Research on the Evaluation Indicator System for Rural Green Building

Yan LI，Jianping JIANG，Fang LI，Longzhao ZHAO

1.School of Management，Xi'an University of Science and Technology，Xi'an 710054，China；2.School of Construction and Safety Engineering，Shanghai Institute of Technology，Shanghai200235，China

Green building（also known as green construction or sustainable building）refers to a structure and using process that is environmentally responsible and resource-efficient throughout a building's life-cycle：from siting to design，construction，operation，maintenance，renovation，and demolition.This requires close cooperation of the design team，the architects，the engineers，and the client at all project stages.The green building practice expands and complements the classical building design concerns of economy，utility，durability，and comfort.

Although new technologies are constantly being developed to complement current practices in creating greener structures，the common objective is that green buildings are designed to reduce the overall impact of the built environment on human health and the natural environment by：

（i）Efficiently using energy，water，and other resources；

（ii）Protecting occupant health and improving employee productivity；

（iii）Reducing waste，pollution and environmental degradation.A 2009 report by the U.S.General Services Administration found 12 sustain ably designed buildings cost less to operate and have excellent energy performance.

In addition，occupants were more satisfied with the overall building than those in typical commercial buildings.According to Notice of the State Council on Issuing the Work Plan for Greenhouse Gas Emission Control during the12th Five-Year Plan Period，the green buildings will be more than 30%of new buildings in 2020，and the energy consumption of buildings will be close to the level of current developed countries［1］.

Currently，the rural population accounts for 80%of the national population，and there are a wide range of rural buildings.Thus，promoting the construction of green building in rural areas will effectively improve the living quality of the residents，reduce energy consumption，and at the same time，achieve the objective of protecting the environment.Green building is the building compatible with the surrounding environment，taking sustainable development as a strategic direction.It aims to save energy，reduce pollution，and create a healthy and comfortable living environment.

Based on the actual situation and survey results in rural areas of Shaanxi Province，we use questionnaire survey，expert interviews and other methods to analyze the factors influencing rural green building，and propose the evaluation indicator system for green building in rural areas.

1 Current situation of the housing construction in rural areas

1.1 Inefficient management of rural residential construction

There are many problems in rural areas，such as unsound construction quality management agencies，lack of necessary incentive policies for improving the quality of rural houses，and lack of rural planning and architectural design institutes，construction companies and materials testing departments.

It results in the rural construction market disorder.A lot of rural construction teams not only lack the necessary technical knowledge，but also lack the sense of safety and quality.The phenomenon of undocumented construction is everywhere，and the construction of rural buildings is basically in the state of spontaneous construction.

The buildings have low technological content，and the waste of resources is serious，which is the main reason for potential safety hazard and great energy consumption in the rural housing con-struction at present［2］.

1.2 Water shortages in rural areasChina is recognized by the United Nations as one of the 13 most water-poor countries.There is difficulty in drinking water for nearly 80 million farmers in China，and 60%of the arable land lack water for irrigation.In rural areas，thewater use efficiency is low and many villagers still continue to dig wells for water.Even if there are water supply facilities in some villages，some serious problems still exist，such as the shortage of safe drinking water source and pipeline leakage phenomenon.

1.3 Poor quality building materials in rural areasThe building materials in rural areas are mainly based on clay brick，with great energy consumption，which produces a lot of carbon dioxide，and destroys a lot of arable land.It lacks supervision in the rural decoration materials market，and many farmers'environmental protection awareness of decoration is weak.Due to limited income，most families choose cheap decoration materials，resulting in poor indoor air quality.

1.4 Great energy consumption for the rural buildingsCurrently the construction of houses in rural areas mainly uses clay brick，ordinary steel windows and other traditional materials.Due to the constraint of technical conditions and construction methods as well as the lack of knowledge in the process of construction，the farmers mostly choose the outmoded building materials，and do not consider the natural environment，orientation，ventilation and other environmental factors.

It makes the heat conservation effect of house outer wall，roof，windowsand doorsunsatisfactory，and the heat transfer coefficient of outer wall and roof is higher than the standard limit for energy-saving building design.There is also a serious phenomenon of waste in heating，causing large energy consumption.In addition，following the traditional method of heating，the rural buildings still use decentralized heating means，resulting in low thermal efficiency.

For rural areas in the moderate or less developed regions，the energy for living is still based on bio-energy，and the fuel for cooking and heating is still the firewood and crop straw，with low thermal efficiency and huge energy consumption.

