Experimental Study On Solar Energy Associated With Wall-Mounted Gas Boiler Heating System

In northern China,the heating energy consumption is an important part of building energy consumption.Most of the traditional heating systems obtain heat by direct combustion of fossil fuels such as coal,natural gas and others.With the growing shortage of conventional energy sources and serious environment pollution,countries all over the world pay more and more attention to the development and utilization of new energy.Solar energy associated with gas-fired heating and hot water combi-boilers system having both the advantages of energy saving and comfortability,can make full use of solar energy resources,reduce gas consumption,exert the superiority of energy conservation and environmental protection,ensure the all-weather stable heating demand of users during winter,which has good prospects for development.Firstly,comprehensive theoretical analysis of the experimental principle was carried out in this paper,which provides a theoretical basis for the design of the system.Secondly,the associated heating system which takes the solar power and gas as heat sources and takes floor heating coil and fan coil units as heating ends was set up to conduct contrast experiment.The 4 kinds of heating systems include wall-mounted gas boiler?WGB?heating system with floor heating coil?System 1?,solar energy associated with wall-mounted gas boiler?SWGB?heating system with floor heating coil?System 2?,WGB heating system with fan coil?System 3?and SWGB heating system with fan coil?System 4?.Finally,the performance,energy consumption and environmental economic benefits of 4 kinds of heating system with variable heat sources and ends were analyzed and discussed.The results are as follows:4 kinds of heating system can meet the requirements of the indoor thermal comfort.The indoor temperature of floor heating coil system changes gently,while the indoor temperature curve of fan coil system is jagged.The average solar fraction of system 2 and 4 are 22.32%and 21.44%.The comprehensive heating energy consumption of system 1⁴ are 35.16kgce,28.27kgce,40.69kgce and33.67kgce,respectively.And the system 2 is the most energy-saving.When taking floor heating coil as the heating end,the energy saving rate of SWGB heating system is 19.60%compared with WGB heating system.And when taking fan coil as the heating end,the energy saving rate of SWGB heating system is 17.25%compared with WGB heating system.Under the condition of same heating effect,when taking WGB as the heat source,the energy saving rate of floor heating coil system is 13.59%compared with fan coil system.And when taking SWGB as the heat source,the energy saving rate of floor heating coil system is 16.04%.The thermal efficiency of system 1⁴ are 75.39%,78.17%,73.51%and 77.12%,respectively.And the exergy efficiency of system 1⁴ are 16.77%,3.17%,17.79%and 3.34%,respectively.The cost of system 2 is the lowest with 132.92 yuan/m² analyzed by the method of annual cost,followed by system 1 and system 4,which is 133.09 yuan/m² and 133.54yuan/m²,respectively.And the annual cost of system 3 is the highest with 134.59yuan/m².Throughout the heating season,compared with system 1,system 2 can save standard coal of 137.7kgce,reduce CO₂,SO₂ and dust emissions of 344.28 kg,2.75kg and 2.07 kg,respectively,which has significant energy saving and environmental benefits.