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See detailOverview and future challenges of nearly Zero Energy Buildings (nZEB) design in Southern Europe
Attia, Shady ULiege; Polyvios, Eleftheriou; Xeni, Flouris et al

in Energy and Buildings (2017), 155

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications ... [more ▼]

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications should help to fill out some of the current gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarises the findings of a cross-comparative study of the societal and technical barriers of nZEB implementation in 7 Southern European countries. The study analyses the present situation and provides an overview on future prospects for nZEB in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEB implementation and especially to the challenge/opportunity of retrofitting existing buildings. Creating a common approach to further develop nZEB targets, concepts and definitions in synergy with the climatic, societal and technical state of progress in Southern Europe is essential. The paper provides recommendations for actions to shift the identified gaps into opportunities for future development of climate adaptive high performance buildings. [less ▲]

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See detailTwenty-year tracking of lighting savings and power density in the residential sector
Attia, Shady ULiege; Hamdy, Mohamed; Ezzeldin, Sherif

in Energy and Buildings (2017), 154

Lighting energy consumption represents a significant percentage of total energy consumption in residential building sector. During the last 20 years, advanced energy-efficient lighting fixtures have been ... [more ▼]

Lighting energy consumption represents a significant percentage of total energy consumption in residential building sector. During the last 20 years, advanced energy-efficient lighting fixtures have been introduced worldwide to conserve the energy consumption in residences. In the Middle East and North Africa (MENA) region, very few studies have been conducted to evaluate the association between the introduced lighting fixtures and the resulted energy savings using valid measurements and verification techniques. This study evaluates the techno-economic impact of replacing new energy efficient lighting in residences in Egypt (a representative MENA region country). A quantitative analysis is applied by tracking the utility bills of 150 residential apartments in Cairo. The average measured power consumption before (1993-1998) and after (2009-2014) installation energy efficient lighting fixtures is analyzed. A building performance simulation model is developed to back the findings. The findings indicate a significant disparity between the estimated savings based on simulation and the real measured savings due to penetration, rebound effect and low quality lamps. Moreover, the findings present an example of quantified benefits of energy efficient lighting, which is very important to inform the decision making of public policy makers, investors and building occupants. [less ▲]

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See detailImpact of Financial Assumptions on the Cost Optimality towards Nearly Zero Energy Buildings- A case study
Hamdy, Mohamed; Siren, Kai; Attia, Shady ULiege

in Energy and Buildings (2017), 153

The energy efficiency challenge in Europe is mainly concerned with existing buildings and the investment scenarios to implement deep renovations. The cost-optimal approach imposed on EU-Member states by ... [more ▼]

The energy efficiency challenge in Europe is mainly concerned with existing buildings and the investment scenarios to implement deep renovations. The cost-optimal approach imposed on EU-Member states by the European Energy Performance of Buildings Directive aims to identify the investment gap and challenges to transform existing buildings into nearly Zero Energy Buildings (nZEBs). The investment gap is function of several volatile financial parameters including discount rate (r), developing of energy price (e), decline rate of technology price (d), as well as nZEB’s incentives like feed-in-tariff (FiT) and investment grant (iG). In this context, the decision making process of individuals or investment institutions is hindered by complexity and uncertainty. In order to assist the decision making process and improve the visibility of financial energy benefits, a novel optimization-based parametric analysis scheme (OptnZEB-I) is developed. The scheme is designed to investigate a large number of economic scenarios (i.e., combinations of financial assumptions) in a short computational time while a holistic optimization approach is adopting for exploring all possible design options including energy conservation measures (ESMs); renewable energy sources (RETs) and mechanical systems (Sys). For demonstration, the scheme is applied to analyse the impact of several financial parameters on the cost-optimal energy performance level (CO-EPL) of a single family house in Finland. In line with the EU-directive, a large number of possible design options (∼3 × 109million) are optimized for 4608 cases of economic scenarios. The results of the address case study show that, in average, the CO-EPL ranges from 90 to 160 [kWh/m2]. The range has most frequent value of 145 kWh/m2. The CO-EPL is significantly sensitive to the e, f, then i, respectively. Less sensitivity is found to the other financial parameters. The robustness of the optimization results are verified by solving the addressed design problem by using four different optimization algorithms (i.e., pattern search, interior-point, simulated annealing and genetic algorithms). [less ▲]

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See detailExergy analysis applied to performance of buildings in Europe
Sartor, Kevin ULiege; Dewallef, Pierre ULiege

in Energy and Buildings (2017), 148

Energy performance of buildings generally assesses the energy consumption of buildings such as heating, domestic heat water, ventilation systems, etc. However, this approach is based on the first law of ... [more ▼]

