Energy Efficiency Evaluation Based On Heating, Air Conditioning System Circulating Pump Transformation

Recently, with more common applications of district heating and centralair-conditioning in residential building, the proportion of energy consumption forheating and cooling in social total energy consumption is increasing. Meanwhile,electricity consumption of pumps holds a considerable proportion in heating andcooling energy consumption. Therefore, there is a great urgency to properly select andmatch circulating pumps, which in turn will guarantee heating and cooling effect, aswell as the operation economy.This study analyzed existing problems of pumps in heating and air-conditioningsystem during selection and use phase, such as larger selection of pump flow and head;low efficiency as a result of operation out of the optimum condition point; highenergy consumption owing to constant flow of pumps. Through analysis of theoperation condition of108heating and48air–conditioning circulating pumps, thispaper studied the deviation of actual operation condition from rated condition and itseffect on pump efficiency, as well as electricity consumption. Furthermore, this paperintroduced how they changed after proper selection of pumps and adoption of variableflow. In the last part of the paper, the economy of energy-saving renovation for thepumps was discussed.As is shown in the study, due to deviation from nominal working condition,measured power of70of total108heating circulating pumps increased by0~196.0%compared to rated power. While the mean power of105pumps reduced by0~85.1%.Accordingly, there are39in overall48air-conditioning pumps whose measuredpower is0~47.1%higher than rated power. The mean power of39air-conditioningpumps is1.1~81.1%lower than the rated one. It is indicated that the deviation has agreat influence on pumps’ electricity consumption and efficiency.According to the analysis, relative and mean energy-saving efficiency of heatingcirculating pumps are47.8~88.8%and69.3%respectively. Meanwhile those ofair-conditioning circulating pumps are respectively47.5%~89.2%and62.4%. Themean static payback time for heating and air-conditioning pumps is2.1and4.3yearsrespectively. So there is a great potential in energy-saving renovation for pumps.