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In recent years building envelope systems have become increasingly more com-plex. Especially in high-performance low-carbon buildings, envelopes comprise several passive and active components such as advanced membranes, mechanical ventilation machines and integrated photovoltaics that must be mutually optimized to ensure a global elevated performance. One of the key expectations from these innovative envelopes is better capabilities of providing highly comfortable and healthy indoor environments while using as little energy as possible. However, the complexity of such envelopes poses two major challenges: (i) standard assessment procedures might not be usable to evaluate them either because these do not fully capture their potential or be-cause the complexity of product makes the standard test unfeasible, and (ii) multiple indoor environmental quality (IEQ) domains are simultaneously affected by these envelopes, and thus complementary tests in different domain are needed to ensure that a benefit in one domain does not lead to issues in others. For this reason, a test-chain for a thorough energy demand, indoor occupants’ comfort, and behaviour analysis performance has been implemented. It comprises a set of labs and additional simulation capabilities to study the building envelope-IEQ interaction at various technology readiness level. This paper provides an overview of the test-chain and its first application for the evaluation of a multifunctional façade. This façade includes a reversible air-to-air heat pump, a mechanical ventilation system, and openable windows, and aims at easing the achievement of the nZEB target while delivering elevated IEQ.

The continuous monitoring of indoor environmental quality (IEQ) plays a crucial role in improving our understanding of the prominent parameters affecting building users' health and perception of their environment. In field studies, indoor environment monitoring often does not go beyond the assessment of air temperature, relative humidity, and CO2 concentration, lacking consideration of other important parameters due to budget constraints and the complexity of multi-dimensional signal analyses. In this paper, we introduce the Environmental Quality bOX (EQ-OX) system, which was designed for the simultaneous monitoring of quantities of some of the main IEQs with a low level of uncertainty and an affordable cost. Up to 15 parameters can be acquired at a time. The system embeds only low-cost sensors (LCSs) within a compact case, enabling vast-scale monitoring campaigns in residential and office buildings. The results of our laboratory and field tests show that most of the selected LCSs can match the accuracy required for indoor campaigns. A lightweight data processing algorithm has been used for the benchmark. Our intent is to estimate the correlation achievable between the detected quantities and reference measurements when a linear correction is applied. Such an approach allows for a preliminary assessment of which LCSs are the most suitable for a cost-effective IEQ monitoring system. [ABSTRACT FROM AUTHOR]

One of the main challenges in visual comfort assessment is controlling daylight in indoor spaces. The effect of daylight's contribution to total light is one of the variables influencing how people perceive illumination in an indoor environment. This study investigates the optimal day-light-to-total light ratio that delivers the most satisfaction with the lighting environment. Therefore, a subjective survey of 509 questionnaires and field measurements in six office buildings in Tehran with a total of 257 rooms was conducted to assess lighting quality (daylight and artificial light). Furthermore, the effects of building characteristics and seasons on the acceptable range of daylight ratio are investigated. The results reveal that occupants prefer daylight to total light ratio ranging between 0.56 and 0.8. In contrast, occupants reported that a ratio less than 0.4 was unacceptable. It was also found that the optimum daylight-to-total light ratio is influenced by the season and the building characteristics. [ABSTRACT FROM AUTHOR]

Nearly Zero Energy Buildings (nZEBs) represent the backbone to achieve ambitious European goals in terms of energy efficiency and CO2 emissions reduction. As defined in the EPBD, by 31 December 2020, all of the new buildings will have to reach a target of nearly zero energy. This target encourages the adoption of innovative business models as well as the technology development in the building sector, aimed at reducing energy demand and exploiting local renewable energy sources (RES). Assessing the share of implementation and the performance of technologies in new or renovated nZEBs is strategic to identify the market trends and to define design guidelines with the most effective solutions according to the context. In this regard, this paper analyses the construction features of a set of nZEBs, collected in 17 European countries within the EU IEE ZEBRA2020 project, with a special focus on the influence of the boundary conditions on the technologies adopted. The results show a general high insulation level of the envelope and recurrent specific technologies in the Heating Ventilation Air Conditioning (HVAC) system (i.e., heat pumps and mechanical ventilation), while the climatic conditions do not drive significantly the design approach and the nZEB features. [ABSTRACT FROM AUTHOR]

