【Haichuan Illustrated Chemical Equipment】Series Posts -- Ground-source heat pumps: Working principle, technical classifications, and comprehensive implementation guide
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This post was last edited by HaiChuan LaoYu on 2026-5-2 17:04. Get to know equipment, understand it, and make good use of it. [HaiChuan’s Illustrated Guide to Chemical Equipment] series of posts: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5719196. Everyone is welcome to participate in the discussions. ----------------------------------------------------------- Driven by both the \"dual carbon\" goals and mandatory requirements for energy efficiency in buildings, ground-source heat pumps, as key devices for the efficient utilization of shallow geothermal energy, have become the preferred solution for heating, cooling, and hot water supply in residential buildings, public facilities, and industrial complexes, thanks to their stability, efficiency, low carbon footprint, and multi-functional capabilities. It overcomes the limitations of air-source heat pumps caused by temperature fluctuations, using the earth, groundwater, and surface water as stable heat sources/heat sinks to provide efficient cooling, heating, and hot water supply throughout the year. Based on industry standards and engineering practices, this article provides a comprehensive analysis of the working principles, technical classifications, key advantages, and practical challenges of ground-source heat pumps. It also covers their application in various scenarios, offering professional guidance for project selection and implementation. I. Core working principle of ground-source heat pumps: Ground-source heat pumps operate on the vapor-compression refrigeration cycle; they function as a kind of \"heat transporter\" – transferring heat from underground to indoor spaces in winter, and transferring heat from indoor spaces to underground in summer. Only a small amount of electrical energy is required to drive the compressor, resulting in an energy efficiency that is 3–5 times higher than that of traditional electric heating systems. The complete cycle consists of 5 key steps: geothermal heat is absorbed by underground pipes/wells, which exchange heat with the soil and water bodies; the circulating medium (water or antifreeze) absorbs the stable underground heat energy (around 10-15°C in winter). The low-temperature, low-pressure liquid refrigerant, which absorbs heat during evaporation, enters the evaporator where it absorbs heat from the circulating medium and vaporizes into a low-temperature, low-pressure vapor. The compressed and heated refrigerant vapor is compressed by the compressor, becoming a high-temperature, high-pressure gas (with a temperature of up to 70–90°C). The high-temperature, high-pressure refrigerant, which releases heat through condensation, enters the condenser and releases heat to the indoor terminals (underfloor heating/air handlers), where it condenses into a medium-temperature, high-pressure liquid. The liquid refrigerant, which has had its pressure reduced through throttling, passes through an expansion valve, where its temperature and pressure are further lowered back to their initial values, thus completing a closed-loop cycle. The cooling mode operates in the reverse direction: it transfers heat from inside the room to the ground where it is released, taking advantage of the low temperature there to achieve efficient heat dissipation. II. Development History of Geothermal Heat Pumps Geothermal heat pumps are not a new technology; after centuries of evolution, they have become a mature solution for clean energy-based heating and cooling: 1912: Switzerland proposed the concept of utilizing shallow geothermal energy, laying the technical foundation ； After 1940: Commercial use began in Europe and the United States, with the U.S. taking the lead in large-scale adoption ； 1990s: Entered China, gradually applied in hospitals, schools, and office buildings ； Currently, among new clean energy heating and cooling projects in China, ground-source heat pumps account for over 30% of such projects, making them the preferred choice for clean heating in the north and efficient cooling in the south. Its international use is particularly widespread: it accounts for 19% of commercial buildings in the United States, 96% of shallow geothermal heating systems in Switzerland, and it is used as a key element in achieving carbon neutrality in buildings in Sweden, Germany, and Austria.
