Beijing is the capital of the great motherland. In order to improve the air environment and reduce air pollution, the municipal government put forward the air pollution control plan as early as 2000 . Use of clean energy to replace coal-fired boilers in urban areas prohibits the construction of new coal-fired boilers. Water source heat pump air conditioning as a clean, energy saving, environmental protection technology quickly recognized and accepted. However, in the popularization and application of water source heat pump system, how to extract and recycle groundwater reasonably is the most important problem for confused users. In regions with relatively poor hydrogeological conditions, it is very difficult to recharge, with 100% recharge of groundwater difficult to achieve in some projects, resulting in instable system operation. Ground source heat pump air conditioning system just make up for the lack of water source heat pump system, it is through a closed PE heat exchange tubes and strata for heat exchange, heat pump to provide hot and cold sources, no longer need to extract and recharge groundwater. Its successful applications and demonstrations have made it possible to use geo-energy resources in areas with poor hydrogeological conditions. This article will compare the water source heat pump and ground source heat pump system, as well as their applicable geological conditions and regions, and through the introduction of introduction of ground source heat pump air conditioning system in the office of Greening Bureau of Chaoyang District, so that we further understand the ground source heat pump.
First, to heat pump system introduction
1, to the overview
The earth upon which mankind depends for its existence is rich in all kinds of mineral resources, and at the same time it is still a very huge energy resource base. Taking shallow ground surface as an example, the strata temperature of 5 to 10 meters below the surface of the earth does not change with the outdoor atmospheric temperature. It is maintained at 15 to 17 Â° C throughout the year. This temperature is comparable to that of northern cities such as Beijing and it is a low-grade heat source available in winter, which is higher than the atmospheric temperature (5-15 Â° C). In summer, it is lower than the atmospheric temperature (25-40 Â° C) and is available Cold source.
Ground energy heat pump system is the use of the characteristics of the winter's warm summer strata, by extracting and releasing the heat in the formation, to achieve winter heating and summer cooling. Winter by input power of 1kW, the absorption heat pump may be 2.5 ~ 3kW of energy, thermal energy is 3.5 ~ 4kW buildings; summer by input power of 1kW, to provide 3.5 ~ 4kW of cooling energy for the building. The key to the project's technical success is how to extract and release heat energy from the formation.
Both water source heat pump and ground source heat pump belong to the category of ground heat pump, the difference is that they extract and release of energy in different ways.
2, water source heat pump and ground source heat pump
2.1 water source heat pump system
Water source heat pump is through the extraction of groundwater with the ground temperature, heat exchange between units and groundwater, groundwater recharge through the recharge wells into the formation. According to the amount of system load and water demand, the ability of the formation of water and recharge capacity to design the number of pumping wells and injection wells. Irrigation wells pumping can be a pumping, pumping more pumping or pumping more irrigation.
2.2 Ground source heat pump system
Ground source heat pump system through a closed heat transfer tube circulation circulating fluid and the formation of heat exchange between the endothermic winter, summer heat. According to the size of the system load, thermal conductivity of the formation to design the form of heat exchange holes, the number and depth.
Second, Beijing's hydrogeological conditions
The areas with relatively good hydrogeological conditions in Beijing are located in the ancient rivers of Yongding River and the ancient rivers of Chaobai River. The areas suitable for applying water source heat pumps are: Haidian District, Shijingshan District, Fengtai District, northern Daxing, urban areas and northeastern Shunyi County And other parts. According to the specific location of the hydrogeological conditions, its single-well pumping and recharging amounts are different. Ground-source heat pumps can be used in almost all areas, but the plains area such as northern Haidian, Chaoyang District, Changping District, southern Shunyi, Tongxian and Daxing southern areas are easy to construct, Lower; mountain and piedmont area, due to the formation of rock strata or larger particles, drilling costs are higher.
Third, the conclusion
Ground source heat pump system is clean, energy saving, economical and environmentally friendly technology, the use of a small amount of electricity to achieve heating and cooling. At the same time, the heat exchange hole system does not need to extract and recycle groundwater, and can also be utilized in areas with poor hydrogeological conditions. The promotion and application of ground source heat pump system will promote the implementation of "blue sky project" and occupy a place in the adjustment of energy structure.