Abstract: This paper discusses the current trends in air conditioning systems and the practical application of ground source heat pump systems, detailing their performance characteristics and working principles. Ground source heat pump is a broad term encompassing systems that use soil, groundwater, and surface water as heat and cold sources. It utilizes the relatively stable soil temperature, relying on a small amount of electricity to drive a compressor. Heat exchange occurs through a closed-loop pipeline system buried deep in the soil, releasing heat to the ground in summer and absorbing heat from the ground in winter to meet cooling or heating requirements. It boasts advantages such as energy saving, high efficiency, and environmental friendliness unmatched by traditional air conditioning systems. Ground source heat pumps are gaining increasing acceptance. Keywords: Ground source heat pump; Air conditioning; Cooling; Heating I. Characteristics of Ground Source Heat Pump Systems 1. Energy Saving and High Efficiency When providing 100 units of energy, 70% of the energy in a ground source heat pump system comes from the soil, and 30% comes from electricity. The electricity consumption is mainly used for the compressor's work and to operate the air conditioning system, essentially "transferring" heat from the soil to the room. It saves more than two-thirds of the electricity compared to electric boilers and more than half the energy compared to fuel boilers. Because the soil temperature is relatively stable throughout the year, generally between 10℃ and 20℃, its cooling and heating coefficients can reach 3.5-4.7, which is more than 40% higher in energy efficiency than traditional air source heat pumps. 2. Environmentally friendly and pollution-free: The pollutant emissions of ground source heat pumps are reduced by more than 40% compared to air source heat pumps and by more than 70% compared to electric heating. The energy saving and emission reduction will be even more significant when combined with other energy-saving measures. Although it also uses refrigerant, it requires 25% less refrigerant than conventional air conditioning units. It is a self-contained system, meaning the device can be pre-assembled and sealed in the factory workshop, thus greatly reducing the chance of refrigerant leakage. The operation of this device is pollution-free and can be built in residential areas. 3. Renewable energy utilization technology: Ground source heat pumps utilize shallow geothermal resources (usually less than 400 meters deep) as a heat source and cold source for energy conversion in heating and air conditioning systems. The shallow Earth's surface is a giant solar collector, gathering 47% of the sun's energy, more than 500 times the energy used by humans annually. It is not limited by location or resources, truly abundant and ubiquitous. This nearly limitless renewable energy stored in the shallow Earth's surface makes geothermal energy a form of clean renewable energy. 4. Low operating costs: The high efficiency and energy-saving characteristics of the earth-gas type ground source heat pump system determine its low operating costs, saving 30%-70% more energy than other heating and cooling equipment. It has a service life of over 25 years, with depreciation and maintenance costs significantly lower than traditional air conditioning. 5. Flexible application, safe and reliable, and wide range of uses: Highly flexible, it can be used in new construction projects or expansion and renovation projects. Construction can be carried out in phases, and the heat pump unit can be flexibly installed anywhere, saving space. There are no hygiene and safety hazards associated with coal or oil storage tanks. Applicable from frigid to tropical regions. It can provide dual-purpose air conditioning systems for heating and cooling in various buildings, while also providing domestic hot water. II. Working Principle of Heat Pumps 1. 1. Cooling Principle: In cooling mode, the compressor in the ground source heat pump unit performs work on the refrigerant, causing it to circulate through a vapor-liquid conversion process. The evaporation of the refrigerant in the refrigerant/air heat exchanger absorbs heat carried by the circulating indoor air into the refrigerant. Simultaneously, the refrigerant condenses in the refrigerant/water heat exchanger, and the heat carried by the refrigerant is absorbed by the water circulation, ultimately transferring it to groundwater or soil. During this continuous transfer of heat from the indoor environment to the ground, the refrigerant-air heat exchanger supplies cooling to the room in the form of cool air below 13°C. 2. Heating Principle: In heating mode, the compressor in the ground source heat pump unit performs work on the refrigerant and reverses the refrigerant flow direction through a four-way valve. Heat is absorbed from the groundwater or soil through the underground water circulation. The evaporation of the refrigerant in the refrigerant/water heat exchanger absorbs heat from the water circulation into the refrigerant. Simultaneously, the refrigerant condenses in the refrigerant/air heat exchanger, and the heat carried by the refrigerant is absorbed by the air circulation. During the process of heat continuously transferring from the ground to the room, it provides heating to the room in the form of hot air above 