Research on the Simulation and Operation Control Strategy of Hybrid Ground Source Heat Pump System

Abstract

Large-scale commercial buildings served by ground source heat pump (GSHP) systems generally require a large land area for ground heat exchanger (GHE) installation. However it is difficult to provide such large area around the buildings, especially in urban area. Additionally, a large-scale GHE may consume more energy consumption compared with a medium or small GHE system because of the significantly large transmission energy consumption in the closed GHE loop. This study takes a commercial building located in northern China as a case study and proposes three different design schemes: chillers plus municipal central heating system, a single GHSP system and a hybrid GSHP system with chiller and municipal central heating as supplemental heat source and sink. The simulation models of the three systems have been established in the platform of TRNSYS. An optimal control strategy has been found with the aim of lowest annual operating cost. The results show that the municipal heating system can be put in operation when the outlet water temperature from GHE is less than 4℃ in winter; the cooling tower would be open to assist heat dissipation when the outlet water temperature from GHE is above 33℃ in summer. In this case the GSHP can provide 42% of the cooling and 83.5% of the heating loads, respectively.