We present a study of natural ventilation design during the early (conceptual) stage of a building's design, based on a field study in a naturally ventilated office in California where we collected data on occupants' window use, local weather conditions, indoor environmental conditions, and air change rates based on tracer-gas decay. We performed uncertainty and sensitivity analyses to determine which design parameters have most impact on the uncertainty associated with ventilation performance predictions. Using the results of the field study along with wind-tunnel measurements and other detailed analysis, we incrementally improved our early-design-stage model. The improved model's natural ventilation performance predictions were significantly more accurate than those of the first draft early-stage-design model that employed model assumptions typical during initial design. This process highlighted significant limitations in the EnergyPlus software's models of occupant-driven window control. We conclude with recommendations on key design parameters including window control, wind pressure coefficients and weather data resolution to help improve early-design-stage predictions of natural ventilation performance using EnergyPlus. [ABSTRACT FROM AUTHOR]

Highlights: [•] Building simulations with minimum number of inputs and acceptable output error. [•] Early stage simplified model for dynamic energy analysis. [•] Simplification methodology to conciliate simulation time and information needs. [Copyright &y& Elsevier]

Net Zero-Energy Buildings (NZEBs) have received increased attention in recent years as a result of constant concerns about energy supply constraints, decreasing energy resources, increasing energy costs and the rising impact of greenhouse gases on world climate. Promoting whole building strategies that employ passive measures together with energy efficient systems and technologies using renewable energy became a European political strategy following the publication of the Energy Performance of Buildings Directive recast in Ma y 2010 by the European Parliament and Council. However designing successful NZEBs represents a challenge because the definitions are somewhat generic while assessment methods and monitoring approaches remain under development and the literature is relatively scarce about the best sets of solutions for different typologies and climates likely to deliver an actual and reliable performance in terms of energy balance (consumed vs generated) on a cost-effective basis. Additionally the lessons learned from existing NZEB examples are relatively scarce. The authors of this paper, who are participants in the IEA SHC Task 40-ECBCS Annex 52, "Towards Net Zero Energy Solar Buildings", are willing to share insights from on-going research work on some best practice leading NZEB residential buildings. Although there is no standard approach for designing a Net Zero-Energy Building (there are many different possible combinations of passive and efficient active measures, utility equipment and on-site energy generation technologies able to achieve the net-zero energy performance), a close examination of the chosen strategies and the relative performance indicators of the selected case studies reveal that it is possible to achieve zero-energy performance using well known strategies adjusted so as to balance climate drivendemand for space heating/cooling, lighting, ventilation and other energy uses with climate-driven supply from renewable energy resources. [ABSTRACT FROM AUTHOR]

Renovation Wave aims to boost the uptake of deep renovation towards the CO2 emission targets for 2030. In this perspective, there is the need of technologies and solution sets for improving the deep renovation process as well as demonstrating the performances for supporting the stakeholders in the decision-making process. To cope with the issue, this work presents a methodology for setting up a repository of building deep renovation packages that integrates industrialised facade technologies and more traditional solutions. The performances feeding into the repository have been evaluated by means of transient detailed simulations on a set of reference buildings in representative European climate conditions. The renovation packages are evaluated in terms of key performance indicators dealing with five areas: energy, comfort, pollutant emissions, cost, and renovation time. The defined repository includes 289 assessed technology packages and associated performances across Europe, providing a comprehensive support to identify the most effective solutions according to the user needs. The paper presents the application of the repository with two examples of stakeholders' decision-making paths for selecting the deep renovation packages according to different priorities and expected targets. [ABSTRACT FROM AUTHOR]

