Influence of Position of Thermal Energy Storage with Different Effectiveness on the Performance of BCHP System

Abstract

Natural gas-driven Building Cooling Heating and Power (BCHP) system shows high energy efficiency and low emission. Nevertheless non-synchronized and fluctuating thermal and electrical demands lead to part load working conditions of the energy supply devices (prime mover and absorption chiller), resulting in low energy efficiency of the whole system. Integrating Thermal Energy Storage (TES) equipment to BCHP proves to be an effective way to improve the system performance. The location of the TES device in BCHP has a great impact on the performance of the whole system. In this paper, a simplified model of BCHP with TES system composed by a Gas Turbine (GT), an Absorption Chiller (AC) and a TES device of different heat exchange effectiveness is presented. Aiming to minimize primary energy consumption, the performances of BCHP systems with different TES locations (upstream and downstream the AC) are compared and analyzed. The preliminary results indicate that it is better for improving efficiency and reducing installed capacities of energy supply devices, to place TES close to users. Moreover, it is shown that the Relative Energy Saving Ratio (RESR) of BCHP with TES system is influenced by whether the co-generated power is merchantable to the power grids. This work is of great significance in further understanding the energy saving mechanism between TES and BCHP and guiding the design of practical BCHP with TES systems.