台灣建築外殼節能法規的成本最佳化策略

Cost‐optimal Strategy for Energy Conservation Design Code of Building Envelop in Taiwan

本文透過EPBD2010的建築能效成本最佳化原則以及建築外殼的熱流解析，來檢討台灣現有建築外殼節能法規的節能效益與成本效益。本文首先強調起源於寒帶氣候「高隔熱、高氣密」節能技術的德國「被動式建築認證」，並不符合溫熱氣候國家之建築節能成本最佳化策略，接著再分析2008年以來一系列論文，曾經揭露建築外殼保溫層設計或雙層外殼設計，在亞熱帶氣候會導致高空調耗能上升之「隔熱反效果現象」，因此呼籲亞熱帶與熱帶氣候國家切忌引入寒帶氣候流行的「高隔熱、高氣密」節能手法，以防止節能反效果效應。透過在亞洲地區303城市一個透天住宅與一間辦公建築空間的全年空調負荷分布分析，發現其中住宅的「隔熱反效果現象」是越往熱帶的南台灣越顯著，而辦公、商業類建築的「隔熱反效果現象」是越往涼爽的北台灣越顯著，但台灣無庸置疑是處於亞熱帶與熱帶的最顯著「隔熱反效果現象」區域，因此台灣現有建築節能法規應避免強化建築外殼的隔熱與氣密規範以避免節能反效果。本文同時採用由寒帶到熱帶12個城市的全年室內外溫差與當地建築節能法規對住宅外殼的熱傳透率U值規範，來分析住宅建築外殼隔熱規範的嚴格程度，由此發現台灣現行建築外殼隔熱法規在12個城市中已接近一個非常合理的嚴格程度、可說已接近成本最佳化水準。本文最後以近零碳建築定義之節能50%基準，來分析包括外殼、空調、照明的整體節能潛力，發現空調、照明的節能設計比建築外殼節能設計有高出4.7~7.1倍的節能潛力。因此在「隔熱反效果現象」與成本最佳化原則雙重考量之下，台灣的淨零建築已不必要求強化建築外殼節能法規，相反地應針對更高CP值、更有節能動力的空調、照明設備系統的能效設計，積極推動強制性法制化工作。

 

This paper used the cost‐optimal principle of EPBD2010 and building envelop thermal analysis to investigate the energy conservation effect and cost efficiency of existing energy conservation design code of building envelop in Taiwan. This paper firstly pointed out the Germany’s passive house certification system which emphasizing the energy conservation technology of high insulation and high airtight design which origin in cold climatic is not march the cost‐optimal strategy of building energy conservation in hot or warm climates, then analyzed a series of papers from 2008 which have revealed that more building envelop insulation or double skin design in subtropical climates might lead the increasing phenomenon of AC energy consumption, so called anti-insulation effect, so as to appeal the tropical and subtropical countries should not to introduce the cold climate’s building energy conservation technologies of high insulation and high airtight design of building envelop to prevent the opposite effect of energy conservation. Through analyzing the air conditioning thermal load distributions in 303 Asian countries for a house and an office building space, this paper found that the anti-insulation effect of residential building appeals to more significant in southerner tropical Taiwan and the anti-insulation effect of office or commercial building appeals to more significant in northerner subtropical Taiwan, it is no doubt that Taiwan is located among tropical and subtropical climates which are the most significant areas of anti-insulation effect, so that the existing Taiwan’s building energy design regulation should to be avoided to strengthen the insulation and airtight code of building envelop to avoid the anti-effect of energy conservation. As the same time, this paper analyzed the strict level of envelop insulation code of residential building in 12 cities from cold to tropical climates by comparing the annual indoor-outdoor temperature difference and the thermal transmission rate U value of the local building regulations and found Taiwan’s existing building envelop insulation code is close to a very appropriate strict standard and could be considered as a cost‐optimal level among the 12 cities. Finally, this paper analyzed the total energy conservation potential of building envelop, air conditioning and lighting by the criteria of 50% energy saving rate in nearly zero carbon building definition and found that the energy conservation potential in air conditioning and lighting design is about to 4.7~7.1 times comparing to building envelop design. So that, to consider both the anti-insulation effect and cost‐optimal strategy, Taiwan’s net zero building policy is not necessary to strengthen the existing building envelop regulation and need more aggressive to promote the mandatory legalization in the energy efficiency design of air conditioning and lighting design which is higher CP value and more energy saving power.