DOI: 10.14457/tu.the.2019.746
title: A new approach for investigating the impact of energy standard on energy and environmental performance of buildings

description: The continual growth of world energy use has raised concerns over a shortage of energy resources as well as drastic impacts on environment. In this respect energy efficiency has become an indispensable policy of many countries in the world. In residential and commercial sectors which consume almost 40 % of the final energy in the world, building energy standards are used to control building design practice and promote energy efficiency in buildings. In order to evaluate the achievement in the implementation of these standards, the energy saving potentials in the building sector must be assessed. Accurate estimation from the assessment is essential for an appropriate planning of national energy policy such as subsidies for energy conservation programs and domestic investment in high-efficiency equipment, as well as a preparation for carbon-credit negotiation. Generally, the estimation is carried out using average energy savings that may raise doubts about the accuracy of the obtained results.This study aims to develop a more accurate approach to be used for investigating the impacts of various building energy standards on energy and environmental performance of buildings. The new approach employed the concept and algorithm of clustering approach to explore a new energy saving estimation method.In order to prove that the proposed method gives more accurate results, two simulation studies are conducted. The parameters selected for the simulation study are the lighting power density (LPD) for the lighting system and three envelope parameters, including U-value of opaque wall, window-to-wall ratio, and shading coefficient of window system for the building envelope system. The values of these parameters are created from Gaussian mixture models with different means, variances, and mixture proportions using MATLAB program. Each set of generated data is then clustered using the Expectation-Maximization (EM) algorithm, while the average values of each set are also calculated. Afterwards the clustering and averaging results are used to estimate the energy saving potentials. In this simulation study, the target values for estimating energy savings are a set specified in Thailand’s building energy code. Both cluster and average results are also compared with the exact savings to determine their errors. It is found that the new approach offers smaller estimated energy savings than those computed from the general approach using the simple average value in all case studies. The differences between errors of cluster and average methods are considered to be statistically significant. Having been proved its validity, the proposed method is applied for the cases in which buildings are improved to comply with prescriptive standards. Both mandatory and voluntary standards are selected to investigate. Actual energy parameters extracted from the energy audit database and energy audit reports are employed in this analysis. It should be noted that the distribution of real data is unable to be described by a normal distribution. The EM algorithm is applied to find groups, or clusters, of these actual data. The obtained results are regarded as the representative of building energy characteristics. Then the energy savings and the CO2 emission reduction from the implementation of both mandatory and voluntary standards are estimated. It is found that the clustering approach gives more accurate results than the averaging method for all cases.The notable advantage of employing the new approach is that this method can estimate the savings with improved accuracy, especially for the case in which the dataset is not normally distributed owing to the fact that the dataset is sufficiently large. The method developed in this study would be beneficial for the policymakers to consider a proper decision to implement national energy-saving measures having impacts on energy economic and environmental protection.