35°C. [b]III. Working Principle of Ground Source Heat Pump System[/b] Ground source heat pump is a heat pump air conditioning technology that uses soil/groundwater as a low-temperature heat source. Its principle is to rely on a small amount of electricity to drive the compressor to complete the refrigeration cycle. Taking advantage of the relatively stable soil temperature (not affected by external climate changes), heat exchange is carried out through a closed-loop pipeline system buried deep in the soil. In summer, heat is released to the ground, and in winter, heat is absorbed from the ground, thereby achieving the requirements of cooling or heating. Due to the special heat exchange method adopted by the system, it has the advantages of high efficiency and energy saving that traditional air conditioning systems cannot match. Geothermal energy is an inexhaustible resource. Many suburban homes or other buildings are surrounded by a huge "reservoir" of low-temperature geothermal energy, which is replenished by the sun and the earth. Compared with ordinary systems, geothermal technology can save you 30% to 60% on your monthly expenses. Geothermal is the safest, cleanest, and most reliable air conditioning system you can buy. The basic geothermal resources are mainly the following four types: 1. 1. When there is ample usable space around the building, a horizontal loop can be considered. The pipeline is laid in a trench, ranging from 30 to 120 meters in length depending on the site length. 2. When the area around the building is limited, a vertical loop is the ideal choice. Deep holes of 22 to 90 meters can be drilled using drilling equipment, and then the pipeline is laid vertically. 3. When there is a pond, lake, or ocean of a certain depth near the building, construction and operating costs are very economical. The pipeline is simply laid at the bottom of the pond or lake. 4. An open-loop system uses groundwater as a direct energy source. Ideally, the open-loop system is the most economical geothermal system. IV. Application of Ground Source Heat Pump Systems The first surge in research on ground source heat pumps began in Europe and the United States in the 1950s. Until the 1970s, the global oil crisis led to increased attention to energy conservation and efficient energy use, and the widespread application of ground source heat pumps rapidly expanded. In my country, research on ground source heat pumps began in the 1980s. In the last five years, this technology has become a hot research topic in the domestic building energy conservation and HVAC industry, and has begun to be widely applied in engineering practice. Currently, resource utilization in isolated island areas is still generally extensive, with economic development heavily reliant on resources. The contradiction between resource shortages and rapid economic development is becoming increasingly prominent. With rising employee incomes and increased environmental awareness, the demand for quality of life is also rising, leading to a gradual shift towards green and environmentally friendly practices. During winter heating, most isolated island areas rely on hydronic heating, consuming a large amount of coal resources annually. From the perspective of resource conservation and sustainable development, the pollution-free and energy-saving "green heating"—ground source heat pump technology—is gradually replacing the traditional "smoke-filled" heating methods and entering people's daily lives. Since 2003, isolated island areas have begun piloting ground source heat pump central air conditioning systems in some residential communities. Due to its significant advantages over traditional air conditioning in terms of investment economy, energy efficiency, and land area, it has developed rapidly. In addition, the gas pipeline team of the Shengli Oilfield's isolated island oil production plant has also piloted ground source heat pump central air conditioning systems. While the construction cost of ground source heat pump heating projects is higher than that of general projects, they are more economical in daily life. They not only conserve resources but, more importantly, are environmentally friendly, meeting people's demands for a high-quality life. They can also increase indoor space while improving heating quality. The Gudao Furong Geothermal Station, which began operation in the winter of 2003, is an example. It is estimated that after switching to geothermal heating, the Furong residential area alone saved 8 tons of crude oil consumption per day, saving over 1 million yuan per heating season. Currently, resource recycling, energy conservation, green development, and environmental protection have been placed at the core of national economic development. The Ministry of Construction has proposed that all regions focus on six key areas in renewable energy utilization in the construction sector, the second of which is the promotion and application of ground source heat pumps and water source heat pumps in buildings. The focus of resource conservation work has been identified as improving resource utilization efficiency, emphasizing energy conservation, land conservation, water conservation, material conservation, developing a circular economy, and vigorously promoting the application of renewable energy in buildings. Ground source heat pump technology will be increasingly applied in various projects.