| 1. |
- Alev, Uellar, et al.
(författare)
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Indoor hygrothermal condition and user satisfaction in naturally ventilated historic houses in temperate humid continental climate around the Baltic Sea
- 2016
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Ingår i: Architectural Science Review. - : Informa UK Limited. - 0003-8628 .- 1758-9622. ; 59:1, s. 53-67
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Tidskriftsartikel (refereegranskat)abstract
- Indoor climate and user satisfaction were analysed by field measurement and a questionnaire in 67 traditional rural houses in Estonia, Finland and Sweden. Our findings showed that the indoor climate in all the investigated historic rural houses needs improvement. The room temperature was mainly too low during winter. Leaky houses had also a larger vertical temperature difference. The relative humidity in the unheated and periodically heated houses was high during winter and caused risk for mould growth in 17% of all houses and 33% of unheated houses. Significant differences of indoor humidity loads in different houses were revealed depending on the living density and usage profile. During the winter period, the design value of moisture excess was 4-5g/m(3) and the average moisture load was 2-3.5g/m(3). The indoor humidity load in historic houses was similar to that in modern houses. The results of the questionnaire showed that main problems were related to unstable or too low temperatures. At the same time, inhabitants rated the overall indoor climate as healthy and no statistically important relations were found between average indoor temperature and complaints about too cold or too warm indoor temperatures.
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| 2. |
- Arumägi, Endrik, et al.
(författare)
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Indoor climate in a naturally ventilated unheated medieval church in Harju-Risti, Estonia
- 2010
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Ingår i: 10th REHVA World congress Clima 2010.
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Konferensbidrag (refereegranskat)abstract
- Indoor climate in a naturally ventilated unheated medieval church was analysed to determine if the conditions existing suit for three medieval wooden sculptures forming the Calvary group that were decorated the church until 1958. The values of temperature and RH were measured with data loggers at 1-h intervals inside and outside the church. Ventilation measurements were performed using a passive tracer gas technique. The current study shows that there is a considerable risk in bringing back the medieval sculptures forming the Calvary group to the Harju-Risti Church without creating conditions for indoor temperature and humidity regulation. To start risk assessment it is required to maintain a RH level that prevents the risk of mould growth, reduce fluctuations of air RH annually and in the short term period, avoid of too high and too low humidity levels in church that could cause flaking, peeling and cracking of wooden sculptures.
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| 3. |
- Asphaug, Silje Kathrin, et al.
(författare)
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Moisture Control Strategies of Habitable Basements in Cold Climates
- 2020
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 169
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Tidskriftsartikel (refereegranskat)abstract
- In many countries with a cold climate, basements are used as dwellings. This presents a major challenge concerning moisture safety design. Climate change is expected to increase the risk of moisture-related damage in basements owing to increasing amounts of stormwater, annual precipitation, and annual temperatures. This study examines the primary moisture control strategies for habitable basements in western cold climate countries by identifying the main differences and similarities in national building recommendations for new buildings. Using Norwegian design guides as a baseline, we identified ten key challenges and compared them with four other cold climate countries’ recommendations given by experts in the field of building physics (building science). The results showed that other countries’ recommendations differ from those of Norway in various key challenges. However, similar but varying recommendations pertaining to ground surface slopes, drainage layers, drainage pipes, capillary breaking layers in floors, avoiding thermal bridges, airtightness, and ventilation were noted. The key differences pertained to the exterior damp proofing of walls, use and position of dimpled membranes and vapour barriers, and use of permeable thermal insulation. The outcome is that countries emphasise the ten key challenges differently. Although the recommendations have many similarities, the weighting (or prioritizing) distinguishes the five countries’ moisture control strategies.
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| 4. |
- Eskola, Lari, et al.
(författare)
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Airtightness, Air Exchange and Energy Performance in Historic Residential Buildings with Different Structures
- 2015
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Ingår i: The International Journal of Ventilation. - 1473-3315 .- 2044-4044. ; 14:1, s. 11-26
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Tidskriftsartikel (refereegranskat)abstract
- Old buildings that represent and maintain historic values often have poor indoor conditions and energy efficiency. The aim of this work was to evaluate the influence of building structures on airtightness and energy performance of certain historic building types. In this study on-site measurements, dynamic simulation and questionnaires were used. Significant differences between the levels of the airtightness of the historic houses exist in the studied region. No statistically significant correlation was found between the structure types and the envelope tightness. The typical air leakage places of the studied houses were at the junctions of the envelope structures. Measured air exchange rates indicated that the level of ventilation is insufficient in some of the houses while some are too leaky. If the airtightness of the naturally ventilated house is improved, the acceptable ventilation rate has to be guaranteed. Tightening the envelope and moving from natural to mechanical ventilation was the most effective way to improve the indoor conditions and energy performance.
