Abstract: Ground source heat pump technology is an air conditioning, heating and hot water supply technology. This paper introduces the popularization and application of ground source heat pump technology in foreign countries. According to the actual situation in our country, this paper analyzes the development advantages of this technology in our country in terms of initial investment, energy, environmental protection and national policies, To the problem, pointed out that the technology in our country has broad application prospects. Keywords: ground source heat pump air conditioning energy saving 1 Introduction Heat pump, just as the water pump can raise the low water to high as the heat can be sent from the low temperature end to the high temperature end. It is a machine that can convert functions between the evaporator and the condenser, essentially another form of refrigerator. Ground Source Heat Pumps (GSHPs) are technologies that use the earth as a heat source to provide air conditioning, heating and hot water supply to buildings. It is well-known that strata maintain a relatively stable temperature for all seasons of the year. In summer, the temperature in the ground is lower than the temperature in the ground and higher in winter than in the ground. Ground source heat pump is the use of this feature of the earth, through underground heat exchangers, exchange heat with soil or rock. Ground source heat pump operating conditions throughout the year stable, without the need for other auxiliary heat and cooling equipment to achieve winter heating, summer cooling. In winter, the liquid in the pipeline draws underground heat and is then directed into the building through the system while storing cold for future use. In the summer, heat is drawn from the building and discharged into the ground through the system Save heat for winter use. Fan system will be sent to the heating and cooling air inside the various sections of the building, similar to the general air-conditioning system. Ground-source heat pumps can reliably provide high-quality warm air all year round, creating a very comfortable indoor environment for us. Ground source heat pump system can be divided according to their cycle form: closed cycle system, open cycle system and mixed cycle system. For closed-cycle systems, most of the underground heat exchangers are closed-loop, the use of high-density polyethylene pipe pipe. Pipes can be buried 150-200 feet underground through vertical wells or 4-6 feet underground, or at the bottom of the pond. In winter, the fluid in the tube extracts heat from the ground and into the building, while in the summer, heat from the building is sent underground to the ground. For open-loop systems, the water in the pipeline comes from lakes, After the water is exchanged with the building in the same way as a closed cycle, the water is returned to its original location or discharged to another suitable location. For a mixed cycle system, the underground heat exchanger is typically heated by heat The load is calculated as summer extra cooling load is provided by the conventional cooling tower. Ground source heat pump technology is currently widely used abroad. According to the U.S. ground-source heat pump system, according to the United States, about 40,000 sets of ground-source heat pumps are installed each year in the United States. At present, some ground-source heat pumps are used in homes, banks, hospitals, airports, chain travelers, supermarkets, office buildings and schools in the United States. System, this speed means that each year can save 8.79 × 1011 watts of energy, while reducing 1.5 million tons of greenhouse gas emissions each year. In recent years, the United States has conducted a great deal of promotion of ground-source heat pumps. The U.S. government has also fully affirmed the potential of ground-source heat pumps and encouraged the use of such air-conditioning technologies with low life cycle costs and low greenhouse gas emissions. The US EPA considers the efficiency of ground-source heat pumps to be at the forefront of heating and cooling equipment. The U.S. Department of Energy and the Environmental Protection Agency have started to jointly set up a ground-source heat pump center, raising more than $ 100 million to fund research projects and market development. At present, there are dozens of geothermal heat pumps in the United States. Although there are a number of research institutions in China that have studied some of the technical performance of ground-source heat pump technology and some of the actual projects completed by foreign companies, people in China are still unfamiliar with this technology. This technology is suitable for the actual situation in China, the development of what exactly? This is a very worthwhile question to discuss. Therefore, while studying and accumulating relevant data on the ground source heat pump technology, it is necessary to systematically study and analyze the technical and economic feasibility of the technology applied in China. 2 The development of ground source heat pump technology and its advantages Ground source heat pump is actually a very old technology, there are applications in the forties, only the development of related technologies in the past five years to make it rapidly commercialized. The name of the ground-source heat pump first appeared in a patent document in Switzerland in 1912. The first climax of the use of ground-source heat pumps appeared in Europe in the 1950s. During this period, Ingersoll and Plass put forward the theory of heat source for underground buried heat exchangers according to Kelvin source concept, but at the time they were not widely used because of low energy prices and high system cost. In the 1970s, the oil crisis focused attention on energy conservation and efficient use of energy, culminating in the development of ground-source heat pumps. At this time, the underground pipe was changed from an early one to a plastic pipe. During this period, many ground-level heat pumps were built in Europe, but they are mainly used for heating in winter. Since the early 1980s, the United States and Canada have carried out research on the ground-source heat pump system for heating and cooling. Quite a few reports on the heat transfer process and models of different types of underground heat exchangers for ground-source heat pumps have been carried out. Some of the projects are under operation Summary and performance comparison. Both DOE and EPA have confirmed that GSHP is the most efficient and environmentally friendly hot water, heating and cooling system available today. On the one hand, it makes use of the relatively stable temperature of underground soil or rock so that the heating and air-conditioning system can maintain efficient operation throughout the year, saving 20-50% of the electricity cost for ground source heat