| 1. |
- Allard, Ingrid
(författare)
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Achieving building energy performance : requirements and evaluation methods for residential buildings in Sweden, Norway, and Finland
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Building energy performance has always been important in the cold climate of Sweden, Norway and Finland. To meet the goal that all new buildings should be nearly zero-energy buildings by 2020, set in the EU directive 2010/31/EU [1] on the energy performance of buildings (EPBD recast), the building sector in Europe now faces a transition towards buildings with improved energy performance. In such a transition, a discussion is needed about the objective of the improvement – why, or to what end, the building energy performance should be improved. The objective of improving building energy performance is often a political decision, but scientific research can contribute with knowledge on how the objectives can be achieved.This thesis addresses how the indicators used in the requirements used to achieve building energy performance in Sweden, Norway, and Finland, and the methods used to evaluate these requirements, reflect building energy performance. It also addresses difficulties in achieving comparable and verifiable indicators in evaluations of building energy performance. The research objective has two parts: to review, compare, and discuss (i) requirements and (ii) evaluation methods used to achieve energy performance of residential buildings in Sweden, Norway and Finland. The work in this thesis includes reviews of the requirements used in national building codes and passive house criteria to achieve building energy performance, of methods used to evaluate compliance with such requirements, and of methods used specifically to evaluate the indicator Envelope Air Tightness. The results show that different sets of indicators are used to achieve building energy performance in the studied building codes and passive house criteria. The methods used to evaluate compliance with requirements used to achieve building energy performance are also different, but calculation methods are generally more often used than measurement methods. The calculation- and measurement methods used are often simple. A methodology to analyze the deviation between predictions- and measurements of building energy performance (the performance gap) was developed, to investigate the effects of different evaluation methods on different indicators used to achieve building energy performance. The methodology was tested in a case-study. This study indicated that the choice of method affects which parts of the performance gap reflected in the indicators Supplied Energy (see Terminology), Net Energy (see Terminology), and Overall U-value. Among the reviewed methods to evaluate air tightness, the Fan/Blower Door Pressurization is well known and preferred by professionals in the field. The results in this thesis may be useful when choosing indicators and evaluation methods to achieve different objectives of improving building energy performance and in the quest towards comparable and verifiable indicators used to achieve building energy performance.
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| 2. |
- Allard, Ingrid, 1986-, et al.
(författare)
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Energy evaluation of residential buildings : Performance gap analysis incorporating uncertainties in the evaluation methods
- 2018
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Ingår i: Building Simulation. - : Tsinghua University Press. - 1996-3599 .- 1996-8744. ; 11:4, s. 725-737
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Tidskriftsartikel (refereegranskat)abstract
- Calculation and measurement-based energy performance evaluations of the same building often provide different results. This difference is referred as "the performance gap". However, a large performance gap may not necessarily mean that there are flaws in the building or deviations from the intended design. The causes for the performance gap can be analysed by calibrating the simulation model to measured data. In this paper, an approach is introduced for verifying compliance with energy performance criteria of residential buildings. The approach is based on a performance gap analysis that takes the uncertainties in the energy evaluation methods into consideration. The scope is to verify building energy performance through simulation and analysis of measured data, identifying any performance gap due to deviations from the intended design or flaws in the finished building based on performance gap analysis. In the approach, a simulation model is calibrated to match the heat loss coefficient of the building envelope [kWh/K] instead of the measured energy. The introduced approach is illustrated using a single-family residential building. The heat loss coefficient was found useful towards identifying any deviations from the intended design or flaws in the finished building. The case study indicated that the method uncertainty was important to consider in the performance gap analysis and that the proposed approach is applicable even when the performance gap appears to be non-existing.
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| 3. |
- Allard, Ingrid, et al.
(författare)
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Energy performance indicators in the Swedish building procurement process
- 2017
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 9:10
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, all new buildings need to comply with the National Board of Housing, Building and Planning’s requirement on specific purchased energy (kWh/m2). Accordingly, this indicator is often used to set design criteria in the building procurement process. However, when energy use is measured in finished buildings, the measurements often deviate significantly from the design calculations. The measured specific purchased energy does not necessarily reflect the responsibility of the building contractor, as it is influenced by the building operation, user behavior and climate. Therefore, Swedish building practitioners may prefer other indicators for setting design criteria in the building procurement process. The aim of this study was twofold: (i) to understand the Swedish building practitioners’ perspectives and opinions on seven building energy performance indicators (envelope air leakage, U-values for different building parts, average U-value, specific heat loss, heat loss coefficient, specific net energy, and specific purchased energy); and (ii) to understand the consequences for the energy performance of multi-family buildings of using the studied indicators to set criteria in the procurement process. The study involved a Delphi approach and simulations of a multi-family case study building. The studied indicators were discussed in terms of how they may meet the needs of the building practitioners when used to set building energy performance criteria in the procurement process.
