Modelling the heating of the Green Energy Lab in Shanghai by the geothermal heat pump combined with the solar thermal energy and ground energy storage

This paper presents a proposed heating system for the Green Energy Lab (GEL) located in Shanghai Jiao Tong University. To make full use of solar energy the system is designed to store the solar thermal energy in the ground soil, using U-tube heat exchange in the seasons when the solar thermal energy is not in use. A simulation model was developed in TRNSYS to develop the ground storage model based on the design parameters of the GEL and weather conditions of Shanghai. The simulation results show that the usage of a solar collector can reduce the electricity use in the systems. This reduction is primarily due to the reduced operation time of the geothermal heat pump and by increasing the ground source temperature. During the simulation the interaction between the borehole heat exchanger, the geothermal heat pump and the evacuated tube collector was investigated. At the same time the load requirements were analyzed. To see how the geothermal storage is affected by the change of design parameters a base case was used. The results show that the systems performance is closely linked to the storage size. With intend to store heat a large number of boreholes with small spacing should be used. The heating of the GEL were established and the building was used as the heat load in the simulation. With a solar collector the electricity usage can be reduced by 26.1%. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).