Simulations of Heat Supply Performance of a Deep Borehole Heat Exchanger under Different Scheduled Operation Conditions

Jiaqi Zhang; Xinli Lu; Wei Zhang; Jiali Liu; Wen Yue; Dongxi Liu; Qingyao Meng; Feng Ma

LAPSE:2023.3207

Published Article

LAPSE:2023.3207

Simulations of Heat Supply Performance of a Deep Borehole Heat Exchanger under Different Scheduled Operation Conditions

Jiaqi Zhang, Xinli Lu, Wei Zhang, Jiali Liu, Wen Yue, Dongxi Liu, Qingyao Meng, Feng Ma

February 22, 2023

Abstract
With the changing world energy structure, the development of renewable energy sources is gradually accelerating. Among them, close attention has been given to geothermal energy because of its abundant resources and supply stability. In this article, a deep borehole heat exchanger (DBHE) is coupled with a heat pump system to calculate the heat supply and daily electricity consumption of the system. To make better use of the peaks and valleys in electricity prices, the following three daily operating modes were studied: 24-h operation (Mode 1), 8-h operation plus 16-h non-operation (Mode 2), and two cycles of 4-h operation and 8-h non-operation (Mode 3). Simulation results show that scheduled non-continuous operation can effectively improve the outlet temperature of the heat extraction fluid circulating in the DBHE. The heat extraction rates of Mode 1 is 190.9 kW for mass flowrate of 9 kg/s; in Mode 2 and Mode 3 cases, the rates change to 304.7 kW and 293.0 kW, respectively. The daily operational electricity cost of Mode 1 is the greatest because of 24-h operation; due to scheduled non-continuous operation, the daily operational electricity cost of Mode 3 is only about 66% of that of Mode 2. After an 8-month period without heating, the formation-temperature can be restored within 4 °C of its original state; 90% recovery of the formation-temperature can be achieved by the end of the second month of the non-operation season.

Record ID

LAPSE:2023.3207

Keywords

deep borehole heat exchanger, geothermal energy, heating, scheduled non-continuous operation

Subject

Planning & Scheduling

Suggested Citation

Zhang J, Lu X, Zhang W, Liu J, Yue W, Liu D, Meng Q, Ma F. Simulations of Heat Supply Performance of a Deep Borehole Heat Exchanger under Different Scheduled Operation Conditions. (2023). LAPSE:2023.3207

Author Affiliations

Zhang J: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Lu X: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Zhang W: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Liu J: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Yue W: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Liu D: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Meng Q: Tianjin Geothermal Research and Training Center, College of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, MOE, College of Mechanical Engineering, Tianjin Universi
Ma F: Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China

Journal Name

Processes

Volume

10

Issue

1

First Page

121

Year

2022

Publication Date

2022-01-07