Global sensitivity analysis on borehole thermal energy storage performances under intermittent operation mode in the first charging phase

A review of thermal energy storage technologies for seasonal loops

“…Zhu et al [78] explored the charging and stopping time frames used for an intermittent charging operation. Following the results, they suggested an operation with intervals of 5 -11.5 h or more than 17.5 h for charging, and a stopping duration of between 11.5 -24 h in between.…”

Proposition of Design Capacity of Borehole Heat Exchangers for Use in the Schematic-Design Stage

“…In this case, if cooling is dominant, only a small amount of heat injected into the ground is recovered during the heating period, leading to heat accumulation in the ground and possibly stronger heat interference between the BHEs. In this study, to analyze the heat interference effect according to the configuration type, the BHE configuration, the representative type commonly used, was selected as shown in Table 1 with reference to the research by Park et al [30]. The selected configurations were a single BHE, compact BHE, and irregular BHE on a uniform grid (2L-, Rec-, U-, 1L-, and I-shapes).…”

“…In Table 1, the configurations are numbered in order of strong to weak heat interference, apart from the case of a single BHE. If the thermal properties of the ground are uniform, the heat interference effect in a specific configuration can be evaluated by the sum of the distances between BHEs as expressed in Equation (1) [30]: S is the total distance, N is the total number of BHEs, and x i and y i are the coordinates of the individual BHE as Cartesian coordinates. As an example, Figure 3 shows how to calculate S using Cartesian coordinates, and the case is the cylindrical configuration proposed in the original DST model.…”

“…The detailed calculation process of the DST model is presented in the work of Chapuis et al [36]. The DST model is a well-known numerical model, and it has been validated through previous studies [23,30,37]. The volume of the heat accumulator (V DST ), including the number of ground boreholes (N), spacing (B), and height (H), is defined in Equation (5).…”

“…Some of the studies have been conducted to provide useful design capacity information for use in the schematic-design stage. Woloszyn [29] and Li Zhu et al [30] investigated the impact of design parameters of the GCHP on the heat exchange rates, especially for borehole thermal energy storage cases where regular arrangements were typically adopted. Ferrantelli et al [31] proposed a simple methodology to estimate the heat transfer yield (kW) per unit length of energy piles, considering the soil types, spacing, and pile depth.…”