III. Three core technical advantages of ground-source heat pumps: extreme energy efficiency and low operating costs. The underground temperature remains stable at 10–15°C throughout the year, allowing heat pumps to achieve a much higher energy efficiency compared to air-source heat pumps. In winter, the COP can reach 3.5–5.0, while in summer the EER can reach 4.0–6.0. It saves 30%-60% more energy compared to traditional air conditioners, and its operating costs are only 50%-60% of those of conventional systems. It is zero-carbon and environmentally friendly: it produces no pollutants, does not burn fossil fuels, and generates no waste gases, waste residues, or wastewater. It also avoids the heat island effect associated with outdoor units, meeting the requirements for green buildings, zero-carbon parks, and low-carbon city development. Stable and reliable, with an extremely long service life; not affected by extreme outdoor weather conditions, and free from issues such as frosting or performance degradation at low temperatures ； The lifespan of buried pipes underground can reach 50-70 years, while the lifespan of the main unit itself is 15-25 years, which is much longer than that of traditional air conditioners. One machine with three functions enables simultaneous heating, cooling, and hot water supply; one system replaces the boiler, air conditioner, and water heater, significantly reducing initial investment and equipment space requirements. IV. Three major technical types and applicable conditions Ground-source heat pumps can be classified into three types based on the type of heat source, each suited to different geological, water source, and site conditions: 1. Buried pipe ground-source heat pump (the most common type): This uses underground soil as the heat exchange medium, with heat exchange taking place through buried pipes; it comes in horizontal and vertical versions. • Horizontal buried pipes: Placed at a depth of 0.8–2 meters underground. This setup is simple to install and requires less investment, but it occupies more space, and the heat exchange efficiency is affected by temperature changes ； • Vertical buried pipes: The drilling depth is 50–200 meters; they require little space and offer stable heat exchange, making them the preferred choice for urban buildings. Applicable to: urban buildings and industrial parks that have some construction space but lack an abundant water source. 2. Surface water source heat pumps use rivers, lakes, seas, reservoirs, and urban wastewater as heat sources, and are available in two types: open-type and closed-type. • Open-type: It directly draws surface water for heat exchange; it has a low investment cost and is suitable for large-scale regional heating ； • Closed system: The coil is submerged in the water for heat exchange; no water is pumped, causing no pollution and thus protecting the aquatic ecosystem. Applicable to buildings and areas near lakes, rivers, and sewage treatment plants. 3. Groundwater-source heat pumps draw groundwater directly for heat exchange, achieving the highest efficiency; however, strict re-injection is required: • Requirements: abundant groundwater, stable water quality, and 100% re-injection into the same stratum ； • Applicable to areas with favorable hydrogeological conditions and approved water withdrawal permits. V. Existing practical challenges in the industry: High initial investment – The costs associated with tasks such as drilling, laying pipes, and well drilling are high, resulting in an overall initial investment that is higher than that of traditional air conditioning systems ； Strong geological dependence requires professional geothermal exploration; rocks, shifting sand, and high groundwater levels increase the difficulty of construction ； The risk of thermal imbalance arises from uneven heat absorption in winter and heat release in summer, which leads to deviations in the temperature of the underground soil and affects long-term energy efficiency ； Water source management is strict; groundwater projects require approval, and substandard recharging can lead to water waste and land subsidence. VI. Implementation in all types of applications 1. Residential buildings: High-end residences, villas, and residential complexes – suitable for use with underfloor heating and air handling units; provides cooling in summer, heating in winter, and hot water throughout the year, offering comfort, quiet operation, as well as energy savings and cost reduction. 2. Public buildings such as schools, hospitals, government offices, stations, and venues have stable loads and long usage periods; they offer significant energy-saving benefits and meet the requirements for green building rating certifications. 3. Commercial establishments such as hotels, shopping malls, and spa centers have high demands for hot water. Ground-source heat pumps can generate hot water free of charge, replacing boilers and significantly reducing operating costs. 4. Industrial sector: Factory workshops, warehousing and logistics facilities, as well as buildings supporting data centers – pipes can be buried in the open spaces within these areas to provide clean heating and cooling, thereby supporting industrial policies aimed at energy savings and carbon reduction. 5. Agricultural applications: Constant temperature control in greenhouses to maintain a stable growing environment for crops, thereby improving yield and quality ； Aquaculture provides water at a constant temperature, shortens the breeding cycle, and reduces mortality rates. VII. In summary, ground-source heat pumps represent the optimal approach for the commercial utilization of shallow geothermal energy. With their core advantages of stability and efficiency, carbon neutrality and environmental friendliness, as well as the ability to serve multiple functions with a single unit, they have become the preferred choice for upgrading heating, cooling, and hot water systems in buildings and industries. Its core value lies in converting stable, low-grade thermal energy underground into usable high-grade cooling and heating resources, thus perfectly meeting the requirements associated with the dual-carbon goals, energy-saving renovations, and green buildings. Despite challenges such as high initial investment and geological dependencies, as technology matures, costs decline, and policy subsidies come into play, ground-source heat pumps are shifting from being a premium option to a standard feature, becoming the dominant equipment in the field of clean-energy heating and cooling between 2026 and 2030.
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