Underground solar energy storage via energy piles: An …
The energy storage rate q sto per unit pile length is calculated using the equation below: (3) q sto = m ̇ c w T i n pile-T o u t pile / L where m ̇ is the mass flowrate of the circulating water; c w is the specific heat capacity of water; L is the length of energy pile; T in pile and T out pile are the inlet and outlet temperature of the ...