Energy Saving Optimization Of Heat Pump Distilled Water Machine

Among the industry,medicine industry and our daily life, distilled water has a wide application. The cost of distilled water is very high, the main reason is that during the production of distilled water it will consume a lot of energy. Compared to the traditional electricity heating technology, the heat pump technology is more energy saving and environmental protection, which makes the heat pump distillation technology become an important method for the production of distilled water. So it is very meaningful to optimize the design of the energy saving of the heat pump distilled water machine.In this paper,the evaporators in the frozen water tank,the evaporator and condenser in the exchange tank were designed, the pipe of evaporator in freeze water tank was designed as diameter of 0.008 m,thickness of 0.5 mm, length of 1.32m; the pipe of evaporator in exchange tank was designed as diameter of 12.7 mm, thickness of 1mm, length of 4.6m; the pipe of condenser in exchange tank was designed as diameter of 10.7 mm, thickness of1 mm, length of 0.876m;the key parameter of injection device is the diameter of nozzle, it was designed as 1.2mm.By means of the CFD simulation of the throttling process in the capillary tube, the liquid phase distribution of the refrigerant in the tube was obtained.Through the CFD simulation of capillary refrigerant under the super-cooling degrees of 3℃、6℃、9℃、12℃、15℃ in five different tubes, the conclusion is that the bigger of the super-cooling degree in the capillary inlet, the higher of the liquid phase volume fraction in the capillary outlet,this has an important guiding role in the selection of capillary.Finally, experiments on five types of capillary were carried out, and the results showed that the first capillary(internal diameter×length is 1.7mm×1700mm)was the most suitable for this system. The reason is that although the liquid phase volume fraction of the first capillary outlet is slightly lower, but the exhaust temperature, the return gas temperature,discharge pressure and return gas pressure and energy efficiency is the most suitable, so in summary, the first capillary is the most appropriate model for this system. The exhaust gas temperature, return gas temperature, exhaust gas pressure,return gas pressure of the second kind of capillary are relatively suitable, but considering that its energy efficiency is the lowest, so it is not suitable for this system.The exhaust gas pressure, return gas pressure of the third and forth capillaries are relatively suitable, but their exhaust temperature, return gas temperature are not suitable, and their energy efficiency are in the middle level, so they are not suitable for this system. The exhaust temperature, return gas temperature of the fifth capillary are both not suitable, and its energy efficiency is also very low, so it is not suitable for this system.For this system,when the capillary’s inner diameter is 1.4mm, length is between1300 mm and 1500 mm, and the refrigerant charge is 528 g, the exhaust temperature decreased with the increasing of the capillary’s length,the return gas temperature decreases with the increasing of the capillary’s length, the trends of discharge pressure and return gas pressure maintain consistency, and the energy efficiency of this system reduced with the increasing of the length of the capillary.