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| 5. |
- Kauniste, Maarja, et al.
(författare)
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Assessment on Strength and Stiffness Properties of Aged Structural Timber
- 2024
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Ingår i: Journal of Sustainable Architecture and Civil Engineering. - : Kauno Technologijos Universitetas. - 2029-9990. ; 34:1, s. 62-74
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Tidskriftsartikel (refereegranskat)abstract
- Despite the growing popularity of wood and wood-based products in the construction industry, there has been insufficient focus on assessing the condition, preservation, and potential reuse of existing timber. While numerous standards evaluate the quality of freshly sawn timber, there is currently no standardized system for assessing the strength properties of aged and reused timber. The lack of these guidelines is also one of the reasons the results obtained in numerous research are often fluctuating, and we cannot draw clear conclusions. The matter is further complicated by the lack of data on old in-situ wood and its exploitation, which would help to evaluate its condition. Consequently, there is a real practical need to assess the condition of old timber to avoid unnecessary demolition and the loss of valuable and structurally sound building material. What sets this study apart from others is that, in addition to destructive testing, the 4-point non-destructive (ND) bending tests were conducted on all four faces of test specimens. This provided an opportunity to assess the wood visually and then find connections to associate external characteristics with real properties. This methodology aimed to determine whether it is feasible to visually assess the most practical way to use wooden elements in construction. If this question arises, which face of the beam would be better suited for the tension side and which for the compression side? The old timber used in testing originated from an old library building located on Vaksali Street, Tartu, Estonia and is estimated to be about 120 years old. This paper investigates and compares the collected data with a Nordic standard for grading fresh-sawn timber and two established Italian standards for visually assessing aged timber. This comparison contributes to developing a standardized framework for future visual assessments. ND and destructive four-point bending tests were performed to validate and find appropriate visual characteristics to determine the strength and stiffness of the timber elements. The primary goals of this study were first to compare the results obtained from existing ND methods with actual results and secondly to provide guidelines for better visual grading of wood in the future, based on Nordic Standard INSTA 142 (2010) and Italian standards UNI 11119 (2004) and UNI 11035 (2010) Contrary to previous research conclusions, the visual assessment results yielded unexpected outcomes. The results show that the grading standards significantly underestimated the real strength of the wood, and even more, none of the visual assessments overestimated the real strength of the specimens. Therefore, based on prior research and the findings derived from this study, there is evident a substantial potential for extensive development and optimization within this field.
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| 6. |
- Maivel, Mikk, et al.
(författare)
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Overview of existing surveys on energy performance related quality and compliance. QUALICHeCK Report: "Status on the Ground"
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is part of a series of reports to be produced in the context of the IEE QUALICHeCK project. The primary objective of this report is to gather preliminary information on quality and compliance issues in 9 focus countries (Austria, Belgium, Cyprus, Estonia, France, Greece, Romania, Spain, and Sweden) on the 4 technology areas specifically addressed in the project (transmission characteristics, ventilation and airtightness, sustainable summer comfort technologies, and renewables in multi-energy systems). It is not meant to accurately and exhaustively describe the status of quality and compliance in those countries for those technology areas. This report also includes some information from countries outside the consortium, in particular from the United Kingdom. The Energy Performance of Buildings Directive recast (EPBD recast) gives ambitious goals for the building sector to reduce energy use as well as greenhouse gas emissions. It requires Member States to engage in the generalisation of Nearly Zero-Energy Buildings (NZEB), both for new and existing buildings. Although experience has shown that such buildings can be realised in practice, there exist many challenges to drive the whole market in this direction. One specific challenge concerns the compliance of buildings to NZEB requirements, in particular how to ensure they actually comply with applicable regulations or programme specifications. Another challenge lies in upgrading the quality of the works to meet NZEB standards at commissioning but also on the longer term. The IEE QUALICHeCK project addresses these two issues with two main objectives: To set up a series of actions which should result in more attention and practical initiatives for: 1. Actual compliance with the claimed energy performance for new and renovated buildings, i.e., ‘boundary conditions which force people to do what they declare’; 2. Achieving a better quality of the works, i.e., ‘boundary conditions which stimulate and allow the building sector to deliver