2 The evaluation indicators for green building in rural areas

2.1 Construction of evaluation indicators for green building in rural areasThe evaluation indicators for green building in rural areas refer to a set of scientific and effective multi-layered indicators that can evaluate whether the buildings in rural areas are green or environment-friendly.In this paper，on the basis of the content of energy-saving evaluation indicators for buildings in the existing literature，we initially determine the evaluation indicators，according to the results of research and survey in rural areas，after drawing on the international advanced green building assessment system.

Then we organize 40 experts on architectural planning，design，construction，management，energy saving，water saving，environment and other aspects in different climate zones for review.According to their recommendations，we make the further modification，and determine the evaluation indicators for green building in rural areas，as shown in Table 1.

Table1 Statisticaldescriptionofevaluationindicatorsforgreenbuildinginruralareas

From four aspects，this system designs the evaluation indicators for green building in rural areas，namely physical properties design of the building，insulation design of the building，application of supporting appropriate technology，and the level of support for development environment.

Moreover，according to the expert scoring method，four second-level indicators are set under each evaluation layer，a total of 16 indicators［3-4］.By the pairwise comparison，we build the judgment matrix A.

where aij＞0，aij＝1／aji，aij＝1（i，j＝1，2，…，n）.

2.2 Construction of review setThis article sets the review set as M＝｛MP｝，p＝1，2，3，4，5（very unsatisfied，unsatisfied，general，satisfied，very satisfied）.

2.3 Construction of weight set using Analytic Hierarchy ProcessW＝［w1，w2，…，wn］.

Using the square root approx imati on method，we calculate the value of W.

From AW＝λmaxW，we can get the eigenvector W.After normalization，the eigenvector W is derived，and W is just theweight vector of evaluation indicators.

3 Data analysis

3.1 Statistical analysis of the questionnaire

（i）Arrangement of research and survey personnel.Led by full-time teachers，this survey selects the college students in rural areas from the majors of Environment，Resources and Environment，Thermal Energy and Construction Environment，using the way of voluntary registration.

The teachers carry out a week of training for students，and take advantage of the vacation to survey the actual situation of local village buildings.

（ii）Research and survey content.The unstructured（informal）interview is carried out on the farmers in the rural areas of different climate zones in Shaanxi Province；the structured interview（questionnaire）is carried out on the construction management agencies；every aspect of the village buildings is observed.

This survey finally selects 10 villages in Shaanxi Province.Nearly 400 questionnaires are distributed，and 361 questionnaires are called back，with the recovery ratio of 90.3%.The effectiveness test is carried out on the recovered questionnaires.Finally，we get 350 effective questionnaires，with the response rate of 90.1%.

The raw data is input to SPSS software，to carry out descriptive statistical analysis.The questionnaire design characteristics are shown in Table 1.

From Table 1，it can be found that in the 360 copies of the questionnaire，the average scoreof factors influencing each indicator is between 2.13 to 3.46，and the average standard deviation value of each indicator is between 0.2 and 0.3，with little difference.

It indicates that various indicator factors of the questionnaire are relatively concentrated in the＂center＂value of average distance degree.The questionnaire indicators are in line with the research themes，which can reflect the energy-saving level of green buildings.

3.2 Evaluation data acquisitionAccording to the previously established evaluation grade，based on the current development situation of rural areas in Shaanxi Province，the experts are invited to score.And we thus get the judgment matrix of relative importance of the indicators.Then we calculate the weight vector of various indicators.

The weight is calculated as follows：

Table1 1-9Scoringscale

If the comparison result is between two scales，it takes2，4，6 and 8.

The steps for evaluating the weight of four first-level indicators using AHP-Delphimethod are as follows：

（i）Building the indicator importance judgment matrix A.The experts conduct pairwise comparison of the four indicators according to 1-9 scale.The results are shown in Table 3.

Table3 Importancejudgment matrix

（ii）Calculating the weight of indicators，as shown in Table4.

Table4 The weightofindicators

W＝（0.302 8，0.081 1，0.479 2，0.136 9）.

（iii）Using the evaluation set V＝｛VP｝，p＝1，2，3，4，5，the experts evaluate and score each second-level indicator.

L1＝（3.8，4.8，3，2）；L2＝（4.8，4.1，3.5，2）；L3＝（3.7，3.3，2，2.6）；L4＝（3，3.6，2，2.5）.

We get the average score：M＝（3.4，3.6，2.9，2.8）.

Total score＝W×M＝3.09.

We calculate the total score of level of rural green building in Shaanxi Province at3.09，indicating that the resp on dents'evalu ation of rural green building in Shaanxi Province is so-so.

In the fourmajor indicators，the experts'scoring of the level of support for development is the lowest，indicating that there are differences in the awareness of energy conservation，funding，geographical location and policy support.

