Building energy saving potential in Hot Summer and Cold Winter (HSCW) Zone,China—Influence of building energy efficiency standards and implications

Hot Summer and Cold Winter (HSCW) region plays an important role in China's building energy conservation task due to its high consumption in recent years for both climate and social reasons. National and local building energy standards according to which the buildings are built and operated can affect the building energy consumption to a great extent. This study investigated the energy saving potential in Hot Summer and Cold Winter Zone under different level of energy efficiency standards (China local, China national, and UK standard). Chongqing was taken as an example, and the commercial energy simulation tool eQuest was applied to analyze the building end-use energy. With the existing situation as a baseline, the building energy saving for residential section could achieve 31.5% if the Chinese national standard were satisfied, and the value would further increase to 45.0% and 53.4% when the Chongqing local and UK standard were met. For public buildings, the corresponding energy saving potentials were 62.8%, 67.4% and 75.9%. Parameter sensitivity analysis was conducted. The analysis was able to provide suggestions on energy saving implementation priorities for residential and public buildings. Indications to improve building energy standards and their implementation were also discussed.     

A sensitivity analysis of a cost optimality study on the energy retrofit of a single-family reference building in Portugal

Improvement of the energy efficiency of residential buildings must ensure compliance with cost optimality criteria, assuming a specific lifespan of the building. At the same time, the energy retrofit of buildings ought to preserve their intrinsic architectural and heritage value. Portuguese residential buildings constructed before 1960 did not follow any energy efficiency rules. They represent 29% of the housing stock in the country and there is a high potential for increasing their energy efficiency. However, it costs more to implement envelope energy efficiency measures through retrofitting works than to provide for them in new buildings. An evaluation based on cost optimality criteria should therefore be performed. This work evaluates the energy performance of a Portuguese reference building typical of the pre-1960 building stock for different thicknesses of thermal insulation retrofit solutions (roof, facade, and ground floor) and systems. The study describes a sensitivity analysis that took a range of climate data, intervention costs, energy prices, discount rates, and energy needs into account. An energy needs factor dealt with the occupants’ habits and the effective reduction of energy consumption compared with the estimated energy needs.     

既有建筑的围护结构节能改造分析

以某办公建筑和住宅楼为模型,对其进行围护结构节能改造分析.通过计算比较改造前后室内负荷的变化,发现节能效果相当显著,证明在我国既有建筑围护结构节能改造存在相当大的潜力.     

Assessing energy efficiency and energy conservation potential among commercial buildings: A statistical approach

Energy conservation in the commercial sector is impeded by the lack of simple yet reliable measures of building energy efficiency. A simple Energy Utilization Index is preferable, but it lacks reliability if it remains unadjusted for significant sources of variation. Linear regression analysis represents a straightforward method for introducing necessary sophistication, but care must be exercised in model specification and sample selection. A model incorporating climate, occupancy patterns, HVAC design, and building type explains 42% of the EUI variance in a sample of Texas school and university buildings.     

试论建筑节能设计问题

分析当前我国的建筑能耗状况，强调建筑节重要意义，详细探讨了诸如建筑规划设计、围护结构（如墙体、门窗、屋顶）以及采暖空调等的各种节能问题。     

夏热冬暖地区办公建筑能耗模拟与分析

夏热冬暖地区是我国经济和建筑产业最发达的地区之一,也是建筑能耗最多的地区之一。分析和研究夏热冬暖地区建筑能耗的特点对建筑节能有重要的意义。本文用eQUEST建筑能耗模拟软件模拟了夏热冬暖气候下不同的建筑围护结构的能耗性能,并与实际调查结果进行了比较。结论表明:办公类建筑中的空调是最大的能耗终端,全年的能耗以办公设备和照明的能耗最稳定。有外保温措施和同时具有内、外保温措施最大区别在于节省空调电力消耗31.3%和39.1%。说明建筑外墙保温系统是建筑节能的重要手段。     

The use of sub-hourly primary meter data to identify electricity savings in municipal buildings

Sub-hourly electricity consumption data is being routinely collected from non-domestic buildings in European countries, yet there is little published guidance on how to analyse this data. A new analysis technique is described that produces electricity load profile indicators to help identify potential electricity savings from 81 municipal buildings of six different types: commercial and public offices, libraries and museums, sport centres, schools, community centres and care homes/hostels. This approach is different from conventional energy management analysis techniques since it uses total electricity consumption data in half-hourly periods rather than annual or monthly data. The analysis enabled the detection of buildings with consumption profiles that differ significantly from the typical profile for that building type. This provided a systematic and rapid procedure to identify potential energy saving opportunities in multiple buildings. The new approach introduces a standard statistical technique, independent of energy manager judgement, to help identify energy saving opportunities in buildings.     

