Research On Exergy Analysis Of Heating And Air Conditioning System And Energy Conservation Optimization

Heating and air conditioning system energy consumption accounts for a largeproportion of building energy consumption, is the key link to building energyconservation. Traditional energy analysis method can only focus on the quantity ofenergy utilization in heating and air conditioning system, but ignore the energy qualityto use. This tends to cause unnecessary waste for high quality energy, and the exergyanalysis can make up for the shortage. Therefore, take the exergy analysis into the eachenergy-using units of heating air conditioning and the system as a whole, can get theenergy saving of each unit and systems, provide the basis for selection and optimization,and get more comprehensive guidance for saving energy.In this paper, the heating of the air conditioning system is divided into fourunits the cold and heat source unit, the heat exchanger unit, the conveying unit and theterminal unit, respectively. And established the general respectively exergy analysismodel, calculate the exergy efficiency, the exergy loss rate and the exergy losscoefficient. Comprehensive exergy efficiency of each unit, then get the main exergyefficiency of the system. Let the ratio of the auxiliary power consumption in the systemand the input exergy to system for auxiliary energy consumption coefficient, to comparethe relative size of auxiliary energy consumption in each system. Finally, get the totalexergy efficiency of the system and the total exergy loss coefficient through the analysisof the established models and the data analysis, for evaluation of energy for heating andair conditioning system, and provide the system optimization Suggestion.Select and exergy analysis common heating and air conditioning systems and thencalculation the operation parameters of available: hot and cold source unit in the heatingand air conditioning system has relatively minimum exergy efficiency, also has thelargest exergy loss, it’s exergy losses accounted for about70%-90%of the system input exergy; Conveying unit’s exergy efficiency is higher than95%, it’s exergy loss is alsothe smallest one, accounting for2%of the system input exergy; Exergy efficiency ofheat exchange unit is relatively consistent, about70%, it’s exergy losses accounted forabout7%of the system input exergy; Terminal unit’s exergy loss get some more.Among them, the difference of terminal unit of the heating system is larger, floorheating equipment’s exergy efficiency is the highest, the radiator is the minimal one.Exergy efficiency of terminal unit in air conditioning system is about40%.Integrated the exergy efficiency of each unit and the exergy analysis of systems: Tototal exergy efficiency, heating systems were5%-10%, air conditioning systems were1%-6%; To the total exergy loss coefficient, heating systems were over85%, airconditioning system were85%-95%.It shows that the heating system is moreenergy-saving than air conditioning system, but both of them has great potential forenergy saving.After comparing heating and air conditioning systems, it shows that, in heatingsystems, heat pump system has the highest total exergy efficiency, about10%, totalexergy loss less than5%to other systems, has a better performance of energy saving; Inair condition systems, the total exergy efficiency of absorption refrigeration system is6%, higher than other systems, the total exergy loss is lower5%-10%, has the highestperformance of energy-saving.