It is notable that indoor environment quality plays a crucial role in guaranteeing health, especially if we consider that people spend more than 90% of their time indoors, a percentage that increases for people on low income. This role assumes even further significance when dealing with distressed urban areas, vulnerable areas within cities that suffer from multiple deprivations. The community-based interdisciplinary research-action group of the University La Sapienza focused on a complex in the outskirts of Rome. The aim was to assess the correlations between architectural aspects of the indoor environment, socio-economic conditions, such as lifestyles and housing conditions, and eventually health outcomes. The intent of providing a comparative methodology in a context where official data is hard to find, led to the integration of social, health, and housing questionnaires with various environmental software simulations. What emerged is that underprivileged housing conditions, characterized by mold, humidity, unhealthiness, thermohygrometric discomfort, architectural barriers, and overcrowding, are often associated with recurrent pathologies linked to arthritis, respiratory diseases, and domestic accidents. [ABSTRACT FROM AUTHOR]

The increasing global energy demand, the foreseen reduction of available fossil fuels and the increasing evidence off global warming during the last decades have generated a high interest in renewable energy sources. However, renewable energy sources, such as wind and solar power, have an intrinsic variability that can seriously affect the stability of the energy system if they account for a high percentage of the total generation. The Energy Flexibility of buildings is commonly suggested as part of the solution to alleviate some of the upcoming challenges in the future demand-respond energy systems (electrical, district heating and gas grids). Buildings can supply flexibility services in different ways, e.g. utilization of thermal mass, adjustability of HVAC system use (e.g. heating/cooling/ventilation), charging of electric vehicles, and shifting of plug-loads. However, there is currently no overview or insight into how much Energy Flexibility different building may be able to offer to the future energy systems in the sense of avoiding excess energy production, increase the stability of the energy networks, minimize congestion problems, enhance the efficiency and cost effectiveness of the future energy networks. Therefore, there is a need for increasing knowledge on and demonstration of the Energy Flexibility buildings can provide to energy networks. At the same time, there is a need for identifying critical aspects and possible solutions to manage this Energy Flexibility, while maintaining the comfort of the occupants and minimizing the use of non-renewable energy. In this context, the IEA (International Energy Agency) EBC (Energy in Buildings and Communities program) Annex 67: “Energy Flexible Buildings” was started in 2015. The article presents the background and the work plan of IEA EBC Annex 67 as well as already obtained results. Annex 67 is a corporation between participants from 16 countries: Austria, Belgium, Canada, China, Denmark, Finland, France, Germany, Ireland, Italy, The Netherlands, Norway, Portugal, Spain, Switzerland and UK. [ABSTRACT FROM AUTHOR]

• Levelized cost method to develop building stock retrofit scenarios. • Ranking of retrofits according to levelized cost of saved energy. • Energy efficiency cost curve minimizing cost per energy saved. • Calibrated baseline from metered energy consumption. • Demonstration of the method on a housing stock in northern Italy. Policy makers need scientific support to set ambitious yet realistic environmental targets for the transition to energy efficient buildings and to develop cost-effective policies to meet these targets, but comprehensive, manageable procedures to this aim are still lacking. Our proposed method ranges from baseline creation to transition scenarios depending on annual retrofit budget and specifies the buildings to renovate according to location, size, and age, and the energy efficiency measures to apply based on cost and energy saving. We show how to extrapolate a baseline from few available data, determine retrofit costs, and create calibrated models to estimate energy savings. Retrofits are ranked by levelized cost of saved energy, which ensures that for any budget allocated to retrofit maximum energy savings are obtained at minimum cost to society. The results are summarized in an energy efficiency cost curve enabling policy makers to estimate potential costs and energy savings. We demonstrate the method on a housing stock in northern Italy and show that facade insulation of old buildings in colder climates can compete with gas heating. About 60% baseline energy consumption can be saved doubling current investments, while a maximum saving of 75% requires over three times the current investments. [ABSTRACT FROM AUTHOR]