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Features of ground-source heat pumps: A. Ground-source heat pumps represent a technology for utilizing clean renewable energy. The shallow soil and water layers at the surface of the earth act as large solar collectors, while the thermal energy from deep within the earth also dissipates into the atmosphere through the surface. The total amount of energy consumed by humanity each year is only a tiny fraction of the solar and geothermal energy absorbed and emitted by the Earth’s surface. After surface energy is utilized, it can be quickly balanced by solar energy and heat conducted from deep within the Earth, without causing any adverse effects on the natural energy system. Therefore, shallow surface energy is an inexhaustible reservoir of renewable clean energy. B. It is a highly efficient and energy-saving technology; heat pumps have a relatively high heating efficiency. This is because the heat generated by a heat pump is not primarily heat produced directly through combustion or electric heating, but rather heat transferred from a low-temperature heat source. We can illustrate the high efficiency of heat pumps through the utilization rate of primary energy. We define the energy utilization coefficient of a certain energy device as EE = heating capacity of the device / primary energy consumed. Assuming that the energy consumed by a heat pump is electricity, with an efficiency of 0.35 for power generation and 0.95 for transmission and distribution, then the EE value for a heat pump is: EE = 0.35×0.95×COP (where COP is the coefficient of performance of the heat pump). The COP value required for a heat pump to achieve an EE value equivalent to that of traditional heating methods is as follows: for small boilers, EE = 0.51–0.50; for small boiler rooms, EE = 0.65–0.95; for centralized heating boiler rooms, EE = 0.74–2.23; and for cogeneration systems, EE = 0.88–2.64. It is known that modern high-efficiency heat pumps have a COP of 3.5–4 or higher. Thus, in terms of overall efficiency in utilizing primary energy (coal), heat pumps are even more efficient than cogeneration systems, whose EE value is 0.88; the efficiency of heat pumps in this regard is: EE = 0.35×0.95×4 = 1.33. In other words, when using heat pumps for heating, their efficiency in utilizing primary energy exceeds 100%, reaching 133%. In other words, burning 1 ton of coal can yield the energy equivalent to 1.33 tons of coal. Isn’t this an efficient and energy-saving thermal energy utilization technology? In addition, ground-source heat pumps use soil heat exchangers, groundwater, and surface water as heat sources or sinks. During heating operations in winter, the temperature of groundwater is higher than the ambient temperature, which raises the evaporation temperature of ground-source heat pumps compared to other types such as air-cooled heat pumps. Moreover, since there is no need for defrosting, the energy efficiency improves significantly, by at least 40% ； During summer cooling, due to groundwater, the temperature of surface water is lower than the ambient air temperature; this results in a reduced condensation pressure and less power input required by the compressor, thereby improving the cooling performance significantly compared to air-cooled or cooling tower-based cooling units. Numerous test data show that the resulting improvement in unit efficiency results in energy savings of over 20%. The efficiency of air-cooled heat pumps is much lower compared to ground-source heat pumps. Even the energy consumption ratio of the most energy-efficient air-cooled air conditioners is only 2.8. The lowest energy consumption ratio of ground-source heat pumps for cooling in summer is also above 4. C. Environmental protection: Geothermal heat pumps draw surface water or groundwater, ensuring 100% re-injection of the groundwater; in some cases, no groundwater is drawn at all (using soil heat exchangers), thus causing no damage to the environment. Heat pumps are driven by electricity and do not produce any harmful pollutants in the environment during operation, whereas large-scale thermal power generation already has mature technologies for reducing or controlling pollutant emissions (with even lower pollution levels in the case of hydroelectric or nuclear power). Therefore, ground-source heat pump systems have quite good environmental protection effects. D. Multi-functional operation with stable reliability: Ground-source heat pump systems can be used for heating, cooling, and providing hot water for domestic use. For buildings that require both heating and cooling, a single ground-source heat pump system can meet these needs simultaneously, thereby saving on the costs associated with installing additional facilities as well as reducing the space required by such facilities. Furthermore, the ranges of variation in surface water, groundwater, and shallow ground temperatures are much smaller than those of ambient air temperatures, enabling the geothermal heat pump to operate stably throughout the year. Coupled with the high degree of automation of such heat pump systems, this ensures that geothermal heat pump heating and cooling systems offer greater safety compared to traditional heating and cooling systems. E. Wide range of applications and strong versatility: 1) The vast majority of areas in our country have hot summers and cold winters; ground-source heat pump systems can be used to provide both heating for buildings and cooling for air conditioning. This is especially true for office or commercial buildings, where centralized air conditioning systems are generally required. Using a geothermal heat pump solves both heating and air conditioning problems, achieving two goals at once. There are two additional advantages to using ground-source heat pump systems: they can meet the building’s energy needs by utilizing the surrounding areas (roads, lawns, parking lots, etc.) near the building, thus avoiding an additional burden on already overloaded municipal infrastructure. (Together with centralized heating source networks, etc.) Office buildings require heating and air conditioning during the day, but there is basically no one working at night; therefore, they do not need to pay for heating and air conditioning 24 hours a day, as is the case with ordinary buildings equipped with centralized heating systems. This approach is more flexible and convenient, and it also results in higher energy savings. 2) The share of building energy consumption in total energy consumption is increasing; in developed countries this proportion reaches 40-45%, while in China it has already reached 35%. Since building energy consumption can make use of low-quality energy at lower temperatures, it is most economical and rational to apply ground-source heat pump systems in building heating and air conditioning.