Can energy piles store solar thermal energy underground?

Ma and Wang proposed using energy piles to store solar thermal energy underground in summer, which can be retrieved later to meet the heat demands in winter, as schematically illustrated in Fig. 1. A mathematical model of the coupled energy pile-solar collector system was developed, and a parametric study was carried out.

Can solar thermal energy be stored underground?

Energy piles, which embed thermal loops into the pile body, have been used as heat exchangers in ground source heat pump systems to replace traditional boreholes. Therefore, it is proposed to store solar thermal energy underground via energy piles.

Can energy piles be used for underground energy exchange?

Energy piles, which are combinations of BHEs with pile foundations, could be used for underground energy exchange without the need for drilling holes [ , , ]. Energy piles have been combined with ground source heat pump (GSHP) systems for building heating or cooling for years [ 33 ].

How much solar energy can a 10 m-long energy pile store?

Under the specific thermal boundary conditions adopted, the maximum daily average rate of solar energy storage reached 150 W/m for the 10 m-long energy pile. It decreased to about 35 W/m as the pile length increased to 50 m.

How does underground thermal energy storage work?

The conventional practice of underground thermal energy storage is burying heat exchange pipes into pre-drilled vertical holes, referred to as the borehole thermal energy storage . Heat transfer occurs by circulating heat carrier fluid through the pipes. However, the cost of drilling deep holes can cause a breakdown of a project .

Can a full-scale energy pile provide thermal injection performance?

A field test was performed to investigate the thermal injection performance of a full-scale energy pile for USES. A bridge deck embedded with heat exchange tubes was employed for solar energy collection, which can provide thermal energy to the energy pile.