| High efficiency fresh air heat recovery system is one of the five technical means of passive building,and it is also the main object of energy consumption in the later operation.In this paper,the passive renovation project of a common office building with a building area of 330m2 in Shanghai is taken as an example.The project adopts the passive fresh air heat pump with the functions of refrigeration,heating,dehumidification and fresh air as the air conditioning system.Through the combination of field measurement and numerical simulation,the actual operation effect and energy-saving characteristics of the fresh air heat pump system of the reconstruction project are analyzed.The thermal comfort simulation and energy consumption calculation of the operation conditions are carried out by using the design builder software.The results show that the fresh air heat pump system can not only provide the fresh air required by the indoor personnel,but also eliminate the indoor heat and humidity load to meet the indoor heat Comfort requirements.The daily energy consumption,the temperature at the inlet and outlet of the new air heat exchange core and the indoor temperature and humidity are measured to analyze the actual operation effect of the unit.Based on the analysis of the monitoring data of the unit,the accumulated power consumption of the unit in July and August in summer is 1130.6kwh and 1262.7kwh respectively,which is about 30% less than the energy consumption of the original multi connected system.Through the data collection and analysis of the temperature at the inlet and outlet of the heat exchange core with different air volume,it is concluded that the apparent heat exchange efficiency of the plate warped heat exchange core of the new air integrated machine is 72% ? 87%,and the indoor air parameters are monitored.The indoor temperature is 23.4 ? 25.2 ?,the relative humidity is kept between 44% ? 59%.The above operation parameters meet the requirements of passive ultra low energy consumption green building technology Requirements of the guidelines.Design builder is used to simulate the thermal comfort and energy consumption of the reconstructed buildings and units.The results show that the simulation values of energy consumption in July and August are basically consistent with the measured values,and the indoor temperature and humidity are also between 24 ? 26 ? and 40% ? 60%,respectively,which verifies the accuracy of the numerical simulation.According to the results of numerical simulation,the maximum cooling load of the building in the whole year is 14.1kw,and the thermal comfort evaluation indexes PMV and PPD reach the comfort level I.At the same time,the energy consumption and temperature and humidity were verified again by using the passive room design software package phpp.The results show that the indoor overtemperature frequency in summer is 4.9%,and the monthly energy consumption deviation rate is 4.6%.The results show that the model is accurate and the reconstruction project has good energy conservation and thermal comfort.The heat and mass transfer mechanism of the heat transfer core of the plate warped triangular channel is studied theoretically,and a comprehensive optimal control strategy of the fresh air system is proposed.In this paper,the energy-saving performance of the fresh air heat recovery system with different heat exchange forms and efficiency is studied.The minimum enthalpy difference method is used to simulate the 225 days of fresh air heat recovery in Shanghai.The recoverable energy of fresh air per unit volume flow in hot summer and cold winter area is calculated by using fresh air hours and enthalpy hours method,which fully shows the applicability and application potential of fresh air system in this area.Finally,the economic benefits of the passive transformation project are analyzed,and the investment payback period is 8.5 years,NPV > 0.The results show that the technical scheme has good economic benefits and practical promotion value. |
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