Energy performance and indoor environmental quality in Hellenic schools

School buildings constitute a major part of the non-residential building stock, though due to their operational characteristics, they represent a low percentage of the overall energy balance of the building sector. Although health and productivity of pupils and teachers is strongly affected by the indoor environmental quality of their school, poor indoor air quality has been reported in published literature, even so for recently constructed school buildings. The same applies for the energy consumption, with large amounts of energy being wasted because no energy saving measures are applied for the operation of schools. This paper presents the outcome of a study on the energy performance of Hellenic school buildings. The general features of the contemporary building stock are presented along with the results from an energy survey in 135 Hellenic schools. The derived energy consumption benchmarks are compared with published literature. Finally, the energy performance and indoor environmental quality of a representative sample of schools in metropolitan Athens are assessed in a holistic approach to the “energy efficiency – thermal comfort – indoor air quality” dilemma. The IEQ assessment was based on an objective evaluation by monitoring crucial indoor conditions and a subjective occupant evaluation using standardized questionnaires. The potential of several energy conservation measures is evaluated in terms of energy savings and reduction of greenhouse gas emissions along with the related payback periods.     

夏热冬冷地区高校既有办公楼热舒适性实测与分析——以湖南城市学院办公楼为例

为了研究湖南省高校办公楼室内热环境,达到优化湖南省高校既有办公楼节能（改造）设计的目的,对湖南省高校办公楼（以湖南城市学院为例）进行了冬夏季两季温度现场测试,对测试结果分析,显示了湖南省高校办公楼室内热环境在不同楼层之间存在差异,整体来说夏季室内热炎热,冬季寒冷,针对此现状采取运用计算机软件DEST对湖南城市学院办公楼的节能改造方案进行节能性能的模拟分析,提出满足建筑节能要求的改造方案措施。     

Indoor environment quality in buildings and its impact on outdoor environment

The main purpose of buildings is to provide a comfortable living environment for their occupants. This includes, among others, thermal, visual and acoustic comfort as well as indoor air quality. Except during the 1950’s and 1960’s, it has always been considered important that an excess use of energy should be avoided in the construction and the management of a building, sometimes even at the cost of user comfort. Energy saving is, however, not the main purpose of the building. Indeed, if it were really so, the largest energy savings would be obtained by not erecting the building in the first place.Since the Rio conference, there have been more and more incentives to save energy and lower the impact of buildings on the environment. Therefore, there is no excuse for the building sector not to adopt a sustainable development policy.Some energy is required to control the indoor climate and indoor air quality. Therefore, it is often suspected that energy savings result in poorer indoor environment quality, or, on the contrary, that a high comfort level is the result of high technology and high energy consumption. This is not true. It is now generally admitted among building scientists that high quality energy services do not necessarily incur a high energy use, and that good environment quality can be obtained with a reasonable amount of energy and power, and with a low environmental impact.The presentation brings some evidence from past and current research to support this assertion.     

Passive climate control in Spanish office buildings for long periods of time

Recent studies have shown that the effect of the internal wall coating on an indoor thermal environment can be seen for short periods of time [Hameury S. Moisture buffering capacity of heavy timber structures directly exposed to an indoor climate: a numerical study. Building and Environment 2005;40(10):1400–12]. However, for long periods of time this effect is hidden by the air renovation and vapour release. These passive methods are gaining popularity because they are energy conscious and environmentally friendly. However, there is little published data on mass transfer between building envelopes and indoor air [Simonson CJ, Salonvaara MH. Mass transfer between indoor air and a porous building envelope: part I—field measurements. In: Proceedings of healthy buildings, vol. 3, 2000; Simonson CJ, Tuomo O. Moisture performance of buildings envelopes with no plastic vapour retarders in cold climates. In: Proceedings of healthy buildings, vol. 3, 2000]. The main objective of this study is to show the internal wall coating effect on indoor air conditions by means of the indoor air parameters. These measurements were taken in 25 office buildings during different seasons. Our results will allow us to understand the internal coating effect for long and short periods of time and, therefore, the thermal comfort and indoor air quality conditions.     

