Performance Analysis On The Distributed Energy System Serving A Building Cluster Of A Campus

The distributed energy system becomes increasing popular in recent years because it can realize the cascade utilization of primary energy and integrate with renewable energy,which is energy efficient and environment friendly.In the hot summer and cold winter regions,only relying on waste heat recovery of distributed energy system is not enough to meet the cooling and heating demand of users.Complementary cooling and heating system is needed.Ground source heat pump?GSHP?can be used as an efficient alternative.In addition,the thermal energy storage system?TES?can store surplus cooling and heating recovered from the waste,which can improve the comprehensive energy utilization of the system.Therefore,this study proposes a new distributed energy system integrating ground source heat pump and thermal energy storage system and evaluates its energy,economic and environmental performance based on TRNSYS simulation platform,and comparing with the traditional system depending on the grid?chillers for cooling,boilers for heating?,supplemental-fired distributed energy systems?complementary-burning CCHP systems?,CCHP+GSHP system.In addition,in the existing research,the model of thermal energy storage tank is usually ideal,which ignores the dynamic characteristics.Such model is simple but not accurate.The effect of using dynamic and static model of thermal storage model is also evaluated by analyzing the performance of DESs using ideal models of TES?CCHP+GSHP+?ideal?TES?.According to the annual hourly simulation and analysis,the following conclusions can be obtained:1)From the perspective of energy performance,the CCHP+GSHP+TES system can obtain a higher comprehensive energy utilization rate?99.02%?,which is 30.49%higher than that of the complementary combustion type CCHP system?68.53%?,0.23%higher than that of CCHP+GSHP system?98.79%?.Compared with the traditional separation supply system,the energy saving of CCHP+GSHP+TES system is 25.06%,which is 25.3%higher than that of the complementary combustion type CCHP system?-0.24%?,0.67%higher than the CCHP+GSHP system?24.39%?.Compared with the CCHP+GSHP system,the CCHP+GSHP+TES system has an energy saving potential of 2.75%compared to the CCHP+GSHP system.2)In terms of economy,the CCHP+GSHP+TES system has better economy,the total annual cost saving of the CCHP+GSHP+TES system is 27.50%compared to the separation supply system,and the investment payback period is 4.38 years.The payback period is 5 years less than that of the complementary combustion type CCHP system?9.38?,and 0.13 years more than that of the CCHP+GSHP system?4.25 years?.3)From the perspective of environment performance,the CCHP+GSHP+TES system has good environmental performance,the total carbon dioxide emissions of CCHP+GSHP+TES system are 48,900 tons,Compared with the traditional separation supply system,the total carbon dioxide emissions rate of CCHP+GSHP+TES system is 42.07%,17.95%less than that of the complementary combustion type CCHP system?24.12%?,and0.59%higher than that of the CCHP+GSHP system?41.48%?.Compared with the CCHP+GSHP system,the CCHP+GSHP+TES system has a potential reduction of 1.42%over the CO₂ reduction rate of the CCHP+GSHP system.The comprehensive analysis shows that CCHP+GSHP+TES has better energy efficiency,economy and environmental performance under the electric heat setting mode.However,the advantage of CCHP+GSHP+TES is limited compared with the CCHP+GSHP system because the TES only works in very limited hours.When using the ideal models of TES,the performance of the CCHP+GSHP+TES is overestimated,?which increase the comprehensive energy utilization rate by 0.59%,energy saving potential increases by 3.15%,decrease the investment payback period by 0.08 years,and carbon dioxide emission reduction potential increases by 1.57%?.The dynamic model is recommended for performance assessment and design optimization of the DESs.