pump users. On the other hand, under the same conditions, The building of the source heat pump system can reduce maintenance costs. Ground-source heat pumps are very durable and have very few mechanical moving parts. All parts are either buried underground or installed indoors, avoiding the harsh outdoor conditions. The underground part is guaranteed for 50 years and the aerial part for 30 years. Therefore, ground-source heat pump is maintenance-free air conditioning, saving maintenance costs, enabling users to invest about three years to recover. Investigations into air-conditioning system maintenance costs were carried out in two places, Lincoln City and Nebraska, and 20 schools. The 20 schools have adopted four different cooling modes: ground-source heat pump system (GHP), air cooler with hot water boiler (ACC / GHWB), water cooler with hot water boiler (WCC / GHWB ), Water cooler with steam boiler (WCC / GSB). Surveys show that the cost of operating a GSHP system is relatively low compared to other air conditioning systems. More importantly, the refrigerant used in ground-source heat pump systems is injected into the plant and completely sealed without any leakage during use, eliminating the need for refrigerant to be replenished by the user at all times, thereby reducing the damage to the ozone layer. The system can be used on different structures, residential buildings of different sizes, can be installed in the new construction, can also be used for the transformation of the old building, its design flexibility makes it a very attractive air-conditioning options. Ground-source heat pumps have particular advantages in dehumidification and are therefore well-suited for hot and humid summer conditions. If an air conditioner is added to the air distribution unit, the ground source heat pump will be more prominent at this point. Therefore, To achieve indoor air quality standards, ground source heat pump system is also a very good choice. Ground source heat pump is just above the advantages of government offices, apartments and restaurants and so on. According to a user survey conducted by Civil America's electricity company in the state of Oklahoma in the Red River valley: 99% of users of ground-source heat pump air-conditioners beat their cooling capacity by more than 8 points in the summer to score 1 to 10 points, 73% of users hit the full score of 10 points. 3 The development of ground source heat pump technology in China 3.1 Less initial investment costs With the continuous deepening of reform and opening up, people's living standards continue to rise, sustained high-speed economic growth led to the pursuit of comfortable living, so that the ground source heat pump this The new technology has huge market potential in China. At the same time, we must also note that there is an acceleration in the pace of urban construction in our country. Each year, 240 million m2 of new residential buildings are made in cities and towns. The cost of incorporating a ground-source heat pump system prior to the construction of a new building is far less than the cost of an older building (maybe even lower than a typical air-conditioning system!) This accounts for almost none of our "cold" and "cold" heating For countries that make up 70% of their land area and 50% of the country's total floor area, the cost savings are enormous. In the United States, due to the relative cheapness of energy (similar to that of China) and the high labor cost, the installation cost of a typical household is about $ 3,000 to $ 5,000. Ground source heat pumps still have strong market competitiveness. However, due to the low labor cost in our country, compared with the developed countries in the west, the cost of infrastructure in our country is low. Infrastructure costs are the most important cost increases for ground-source heat pumps. Thus, compared with developed countries in other countries, initial investment in China is relatively less. 3.2 can improve the quality of urban environment With the improvement of people's living standards, the quality of life is getting higher and higher, environmental awareness increased, people began to realize that high-quality air is the guarantee of human health. At present, inhabitants pay more and more attention to air pollution. The impact of cities (including indoor) on people's lives and their bodies has been paid more and more attention. When they encounter physical discomfort, many residents begin to consider the influence of air factors. According to the "Bulletin on the State of China's Environment in 1997," urban air quality in our country is still at a relatively heavy level of pollution. According to statistics, the air quality in the 10 cities with the most serious air pollution in the world is not optimistic. It is now an urgent time to step up air pollution control. At present, China's energy structure has one of the most adverse factors, that is, the proportion of coal in the production and consumption of energy has long accounted for about 70%. Figure 3 is about China's energy consumption structure in 1997. In order to completely rehabilitate the environment and reduce greenhouse gas emissions, our government is planning to change the coal-based energy structure in order to achieve a sustainable development strategy. Cities such as Beijing are considering the issue of substituting electricity for coal to solve urban pollution. Ground-source heat pumps, which sketch heats of 3 to 4 kilowatts for every kilowatt of electricity, will be highly competitive technologies. Since electricity is the only power source of ground-source heat pumps, there is no air pollution caused by fuel-dispersed combustion. At the same time as the manufacturer sealed preparations. The use of the process does not leak, do not add to reduce the damage to stinky layer. Analysis and investigation show that the application of ground source heat pump to the destruction of the ozone layer. Analysis and investigation show that the application of ground source heat pump has played a positive role in reducing the greenhouse effect. Visible, the application of this technology to reduce the greenhouse effect played a positive role. Visible, this technology applied to China will ease the city air pollution problem. 3.3 Able to Reduce Energy Tensions In the new century, with the rapid development of productive forces, people are increasingly realizing that there is an increasingly scarce resource and energy on Earth. The energy shortage in our country is a matter of contention. At the same time, there is a contradiction of low energy rate in our country. According to statistics, China's total energy utilization rate is about 30%, which is only equivalent to the level of the developed countries in the 1950s. China's building energy consumption accounts for about 25% of total energy consumption, of which heating and heating energy