Reinforcement learning for energy conservation and comfort in buildings

This paper deals with the issue of achieving comfort in buildings with minimal energy consumption. Specifically a reinforcement learning controller is developed and simulated using the Matlab/Simulink environment. The reinforcement learning signal used is a function of the thermal comfort of the building occupants, the indoor air quality and the energy consumption. This controller is then compared with a traditional on/off controller, as well as a Fuzzy-PD controller. The results show that, even after a couple of simulated years of training, the reinforcement learning controller has equivalent or better performance when compared to the other controllers.     

Life cycle inventory of buildings: A calculation method

Traditionally, life cycle assessment (LCA) is mostly concerned with product design and hardly considers large systems, such as buildings, as a whole. Though, by limiting LCA to building materials or building components, boundary conditions, such as thermal comfort and indoor air quality, cannot be taken into account. The life cycle inventory (LCI) model presented in this paper forms part of a global methodology that combines advanced optimisation techniques, LCI and cost-benefit assessment to optimise low energy buildings simultaneously for energy, environmental impact and costs without neglecting the boundary conditions for thermal comfort, indoor air quality and legal requirements for energy performance. This paper first outlines the goal and scope of the LCI. Then, the partial inventory models as well as the overall building inventory model are presented. Finally, the LCI results are shown and discussed for one reference dwelling for the context of Belgium.     

Energy consumption and potential energy savings in old school buildings

Energy and indoor environmental audits of energy consumption and indoor air quality were taken in 24 school buildings in Slovenia. The audits show that these buildings are high energy consumers and have poor indoor air quality, as expressed by 60% of the surveyed pupils. This article deals with energy consumption in the analysed schools. The nominal heating power of boilers, and heat exchangers, which are used in district heating, show a 57% overcapacity. The heat losses of the school buildings are 89% higher than the recommended values. According to our analysis of the possible measures to improve the situation in the school buildings, it will not be possible to ensure rational energy use and good indoor air quality with low investment costs. Should we change from hot-water heating systems and natural ventilation to energy efficient blown air systems with which one device provides the comfort of both heating and air conditioning?     

确定长江流域供暖空调能耗指标的边界条件

讨论了影响长江流域住宅供暖空调能耗水平的诸因素,包括热环境质量、室内空气品质和新风量、供暖空调系统和比和性能系数、供暖期空调期除湿期天数及建筑热工特性等,给出了这些因素的建议值。     

建筑节能性能对室内环境影响评估

室内环境质量是影响建筑舒适度的重要因素.建筑节能性能对室内环境的影响极少被关注.借助计算机建造模型及计算数据,对3种不同节能性能的建筑进行室内环境比较分析,包括对室内空气温度、空气交换速度及室内光线质量比较分析.研究表明：建筑节能性能不仅影响到建筑的能耗,而且对室内环境也会产生影响,但节能性能的优劣并不与室内环境成正比,节能性能好的建筑其室内环境质量并不绝对优于节能性能差的建筑;对同一建筑,可持续能源的使用在短期内只会对室内环境质量产生微小的影响.     

Simulation of coupled heat and moisture transfer in air-conditioned buildings

The simultaneous heat and moisture transfer in the building envelope has an important influence on the indoor environment and the overall performance of buildings. In this paper, a model for predicting whole building heat and moisture transfer was presented. Both heat and moisture transfer in the building envelope and indoor air were simultaneously considered; their interactions were modeled. The coupled model takes into account most of the main hygrothermal effects in buildings. The coupled system model was implemented in MATLAB-Simulink, and validated by using a series of published testing tools. The new program was applied to investigate the moisture transfer effect on indoor air humidity and building energy consumption under different climates. The results show that the use of more detailed simulation routines can result in improvements to the building's design for energy optimisation through the choice of proper hygroscopic materials, which would not be indicated by simpler calculation techniques.     