Using climate classification to evaluate building energy performance

Traditional benchmarking of building energy performance usually starts by considering a wide range of different factors and giving these factors different weights to help reach one general indicator measuring a building’s overall energy performance. For obtaining more specific information in building energy management performance, this paper proposes an adjustment to the traditional approach by using climate classification and data envelopment analysis (DEA). The study first adopts cluster analysis to classify the evaluated buildings into different climate clusters. Secondly, scale factors are identified by regression analysis. DEA is then employed to assess the energy management efficiency of the evaluated buildings. The samples of 122 office buildings in Taiwan in summer are classified into three climate clusters (warm and long rain hour, hot and middle rain hour, and hot and short rain hour). Research results indicate that the average indicators of energy management performance in each of the three climate clusters are 0.5, 0.56, and 0.56 respectively. The lower value indicator of energy management performance, resulted from the comparison between the energy consumption of the evaluated building and the minimum energy consumption among buildings in the same scale and similar climate conditions, indicates a more potential in energy saving.     

Local strategies to promote energy retrofitting of single-family houses

Energy retrofitting of existing buildings is a central challenge for local, national, and international climate policies, and in several countries, single-family houses represent a major energy-saving potential. Although many municipalities are implementing local climate policies with initiatives to promote energy retrofitting of buildings, little research has been done regarding the role of single-family houses in local climate policies. Thus, we have little knowledge about specific initiatives to promote energy retrofitting amongst owners of single-family houses, we know little about experience from such initiatives, and we lack knowledge about the extent to which national and EU policies support local initiatives directed at homeowners. This article provides insights into these issues from an explorative study on local climate strategies in Danish front-runner municipalities where single-family housing is the dominating building segment. Based on a study of local governance strategies in 12 municipalities targeting homeowners’ engagement in energy retrofitting, the paper finds that these municipalities have developed promising local network-based ways to engage homeowners in energy retrofitting, but finds simultaneously that the national policy mix is only partly supporting these local initiatives. The paper also points out that the local and regional context for the programmes, including the local economic situation, is of great importance, and this context creates both potentials and challenges for the local programmes.     

华南地区城市建筑物防热节能控制指标的选取

根据建筑物热工气候分区及设计特点,对夏热冬暖地区建筑物防热和节能从不同环节进行了详细的分析研究,主要包括建筑物设计本身的体形构造和确定,门窗的材料及窗玻璃材料的选择、建筑物窗墙比例、不同的内外遮阳形式,建筑物墙体材料、墙体外表面处理,屋顶材料和屋顶不同型式的节能效应以及下垫面及绿化植被、水体景观等方面。这些措施是实现建筑防热节能的关键环节,综合这些措施可达到夏热冬暖地区建筑防热节能的热工要求。     

Promoting conservation in buildings: A promising route

More attention would be paid to energy conservation if the property market in the UK reflected the true benefits of energy conservation improvements on the value of buildings. The benefits extend beyond the saving in fuel bills during the investor's period of occupation to a real appreciation in property value as the saving generally continues during the lifetime of the building. When the full extent of this is recognized a free market approach to investing in these measures can be more properly effective and the potential for saving up to £6 billion and for creating up to 150 000 jobs can be realized.     