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| 4. |
- Azizi, Shoaib, 1989-, et al.
(författare)
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Analysing the house-owners’ perceptions on benefits and barriers of energy renovation in Swedish single-family houses
- 2019
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 198, s. 187-196
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Tidskriftsartikel (refereegranskat)abstract
- Single-family houses offer a large potential for energy savings by energy renovation (ER). Homeowners’ motivation to implement ER derives from the benefits and barriers they perceive. Benefits are the positive consequences that can motivate homeowners to act and barriers are the challenges that demotivate them to undertake ER. Different benefits and barriers do not homogenously affect every homeowner. Identifying motivating benefits and demotivating barriers for each specific group among homeowners can shed lights on ER decision-making and enable policies that are more effective. The objective of this study is to contextualize the implementation of ER by understanding how the perceived benefits and barriers influence homeowners. This study links the expected consequences, which are benefits and barriers to the influential factors on ER, which are used to group the homeowners.The analysis is based on a questionnaire survey mailed to 1550 owners of single-family houses in northern Sweden. The perceptions of homeowners on benefits and barriers of ER are significantly different between the groups that are motivated and unmotivated to implement ER. Despite the perceived importance of some of the benefits such as energy cost reduction, they may not be determinative for the homeowners’ decision to undertake ER. The homeowners are more likely to implement ER for reasons other than energy use reduction such as for improving the indoor environment. The barriers such as the difficulty of finding a low-interest loan and reliable information sources are found to impede the intention to implement ER among different groups. Policy implications to facilitate ER in single-family houses are discussed.
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| 5. |
- Azizi, Shoaib, 1989-, et al.
(författare)
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Comparative Study of Influential Factors on Implementation of Energy Efficiency Measures in Single-Family Houses in Cold Climate
- 2018
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Konferensbidrag (refereegranskat)abstract
- A combination of factors, which include occupants and building related aspects, could motivate homeowners to implement energy renovation (ER). This study applies a comparative approach to assess perspectives of single-family homeowners towards different energy efficiency measures (EEMs). The aim is to unveil the factors that are effective on the residents’ attitude and decision making to implement an EEM or a set of EEMs. The analysis is based on a questionnaire survey conducted during spring 2017 among1550 owners of single-family houses in seven municipalities in northern Sweden. Approximately, 35% of respondents expressed their interest to install energy efficient household appliances and solar photovoltaic (PV) systems. The analysis suggests significant relations between the homeowners’ interest to implement thermal envelope measures and the quality of the house such as age and indoor environmental problems such as cold surfaces. The group of respondents, who reported their heating cost to be high, are more likely to be interested in implementing thermal envelope measures than other measures such as HVAC. Several socio-economic factors are found to be significantly related with homeowners’ interest to implement EEMs.
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| 6. |
- Azizi, Shoaib, 1989-, et al.
(författare)
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Demand-controlled energy systems in commercial and institutional buildings : a review of methods and potentials
- 2019
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Ingår i: eceee 2019 Summer Study on energy efficiency. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387858 - 9789198387841 ; , s. 1444-1450
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Konferensbidrag (refereegranskat)abstract
- Heating, ventilation and air-conditioning (HVAC) are by farthe most energy intensive systems in commercial and institutionalbuildings with office spaces. This makes HVAC systemsattractive targets for energy efficiency improvement. New technologicaladvancements can play significant role on improvingenergy efficiency. Such advancements have been also emergedin form of novel management and control strategies, whichmight lead to considerable energy savings with relatively minorinvestments. This paper evaluates demand control HVAC andlighting to assess the energy saving potential of upgrading theconventional building energy systems.This paper provides a summary of different methods and occupancydetection technologies. A range of technologies andmethods are covered that vary in complexity, limitations andenergy saving potential. Additional benefits such as demandresponse are evaluated and other emerging applications arediscussed. Based on the review of methods and potentials, thepaper assesses the state of the art in demand controlled energysystems and suggests areas for further research.
