Research direction of heat pump

- May 07, 2019 -

The research of < U > heat pump technology needs to be innovated constantly. While achieving the expected results, we need to find a balance between economy and environmental protection and energy saving.

1) The research and development of key equipment, reliable and energy-saving capacity regulation and operation control mode of heat pump units with high efficiency, long life and low cost will further improve the potential and advantages of heat pump in energy-saving effect. At present, in addition to continuing the research on heat transfer enhancement, an important task to be carried out is to study the flow and heat transfer mechanism of refrigerant in plate heat exchanger according to different operating parameters of refrigerant and heat pump. With the continuous expansion of the application scope of heat pump, the development of large and medium heat pump units has become a hot spot.

2) To study the theory and application of heat pump systems with various heat sources, the emphasis should be laid on the theoretical research of ground source heat pump with buried tube heat exchanger. Air source heat pump (ASHP) has been widely used in the field of air conditioning. The performance of ASHP is restricted by seasonal temperature variation of outdoor meteorological conditions. It is difficult for refrigeration capacity and heat generation to adapt to the cooling and heating loads of buildings, and the frosting of outdoor heat exchangers in winter, which limits its application field and scope to a large extent. In general, the groundwater temperature buried in a certain depth of the surface can be maintained around the annual average temperature in this area. From the point of view of thermodynamic cycle analysis, the cycle efficiency of groundwater source heat pump is higher than that of other ground source heat pumps. In recent years, Groundwater Source Heat Pump (GSHP) has received unprecedented attention in China. However, groundwater recharge is a technical problem that has not been effectively solved so far. The environmental geological problems such as waste of groundwater resources, decline of water level and land subsidence caused by over-exploitation of groundwater, and secondary pollution caused by groundwater recharge should be paid enough attention to. For a country with a shortage of water resources, the protection of groundwater resources is an important issue related to sustainable development.

adopts buried ground source heat pump mode. Because the annual soil temperature below a certain depth of the surface is stable and approximately equal to the annual average temperature, it can provide relatively low condensation temperature and higher evaporation temperature in summer and winter respectively, thus achieving better energy-saving effect than air source heat pump, and avoiding the low efficiency of air source heat pump under low temperature conditions. The problem can be applied in a wider range. Secondly, because groundwater is not directly extracted, it can effectively avoid the destruction of groundwater resources, and it is a reasonable way to develop and utilize geothermal resources. Although large heat exchanger area and high investment cost are needed due to the influence of heat exchange rate between fluid and soil in underground buried pipe, ground source heat pump is still recognized as a promising energy-saving device and system at present and in the future, and it is one of the hot topics in the international air-conditioning and refrigeration industry.

p>3) Pay attention to and accelerate the theoretical research and application development of natural refrigerants. When heat pump system is used in building air-conditioning system, higher condensation temperature and larger temperature change are generally required, which is also a major difficulty for synthetic refrigerants to be used in high temperature heat pumps.

In view of the long-term safety of the environment, we should try to avoid the use of non-natural working substances that will always be discharged into the biosphere. Reusing natural working substances is a very safe choice, and may be a choice we have to make. The unique properties of some natural refrigerants used in heat pump field may provide a good opportunity to solve the technical problems of medium and high temperature heat pump. For example, carbon dioxide transcritical cycle, higher compressor exhaust temperature and larger temperature slip of carbon dioxide in gas cooler create favorable conditions for the recovery of exhaust heat. Heat pumps using traditional refrigerants can only get hot water of no more than 55 degrees Celsius, while carbon dioxide heat pump systems can get hot water of 90 degrees Celsius or even higher temperature, so its application scope will be wider.

4) The energy structure of coal-dominated China determines that electricity is not a clean energy source. It is of great significance to study the mode of natural gas driven heat pump in China. As a part of China's energy structure adjustment strategy, China will gradually increase the proportion of natural gas in the energy structure. Natural gas-driven heat pump is an efficient end-use mode of natural gas, and also an air-conditioning cooling and heating source conducive to greenhouse gas subtraction and environmental protection.

上一篇:Development Direction and Prospect of Drying Industry in China 下一篇:没有了

Related News

Related Products