Transient Modeling of Seasonal Borehole Thermal Energy Storage System During Heat Energy Storing Process

Abstract

The borehole thermal energy system, KINTEX, located in Ilsan, South Korea was simulated using TRNSYS. The effect of the depth and spacing of the boreholes in this Borehole Thermal Energy Storage (BTES) system on the average stored energy and ground temperature were investigated over three years of its operation. Borehole thermal energy storage was simulated using the Duct Ground Heat Storage Model built in TRNSYS. The BTES system is composed of solar collectors, a heat exchanger, borehole thermal energy storage, and a thermal storage tank. The effects on the internal energy of the system were investigated by varying borehole depth and spacing while the volume and number of boreholes were kept constant. The total number of boreholes is 90 and all boreholes are connected in series. The borehole depths varied from 40 to 47.5[Formula: see text]m with steps of 2.5[Formula: see text]m, and the borehole spacing varied from 2.5 to 4.0[Formula: see text]m while the total volume of the BTES was maintained at 21,[Formula: see text]236 [Formula: see text]m3. The internal energy stored ranged from 1528.91 GJ to 1618.69 GJ over three years of calculations. With an increase of borehole depth and associated decrease of borehole spacing, the internal energy increased and ground temperatures approached 35∘C over a simulation period of three years.

A review study on the design and control of optimised greenhouse environments

“…Thermal energy is transmitted to the subsurface via conductive flow from a series of closely spaced boreholes in a BTES system. By altering drilling depth and spacing while keeping the volume and number of boreholes constant, Seokhwa Hwang et al (Hwang et al 2020) study the impacts of internal energy on the system. Over three years of computations, the internal energy stored ranged from 1528.91 GJ to 1618.69 GJ.…”