低能耗绿色建筑中针对被动式太阳能技术应用评价方法研究

建筑作为人类文明最重要的产物之一,在全球范围内消耗约40%的一次能源,排放约30%温室气体。在全球能源危机与气候问题的背景下,应采取积极措施减少和取代化石燃料的消耗,同时又不能降低建成环境的舒适度水平。实际上,为实现建筑的"开源""节流"并举的目标,提高建筑能源效率与应用可再生能源的建筑技术已经在建筑领域取得诸多成就。被动式太阳能建筑技术是指通过建筑朝向的合理选择和周围环境的合理布置,内部空间和外部形体的巧妙处理,以及建筑材料和构造的恰当选择,使其在冬季能够收集、储存并使用太阳能,辅助建筑的采暖;同时在夏季通过采取遮阳、自然通风等措施又能屏蔽太阳辐射,帮助室内散热,从而辅助建筑的降温。常见的被动式太阳能建筑技术,例如直接受益太阳能系统、间接受益太阳能系统、独立太阳能系统已经被广泛应用于各类建筑之中。但是,通过综述美国LEED与德国En EV,以及我国《绿色建筑评价标准》与《被动式超低能耗绿色建筑技术导则》等评价体系的相关调研情况发现,在现行的绿色建筑、低能耗建筑评价标准中,太阳能利用的评价方法是以主动式技术应用为基础的,并未全面考虑被动式太阳能建筑技术的贡献率问题。针对此问题,通过分析评价原则与目标、评价指标性质、核心评价指标遴选,提出一种低能耗绿色建筑中针对被动式太阳能贡献率问题的评价方法,以相对太阳能贡献率概念,应对我国太阳能资源分配不均的问题,并提出评价被动式太阳能建筑技术的算法。最后对评价结果的交流、弹性与适应性进行了讨论。并以一栋坐落于中国天津的绿色建筑为例。天津属于太阳能采暖适宜气候区A区,《被动式太阳能建筑技术规范》中的太阳能贡献率参考值为20%。在室内设计温度设置为18℃的情况下,若通过实测计算该建筑的太阳能贡献率为25%,则相对太阳能贡献率在15%~30%区间范围内,因此该建筑可以被认定为第二等级或加分。该评价方法坚持了低能耗绿色建筑"被动设计优先,主动技术优化"的设计原则,完善了现行绿色建筑评价标准中对被动式太阳能技术应用的考虑。寄希望于建筑参与者可以理解、应用这个方法在被动式太阳能建筑中的技术评价,以推动建筑可再生能源技术的发展,并有利于建设资源节约型与环境友好型社会。

Assessment Method of Passive Solar Technologies for Low-energy Green Buildings

As one of the most important products of human civilization, buildings all around the world consume and emit a significant amount of energy and carbon dioxide, which are about 40% of the total primary energy resources and 30% of greenhouse gas emission, respectively.In the global context of energy crisis and environmental issues, it is time to look into these problems, to reduce and replace fossil fuels without compromising the comfort conditions of built environment.Actually, concerted efforts have been carried out to improve building energy efficiency and apply renewable energy technology in building sector, and to achieve reduction of building energy consumption and addition of building energy supply simultaneously.Passive solar building technologies refer to the reasonable choice of building orientation, the rational arrangement of surrounding environment, the ingenious handling of internal space and external body, and the proper choice of materials and structures, to collect, store and distribute solar energy in the form of heat in the winter, and to reject, shield and disperse solar radiation in the form of cool in the summer.As the representative technologies of passive solar building technologies, direct solar system, indirect solar system and isolated solar system have already been applied to various building types.However, this paper reviews the mainstreaming Green Building and Low-energy Building assessment standards currently both at home and abroad, such as American LEED(Leadership in Energy and Environmental Design), Germany EnEV(Energieeinsparverordnung), "Assessment Standard for Green Building(GB/T 50378)"and "Technical Guideline for Passive Ultra-low Energy Green Building" in China, and finds that the assessment method of solar energy utilization is based on active technology application in these assessment standards, and does not fully consider the contribution rate of passive solar building technologies in the current green building and low energy building assessment standard.Therefore, to address this issue, this paper analyzes the assessment principles and objectives, the properties of assessment indicators, the selection of key assessment indicator, and then proposes an assessment method of passive solar contribution rate for Low-energy and Green Buildings and a concept of relative solar energy contribution rate to deal with inhomogeneous distribution of solar energy resources in China.Besides, this paper develops the corresponding algorithm of passive solar building technologies assessment.In the end, the communication of assessment result, flexibility and adaptability of this assessment method are discussed.And a green building located in Tianjin, China as the case study.According to "Technical Code for Passive Solar Building(JGJ/T 267)", Tianjin is a climatically optimum region of passive solar energy utilization, and the proposed solar contribution rate is 20%.The air temperature of indoor environment is set at 18℃.If the actual solar contribution rate is 25% by measuring and calculating, the value of relative solar contribution rate is between 15% and 30%.Then this building could be identified the second rating or added the corresponding grade according to this assessment method.This promising method could stick to the principle of "passive design priority, active technology optimization" for low-energy and green building, as well as improve the consideration of passive solar energy application of the current assessment standard for low-energy and green building.It is expected that researchers and practitioners could understand and adopt this method in passive solar building technologies assessment to promote the development of renewable energy building technology, and to facilitate the construction of resource-saving and environment-friendly society.