good quality of the works’. Chapter 2 of this report describes the overall situation in the 9 focus countries, with specific attention to the status on the quality of input data, the quality of the works and the effectiveness of compliance frameworks. Chapter 3 gives examples of observed performance in daily practice grouped according to the 4 focus technology areas. Chapter 4 briefly presents some examples of interesting schemes, whether already implemented or under development. Several studies and expert-statements highlight critical issues on the input data used in Energy Performance Certificates (EPC). This seems to arise, at least to a significant extent, from the absence of verification after the works are finished. Compliance frameworks are typically limited to verifications at building permit stage, therefore, not with "as-built" data. Most countries do not have control mechanisms at later stages, including design changes during construction, commissioning, final design/production information, and operation. Therefore, errors due to design modifications compared to the initial EPC submission or poor workmanship (affecting the EPC input data) seem common. In addition, EPC calculations are checked by authorities with very small and seldom random samples. To overcome this problem, several countries or regions (AU (in Salzburg region), BE, FR) have recently introduced interesting schemes to check the consistency of the input data after completion of the works. Other problems identified on the EPC input data include: - unclear procedures; - uneasy access to the EPC input data; - mistakes or fraud by persons providing the input data; - lack of competence of persons providing the input data. Chapter 3 summarises 31 specific studies addressing specific concerns on performance data from the field, the compliance of the input data, the quality of the works, or the compliance frameworks. Although the situation is contrasted between countries and technologies, this partial information confirms the need to further work on schemes to improve the confidence in the compliance of input values and in the quality of the works. As illustration with regard to transmission characteristics, a Belgian field study conducted in the late 90s on 200 dwellings has shown significant discrepancies between reported and actual insulation levels, with little impact on the requirements supposed to be met. A Swedish study has highlighted challenges for the determination of thermal bridges with an appropriate trade-off between simplicity and accuracy. Regarding ventilation and airtightness, several studies have shown significant deviations 2 Overview of existing surveys on energy performance related quality and compliance between expected and actual performance (as per EPC rules) and suggest major sources of problems in the design and the quality of the works. There are also interesting examples regarding renewables, e.g., on domestic hot water solar thermal installations in France with, on the one hand, a field campaign on 9 large installations showing an even distribution of very good to very poor results; on the other hand, very good results on 11.817 installations in individual houses audited under a specific certification programme. This chapter also shows the difficulty to define compliance criteria for summer thermal comfort criteria, based on an Estonian field study on 28 apartments buildings, as 65% of the apartments monitored did not comply with the present requirement (less than 150 degree-hours below 27 °C). In all EU countries, national procedures exist to support the mandatory availability of EPCs for new and renovated buildings. Chapter 4 describes approaches developed or under development to (or potentially interesting to) increase confidence in the compliance of the EPC input data and the quality of the works, and to ease the access to EPC input data. Some approaches are also briefly mentioned in Chapters 2 & 3. The approaches mentioned or briefly described in this report to increase the confidence the EPC input data include: - standard format for documenting the input data and reporting the results of the energy calculations, in order to make the EPC input data and the results documentation transparent (Estonia); - automatic checks in the calculation software and/or during upload into the EPC database (Austria, Belgium) ; - product data databases to help ensure that correct product data is used (e.g., in Belgium and France); - catalogues of construction methods (e.g. thermal bridges catalogues). As for the quality of the works, the approaches include: - voluntary building certification schemes that require measurements and tests (e.g., in Austria and Spain); - voluntary certification schemes for construction workers and/or companies (e.g., in Belgium, France, or Romania); - mandatory inspection of the building service systems (e.g., in Cyprus, or Sweden). Overall, although this report does not pretend to give an accurate picture of the quality and compliance status in the 9 focus countries for the 4 technology areas of interest, it suggests that the awareness on those issues, as well as on the measures taken to overcome them range very widely, from little or no field knowledge to in-depth analysis, and from naïve to fairly elaborated schemes. Some very interesting approaches should be analysed in more detail in later phases of the QUALICHeCK project. This report also confirms the need to tackle quality and compliance issues for successful EPBD implementation, both in terms of awareness raising, as well as development of appropriate tools and schemes to increase confidence in the effectiveness of the implementation of the EPBD.