A study of energy performance and audit of commercial mall in hot-summer/warm-winter climate zone in China

The building energy performance improvement of large-scale public buildings is very important to release China’s energy shortage pressure. The aim of the study is to find out the building energy saving potentials of large-scale public and commercial buildings by energy audit. In this paper, the energy consumption, energy performance, and audit were carried out for a typical commercial mall, the so-called largest mall in Asia, located in a hot-summer and warm-winter climate zone. The total annual energy consumption reaches 210.01 kWh/m², of which lighting energy consumption accounts for 30.03 kWh/m² and the lift and elevator energy consumption accounts for 40.46 kWh/m². It is by far higher than that of the average building energy consumption in the same category. However, the annual heating, ventilation, and air-conditioning (HVAC) energy consumption is only 87.19 kWh/m² even though they run 24/7. It proves that the energy performance of the HVAC system is good. Therefore, the building energy savings potential mainly relies on reducing the excessive usage of lighting, lifts, and elevators.     

楼宇节能潜力评估和能源管理方法探讨

本文在阐述楼宇能耗构成比例的基础上,叙述了楼宇节能潜力的评估方法和降低楼宇能源消耗的节能管理措施。     

Assessment of energy savings from the revised building energy code of Thailand

The government of Thailand legislated an Energy Conservation Promotion Act (ECP Act) in 1992 and set bye-laws that identify designated buildings (DBs) and detail mandatory requirements for energy conservation for DBs in 1995. An Energy Conservation Promotion Fund (ENCON Fund) was also created to fund energy audits on 1900 DBs. Recently the requirements and procedures for energy conservation in buildings have been revised where system performance requirements for building envelope, lighting, air-conditioning, and hot water generation are adopted. Moreover, the new building energy code (BEC) distinguishes different categories of DBs, provides credit for use of solar energy, and introduces a new option of whole building energy compliance. The authors develop building models from data obtained from energy audit reports and use them to estimate savings on energy and peak demand from future new buildings using forecasted energy and peak demand data from the Load Forecast Subcommittee, a panel tasked to forecast future electric load of Thailand. From a modest level of energy saving in the first year that the code is expected to be enforced, the level of saving rise to over 10% and 20% annually of requirement of target buildings in 6 and 12 years respectively.     

The energy saving index and the performance evaluation of thermochromic windows in passive buildings

The concepts of the energy saving equivalent (ESE) and energy saving index (ESI) are presented in this paper to evaluate the performance of new materials and components in passive buildings. The ESE represents the hypothetical energy that should be input to maintain a passive room at the same thermal state as that when a particular material or component is adopted. The ESI is the ratio of a particular material or component's energy saving equivalent to the corresponding value of the ideal material or component that can maintain the room at an ideal thermal state in passive mode. The former can be used to estimate the effect of the adoption of a certain building component or material on the building's thermal state from an energy standpoint, while the latter can be used to characterize the performance of the actual building component or material from a common standpoint and be used to evaluate the performance of components or materials in different climatic regions or under different operating situations. In this study, the ESI was used to evaluate the performance of a thermochromic window, represented by a single vanadium dioxide (VO₂) glazing, in passive residential buildings in three climatic regions of China (cold zone, hot summer and cold winter zone, and hot summer and warm winter zone).     

Economic potential of energy-efficient retrofitting in the Swiss residential building sector: The effects of policy instruments and energy price expectations

The aim of this paper is to analyse the profitability of energy-efficient retrofit investments in the Swiss residential building sector from the house owner's perspective. Different energy price expectations, policy instruments such as subsidies, income tax deduction and a carbon tax, as well as potential future cost degression of energy efficiency measures were taken into account. The discounted cash flow method was used for the investment analysis of different retrofit packages applied to a model building scheduled for renovation, i.e. a single-family house constructed between 1948 and 1975. The results show that present Swiss policy instruments push investments for energy-efficient retrofitting to profitability. Cost degression has a minor significance for investment profitability. However, the most relevant factor for the investment analysis is the expected energy price. Expecting a future fuel oil price at the level of 2005, efficiency investments are close to profitability even without policy support. If higher energy prices were expected, energy-efficient retrofitting would be an attractive investment opportunity.     

