Energy efficiency design of residential buildings in North China cities

With the rapid growth of housing development in China, energy inefficiency in domestic architectures is becoming a crucial problem for the nation's sustainable development. At present, the average energy consumption of housings in North China cities is three times that in developed countries. The energy conservation regulation introduced by the government requires 65% heating energy saving in dwellings compared with the 1980's standard. However most of the current buildings cannot meet that regulation the problem is mainly due to the lack of detailed technology and construction requirements, and difficulties in relation to enforcement. The main aim of this research is to investigate the potential of using environmental design strategies to increase the energy efficiency of residential architectures in North China cities while provide reasonable comfort conditions. Literature review, on-site observations, field experiments and computer simulation were used. The field experiments were conducted in five flats in Tianjin and Xi'an cities to assess their thermal performance. Thermal simulations by using the building energy model HTB2 were employed to analysis these designs, and what improvements can be reasonably achieved, in line with China's targets for reducing housing energy demand by adapting certain environmental design strategies. The findings of this work showed that with the adaptation of environmental design strategies, significant improvements of energy efficiency of residential buildings in North China cities can be achieved and considerable portion of energy can be saved. The most effective parameter in heating reduction is improve thermal insulation, having 50mm and 100mm polystyrene insulation achieved reductions of 26.5% and 38.8‰ respectively. Reduce the infiltration rate is the second most effective method, limit the air change rate to 0.5 ach reduced 21.6% of the heating demand from the existing condition. The parameters that reduce most cooling demand are having a reasonable window area and night time controlled ventilation the reduction rate is around 23% and 13% respectively. Moreover, combining appropriate design parameters will maximise their effectiveness in energy reduction. Having parameters including appropriate glazing ratio, improve insulation of the building envelope, reduce infiltration etc. will enable case studies to match the 65% saving regulations straightforward and the cooling load was also substantially reduced. Moreover, by following further modification suggestions, the energy reduction rate reached 90%. Considerable reduction in energy use and carbon emission can be achieved in North China cities and other places experiencing similar climates, by adapting the suggested design strategies. The findings of this research could help the decision-makers and architects to improve thermal performance and energy efficiency of both existing housings and future designs.