Design And Technical Research Of "Coal To Electricity" Heating System For Primary And Middle Schools In Villages And Towns Of Tianjin

This paper makes a technical and economic analysis of the air conditioning and heating system in the main teaching building of a primary school in a village of tianjin city after "coal to electricity",and optimizes different air conditioning and heating methods.In this paper,building energy consumption simulation software is used to model the building.On this basis,six heating system schemes are designed for the building to compare and analyze which heating form has the minimum energy consumption.Considering the initial investment and operation cost,the average annual life cycle cost is calculated to determine the best heating form.Compare the buildings before and after renovation,and make the same type of air conditioning system design.By calculating the cost saved in the whole life cycle,the importance of heat preservation renovation of building envelope to reduce energy consumption and save cost is demonstrated.Energy consumption simulation software e-quest was used to simulate six heating systems: electric boiler radiator system,electric boiler radiant heating system,soil source heat pump radiator system,soil source heat pump radiant heating system,air source heat pump radiator system and air source heat pump radiant heating system.According to the simulation results,the annual heating energy consumption of the soil source heat pump radiant heating system is the minimum,and that of the electric boiler radiator heating system is the maximum.The annual operating electricity cost of the air source heat pump radiator system is the highest(37,000 yuan/year),and that of the electric boiler radiant heating system is the lowest(25,300 yuan/year).To determine the best heating method,the initial investment and operation cost of the system need to be comprehensively analyzed.The initial investment includes equipment cost,pipeline valve cost,installation cost,electricity fee for transformer and distribution,and operation cost includes management fee,depreciation fee and equipment maintenance fee.Through calculation,among the above six heating systems,the initial investment of soil source heat pump radiant heating system is up to 500,000 yuan,and the initial investment of air source heat pump radiator heating system is up to 21,100 yuan.The annual operating cost of the electric boiler system is the highest,at 121,600 yuan,and the annual operating cost of the air source heat pump radiant heating system is the lowest,at 93,000 yuan.Using static evaluation method to analyze the system can only get the number of years of investment recovery,can not comprehensively reflect the economy of the system.In this paper,by using system analysis method of dynamic evaluation,the service life of heat pump system fixed number of year for 20 years,the service life of electric boiler system fixed number of year for 10 years,calculate the average total life cycle cost of six kinds of heating system,the results show that the electric boiler annual average LCC radiator heating system,the maximum is 267300 yuan/year annual radiator air source heat pump system LCC minimum is RMB 190200 / year.Using the dynamic analysis method,the life span of the heat pump is 20 years,the life span of the electric boiler is 10 years,the average life cycle cost is calculated,the maximum of the electric boiler radiator heating system is 267,300 yuan/year,the minimum of the air source heat pump radiator system is 190,200 yuan/year.Synthetically,the air source heat pump radiator system is the best heating form.The soil source heat pump has large initial investment and low operation cost.Although the electric boiler has the function of "cutting peak and filling valley",it has a large initial investment and a high operating cost,which is the least energy-saving form of heating.The air source heat pump has low initial investment,low operation cost and high electricity cost,but it has the lowest average life cycle cost and is the most ideal heating method.The renovation of building envelope has great influence on the annual energy consumption of air conditioning system.Before the renovation,the heating heating load of the building is 190.6kw,the cooling load of air conditioning is 320.84 kw,and the annual operating energy consumption of heating is 131720kW·h.After the renovation,the heat load of the building is 107 kW,the cooling load of air conditioning is 280 kW,and the annual operating energy consumption of heating is 42340 kw ·h.Before the renovation of the building envelope,the building adopts the air source heat pump radiator system,with an initial investment of 397,800 yuan and an annual operating cost of 152,900 yuan.After the renovation of the external protection structure,the building adopts the air source heat pump radiator system,with an initial investment of 21,100 yuan and an annual operating cost of 93,200 yuan.After the unit has been running for 20 years,the cost of the air-conditioning system can be reduced by 40% in the whole life cycle after the renovation of the building envelope compared with that before the renovation.