Pros and Cons of Buried Tube Heat Exchanger in Ground Source Heat Pump System

Drilling depth less than 60m Drilling costs less, the cost is low, if more than 60m, the rig costs will increase;

② well depth of 80m, commonly used domestic pressure (pressure 1.0MPa) plastic pipe, such as depth greater than 80m, the need to adopt high pressure plastic pipe, the cost increased greatly;

③ According to comparison, the cost of well 50m is 30% ~ 50% lower than that of 100m.

The above is for the central ground room, if the use of sub-room-type water source heat pump system also takes into account the impact of building height.

In general, the advantages of shallow buried pipe are: less investment, low cost, less rig requirements, the use of ordinary pressure (0.6 ~ 1.0MPa) of plastic pipe, due to the influence of ground temperature, it is good. The disadvantage is that it occupies a large area of the venue, pipe joints, buried heat exchange efficiency is lower than those buried in the deep.

The advantages of deep buried pipe are: small occupied area, stable underground rock temperature, high heat exchange efficiency, large unit pipe heat exchange capacity, and fewer pipe joints. The disadvantage is the large investment, high cost, the need to use high pressure (1.6 ~ 2.0MPa) plastic pipe, drilling rig performance requirements; due to the temperature of deep rock and soil surface temperature is very small, so must pay attention to winter heat absorption and summer Exhaust heat balance, otherwise it will affect the long-term use of ground source heat pump effect. Abroad, some have adopted the installation of cooling towers in the system and auxiliary heating measures to help achieve the balance of underground rock.

In the buried pipe between shallow, buried between the two, plastic pipe can be used ordinary pressure-type. From the statistics of domestic and foreign engineering examples, buried in the majority of ground source heat pump.

In the actual project using horizontal or vertical buried pipe, vertical pipe depth how much depends on the size of the site, the type of local rock and excavation costs. If the site is large enough and no hard rock, the level of more economical, if the use of pipe machines for multi-tube arrangement can also reduce the area occupied by the site. Vertical pipe should be used when space is limited, and in many cases this is the only option. If there are hard rocks in the site, drill holes can be successfully drilled with rock drills.