The Evaluation And Optimization Study On Energy Saving Design Of Rural Houses In Northern Hunan Based On Value Engineering

Under ecological and sustainable background, with the rapid development ofChinese rural area economy, the improvement of peasants’living standards and withthe popularity of new rural construction, one of most important issues in sustainablebuilding design is how to design and build rural houses reasonably and scientifically tomeet with peasants’demands. Nowdays, many peasants have abundant experiencesabout living and working in large cities beause of acceleration of urbanizationresulting in pushing many peasant-workers into cities. Therefore, they are oftenobsessed with styles and constructing ways of urban buildings when they build theirown. What they need indeed are not fully known restricted by economic conditions,and cannot be expressed correctly to architects. On the other hand, architects hardlyunderstand aesthetic requirements, functional demands and economic conditions ofpeasants, so their design often cannot be accepted, all of which finally owing to thekey contradiction: the confliction betwteen predicted energy-saving effects andconstruction feasibility, the former is put forward by architects, the latter is decided bypeasants, both are important but paradox factors in energy-saving design. So, it isnecessary to establish rational system to solve the contradiction, in which, botharchitects and peasants can understand their demands and what they want to express,meanwhile, they may also find appropriate ways to express mutual requirments whenmaking design decision together.Taking rural houses in Northern Hunan as the research subject, the paper introducesValue Egineering (VE) into energy-saving design. Guided by the vital principle of“passive technology has priority, active ones afford optimization, and new energyresources may supplement”, the paper has researched the evaluation on energy-savingdesign of rural houses in Northern Hunan based on Value Engineering theories. Thisassessment system cannot put emphasize on concrete energy-saving methods andtechnology exploration, rather than taking these technologies as the vital indexes forevaluation and optimization. The assessment system can also be acted as the evaluatingand deciding orientation for architects and peasants, which may afford great help forrefining energy efficiency technologies. The paper takes rural houses in NorthernHunan as example, to demonstrate the evaluation system.Firstly, Value Egineering theories the feasibility of introduce VE to building design have been totally presented. Then, by analyzing the cost generalization of rural houses,transforming the “function-cost” into the “function-benifit” idea, VE equation hasbeen deduced afresh which can be expressed: V=F×S. This new VE equation hasshown that the final value of an energy-saving design can be determined by themultiplication of function coefficient F and benefit coefficient S, based on which, abinary evaluation system composed with function coefficient and benefit coefficienthas been established to guide energy-saving design. Function coefficient F means thepredicted energy-saving effect put forward by architects, benefit coefficient S meansthe construction feasibility of an enegy-saving project decided by peasants.Secondly, according to composed factors of the binary evaluation system, theinvestigation of rural houses in Northern Hunan was carried out including naturalventilation, shading, daylighting, thermal insulation of the envelopes and energyconsumption, all of which are related to function coefficient. Based on summing upinvestigation and adaptability of rural houses in Northern Hunan, the idea ofenergy-saving design centering on the value has been formed. Using the functionanalysis ways of Value Engineering, the paper has summarized the FAST aboutenegy-saving design of rural houses in Northern Hunan, including6secondary and17three-level function indexes; through AHP combined with scoring by experts, theweight of each function index is confirmed deailly.Thus, the calculating list of functioncoefficient has been reached clearly.Thirdly, the paper mentions that the meaning of contemporary rural houses has beenexpanded under the green, ecological social context, including design, technology,economy and ecology. These four aspects make up benefit coefficient S of the binaryevaluation system, which are design benefit, technology benefit, economy benefit andecology benefit, all of wich embody the construction feasibility of an energy-savingdesign project. According to comprehend evaluation methods of Value Engineering,the4bennefits have been evaluated detailly, the arithmetic mean is cacaulated, whichis the benefit coefficient S. By evaluating the S, peasants can understand the project indetail and visually, so as to determine the construction feasibility of the project.At last, by synthesizing previous researches, the binary evaluation system aboutenergy-saving design of rural houses in Northern Hunan based on Value Engineeringhas been established. Architects and peasants may apply this system to the practice,guiding the energy-saving design. What’s more, in order to popularize the systemeasier and more convenient, related evaluating software is already developed by VisualBasic. Functions and benefits are both considered in the binary evaluation system aboutenergy-saving design of rural houses in Northern Hunan based on Value Engineering,which also takes opinions of architects and peasants into account. This evaluationsystem afford a platform to solve the pair of contradictions during enegy-saving design,assess and optimize design project, which is meaningful and has certain practicalvalues as to rural house design.