Environmental efficiency in residential buildings – A simplified communication approach

For all actors involved with planning, developing and managing buildings, the environmental impact relating to energy use and the quality of the indoor environment are both aspects of major concern. It is crucial that a reduction in the environmental impact of a building is not achieved through compromising the indoor environment. This paper presents a method to assess user satisfaction related to the indoor environment and the environmental impact related to the energy use of the building, i.e. the environmental efficiency of the building. This environmental efficiency comprises two indices that are calculated separately but displayed in the same diagram to facilitate communication of complex information. This approach forms part of the Swedish life cycle based environmental assessment tool for buildings, EcoEffect. The present paper presents and exemplifies the environmental efficiency of buildings using data from 26 Swedish multi-family residential buildings and proposes a number of reference values. The concept can be used as an overarching objective for environmental management of a property firm's building stock or for evaluating targets set in the planning process for a new building. It can also be used for environmental rating of buildings, which would probably increase the communication value further. The aggregated indices are rough but proportionately straightforward to calculate and easily communicated. In addition, they address the environmental impacts of buildings in a much more comprehensive way than the current practice.     

Life cycle inventory of buildings: A contribution analysis

A companion paper presented the life cycle inventory (LCI) calculation model for buildings as a whole, developed within a global methodology to optimise low energy buildings simultaneously for energy, environmental impact and costs without neglecting the boundary conditions for thermal comfort and indoor air quality. This paper presents the results of a contribution analysis of the life cycle inventory of four typical Belgian residential buildings. The analysis shows the relative small importance of the embodied energy of a building compared to the energy consumption during the usage phase. This conclusion is even more valid when comparing the embodied energy of energy saving measures with the energy savings they realise. In most studied cases, the extra embodied energy for energy saving measures is gained back by the savings in less than 2 years. Only extremely low energy buildings might have a total embodied energy higher than the energy use of the utilisation phase. However, the sum of both remains small and the energy savings realised with these dwellings are large, compared to the energy consumption of average dwellings.     

The Energy Concept Adviser—A tool to improve energy efficiency in educational buildings

Educational buildings such as kindergartens, schools and universities display many similar design, operation and maintenance features in most countries. The two most noteworthy similarities amongst these building types are the high energy consumption and the necessity for retrofitting many buildings within this sector. However, studies have shown that during retrofit, energy saving measures are only rarely applied, because the decision-makers lack knowledge of investments and the efficiency of potential energy saving measures. The main goal of the International Energy Agency ECBCS Annex 36 is to provide the educational building decision-makers with sufficient data, information and tools to improve their learning and teaching environments by improving the energy efficiency of their buildings.     

夏热冬暖地区绿色建筑性能后评估研究

为了解夏热冬暖地区绿色建筑运行后实际能耗和室内环境品质，文章详细介绍了该气候区内绿色建筑主要技术的应用情况及应用效果。选取位于该气候区内共11个获得绿色建筑认证的办公建筑，通过调研实际能耗，结合用户主观问卷调研，与常规办公建筑的能耗和室内环境品质主观满意度进行了对比研究。结果表明，对于A类办公建筑，绿色建筑与常规建筑无明显差异，均略低于引导值；对于B类而言，绿色办公建筑的总能耗显著低于常规办公建筑，但与能耗指标相比二者能耗均较高，是建筑节能工作的重点。在室内环境品质满意度方面，用户对绿色建筑的满意度明显高于常规建筑，在空气品质和室内环境控制上尤为明显，光环境的差异则更多是归因于天然采光的设计，而非人工照明的优化。最后通过一个案例从节地、节能和室内环境等3个方面全面地介绍了适宜于夏热冬暖地区的绿色建筑设计。     

Improving energy performance of school buildings while ensuring indoor air quality ventilation

Energy conscious design of school buildings, as well as deemed-to-satisfy provisions in a Performance Based Energy Code, should address the problem known as the energy efficiency—thermal comfort—indoor air quality dilemma (EE-TC-IAQ Dilemma). In warm and moderate climates, the large internal heat sources usually found in school buildings prevent achieving thermal comfort without active cooling in summer, but are not sufficient to eliminate the need for heating in winter. Commonly used air-conditioners do not improve air quality, while natural ventilation induces uncontrolled energy losses. In this study, a step by step process was used for the development of deemed-to-satisfy design solutions, which cope with the EE-TC-IAQ Dilemma, for a performance based code. A distinction is made between improving building design variables and improving ventilation schemes. Results indicate that implementation of improved ventilation schemes in an otherwise well designed energy-conscious building result in savings of 28–30% and 17–18% for northern and southern classroom orientations, respectively.     