German and Norwegian policy approach to residential buildings’ energy efficiency—a comparative assessment

Buildings in private and domestic use are responsible for about 30% of the global greenhouse gas emissions attributable mainly to their need for heating and cooling energy. This corresponds to about 40% of the global final energy consumption. Therefore, a viable implementation of building energy efficiency policies is inevitable to realize a transformation of the energy system to mitigate climate change. Within the building sector lies a huge potential for emission reduction consisting in the renovation of the existing building stock and climate-friendly building guidelines applicable to new constructions, both adapting CO₂-neutral technology solutions. However, as there are several different pathways leading to a decarbonized energy system, there is always the question which political and technological solutions are most efficient, effective, and feasible. This paper aims to analyze building efficiency policy measures and instruments and the related technological solutions in two front-runner countries of the energy transition, possessing different structural conditions: Germany and Norway. We hence apply a comparative approach which allows us to present and assess the policies in place. The paper answers three research questions: (1) Which policies prevail in Germany and Norway to foster the deployment of energy efficient and decarbonized solutions for residential buildings? (2) How do these policies respond to country-specific barriers to the energy transition in the building sector, and (3) What effects do they have on the actual implementation of technological and societal solutions? This research provides a new insight to the highly relevant topic of energy efficiency in buildings in the context of international Intended Nationally Determined Contribution benchmarking and discusses some unsolved trade-offs in the translation of the global climate governance into the national building sector.     

The analysis of energy consumption of a commercial building in Tianjin,China

According to statistics and field investigation, the energy consumption situation and reality of commercial building is described in this paper. As the first step of large-scale public building energy efficiency supervision system encouraged by central government of China, the energy consumption of several typical commercial buildings and public buildings was analyzed in detail. The main contents of investigation are as follows: basic information of building, operational record of energy consumption equipment, energy consumption of indoor equipments, energy-efficiency assessment of energy consumption systems and equipments, investigation of behavior energy saving, etc. On this basis further analysis and diagnosis including indoor thermal and humid environment, operation state of air-conditioning water system, operation state of air-conditioning duct system and operation management of air-conditioning system were implemented. The results show that the most energy consumption of buildings in this city is commercial buildings, which can reach to about 240 W/m² per year. Further analysis tells that air conditioning systems play the major role of building energy consumption, and building energy saving has great potential in this city. In this paper, the ways of diagnosis work for building energy consumption are also described and discussed. Reasonable test, diagnosis and analysis are meaningful for building energy efficiency retrofit and management.     

Energy efficiency supervision strategy selection of Chinese large-scale public buildings

This paper discusses energy consumption, building development and building energy consumption in China, and points that energy efficiency management and maintenance of large-scale public buildings is the breakthrough point of building energy saving in China. Three obstacles are lack of basic statistics data, lack of service market for building energy saving, and lack of effective management measures account for the necessity of energy efficiency supervision for large-scale public buildings. And then the paper introduces the supervision aims, the supervision system and the five basic systems’ role in the supervision system, and analyzes the working mechanism of the five basic systems. The energy efficiency supervision system of large-scale public buildings takes energy consumption statistics as a data basis, Energy auditing as a technical support, energy consumption ration as a benchmark of energy saving and price increase beyond ration as a price lever, and energy efficiency public-noticing as an amplifier. The supervision system promotes energy efficiency operation and maintenance of large-scale public building, and drives a comprehensive building energy saving in China.     

THE HIGH-RISE OPPOSING FACADE IN CLEAR SKY CONDITIONS—NOT ALWAYS AN “OBSTRUCTION” TO DAYLIGHT

The opposing building facade is an omnipresent feature for buildings in the urban commercial setting. In clear sky conditions, there are large surfaces of building facades that have the potential of reflecting sunlight incident on them. When the sun is behind a building (so that the solar facade azimuth is greater than 90°), the building opposite potentially acts as a passive daylighting device to it. The work discussed in this paper shows that the performance of this device varies for each floor and for different building densities. Using the ADELINE simulation software, a street with high rise buildings opposite each other is modelled in clear skies, and daylighting is calculated in rooms at different floor levels. Comparisons are made with daylighting of the same rooms without an obstructing building in order to observe the effect of the “obstructing building” to daylighting. Preliminary results indicate that the opposite facade of high rise buildings has the potential to be considered a passive daylighting device in particular contexts. As a passive device, the opposing facade could be given attention by urban designers and planners, as well as by those drawing up building legislation for the urban built environment. It would be desirable and important for users of the built environment, to determine future developments from the point of view of how opposing facades affect daylighting. This approach could have implications for energy efficiency and conservation and would utilise the free resource of solar radiation more effectively.