It requires us to take certain measures to improve the level of green building in rural areas.

4 Recommendations for enhancing the green building in rural areas

4.1 Strengthening the energy-saving design and improving the living com fortEnergy-saving design must be based on the local conditions and vary with each individual.It is necessary to carry out scientific analysis of the local climate characteristics and the villagers'basic living habits，and take into consideration the farmers'family income.

Thus，the energy-saving design of green building in ruralareas should first consider the insulation，ventilation，heat conservation and other passive energy-saving technologies for buildings，and then selects the active energy-saving technologies in line with the local rural village building features，which can improve living comfort［5］.

（i）Physical properties design of the building.In the regions with different climate，it is not scientific to choose the north south frontage.We should take into account the sunshine hours for the wall，the direct radiation，the prevailing winter wind direction and so on.In summer，the inside of the houses should avoid direct sunlight，and pay attention to ventilation.In winter，it is necessary to avoid the influx of cold air into the room，to let more sunlight into the room，and keep the room warm and comfortable.

Residential ventilation must meet the basic requirements of human on air flow.When the doors and windows are opened，the indoor and outdoor air can flow smoothly，and particularly in summer，there should be draught.

The buildings with poor lighting make people live long in the dark，and mainly use artificial lighting.It will have an impact on physical and mental health of residents.

Reasonable natural ventilation and lighting can not only effectively reduce the residential energy consumption，but also improve indoor comfort，and provide a healthy and comfortable environment.

（ii）Insulation design of the building.As for the wall，we can choose the new wall materials，mainly with fly ash，coal gangue，stone dust，slag and other wastes as the main raw materials.The materials have a wide range of sources.

We get raw materials from local resources according to local conditions，and the new wallmaterials have characteristics of light weight，heat insulation，sound insulation and thermal insulation.And somematerials can achieve fire safety features.

As for the roof，it suffers the in tensest solar radiation in the summer.At present，the rural residential roofing heat consumption accounts for about15%of the total energy consumption of the entire exterior protected construction.

Therefore，we can use sloping roof，set overhead layer，or make the suspended ceiling.Meanwhile，we can choose the insulation materials with small thermal conductivity and low water absorption.And we can carry out soilless greening on the roof.

As for the windows，it is necessary to well control the proportion of wall and windows，well arrange the location between doors and windows as well as the opening and closing way，and design the draft passing.

In the process of design，we should carry out the construction from three aspects，namely the amount of infiltration，heat transfer，and solar radiation，and should first consider the use of vertical hinged doors and windows.

（iii）External shading.To effectively give equal attention to summer shading and winter heating requirements，the outside windows should use the movable external sunshade.

4.2 Enhancing the application of appropriate technologies

（i）The indoor facility of green building should take into consideration the energy-saving requirements，to choose the energy-saving facilities，such as LED energy-saving lights，solar water heaters，and water-saving sanitary appliances.

（ii）The home air conditioner should choose the energy-efficient type，and install the air conditioner in the position without direct solar radiation.In the use of air conditioner，it is necessary to frequently clean it，and avoid setting too low temperature.

（iii）In rural areas，it is necessary to increase the building energy efficiency promotion，to raise farmers'awareness of energy conservation.In the cultural training activities，it is necessary to add the residential energy conservation knowledge popularization，issue the brochures and arrange the professional staff to carry out home publicity.

In the activities of home appliances to the countryside，the selected products should give more consideration to energy-saving products，and focus on the energy consumption factors.

（iv）In the design of the rural village building，it is necessary to get raw materials from local resources，and increase the use of renewable energy sources，such as solar energy，biogas and biomass.

（v）It is necessary to use the ecological dustbin.The ecological dustbin uses the solar energy-bio-technology to realize pollution-free treatment of the food garbage in rural areas.

The treated food garbage can be applied to farmland as a soil conditioner，and the living garbage volume after being treated can be reduced by more than 80%.The remaining part can also be used as the organicmatter of bio-fertilizer.

4.3 Improving the level of development environmentThe development of foreign and domestic energy-saving buildings and the improvement of living environment are inseparable from the integrated planning and leading of government.Due to the low education level and less income of rural residents，it is difficult to construct the green buildings by themselves.

Therefore，the local government should first guide the farmers'awareness of energy conservation；secondly，the government should raise the funds by a variety of channels，and increase the financial support for the improvement of rural living environment.

Finally，the government should promulgate some energysaving systems，and develop incentives，to drive the villagers to carry out the transformation of energy saving and emission reduction of buildings，and improve the indoor and outdoor living environment.

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