Energy performance of buildings generally assesses the energy consumption of buildings such as heating, domestic heat water, ventilation systems, etc. However, this approach is based on the first law of thermodynamics and considers only the quantity of energy used without considering its ‘quality’ and leads to a lack of information about the energy conversion processes. This is particularly true in the new low-energy buildings where sometimes high temperatures sources are used to meet low-temperature needs. The exergy analysis of a system, based on first and second thermodynamic laws, can be used to overcome this. In this work, it is proposed to compare the energy and the exergy consumption and the related CO2 emissions of several kinds of buildings to determine the best systems in terms of energy and exergy needs. The energy demand calculations are performed using the official software available in Belgium and some assumptions are implemented to consider the exergy approach. As exergy calculations require a reference state, some different climatic conditions are also investigated. Finally, some conclusions are discussed to rank the sources of energy and their related exergy losses. [less ▲]

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See detailAssessing household energy uses: an online interactive tool dedicated to citizens and local stakeholders
Marique, Anne-Françoise ULiege; Cuvellier, Simon; De Herde, André et al

in Energy and Buildings (2017), 151C

This paper presents the SOLEN integrated online tool, dedicated to citizens and local authorities. This methodology, developed to allow precise energy assessment (heating, cooling, ventilation, lighting ... [more ▼]

This paper presents the SOLEN integrated online tool, dedicated to citizens and local authorities. This methodology, developed to allow precise energy assessment (heating, cooling, ventilation, lighting, appliances, and cooking but also local production of renewable energy) of household energy uses, is firstly introduced. SOLEN uses a typological classification of buildings and thermal simulations. Many parameters are defined and taken into account to capture the specificities of numerous types of buildings exhaustively (e.g. type of buildings; number of floors; common ownership; orientation; thermal performances of the walls, floors, roofs, and windows; and ventilation type). These results related to building energy consumption are then crossed, in an integrated approach, with several indicators of urban sustainability, to take into account in the balance of the impact of the location of buildings on transportation energy consumption or the impact of the urban form on the production of solar renewable energy. This tool makes accessible to a large non-specialized audience the results of a three-year scientific research study in Wallonia (Belgium) and was awarded an Energy Globe Award (Belgium) in 2014. The first feedback from users is presented to conclude this contribution. [less ▲]

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See detailReducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings
Dabaieh, Marwa; Wanas, Omar; Amer, Mohamed ULiege et al

in Energy and Buildings (2015), 89(Supplement C), 142-152

In hot dry climates, it is estimated that almost half the urban peak load of energy consumption is used to satisfy air-conditioning cooling demands in summer time. Since the urbanization rate in ... [more ▼]

In hot dry climates, it is estimated that almost half the urban peak load of energy consumption is used to satisfy air-conditioning cooling demands in summer time. Since the urbanization rate in developing countries – like the case in Egypt – is rising rapidly, the pressure placed on energy resources to satisfy inhabitants’ indoor comfort requirements is consequently increasing too. This paper introduces passive cool roof as a means of reducing energy cooling loads for satisfying human comfort requirements in a hot climate. A designed algorithmic hybrid matrix was used to simulate 37 roof design probabilities alternating roof shape, roof material and construction. The result of using a vault roof with high albedo coating shows a fall of 53% in discomfort hours and saves 826 kW h during the summer season compared to the base case of the conventional non insulated flat roof in a typical Cairo residential buildings. It is recommended that the selected cool roof solution be combined with natural ventilation to increase the indoor thermal comfort, and with passive heating strategies to compensate the increase in heating hours. The application is intended for low cost residential buildings in a hot dry climate. [less ▲]

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See detailA simplified framework to assess the feasibility of zero-energy at the neighbourhood / community scale
Marique, Anne-Françoise ULiege; Reiter, Sigrid ULiege

in Energy and Buildings (2014), 82

Zero-energy buildings (ZEBs) are attracting increasing interest internationally in policies aiming at a more sustainably built environment, the scientific literature and practical applications. Although ... [more ▼]

Zero-energy buildings (ZEBs) are attracting increasing interest internationally in policies aiming at a more sustainably built environment, the scientific literature and practical applications. Although “zero energy” can be considered at different scales (e.g., community, city), the most common approach adopts only the perspective of the individual building. Moreover, the feasibility of this objective is not really addressed, especially as far as the retrofitting of the existing building stock is concerned. Therefore, this paper aims first to investigate the opportunity to extend the “zero-energy building” concept to the neighbourhood scale by taking into account two main challenges: (1) the impact of urban form on energy needs and the on-site production of renewable energy and (2) the impact of location on transportation energy consumption. It proposes a simplified framework and a calculation method that is then applied to two representative case studies (one urban neighbourhood and one rural neighbourhood) to investigate the feasibility of zero-energy in existing neighbourhoods. The main parameters that act upon the energy balance are identified. The potential of “energy mutualisation” at the neighbourhood scale is highlighted. This paper thereby shows the potentialities of an integrated approach linking transportation and building energy consumptions. [less ▲]

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See detailAn online interactive tool to assess energy consumption in residential buildings and for daily mobility
Marique, Anne-Françoise ULiege; de Meester, Tatiana; De Herde, André et al

in Energy and Buildings (2014), 78C

Improving energy efficiency in the building and transportation sectors is a viable approach to mitigate the effects of climate change and has become an important policy target. As a result, in addition to ... [more ▼]

