The principle of groundwater heating is to use the temperature of groundwater to remain constant all the year round, while the temperature is changing. In winter, the temperature of groundwater is higher than the surface temperature, so it is pumped by groundwater and exchanged with air to keep warm. In summer, the temperature of groundwater is lower than the surface temperature, which is the same as heat exchange and cooling.

Generally, the groundwater temperature is the local annual average temperature, and it is 15- 18 degrees in Beijing. Most water source heat pumps absorb heat from groundwater, and the drainage temperature is about 7 degrees. This method is very energy-saving for heating and cooling.

Extended data:

Formation principle:

When the soil moisture exceeds the field capacity, the excess moisture can not be absorbed by the capillary, but will penetrate downward along the soil macropores under the action of gravity. This part of the water dominated by gravity is called gravity water.

Gravity water is groundwater existing in permeable soil below groundwater level. It is the movement of free water under the action of gravity or pressure difference that produces buoyancy effect on soil particles. Gravity water has an important influence on the stress state in soil and the drainage and waterproof measures that should be taken when excavating foundation pits and building underground structures.