| Ultra low-energy building is the future development trend in the field of building energy conservation around the world.The development of ultra-low-energy building in China is deeply influenced by foreign theoriess,especially the passive house system of Germany,and the current design concept and methods actually build on passive houses.This paper revealed the key conflicts between the German passive house system and the hot summer and cold winter zone of China(HSCW).(1)Full-time and full-space operation mode adopted by passive house shall inevitably lead to high energy consumption,and it is not always equivalent to high comfort.This mode is unsuitable for implementation in HSCW.(2)The energy consumption control indexs of annual average heating energy load 15 kWh/(m2·a)and the total primary energy consumption 110 kWh/(m2·a)set by the passive house standard are significantly higher than the current level of energy use in HSCW,which means the passive house cannot meet the real requirements of developing ultra low-energy buildings in the region.(3)In Germany the winter is cold while the summer is rather cool.Such climatic conditions determine that the core goal of passive houses is to control the winter heating energy consumption of buildings.However,in HSCW,due to the severe thermal environment in winter and summer,there exists huge demand in winter heating and summer cooling simultaneously,which is contrast with the design concept of passive houses.Passive house technology cannot reduce annual cooling and dehimidification energy consumption in HSCW effectively.(4)Continuous mechanical ventilation in passive house results in excessive ventilation energy consumption.(5)The indoor comfort standard set by the passive room is 20 to 26? for indoor temperature,30%to 60%for relative humidity,and the over-temperature and super-humidity frequency not exceeding 10%.However,the simulation results showed that in a non-heating and non-cooling building with all passive housing technology in HSCW,the satisfaction rates of indoor temperature and relative humidity all year round are only 33%and 70%respectively,which is far from the standard.Therefore,this paper believes that the German passive house system is unrealizable and unsustainable in HSCW,and the development of ultra low energy buildings in this region cannot simply apply the passive house system.Based on the natural climate and human conditions,this paper established a new set of ultra-low energy building design system in HSCW,with many research methods adopted like the Bio-climatic design theory,building energy consumption simulation and full-scale experimental verification.Mainly including:(1)Air conditioning system is operated in the intermittent and compartment operation mode for heating,cooling and mechanical ventilation.(2)The electricity consumption control index of air conditioning equipment(including heating,cooling,dehumidification and mechanical ventilation)is 8 kWh/(m2·a),and the annual total electricity consumption control index is 24 kWh(m2·a)for ultra low energy buildings in HSCW.(3)The movable external sunshading with the high-permeability glass material should be prioritized.(4)The air change rate of infiltration shall not exceed 0.25 h-1.Natural ventilation shall be made full use of,and mechanical ventilation is only used when the outdoor air condition is bad or the heating and cooling equipment is operating.(6)The external wall heat transfer coefficient value control value is 0.15 W/(m2·K),the external window heat transfer coefficient value control value is 2.00 W/(m2·K);(5)The inner envelope structure heat transfer coefficient control value is 1.00 W/(m2·K).In terms of energy saving,according to the simulation results,the annual electricity consumption of air conditioning equipment is only 6.95 kWh/(m2·a),which can meet the energy consumption control index proposed in this paper,and is 61%lower than the simulation results of the passive house.In addition,a full-scale test was carried out to compare the energy consumption of ultra low-energy rooms and normal rooms through one-year data monitoring.The results confirmed that the energy-saving effect of the ultra low-energy room is very significant,and the annual energy consumption could be reduced by nearly 60%when compared with the normal rooms..In terms of indoor environment,by the standard of passive house,the satisfaction rates of indoor temperature and relative humidity all year round are only 33%and 70%respectively in the ultra low-energy building designed by this paper when heating and cooling is not used.Referring to the living habits of residents in HSCW and the existing domestic standards for setting comfortable indoor temperature and relative humidity,some adjustment should be taken for the comfort range of temperature and relative humudity appropriately.When the temperature comfort range is 16 to 28?,the satisfaction rates of indoor temperature for the ultra-low energy buildings is 83%,while the corresponding value for passive house is only 55%.When the relative humidity comfort range is 20%to 80%,the satisfaction rates of relative humidity for the ultra-low energy buildings is 87%,while the corresponding value for passive house is only 88%.Overall,the indoor environment in the ultra low-energy building designed by this paper is more comfortable than passive house in HSCW. |
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