Energy and cost savings through heat trading between two massive prosumers using solar and ground energy systems connected to district heating networks

Prosumers of renewable energy have recently emerged worldwide. In Korea, massive prosumers with large-scale renewable energy systems are emerging because of the obligation policy imposed on large-scale public buildings. However, heat trading between prosumers has not yet been established in the country or worldwide. In this study, the heat trading between two massive prosumers using solar and ground energy systems was investigated using TRNSYS simulation, in which two large-scale public buildings in Korea were assumed to trade the heat produced from renewable energy systems at a reasonable price. Based on the simulation results for 20 years, the two prosumers can increase their share of renewable energy provision by 8.7% and 1.2%, respectively, through heat trading compared to those without heat trading. In addition, heat trading can reduce the total cost for prosumers by up to 4.3%. Moreover, increasing the size of the solar collector and ground-source heat pump can effectively increase the share of the renewable energy provision and total cost reduction owing to active heat trading. However, because of the different supply and demand characteristics of the two prosumers, the heat sales cost between them should be reasonably determined to guarantee the benefits of heat trading for both prosumers.