Improving energy efficiency in the building and transportation sectors is a viable approach to mitigate the effects of climate change and has become an important policy target. As a result, in addition to scientific research and public policies addressing energy efficiency, raising public awareness of the impact of the behaviour of citizens to energy efficiency is crucial and could quickly lead to significant reductions in the total energy consumption of a territory. In this context, this paper presents a new online interactive tool that enables not only citizens but also local authorities and private developers to (1) assess the sources of energy consumption related to housing and to daily mobility at both the individual and neighbourhood scales, (2) compare these sources and (3) determine relevant and personalised suggestions to reduce energy consumption. Numerous methods and tools, including a typological classification of buildings, thermal dynamic simulations, life-cycle assessments and statistical treatments of national censuses, were used to produce the two large databases used in this interactive tool. This report represents the primary results of a three-year long scientific research project dedicated to the study of energy efficiency in buildings and for daily mobility that is accessible to a large non-specialised audience. [less ▲]

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See detailAssessing gaps and needs for integrating building performance optimization tools in net zero energy buildings design
Attia, Shady ULiege; Hamdy, Mohamed; O’Brien, William et al

in Energy and Buildings (2013), 60

This paper summarizes a study undertaken to reveal potential challenges and opportunities for integrating optimization tools in net zero energy buildings (NZEB) design. The paper reviews current trends in ... [more ▼]

This paper summarizes a study undertaken to reveal potential challenges and opportunities for integrating optimization tools in net zero energy buildings (NZEB) design. The paper reviews current trends in simulation-based building performance optimization (BPO) and outlines major criteria for optimization tools selection and evaluation. This is based on analyzing user's needs for tools capabilities and requirement specifications. The review is carried out by means of a literature review of 165 publications and interviews with 28 optimization experts. The findings are based on an inter-group comparison between experts. The aim is to assess the gaps and needs for integrating BPO tools in NZEB design. The findings indicate a breakthrough in using evolutionary algorithms in solving highly constrained envelope, HVAC and renewable optimization problems. Simple genetic algorithm solved many design and operation problems and allowed measuring the improvement in the optimality of a solution against a base case. Evolutionary algorithms are also easily adapted to enable them to solve a particular optimization problem more effectively. However, existing limitations including model uncertainty, computation time, difficulty of use and steep learning curve. Some future directions anticipated or needed for improvement of current tools are presented. [less ▲]

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See detailSimulation-based decision support tool for early stages of zero-energy building design
Attia, Shady ULiege; Gratia, Elisabeth; De Herde, André et al

in Energy and Buildings (2012), 49

There is a need for decision support tools that integrate energy simulation into early design of zero energy buildings in the architectural practice. Despite the proliferation of simulation programs in ... [more ▼]

There is a need for decision support tools that integrate energy simulation into early design of zero energy buildings in the architectural practice. Despite the proliferation of simulation programs in the last decade, there are no ready-to-use applications that cater specifically for the hot climates and their comfort conditions. Furthermore, the majority of existing tools focus on evaluating the design alternatives after the decision making, and largely overlook the issue of informing the design before the decision making. This paper presents energy-oriented software tool that both accommodates the Egyptian context and provides informative support that aims to facilitate decision making of zero energy buildings. A residential benchmark was established coupling sensitivity analysis modelling and energy simulation software (EnergyPlus) as a means of developing a decision support tool to allow designers to rapidly and flexibly assess the thermal comfort and energy performance of early design alternatives. Validation of the results generated by the tool and ability to support the decision making are presented in the context of a case study and usability testing. [less ▲]

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See detailAn investigation on thermal performance of a low cost apartment in hot humid climate of Danang
Nguyen, Anh Tuan ULiege; Reiter, Sigrid ULiege

in Energy and Buildings (2012), 47

Low cost apartment has recently become one of the essential state policies to deal with rapid urbanisation and population boom in Vietnam. Thermal performance of a low cost apartment in Danang was ... [more ▼]

Low cost apartment has recently become one of the essential state policies to deal with rapid urbanisation and population boom in Vietnam. Thermal performance of a low cost apartment in Danang was examined using building simulation approach. The simulated results created by COMFIE were first calibrated by comparing them with measured data. The statistical indicators CV(RMSE) and NMBE as well as linear regression analysis were applied to assess the calibration. The calibrated model was then used to perform whole year simulations in which various ventilation and design strategies were applied. Thermal comfort potentials of these strategies were graphically defined by Brager’s adaptive comfort model from which the efficiency of each strategy was quantitatively determined. In the present paper, details of the calibration approach, assessment of simulated results and comparison of the findings were discussed. Results of these analyses revealed many notable findings which are in good agreement with those obtained from other publications. The limitation and recommendations for further study are also outlined. [less ▲]

Detailed reference viewed: 132 (15 ULiège)