| About 30% of the world's population lives in earth buildings,and the proportion is as high as 50% in developing countries.Currently,there are about 200 million people live in earth buildings in china.Earth building is so ancient that it cannot meet demands of people in residential environment and facilities.The author proposed three aspects(cooking equipment,heating equipment and passive technologies of building)to improve earth building's indoor environment.Multi-objective evaluation of passive technology is also carried out.This study has been conducted to give guidance to construct or reconstruct traditional dwellings in northwest China,as well as,provide reference and guidance to improve the living environment for poor rural areas in northwest China.Firstly,field investigation and questionnaire survey of 369 households in northwest China was carried out.Of which,125 households carried out testing on indoor thermal environment in winter.Results show that indoor thermal comfort of earth buildings in the northwest is poor,and there are some problems mainly for cooking and heating equipment.In addition,indoor environment and building thermal performance are tested and compared between two types of earth dwellings.Besides that,indoor air quality and its influence on human health are also analyzed.The results showed that concentrations of PM2.5 and PM10 were far above the requirement of standard for both burning biomass and coal.It is urgent to improve its indoor environment.Secondly,based on the survey results,study on the performance improvement on equipment of heat and cook are carried out.A kind of Zao with good performance is presented.The experimental results show that energy saving effect of the improved Zao is better.It can increase heating speed effectively,reduce its heat loss,and reduce the temperature of exhausted gas by 40?,and the thermal efficiency can be increased by more than 16%.In addition,the design of U-type and S-type coil water chimney is put forward.Results show that heat exchange efficiency of the two water chimneys can reach to 60% ~ 80%.And the performance of S-type coil water chimney is slightly better,and put forward improvement suggestions to water chimney in safety performance.In this paper,a plate-type heat recovery device integrated into the heating furnace is put forward.Test results show that the device can reduce the temperature of exhausted gas by 118?,and the heat efficiency can be increased by more than 28%.It can significantly improve the performance of the heating furnace,and has a good prospect of promotion and application.Thirdly,based on the existing research on the principles of architectural design in northwest China,passive technologies to improve the indoor environment are proposed and selected.In addition,it also puts forward the evaluation index in ecology,economy,energy saving and thermal comfort.The entropy weight analysis method is used to calculate the weight,and the grey interval relational decision algorithm is introduced to evaluate the multi-objective decision making.This paper solves the practical problems in the process of evaluation and optimization,such as the uncertainty of the target weight and the target value in numerical interval.Finally,the proposed evaluation index and algorithm are presented through an example.The recommended method is roofing insulation material in rice husk.The results show that the proposed evaluation index and evaluation method can do strategy optimization effectively in passive building technologies,and they can be used for active technologies also. |
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