Study On The Application Of Compoundheat-source Heating System In Western Sichuan

Located in the cold or severe cold area in China,heating is need in Western Sichuan during the winter.Since this region is rich in natural resources,the environmentally friendly and efficient heating system with renewable energy could be used in buildings.By summarizing the current research and application of the compound heat-source heating system worldwide,a compound heat-source heating system and a monitoring and controlling system were designed and built in western Sichuan.And the operating performances of compound heat-source heating system in western Sichuan and the influential factors of the system energy consumption were studied experimentally.Based on the theoretical analysis of compound heat-source heating system in western Sichuan,the experimental methods and project of a practice office building were analyzed and designed.This study proposed the indexes to evaluate the practical operation performance of the heating system,specifically,1)the indoor temperature should not be less than 15?;2)COP of heat pump should be over 1.8;3)the annual system energy consumption should be less than 15kWh/m~2.To investigate the performance and energy consumption of the system in various conditions,various experiments were conducted in various conditions and patterns.This study aims to investigate the system performance of a regular office building,therefore,the analysis of energy consumption of heating system is under the regular office work condition in this topic.The experiments demonstrated that:the heating system and control system could work normally,the system was capable to switchover automatically;the proper switch temperature(50?)which meeted the demand of building load was confirmed;the system energy consumption was high in low-load work condition because the heat pump with constant frequency compressor was unable to adjust to the load;heat loss in solar system was high and the heat pump worked in bad conditions for the low load-ratio;the energy consumption of heating system was12.8kWh/m~2,and the mean solar pattern working time was 6 hours per day in winter;the heating system wasable to meet the expectation of the topic and the solar system wasable to meet the load demand in the daytime under the regular office work condition basically;the energy consumption was able to reach expectation of zero energy if the solar system was well insulated under the regular operating condition;the system wasable to reduce energy consumption with improvement.Based on the practical operationconditions of the compound heat-source heating system,the influential factors of system energy consumption were analyzed,and various improvements were demonstrateed,including:the building envelope and heat pump model redesigning;solar system insulation improving;supplying water temperature and switch temperature variation.By analyzing the experimental and numerical results,the heat loss of solar system could be reduced by at least 50%if the solar system was well insulated,and the energy consumption could be reduceed by 4%if the supply water temperature and the switch temperature variation were changing,the energy consumption of heating system is 4.8kWh/m~2,and the mean solar pattern working time is 7.5 hours per day in winter if the building envelope were improving and heat pump model were redesigning;the payback years of improvement of building envelope improving and heat pump model redesigning are 7 years.By conducting the improvements,the system was able to reduce energy consumption effectively.The practical operation performance of the compound heat-source heating system in a local office building demonstrated that,the heat-source pattern of compound heat-source heating system with solar energy and heat pump was able to switchover automatically to fulfill the unmanned management in heating system.The practical system was able to meet the topic expectation that of the indoor temperature should be over 15?and annual system energy consumption should be under 15kWh/m~2.Moreover,the system performance could be enhanced if the improvements including the equipment configuration were conducted.The proposed improvement approaches were able to reduce energy consumption and meet the economic requirement in the engineering application.This study can contribute towards the application of compound heat-source heating system in western Sichuanand provide theoretical and technical guidance to reduce the energy consumption and construction cost.