| From the current energy situation of our country, the demand of energy is increasing year by year and environmental pollution is becoming serious, energy conservation and emissions reduction has been one of the state policies which is strongly advocated, the equipment with the energy saving draws much attention. In the refrigeration field, evaporative condenser has the advantages of water and energy saving, compared to other condensers its heat transfer effect is much better and widely used, so improve the thermal efficiency of evaporative condenser and energy saving effect are the present research focus. This paper studies the evaporative condenser heat transfer effect and energy saving situation, actual project area for evaporative condenser selection of ideas are carried out, provides the model support and theoretical basis for equipment design optimization and actual operation.Firstly, theoretically analyzes evaporative condenser heat and mass transfer, and heat transfer characteristics, introduces the calculation method of the heat transfer coefficient and temperature drop process of refrigerant, sums up the relationship between the structural parameters and heat transfer coefficients of the evaporative condenser. Appropriately increases spacing can improve heat transfer efficiency. Secondly, through macro CFD simulation establishes three-dimensional physical model of some non-isometric coil, obtains the transient temperature distribution of refrigerant inside tube, heat transfer medium air and water in the process of heat exchange, and can reach the condensation temperature, obtains the north, northeast and northwest areas due to the wet bulb temperature and low ambient temperature good choice countercurrent evaporative condenser energy savings. Through the microscopic molecular dynamics simulation of phase transitions of water on the heat exchanger coil, obtains the time of water turns into steam and the percentage of water turns into vapor, using the formula calculated heat equation can reach the needs condensation temperature, obtains drawn in the north, northeast and northwest area considering the wet bulb temperature, water consumption and water quality and other factors, such counterflow evaporative condenser selection can reduce system power consumption.Finally, through comparing the characteristics of different types of evaporative condenser, on the basis of theoretical analysis and simulation results, proposes the main points of evaporative condenser design and operation, put forward choice principles of evaporative condenser in different regions affected by temperature, humidity and water quality. Combined with a practical engineering, a ranch refrigeration project in Shangzhi of Heilongjiang province, applies the choice principles of evaporative condenser in the project,analyzes the energy conservation and power consumption. Meanwhile, analyzes and concludes problems occurring in practical engineering, puts forward reasonable solution, for the system which demands small refrigerating capacity using the form of box machine, reducing power consumption and running resistance. |