对热舒适、空气感觉质量及能耗的模拟研究

室内空调设计温度和新风量对热舒适，室内空气质量及能耗量有重要影响，然而对它们之间相互关系进行研究的文献却较少。通过计算机模拟空调系统在7种室内设计温度和7种新风量条件下的运行情况，得到不同的设计条件组合对热舒适、人体感觉空气质量及建筑能耗量的影响。基于这项分析，提出了此办公建筑合理的室内设计温度和新风量取值。     

西北村镇单体建筑室内空气质量研究

基于西北村镇传统单体建筑能源利用率低、室内空气质量差的现状,将传统建筑的供能系统改为冬季主要由太阳能热水系统为室内供暖且为住户提供生活热水,并对建筑室内空气质量进行试验测试,测试结果得到:室内SO_2、NO_2、CO含量的1 h平均值,TVOC含量的8 h平均值,CO_2、PM_(10)含量的日平均值、室内风速和室内空气相对湿度在试验周期内都符合GB/T 18883—2002《室内空气质量标准》的相关规定,室内温度平均值在太阳能热水系统供暖期间符合GB/T 50824—2013《农村居住建筑节能设计标准》的相关规定;经综合指数对室内空气质量进行评价,得出太阳能热水系统供能的西北村镇单体建筑空气质量级别属于Ⅱ级,空气质量评价结果为未污染。     

寒冷地区绿色三星级住宅建筑的创新与集成——天津万通生态城新新家园项目实践

本文介绍了天津万通生态城新新家园的绿色建筑实践,包括住宅节能、室内空气质量、声环境、高层太阳能热水、水资源利用、垃圾处理技术等方面的创新措施。重点分析了该项目具有创新性和示范意义的主要技术集成,为寒冷地区绿色住宅建筑的建设提供了思路和借鉴。     

A study on the energy penalty of various air-side system faults in buildings

Automatic fault detection and diagnosis (FDD) can help enhance building energy efficiency by facilitating early detection of occurrence of system faults, especially those of air-conditioning systems, thus enabling rectification of the faults before much energy is wasted due to such faults. However, building owners may not invest in FDD unless they are convinced of the energy cost savings that can be achieved. This paper presents the results of a study on the energy cost impacts of a range of common system faults in variable air volume (VAV) air-conditioning systems, which are widely adopted for their good part-load energy efficiency. The faults studied include room air temperature sensor offset, stuck VAV box damper, supply air temperature sensor offset, stuck outdoor air damper and stuck/leaking cooling coil valve. The simulation results indicate that some faults may significantly increase energy use in buildings, for example, negative room air temperature sensor offset, stuck open VAV box damper, negative supply air temperature sensor offset, stuck open outdoor air damper and stuck open and leaking cooling coil valve. Since building occupants may adapt to the symptoms of these faults, such as reduced room air temperature, and thus may not complain about them, the occurrence of such faults are not immediately apparent unless a FDD system is available. Some other faults, e.g. positive supply air temperature sensor offset, positive room air temperature sensor offset, stuck closed cooling coil valve and stuck closed VAV box damper, may allow less energy to be used but will lead to unbearable indoor environmental conditions, such as high indoor temperature. Such faults, therefore, can easily be detected even without a FDD system, as there will be feedback from the building occupants.     

自然通风与建筑节能

自然通风是改善室内热环境和空气品质的主要手段,热压、风压是通风形成的基本条件,合理组织自然通风能够节约建筑耗能,通过分析建筑室内通风组织的措施,为建筑师提供一定的设计依据。