temperature, middle temperature and system energy level difference is analyzed The results show that the energy level difference of single PV electric heating is maximum, when the energy gap of thermal and PV combined seawater distillation is small relatively, meaning that the energy utilization is more reasonable for high energy efficiency; the relationship among environment temperature, middle temperature and energy level difference is nonlinear; the energy level difference reaches the lowest point 0.18, when the initial environment temperature is 28 Ό and the middle temperature is controlled at 55.4°C.