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| 7. |
- Danielski, Itai, et al.
(författare)
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Heated atrium in multi-storey apartment buildings, a design with potential to enhance energy efficiency and to facilitate social interactions
- 2016
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 106, s. 352-364
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Tidskriftsartikel (refereegranskat)abstract
- The design concept of conditioned atria gains increasing popularity in commercial and service buildings all over the world, but is still not a common building design in the residential sector. This study investigates the potential of such design in residential buildings in Nordic climates as means to enhance both energy efficiency as well as social interaction among residents. Energy modelling was used to compare energy efficiency among designs of residential buildings with and without atrium and to identify important design parameters. Social interaction was analysed, based on a survey evaluating the perception of residents living in an existing multi-storey apartment building designed with a heated atrium in the north of Sweden.The results show that heated atrium in Nordic climates have a potential to reduce the total final energy demand while at the same time increase the conditioned space of the building. To positively impact energy efficiency, the atrium should fulfil three requirements: (i) it should be designed to reduce the shape factor for the whole building; (ii) it should have the minimum glazed area that comply with the building requirements concerning natural light and visual comfort; and (iii) adjustable solar shading should be installed in the atrium’s façades to avoid unwanted overheating. The survey results indicate that the additional space created by the atrium has a potential to facilitate and promote social interaction among residents and to increases a sense of neighbourliness and belongingness, which are often discussed as important parameters in relation to social sustainability.
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| 8. |
- Nair, Gireesh, et al.
(författare)
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A management perspective on energy efficient renovations in Swedish multi-family buildings
- 2017
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 132, s. 994-999
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Tidskriftsartikel (refereegranskat)abstract
- Sweden has around 2.5 million dwellings in multi-family buildings, which constitute about 55% of the total dwelling units. The multi-family building ownership in Sweden can be categorized into municipal, private and co-operative ownership. Approximately 40% of apartments in multi-family buildings belong to municipal housing companies, while the rest is equally shared by private companies and co-operative housing associations. These organizations have different priorities, limitations and concerns related to energy renovations. Accordingly, in this sector the decisions to invest in energy efficiency improvement depends to a large extent on the type of ownership.In this study we analyzed the perspectives of different types of building ownership on energy efficient renovation. The analysis is based on detailed interviews of 4 senior managers representing the multi-family buildings under different ownership categories. Along with this we also interviewed a municipality energy adviser. All the interviewees are based in in North Sweden. The drivers to facilitate the rate of adoption of energy renovation in such buildings are discussed.
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| 9. |
- Nair, Gireesh, et al.
(författare)
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Building professionals' views on energy efficiency compliance requirements
- 2017
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Ingår i: 11th Nordic Symposium on Building Physics, NSB 2017. - : Elsevier. ; , s. 988-993
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Konferensbidrag (refereegranskat)abstract
- In Sweden, the national building code (BBR) stipulates the specific energy use as an indicator to verify whether a newbuilding is complying with its design-phase energy performance values. However, previous studies have shown that there may belarge differences between the calculated specific energy and the actual monitored energy use. The differences are attributed tovarious reasons including the actual energy behaviour of the occupants as compared to the standard values used in thesimulations. This may lead to disputes between the client and the contractor on the responsibility of meeting the energyrequirements.In this study an adapted version of Delphi methodology was used to understand the building professionals’ view on variousindicators used to verify building energy performance. The study showed that professionals are concerned with the use of specificenergy as an indicator in the building procurement process as they do not have control over the occupants’ energy behaviour.Majority of the professionals expressed a large confidence in the average U-value of the building, component U-values and thespecific heat loss figure by the Swedish center for zero-energy buildings as indicators of building energy performance.
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| 10. |
- Nair, Gireesh, et al.
