Comparative Research On Energy Saving Effect Of Wall Insulation Based On Intermittent Energy Use Characteristics In Hot Summer And Cold Winter Zone

Exterior insulation structure has been proved energy-efficiency in the north of China, but the energy-saving effect is less than ideal in hot summer and cold winter zone. It is mainly due to the difference of energy use characteristics in two areas. To find the suitable wall insulation structure, the energy use characteristics should be considered.Based on the intermittent energy use characteristics of a hot summer and cold winter zone, a three dimensional dynamic heat transfer model is presentedto study the intermittent cooling and heating requirements for a typical residential living space. Good agreement is demonstrated when the numeric results are compared to experimental results. A determination of the influence of different wall structures (non-insulation structure, self-insulated structure, exterior insulation structure, interior insulation structure) on the energy consumption is made using numerical calculations and analysis.Results show that energy-saving effect of exterior insulation structure is less than ideal, while interior insulation structure and self-insulated structure are better choices. The difference in cold or heat consumption is mainly due to the difference in heat flux of the interior wall surface.1) For interior insulation structure, highest temperature of the interior surface can be achievedin winter and lowest temperature of the interior surface can be achievedin summer, which means lowest temperature difference between interior surface and indoor air can be achieved. Thus lowest heat flux of the interior surface can be achieved, which means interior insulation structure saves energy most.2) Modest level of energy-saving effect can be found for self-insulation structure.As its low thermal capacity and high thermal diffusivity, there is a quickly wide variation in its wall temperature.3) For exterior insulation structure, in summer, though its lower wall temperature can reduce wall heat dissipation,it prevents heat dissipation to the outside as its exterior insulation layer; In winter, its exterior insulation layer has little influence on heat flux of the interior surface. On the whole its energy saving effect is not good.Then based on interior insulation structure, further study on relationship between energy cost and set temperture for air conditioning is made. Results show that it can save6%energy when set temperture increases by1℃in summer and save8%energy when set temperture decreases by1℃.Finally, Life Cycle Cost analysis method is used to determine the Optimum insulation thicknessof interior insulation structure. Results show that0.03m is the optimum insulation thickness, which means that in this insulation thickness, the sum of system initial cost and energy cost is lowest.