Study On Application Of Solid State Electric Heat Storage In Office Buildings In North China

For a long time,the main energy used in winter heating in northern China is coal burning and bring serious environmental pollution and energy consumption.In order to optimize the energy structure,save resources and protect the environment,the Chinese government has proposed a policy of "clean heating" and issued the "winter clean heating plan for northern China(2017-2021)".Regions rich in renewable energy resources,such as Liaoning,Heilongjiang,Beijing and Hebei,should make full use of surplus wind power in the trough,encourage the construction of electric heating facilities with thermal storage functions,and promote the consumption of renewable energy power,the document said.The potential of electricity substitution industry is very great.According to the survey,at present,the measures of "replacing coal with electricity" mainly include heat pump,electrothermal film,carbon crystal plate and other direct heating equipment,it is mostly applied in rural areas.However,studies on electric heating in public buildings such as government offices,schools and office buildings are relatively few.Office buildings consume a lot of energy and have relatively fixed working hours.If off-duty heating system is set to operate at on-duty temperature,the energy saving potential is huge.However,the electrical thermal storage system has high automation and adjustable operating parameters,which is an optional scheme for office buildings.Based on the above background,entrusted by the department of housing and construction of liaoning province,and funded by the project "study on promoting the use of coal to replace clean heating system with electricity"(17-08-149),the research group carried out an exploratory study on the feasibility of using electric heat storage for winter heating in office buildings in Harbin,Shenyang and Beijing,typical heating cities in the north.The main conclusions of the study are as follows:(1)The energy structure of heating in typical cities is investigated,it is found that regional coal-fired boilers and combined thermal power generation are the main heat sources of central heating,and the use of clean energy is relatively small.The use of clean energy in Beijing is better than that in Harbin and Shenyang.In the energy consumption structure of Harbin and Shenyang,coal is the main energy,but the consumption is decreasing year by year.The main energy sources in Beijing are coal,oil,natural gas and electricity,and the consumption of coal is decreasing rapidly,while the consumption of natural gas is increasing year by year.According to the survey,the clean energy generation forms in typical cities are mainly wind power,nuclear power and hydropower.(2)To the national and provincial government "coal to electricity" related policies to interpret.To understand the application prospect of electric energy replacement technology,the government’s promotion of "coal to electricity",and the preferential policies of electricity price in various regions,so as to provide policy support for the application of electric energy storage technology.The comparative analysis found that Beijing electricity price preferential intensity,coal heating charges the highest.(3)Energy Plus energy consumption simulation software was used to analyze the energy consumption of solid electric heat storage system.Energy Plus energy consumption simulation software was used to analyze the energy consumption of solid electric heat storage system.For comparative analysis,the selected office buildings in each region are provided with three types of heating: solid electric accumulators,gas-fired boilers and municipal heating.et the indoor temperature adjustable(plan 2-three systems are set on duty temperature)and non-adjustable(plan 1-municipal heat according to the design temperature heating throughout the day).According to the simulation results of plan two,the indoor thermal load of the building fluctuates greatly and the peak value is also large.The solid electric heat storage system can save nearly 20% energy than the municipal thermal energy,but it consumes nearly 10% more energy than the gas-fired boiler.During the actual operation,municipal heating is often provided at the designed temperature throughout the day,which will lead to higher energy consumption of the system.In this case,the energy-saving effect of solid electric heat storage system is more significant.(4)The dynamic economic analysis method is used to analyze the solid electric heat storage system economically.The initial investment only considers the equipment cost and installation cost of electric heat storage unit,gas-fired boiler and heat exchange unit,not the construction cost of heat source boiler room and heat station.At the beginning of investment: initial investment: Solid electric heat storage unit > gas-fired boiler > heat exchanger unit;operation cost: Municipal heating(Based on heating charges)> gas-fired boiler unit > Solid electric heat storage unit.The annual cost of solid-state electric heat storage is 39% higher than that of gas-fired boilers and 52% lower than that of municipal heating.It can be seen that the heating economy of solid electric accumulator is better than that of municipal heat,but not as good as that of gas-fired boiler.If we want to improve the economy of electric thermal storage units,the most fundamental reason is to reduce the equipment cost of electric thermal storage units and increase the power concessions.(5)The method of pollutant emission factor was used to analyze the environmental benefit of solid electric heat storage system.Clean energy generation of solid electric thermal storage system can achieve zero emissions,zero pollution.Compared with municipal heat and gas boiler,the environmental benefit of heating is the best.After research,it was found that the application of solid electric heat storage technology is influenced by many factors.Such as climate,local clean energy power supply capacity,"coal to electricity" policy and electricity price incentives,solid electric heat storage unit price,unit thermal efficiency,equipment heat exchange efficiency and so on.Both will affect the energy consumption level and economy of solid electric heat storage,so the energy saving rate and economy depend on the actual project.Solid electric heat storage is more suitable for small office buildings in areas without municipal heat.