Evaluation on overheating risk of a typical Norwegian residential building under future extreme weather conditions

As the temperature in the summer period in Norway has been always moderate, little study on the indoor comfort of typical Norwegian residential buildings in summer seasons can be found. Heat waves have attacked Norway in recent years, including in 2018 and 2019. Zero energy buildings, even neighborhoods, have been a hot research topic in Norway. There is overheating risk in typical Norwegian residential buildings without cooling devices installed under these uncommon weather conditions, like the hot summers in 2018 and 2019. Three weather scenarios consisting of present-day weather data, 2050 weather data, and 2080 weather data are investigated in this study. The overheating risk of a typical Norwegian residential building is evaluated under these three weather scenarios. 72 scenarios are simulated in this study, including different orientations, window-to-wall ratios, and infiltration rates. Two different overheating evaluation criteria and guidelines, the Passive House Planning Package (PHPP) and the CIBSE TM 59, are compared in this study

Solutions for retrofitting existing, wooden houses in cold climates

Upgrading existing one-family houses to higher energy standards can be a challenge for owners, among others, due to the unclear status of technical regulations in the case of retrofitting at the national level. Retrofitting projects face technical obstacles that can be difficult to exclude with sensible measures. As a result, retrofitting projects are more difficult to complete. How can we effectively increase the rate of retrofitting projects for private owned residential buildings? Challenges associated with a complete renovation were listed, analysed and illustrated based on one of the smallest Norwegian typical wooden houses from the 1960s. Optimal packages of solutions for the retrofitting, based on energy simulation models, were proposed. The analysis showed that existing buildings are vulnerable meeting today’s, much stronger, energy requirements equal for all buildings. More attention should be given to the development of separate regulations at the national level as well as to the development of retrofitting solutions, if the goal of increasing the number of renovations is to be achieved. The efficient use of solar energy becomes an important measure, especially in the context of expected climate change, and a key to achieve sustainable energy management and a better indoor climate. To avoid unnecessary cooling loads and ensure optimal thermal comfort for residents, overheating criteria should be included in energy requirements even in cold climates in the near future

Overheating risk of a typical Norwegian residential building retrofitted to higher energy standards under future climate conditions

Heat waves had attacked Norway in 2018 and 2019. Residents in Norway experienced a very uncomfortable indoor environment in the summer of 2018 and 2019. Few publications on the overheating risk of a typical Norwegian residential building under future climate change conditions were found. The typical Norwegian residential building retrofitted according to the minimum Norwegian energy requirements in the Norwegian Building Act of 2010 (Pbl2010/TEK17) and the international EnerPHit Standard was modelled in this study. Overheating risk of the typical residential building was simulated by Energy Plus engine via Ladybug and Honeybee plugins based on the Grasshopper. Overheating hours of the studied rooms under present-day, the 2050s and the 2080s weather conditions were shown. Too good airtightness does increase the overheating risk of the building when retrofitted to higher energy standards. It was found in this study that better insulation does reduce the overheating hours of the bedrooms slightly. This may be caused by low g-value of the windows based on recommendation according to the EnerPHit Standard. Overheating should be paid more attention in term of the expected future climate conditions. These results can provide some references to the buildings retrofitted to high-performance buildings

Building-Integrated Photovoltaics from Products to System Integration - A Critical Review

This review brings together research on the integration aspect of photovoltaic technologies in the building sector. Buildings are among the significant contributors of negative, yet not avoidable, environmental impact. Two primary drivers are pushing the building industry toward sustainability: a goal of lowering the emission levels emitted by the industry, and new norms and regulations on a zero-energy building. The zero-energy building concept is primarily based on the principle that the amount of renewable energy created on the site will be equal to the total amount of energy used by the building during its operational phase throughout its entire lifetime. As a result, the photovoltaic technology was introduced to the building sector, and from there started a rapid research and development of a merged field, building-integrated photovoltaics (BIPV). The market of BIPV is still young and is hence constantly changing. A few BIPV product manufacturers are steadily represented on the market, while new products and manufacturers are emerging and others disappearing now and then. A critical review presented herein provides technical information on existing BIPV products and systems, considering their multi-functionality as a climate screen, energy generator and aesthetic component. Therefore, this paper aims to help to understand BIPV products and systems as well as possibilities and challenges associated with their integration into the built environment of today, thus also giving guidelines for the development and design of BIPV components for the future.publishedVersio

Optimization of Window Design for Daylight and Thermal Comfort in Cold Climate Conditions

Window design affects the overall performance of a building. It is important to include window design during the initial stages of a project since it influences the performance of daylight and thermal comfort as well as the energy demand for heating and cooling. The Norwegian building code facilitates two alternative methods for achieving a sufficient daylight, and only guidelines for adequate indoor thermal comfort. In this study, a typical Norwegian residential building was modeled to investigate whether the criteria and methods facilitate consistent and good performance through different scenario changes and furthermore, how the national regulations compare to European standards. A better insulated and more air-tight building has usually a lower annual heating demand, with only a marginal decrease in the daylight performance when the window design is unchanged. A more air-tight construction increases the risk of overheating, even in cold climates. This study confirms that a revision of the window design improves the overall performance of a building, which highlights the importance of proper window design. The pursuit of lower energy demand should not be at the expense of indoor thermal comfort considering the anticipated future weather conditions. This study indicates that criteria for thermal comfort and daylight, if clearly defined, can affect the energy demand for heating and cooling, as well as the indoor climate positively, and should be taken into account at the national level. A comparison between the national regulations and the European standards was made, and this study found that the results are not consistent

Optimization of Window Design for Daylight and Thermal Comfort in Cold Climate Conditions

