Heat pumps enter the renewable resources industry

Heat pump technology as an important energy-saving emission reduction technology, the market prospects are very broad. More and more countries and government enterprises are aware of the energy saving and environmental benefits that heat pumps can bring. Market data also shows that the future development trend is good. Nowadays, as the low heat source of renewable energy makes the heat pump system greatly affected by its changes, according to the actual conditions of different countries and regions, using composite heat pump technology can achieve better energy saving and environmental protection effects. It is precisely because of this that various countries and regions have different ground-source heat pump technologies due to different actual conditions, and they have studied from the aspects of heat exchangers and heat pump units to system control optimization. It is worth mentioning that the application of various heat pump types in different buildings and optimization research is also one of the focuses of heat pump technology research.

At the "2011 National Heat Pump Annual Meeting and Technical Innovation and Industry Development High-level Forum", Mr. Xu Wei, Chairman of the National HVAC Society, introduced the 10th IEA Heat Pump Conference and analyzed and summarized the IEA meeting. The keynote speech was "International Heat Pump Technology Development".

According to reports, the IEA heat pump conference is the world's top heat pump conference. The conference is mainly based on technical exchanges and covers academic, business, management, and engineering aspects of the industry. Relevant data show that the 10th IEA Heat Pump Conference in Europe and Japan still has more research on heat pump technology. In terms of collecting articles, the total number of records collected in the previous session increased by 16%. This undoubtedly indicates that heat pump research has been active in recent years. When talking about the article collection of the 10th IEA Heat Pump Conference, Xu Wei pointed out that “The domestic papers mainly involve technology development, ground source heat pump, and heat pump applications in terms of technology. The number of articles collected is ranked second, involving The most common are systems and devices, followed by ground-source heat pumps and air-source heat pumps again. It can be said that heat pump research in China has continued to expand in recent years and is on the rise.

In recent years, the installed capacity of heat pumps in all countries is on the rise. The rise in heat pump sales and installed capacity is related to the current pressure on energy prices and greenhouse gas emission reductions in various countries. At the same time as the quantity is increased, research on the improvement of the energy efficiency of heat pump units in various countries is also continuously strengthened. At the annual meeting, Xu Wei conducted a specific analysis of the policies and market development trends of heat pumps in various countries, and explained in detail the status of heat pump technology and applications.

Xu Wei pointed out in his analysis that ground-source heat pumps account for a significant proportion of this high-latitude cold region in Canada.

Therefore, the study of ground source heat pump technology is particularly important. Through corresponding research on ground-source heat pumps used in single-family houses, the results show that there is a gap between the theoretical calculation of COP and the actual test SCOP. The measured COP is about 15% lower than the theoretical calculation. Canada also conducted thermal response experiments on 31 project sites in the Toronto area, and obtained the range of thermal properties across the Toronto area. It also demonstrated that groundwater can increase the heat transfer coefficient and reduce the thermal resistance. This shows that both the development of technology and the development of the market have achieved certain results.

At the annual meeting, Dean Xu Wei analyzed the development of the ground-source heat pump industry in Sweden. He pointed out that Sweden's heat pump technology is at the leading level in Northern Europe. The Heat Pump Committee Secretariat hangs on the Swedish National Testing Institute. Different from our country, their heat pump classification methods are not classified by air source and ground source, but are related to the way of heat pump units, and Sweden does not do backfilling. Xu Wei also pointed out in the report that in terms of technology research, Sweden's data for vertical buried heat exchangers, the system operation coefficient SPF of new heat exchangers and ground source heat pump systems, and the application of ground source heat pump systems in different types of buildings, The application of new refrigerants in heat pumps, the application of heat pumps in low-energy buildings and the evaluation of performance coefficients of heat pump systems have carried out in-depth research.

In his report, Xu Wei highlighted Japan as the host country of the 2011 heat pump meeting. Japan is at the world's leading level in heat pump technology, and technological research has also achieved outstanding results. According to statistics, RAC's revenue value rose from 3.5 in 1997 to 6.8 in 2010, an alarming rate of increase. Xu Wei also introduced Japan's heat pump technology. He said that Japan has conducted research on ground-source heat pump systems in conjunction with solar, air, and storage tanks. Based on the actual operational data of the study of the pile-based short-term energy storage ground source heat pump system, the results show that the daytime cooling and nighttime domestic hot water operation mode can make the ground source heat pump system achieve better efficiency. The groundwater source heat pump that uses the energy storage of the underground aquifer was studied. The test results were used to evaluate the changes in the soil temperature field since the ground source heat pump system was operated. For the multi-source heat pump system, solar energy, soil energy, and air source are used as the low heat source of the heat pump. Compared with the traditional heat pump, the power consumption can be reduced by 44% in summer and 39% in winter. In selecting refrigerant substitution schemes, developed and developing countries should select different refrigerant substitution schemes according to different regions and different application conditions. While analyzing the theoretical and practical application research problems of changing the refrigerant flow heat pump system, Xu Wei stated that using an algorithm that reduces the energy consumption of the refrigerant flow system can make the system have a higher COP. Japan is also in the process of vertically burying heat exchanger data and new heat exchangers, composite heat pump systems, new refrigerants in heat pumps, absorption heat pumps, heat pumps in industrial applications, and heat pump systems to evaluate performance coefficients. Significant results have been achieved in the study.

Xu Wei analyzed China's development situation, said that when using ground source heat pump systems in different buildings, based on the theory of probability, the TRT test results were statistically analyzed, this method improves the reliability of the results and can provide more effective Design guidance. The effects of simulated soil thermal conductivity, groundwater percolation velocity, vertical drilling parameters and operating strategy on ground source heat pump heat exchange capacity.

It is necessary to simplify the design by studying the linear and nonlinear relationships between various factors.

Talking about the research of compound heat pump systems, Xu Wei said that taking a villa building in Beijing as an example to simulate a ground source heat pump and solar composite system, the simulation results show that when the local heat exchanger is buried, the compound system can significantly improve the system performance. Then, Xu Wei also analyzed the research on the actual measurement of the river water source heat pump. The analysis pointed out that the COP of the river water source heat pump in the Chongqing area is not less than 3.0, and the transmission energy consumption is less than 39%, which has good energy-saving characteristics. In terms of evaluating the performance coefficient of heat pump systems, he told everyone that the long-term operation and performance monitoring of heat pump systems in residential areas aims to obtain the characteristics of reliability, stability, and SPF characteristics during the entire life cycle of heat pump systems through long-term testing.