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| 7. |
- Napp, Margus, et al.
(författare)
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Adaptive ventilation for climate control in a medieval church in cold climate
- 2016
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Ingår i: The International Journal of Ventilation. - : Informa UK Limited. - 1473-3315 .- 2044-4044. ; 15:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Old medieval churches hold objects of great historical and cultural value: organs, altars, paintings. But they have no systems for indoor climate control or the church may be heated only at services. These conditions are inadequate for the preservation of cultural heritage. The objective of this paper is to assess an adaptive ventilation (AV) solution in a church for reduction of the relative humidity (RH) in an unheated church to prevent mould growth and disintegration of wooden parts. The operation principle of the system is to ensure ventilation in the church when water vapour content in the outdoor air is lower than that indoors, to lower the RH in the church. A case study in Hangvar Church in Gotland, Sweden, was conducted to test the performance of AV to reduce the RH in the church. Field measurements showed that AV has a positive impact on the indoor RH of the church. During the measurement period without climate control, the RH in the church was higher than 70% of 98% of the time; with AV, the indoor RH was higher than 70% only 78% of the time. Building simulation was carried out to test the performance and energy consumption of AV under different conditions. The simulations showed that auxiliary heating and airflow rate both have high impact on the system performance. The higher the heating power, the more effective the system is; thus, lower airflow rates are needed. Infiltration has also high impact on the system performance: the lower the infiltration rate, the better the AV performance is.
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| 8. |
- Thorsell, Thomas
(författare)
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Advances in Thermal Insulation : Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60% if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hygrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The procedure incorporates specific steps exposing the wall to different climate conditions, ranging from cold and dry to hot and humid, with and without a pressure gradient. This study showed that air infiltration alone might decrease the thermal resistance of a residential wall by 15%, more for industrial walls. Results from the research underpin a discussion concerning the importance of a holistic approach to building design if we are to meet the challenge of energy savings and sustainability. Thermal insulation efficiency is a main concept used throughout, and since it measures utilization it is a partial measure of sustainability. It is therefore proposed as a necessary design parameter in addition to a performance indicator when designing building envelopes. The thermal insulation efficiency ranges from below 50% for a wood stud wall poorly designed with incorporated VIP, while an optimized design with VIP placed in an uninterrupted external layer shows an efficiency of 99%, almost perfect. Thermal insulation efficiency reflects the measured wall performance full scale test, thus indicating efficiency under varied environmental loads: heat, moisture and pressure. The building design must be as a system, integrating all the subsystems together to function in concert. New design methodologies must be created along with new, more reliable and comprehensive measuring, testing and integrating procedures. New super insulators are capable of reducing energy usage below zero energy in buildings. It would be a shame to waste them by not taking care of the rest of the system. This thesis details the steps that went into this study and shows how this can be done.
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| 9. |
- Woloszyn, Monika, et al.
(författare)
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Assessing possibilities of moisture management in buildings using simulation tools
- 2009
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 44:3, s. 515-524
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Tidskriftsartikel (refereegranskat)abstract
- Indoor moisture management, which means keeping the indoor relative humidity (RH) at correct levels, is very important for whole building performance in terms of indoor air quality (IAQ), energy performance and durability of the building. In this study, the effect of combining a relative-humidity-sensitive (RHS) ventilation system with indoor moisture buffering materials was investigated. Four comprehensive heat–air–moisture (HAM) simulation tools were used to analyse the performance of different moisture management strategies in terms of IAQ and of energy efficiency. Despite some differences in results, a good agreement was found and similar trends were detected from the results, using the four different simulation tools. The results from simulations demonstrate that RHS ventilation reduces the spread between the minimum and maximum values of the RH in the indoor air and generates energy savings. Energy savings are achieved while keeping the RH at target level, not allowing for possible risk of condensations. The disadvantage of this type of demand controlled-ventilation is that other pollutants (such as CO2) may exceed target values. This study also confirmed that the use of moisture-buffering materials is a very efficient way to reduce the amplitude of daily moisture variations. It was possible, by the combined effect of ventilation and wood as buffering material, to keep the indoor RH at a very stable level.
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