Window design affects the overall performance of a building. It is important to include window design during the initial stages of a project since it influences the performance of daylight and thermal comfort as well as the energy demand for heating and cooling. The Norwegian building code facilitates two alternative methods for achieving a sufficient daylight, and only guidelines for adequate indoor thermal comfort. In this study, a typical Norwegian residential building was modeled to investigate whether the criteria and methods facilitate consistent and good performance through different scenario changes and furthermore, how the national regulations compare to European standards. A better insulated and more air-tight building has usually a lower annual heating demand, with only a marginal decrease in the daylight performance when the window design is unchanged. A more air-tight construction increases the risk of overheating, even in cold climates. This study confirms that a revision of the window design improves the overall performance of a building, which highlights the importance of proper window design. The pursuit of lower energy demand should not be at the expense of indoor thermal comfort considering the anticipated future weather conditions. This study indicates that criteria for thermal comfort and daylight, if clearly defined, can affect the energy demand for heating and cooling, as well as the indoor climate positively, and should be taken into account at the national level. A comparison between the national regulations and the European standards was made, and this study found that the results are not consistent

Building-Integrated Photovoltaics from Products to System Integration - A Critical Review

This review brings together research on the integration aspect of photovoltaic technologies in the building sector. Buildings are among the significant contributors of negative, yet not avoidable, environmental impact. Two primary drivers are pushing the building industry toward sustainability: a goal of lowering the emission levels emitted by the industry, and new norms and regulations on a zero-energy building. The zero-energy building concept is primarily based on the principle that the amount of renewable energy created on the site will be equal to the total amount of energy used by the building during its operational phase throughout its entire lifetime. As a result, the photovoltaic technology was introduced to the building sector, and from there started a rapid research and development of a merged field, building-integrated photovoltaics (BIPV). The market of BIPV is still young and is hence constantly changing. A few BIPV product manufacturers are steadily represented on the market, while new products and manufacturers are emerging and others disappearing now and then. A critical review presented herein provides technical information on existing BIPV products and systems, considering their multi-functionality as a climate screen, energy generator and aesthetic component. Therefore, this paper aims to help to understand BIPV products and systems as well as possibilities and challenges associated with their integration into the built environment of today, thus also giving guidelines for the development and design of BIPV components for the future

Building-Integrated Photovoltaics from Products to System Integration - A Critical Review

This review brings together research on the integration aspect of photovoltaic technologies in the building sector. Buildings are among the significant contributors of negative, yet not avoidable, environmental impact. Two primary drivers are pushing the building industry toward sustainability: a goal of lowering the emission levels emitted by the industry, and new norms and regulations on a zero-energy building. The zero-energy building concept is primarily based on the principle that the amount of renewable energy created on the site will be equal to the total amount of energy used by the building during its operational phase throughout its entire lifetime. As a result, the photovoltaic technology was introduced to the building sector, and from there started a rapid research and development of a merged field, building-integrated photovoltaics (BIPV). The market of BIPV is still young and is hence constantly changing. A few BIPV product manufacturers are steadily represented on the market, while new products and manufacturers are emerging and others disappearing now and then. A critical review presented herein provides technical information on existing BIPV products and systems, considering their multi-functionality as a climate screen, energy generator and aesthetic component. Therefore, this paper aims to help to understand BIPV products and systems as well as possibilities and challenges associated with their integration into the built environment of today, thus also giving guidelines for the development and design of BIPV components for the future

A Testing Methodology for Quantification of Wind-Driven Rain Intrusion for Building-Integrated Photovoltaic Systems

Wind-driven rain (WDR) exposure is a crucial impact factor to consider for building envelope components and systems. The roof being a climate screen, shields inner structures from various precipitations preventing most of the water from intruding. Although WDR exposure tests are quite common, there is a lack of studies that explore a quantification of water intrusion during such an experiment. Novel technologies such as e.g. building-integrated photovoltaic (BIPV) systems have been steadily more used as the building envelope components, and majority of BIPV systems are designed for roof integration. Such systems are mainly viewed as electricity generators, consequently, the power output and parameters that affect them are usually in focus when these systems are evaluated, whereas little information is available on the weather protection performance of BIPV systems. To address this gap, a series of experiments were conducted to improve the testing methodology of WDR exposure for BIPV systems where quantification of water intrusion was implemented. As a result, a novel framework is presented, which includes a step-by-step test methodology and a detailed description of the construction of a water collection system. Selected BIPV system for roof integration was tested according to the methodology and collected water amounts were provided. The findings in this study demonstrate that quantification of water intrusion is feasible and provides performance-based information that will help improving the design of BIPV systems as climate screens

Quantification of Wind-Driven Rain Intrusion in Building-Integrated Photovoltaic Systems

Wind-driven rain (WDR) impact is a serious exposure that affects performance of the building envelope components and systems. This study presents results from a laboratory investigation of a testing methodology of WDR intrusion in building-integrated photovoltaic (BIPV) systems. The major aspect proposed in this work is a quantification of water intrusion through BIPV systems. For that matter, a water collection system was designed and tested. When water intrusion is quantified, it may enable categorisation and comparison of various BIPV systems according to their watertightness level. This methodology was applied to three BIPV systems designed for roof integration. The methodology can also be modified and used for various building envelope systems, including traditional roof and facade systems without PV or BIPV systems. As the methodology was developed with climate conditions in northern Europe in mind, WDR exposure of extreme levels was applied. Wind speed ranges from 12.9 m/s (strong breeze) to 35.3 m/s (hurricane) were used. When it comes to newly developed and not well-studied building envelope systems, such as various BIPV systems, they should be subjected to a more extensive investigation. The proposed testing methodology could become an extension of the standard investigations of BIPV systems carried out at accredited laboratories