(författare)
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Comparative evaluation of city dwellers' perspectives on household energy use based on housing tenure : survey results from Northern Sweden
- 2019. - 1
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Ingår i: Cold climate HVAC 2018. - Switzerland : Springer Publishing Company. - 9783030006617 - 9783030006624 ; , s. 791-801
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Konferensbidrag (refereegranskat)abstract
- The successful implementation of energy efficiency measures in the residential sector will depend to a large extent on the attitudes and perceptions of the end-users since they are the final decision maker. The tenure of the housing could influence the building occupants' perspectives on energy issues. In this study we conducted a comparative evaluation of perspectives on energy use of three categories of households: those living in single family houses, tenants and owners' of apartment. The analysis is based on responses to a mail-in questionnaire by approximately 650 residents in Umeå, Sweden. Majority of the respondents believed that their annual household energy use is less. Residents in single-family houses, as compared to the other two types of tenure of the housing, were more likely to believe their heat energy use as high and likely to take actions to reduce the energy use. Financial incentives such as subsidy or lower interest rate were preferred by most of single-family homeowners (45%) to motivate them to take actions to reduce energy use. While personalized information to reduce energy use and lower interest rate and reduced rent are preferred by more residents in the other two categories. The implications for promoting energy efficient measures based on housing tenure is discussed.
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| 11. |
- Nair, Gireesh, et al.
(författare)
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“Energy visualization” as a tool to influence the energy use in a municipality kitchen
- 2019
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Ingår i: eceee 2019 Summer Study on energy efficiency: Is efficient sufficient?, 3–8 June, Presqu’île de Giens, Hyères, France. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387841 ; , s. 13-18
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Konferensbidrag (refereegranskat)abstract
- In Sweden, municipalities’ own and operate the kitchens that cook food for pre-schools, schools and the elderly care facilities. There are 68 kitchens in the municipality of Umeå and providing feedback to the kitchen staff on energy use could facilitate them to reduce the energy use in these facilities. Accordingly, an “energy visualization” project was initiated in one of the kitchen: Nordstjärnan, which is a newly built kitchen equipped with separate meters for appliances that continuously record the energy use.For the “energy visualization” project, a visualization design software called “Siemens Control Point” is used. The software is integrated with the existing steering and control system and connected to almost all sensors/meters in the building.The electricity use data from the kitchen was collected for 5 months prior to installation of the “energy visualization” project to establish a base line for the energy use. The average electricity use is referred in this paper as “Electricity budget”, which is calculated for each kitchen appliance that has an electricity meter.A trial was started in the kitchen from December 2018 onwards, wherein a display unit was designed to project the electricity use of the kitchen. The display unit, which is a large television screen, has different “slides”. For example, one of the slide is modelled to energy labelling. The energy labelling in the display has a rating from A+++ to D, which is calculated continuously based on the daily electricity use and the electricity budget. If the kitchen uses more electricity than budgeted then the rating will drop, and if the electricity use is less than the budget then the rating will increase. Furthermore, depending upon the energy performance of the kitchen the visualization screens also display “smileys” which are used as injunctive norms.
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| 12. |
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| 13. |
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| 14. |
- Soleimani-Mohseni, Mohsen, et al.
(författare)
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Energy simulation for a high-rise building using IDA ICE : investigations in different climates
- 2016
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Ingår i: Building Simulation. - Beijing : Tsinghua University Press. - 1996-3599 .- 1996-8744. ; 9:6, s. 629-640
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Tidskriftsartikel (refereegranskat)abstract
- In this paper a model of a high-rise building is constructed in the simulation program IDA ICE. The model is based on an IFC-model of a demonstration building constructed in Ljubljana, Slovenia, as part of an EU-project, EE-high-rise. The model's energy performance was simulated for four cities: Umeå (Scandinavia), Ljubljana (Central Europe), Sibenik (Mediterranean) and Dubai (The Persian Gulf). Furthermore, the climate envelope of the building was modified with the aim to improve the model's energy performance in each of the regions. The results were evaluated according to the energy requirements of passive house standard by the German Passive House Institute. The analysis suggests that the reference building model, which itself incorporates several energy efficient components, was unable to meet the German passive house standard in none of the four cities (Umeå, Ljubljana, Sibenik and Dubai) studied. By providing a combination of energy saving measures, such as modifications of thermal resistance of building envelope, the building may be able to meet the passive house standard in Ljubljana. The analysis concludes that the reduction in window area results in reduction of both heating and cooling demand. Increase in the thickness of the insulation and the thermal resistance of windows reduces the space heating demand for Umeå, Ljubljana and Sibenik (not applied for Dubai) while increasing the cooling demand for these cities. Increased airtightness has marginal effect on heating and cooling demand for all investigated cities. Reduced thermal resistance of windows will decrease cooling demand for Ljubljana, Sibenik and Dubai (not applied for Umeå). Reduced insulation thickness (not applied for Umeå) will decrease cooling demand for Ljubljana and Sibenik but not for Dubai. Reducing the insulation thickness may often result in reduced cooling demand for moderately warm countries since the average outdoor temperature could be lower than the indoor temperature during part of the cooling season. In those situations a reduced insulation thickness can cause heat flow from the relatively hot inside to the colder outside. However, for hot climates like in Dubai where outdoor temperature is higher than the indoor temperature for most of the year, reducing the insulation thickness will increase the cooling demand. This result suggests that the insulation thickness must be chosen and optimized based on heating and cooling demand, internal heat gain, and outdoor climate
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| 15. |
- Yang, Bin, et al.
