Heating Optimization Research Under The Constraints Of Environment And Energy

Based on the characteristic and the utilization technology of the coal,household coals and heating boiler coals feature low energy efficiency and high pollutant emissions,are harmful to the environment.Thus,the reduction of household coals and boiler coals would make a great contribution to improving the air quality.In this study,the current heating scenario of Jing-Jin-Ji Region was analyzed firstly.Then,two improved heating approaches using natural gas(first heating system or natural gas-based heating system)and air source heat pumps(ASHP)(second heating system or ASHP-based heating system)to replace the household coals and coal-fired boilers for heating were proposed based on the policies of the“coal to natural gas”and“the replacement of the coals with electricity”.The primary energy efficiencies,pollutant emission reductions and economic viability of different heating systems were calculated and analyzed quantitatively based on Jing-Jin-Ji Region’s scenario.In addition,the pollutant emissions(particulate matter,SO2,NOx)and CO2 per MJ-heating output for household coal,boiler coal,thermal coal used for heat pumps,household natural gas and boiler natural gas were analyzed and calculated quantitatively.Based on the total reduction of the particulate matter,SO2,NOx emissions,the specific costs of the pollutant emission mitigations of these two improved heating approaches were calculated.The results showed that:the primary energy efficiencies of the first and second heating systems are improved by 31 and 45 percentage points,respectively,compared to the original coal-based heating system.The pollutant emissions per MJ-heating output for household coal is the highest among the different heating pattern.Quantitatively,the particulate matter,SO2,NO,emissions factors for household coal are 51,79 and 6 times greater than that of thermal coal used for heat pump,respectively.And the particulate matter and SO2 emissions per MJ-heating output of thermal coal used for the heat pump are higher than boiler natural gas,while the NOx emissions per MJ-heating output is lower.Furthermore,the CO2 emissions from these coals are higher than that of the natural gas,and the highest CO2 emissions are generated by the household coal with 183.73 g/MJ.The emissions of the main pollutants could be significantly reduced.Specifically,the first and the second heating system could decrease the PM,SO2 and NOx by 72.6,30.98,65.5 thousand tons,and 72.6,309.1,74.1 thousand tons,respectively.The CO2 reduction emissions of the first heating system are higher than that of the second heating system 23.0076 million tons.Moreover,the annualized additional expenditures of the first heating system are 3.72 Chinese Yuan/m2 greater than that of the second heating system.Besides,the specific cost of the pollutant emission mitigations of the first heating system is 13.4 Chinese Yuan/kg higher than that of the second heating system based on the total reduction of particulate matter,SO2,NO,emissions.In order to obtain the optimal heating system,the proposed heating systems were analyzed comprehensively in terms of environmental benefit,economic viability,thermodynamic superiority and technology performance by Fuzzy Hierarchy Comprehensive Analytic Evaluation(FHCAE)in this paper.The calculated results of the original coal-based heating system,the first and the second heating systems are 0.608,0.758,0.780,which means the second heating system is the optimal heating system amongst these three heating systems.The research results of this study can lay a scientific theory foundation for building the optimal heating system,which features environmentally friendly,economic viability and energy saving in China,and it can provide certain reference meanings for optimizing district heating for China.