Study On Thermal Environment And Applicable Materials For Passive Buildings

The consumption of fossil energy has been causing energy shortage and environmental pollution worldwide,while the construction industry is still one of the three major energy consuming industries in China nowadays.The development of passive buildings provides an effective measure to alleviate energy crisis and environmental problems.In this context,we choose to study"The thermal environment and applicable materials for passive buildings".The thermal parameters of three kinds of envelope structures constituted by three traditional building materials and the indoor temperature of the buildings they constituted were calculated,respectively.The outdoor temperatures in Lanzhou were recorded.A program was written to study the response of the indoor temperatures to outdoor temperatures.Besides,a new kind of paraffin-gypsum composite blocks with high heat storage ability were manufactured and the thermal performances of the wall they constituted were studied comparatively.The main contents are as follows:(1)Three kinds of traditional building materials,i.e.,the reinforced concrete,foamed concrete blocks and clay hollow blocks,are selected respectively as the main material to construct three kinds of envelope structures.Rock wool boards and cement mortar are selected as the insulation material,the internal/external painting materials respectively.According to the standards of passive buildings and the relevant parameters of the materials used,three kinds of envelope structures are determined using 0.15W/(m~2·K)as the heat transfer coefficient of the envelope.Then,the thermal inertness index,the heat storage coefficient of the material layer surface,the temperature fluctuation resistance and heat storage capacity of the three kinds of envelope structures were studied,respectively.(2)The indoor thermal environment of the three envelope structures under the modes of stable heat transfer and unstable heat transfer were studied respectively.Under the stable heat transfer conditions,the outdoor temperature,and the internal surface temperature of the indoor walls of the three envelope structures are the same,respectively.Under the unstable heat transfer conditions,the thermal stability of the structures was studied by analyzing the total delay times of the temperature transmission in the three envelope structures.The outdoor temperatures in Lanzhou were recorded.Taking the temperatures in December 28,2020 as an example,the internal surface temperature of the indoor wall was calculated,and the temperature change chart was drawn.A program for the response of the indoor temperature to the change of the outdoor temperature was written and the temperature change charts of the inner surface of the four walls in January of 2021 were drawn,respectively.(3)Paraffin/gypsum phase change composite blocks with heat storage ability were manufactured.The thermal insulation performances of the two walls of 600mm×600 mm×150 mm constructed by the paraffin/gypsum composite blocks and the blocks contained no paraffin,were studied respectively.Finally,the thermal performance and indoor thermal environment of the envelope constituted of the paraffin/gypsum blocks are studied.The results show that the paraffin/gypsum composite blocks are more applicable for passive buildings than the traditional building materials.(4)The energy consumption of the buildings composed of the four kinds of envelope structures was calculated using the energy-saving design software BECS2016,respectively,and the applicability of the four envelopes as the walls of passive buildings are evaluated.