(författare)
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Outdoor thermal comfort under subarctic climate of north Sweden : a pilot study in Umeå
- 2017
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Ingår i: Sustainable cities and society. - : Elsevier BV. - 2210-6707. ; 28, s. 387-397
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Tidskriftsartikel (refereegranskat)abstract
- Outdoor microclimate is important to determine the quality of outdoor spaces. Swedish people cherish summer period and prefer more outdoor activities in summer because of long winter with harsh outdoor environments. People in urban areas use parks for recreation and outdoor activities frequently in summer. Under subarctic climate, limited studies have been performed to explore the effect of microclimate environments on usage of outdoor spaces such as parks. The study explored the relationship of microclimate environments, park use and human behavioral patterns in urban area of Umeå, Sweden, which is under subarctic climate. Observations of naturally occurring behavior were recorded. Structured interviews, based on specially designed questionnaires, were performed during July to August in 2015. Measurements of objective parameters for microclimate environments, including air dry bulb temperature, relative humidity, wind speed, solar radiation and globe temperature, were performed. Human subjective responses from the questionnaire survey were compared with objectively measured results. 49% of local persons still prefer higher solar radiation even under "slightly warm" Thermal Sensation Vote (TSV), which reflects their high expectation to solar radiation. Local persons in Umeå, who expose themselves to a wider climate, are more adapted to subarctic climate than non-local persons. Practical implications: The pilot study demonstrated that wind attenuation together with strong sunshine can improve Thermal Sensation Vote (TSV), which could be realized by specially designed hump terrain for attenuating wind without shading effects. The results will be used for optimizing design of urban outdoor environments such as parks under subarctic or arctic climate.
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| 16. |
- Östin, Ronny, et al.
(författare)
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Energy performance and lessons learned from detailed measurement of a passive house preschool in cold climate
- 2019
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Ingår i: Is efficient sufficient?. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387803 - 9789198387810 ; , s. 1433-1442
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Konferensbidrag (refereegranskat)abstract
- Public passive house buildings are rare in high northern latitudes. This study reports on extensive measurements and evaluations of the most northerly (640 N) built passive house preschool in Sweden. The two storied preschool, built in 2014, has a total heated floor area of 1407 m2. The building was certified according to the international passive house standard. The building has several smart solutions such as demand controlled ventilation of individual rooms and automatic solar shading system.Energy measurements conducted during 2017-2018 showed that the preschool annually uses 44.4 kWhm-2, which is approximately 25 % lower than the passive house requirement for energy demand. However, the annual specific space heating requirement of 15 kWhm-2 and the peak heat power demand of 10 Wm-2 were not fulfilled. This non-compliance was mainly due to excessive ventilation during the heating season which was found to have 2.7 times higher air changes than the requirement in the Swedish building code. Furthermore, the building was found to be over heated from the sun during several occasions in a year. For example, excessive indoor air temperatures in the range 28 – 31°C were found during summer.The study revealed that the default winter operation by turning off the ventilation system during nights and weekends is continued in other seasons as well. This practice was not a “smart” approach for the air handling units as it was found to be one of the reasons for high indoor temperatures during non-winter months. Also, a mismatch between the operation of the automatic shading device and the ventilation control units was noted.The investigation shows that smart technical solutions in buildings may not be able to deliver its’ promised results if such systems are not monitored, adjusted and carefully evaluated. The paper identifies areas that need attention to ensure that a public building built to passive house standard actually deliver the energy efficiency it promises.
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