Abstract
As one of the critical concepts in residential energy performance research field, shape coefficient has long been disputed for its validity of evaluating energy consumption. Although suggestions have been brought forward to try to optimize this concept, these proposals still have shortcomings and have not been tested. Based on analysing these existing optimizing proposals, this paper starts from prototype study and summarizes the problems of concept of shape coefficient in terms of definition and relationship with building energy. According to these current issues, the reason for negatively influencing the accuracy of shape coefficient with regard to assessing the building energy consumption is confirmed. By correcting the expression of shape coefficient through inserting a correction factor related to story height, corrected shape coefficient is proposed. Combined with built residential building samples, the corrected and original shape coefficient is contrasted at the macro statistical and micro experimental levels respectively. It is found that the new coefficient has closer correlation with residential building energy performance and is more accurate in evaluating the energy consumption.
Highlights
Residential buildings, which comprises more than 70% of land use in most cities and responsible for 70% of the energy consumption by buildings, significantly contributes to greenhouse gas emissions [1]
The parameters were as follows: As Yangtze River Delta is situated in the hot summer and cold winter climate zones, the values of indoor set temperature, Energy Efficiency Ratio (EER) and indoor heat loads which stands for the energy consumption of occupants, lighting, equipment, etc. were from Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Cold Winter Zones of China
Starting from analysing the dispute over the current concept of shape coefficient, this paper proposes corrected shape coefficient by inserting a new parameter called modified story height factor into the expression of original shape coefficient based on thermal and geometric principles
Summary
Residential buildings, which comprises more than 70% of land use in most cities and responsible for 70% of the energy consumption by buildings, significantly contributes to greenhouse gas emissions [1]. Lin for the first time in 1981 [4], shape coefficient has long been deemed as a key concept in residential building design and building energy related research. The Energy-saving design standard for residential buildings (JGJ134-2010) states that a building will consume more energy by 2.4%~3% when shape coefficient increases by 0.01 [7]. Experiments were performed to verify that the increase of the story height of residential buildings would lead to the smaller shape coefficients, the consequent energy expenditure would rise at the same time [16-17], which was contradictory to most conclusions of the related research mentioned above. It is undeniable that the concept of shape coefficient is imperfect Why such a coefficient with a barrage of questions is still considered to be a critical indicator related to residential energy consumption? Why such a coefficient with a barrage of questions is still considered to be a critical indicator related to residential energy consumption? Is the shape coefficient, even partly, reasonable? What is the problem with its relationship with residential energy performance? Facing the drawbacks, how to correct the shape coefficient drawbacks and can the corrected coefficient eventually achieve the purpose of optimizing the existing one? These questions are discussed in this paper
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