Pub Date : 2021-09-27DOI: 10.1177/17442591211045418
M. Juaristi, F. Favoino, T. Gómez-Acebo, Aurora Monge-Barrio
Adaptive façades are a promising choice to achieve comfortable low-energy buildings. Their effective performance is highly dependent on the local boundary conditions of each application and on the way the dynamic properties are controlled. The evaluation of whole building performance through building performance simulation can be useful to understand the potential of different Adaptive opaque façades (AOF) in a specific context. This paper evaluates through dynamic simulations promising design solutions of AOF for a residential building use in six different climates. It quantifies the total delivered thermal energy of 15 typologies of AOFs which consist of alternative adaptation strategies: (i) variation of solar absorptance of the cladding, (ii) variation of the convective heat transfer of air cavities and (iii) adaptive insulation strategies. For the first time, it also quantifies the performance of AOF which combine more than one adaptation strategy. The results show that the variation of the heat transfer by means of Adaptive Insulation components has the most significant impact on the reduction of the thermal energy use. The variation of the solar absorptance has also a significant positive impact when reducing heating consumption, but only if this adaptation strategy is actively controlled and combined with Adaptive Insulation components.
{"title":"Adaptive opaque façades and their potential to reduce thermal energy use in residential buildings: A simulation-based evaluation","authors":"M. Juaristi, F. Favoino, T. Gómez-Acebo, Aurora Monge-Barrio","doi":"10.1177/17442591211045418","DOIUrl":"https://doi.org/10.1177/17442591211045418","url":null,"abstract":"Adaptive façades are a promising choice to achieve comfortable low-energy buildings. Their effective performance is highly dependent on the local boundary conditions of each application and on the way the dynamic properties are controlled. The evaluation of whole building performance through building performance simulation can be useful to understand the potential of different Adaptive opaque façades (AOF) in a specific context. This paper evaluates through dynamic simulations promising design solutions of AOF for a residential building use in six different climates. It quantifies the total delivered thermal energy of 15 typologies of AOFs which consist of alternative adaptation strategies: (i) variation of solar absorptance of the cladding, (ii) variation of the convective heat transfer of air cavities and (iii) adaptive insulation strategies. For the first time, it also quantifies the performance of AOF which combine more than one adaptation strategy. The results show that the variation of the heat transfer by means of Adaptive Insulation components has the most significant impact on the reduction of the thermal energy use. The variation of the solar absorptance has also a significant positive impact when reducing heating consumption, but only if this adaptation strategy is actively controlled and combined with Adaptive Insulation components.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"22 1","pages":"675 - 720"},"PeriodicalIF":2.0,"publicationDate":"2021-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77278443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-19DOI: 10.1177/17442591211040545
Erlin Meng, Jiawang Yang, Ruonan Cai, Bo Zhou, Junqi Wang
Subtropical climate is characterized by high solar altitude angle in summer which causes the roof get more heat through solar radiation. GR, DSR, and CR all can decrease solar radiation heat gain of the roof. However, few researches have been done to the comparison of the thermal performance of these three roofs, especially in subtropical climate. In this study, four rooms were built separately with GR, DSR, CR, and ordinary roof (OR). The experiment was done from July 23 to August 4. Results showed that stabilities of the indoor air temperature of the four rooms were: DSR room > GR room > CR room > OR room. The GR, CR, and DSR can reduce the external surface temperature by 13.7°C, 12.0°C, and 4.8°C during the day while bring a temperature rise of 2.3°C, 1.9°C, and 0.9°C at night. Correlation analysis results showed that the internal surface heat flux of GR and DSR were negative correlated with weather factors while internal surface heat flux of OR and CR were positive correlated with weather factors. This study can give support to the selection between GR, DSR, and CR.
{"title":"Experimental comparison of summer thermal performance of green roof (GR), double skin roof (DSR) and cool roof (CR) in lightweight rooms in subtropical climate","authors":"Erlin Meng, Jiawang Yang, Ruonan Cai, Bo Zhou, Junqi Wang","doi":"10.1177/17442591211040545","DOIUrl":"https://doi.org/10.1177/17442591211040545","url":null,"abstract":"Subtropical climate is characterized by high solar altitude angle in summer which causes the roof get more heat through solar radiation. GR, DSR, and CR all can decrease solar radiation heat gain of the roof. However, few researches have been done to the comparison of the thermal performance of these three roofs, especially in subtropical climate. In this study, four rooms were built separately with GR, DSR, CR, and ordinary roof (OR). The experiment was done from July 23 to August 4. Results showed that stabilities of the indoor air temperature of the four rooms were: DSR room > GR room > CR room > OR room. The GR, CR, and DSR can reduce the external surface temperature by 13.7°C, 12.0°C, and 4.8°C during the day while bring a temperature rise of 2.3°C, 1.9°C, and 0.9°C at night. Correlation analysis results showed that the internal surface heat flux of GR and DSR were negative correlated with weather factors while internal surface heat flux of OR and CR were positive correlated with weather factors. This study can give support to the selection between GR, DSR, and CR.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"50 1","pages":"809 - 832"},"PeriodicalIF":2.0,"publicationDate":"2021-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74209681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-15DOI: 10.1177/17442591211045415
N. Holcroft
The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.
{"title":"Temperature dependency of the long-term thermal conductivity of spray polyurethane foam","authors":"N. Holcroft","doi":"10.1177/17442591211045415","DOIUrl":"https://doi.org/10.1177/17442591211045415","url":null,"abstract":"The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"20 1","pages":"571 - 603"},"PeriodicalIF":2.0,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80400122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-26DOI: 10.1177/17442591211034193
M. Shah
Calculation of evaporation is needed in many applications including swimming pools, water reservoirs, nuclear fuel pools, pools for rejection of heat from refrigeration systems, process tanks, etc. Hence accurate methods for prediction of evaporation are needed. Many prediction methods have been published including analytical models and empirical correlations. In the present study, 18 published prediction methods are compared to a very wide-ranging database which includes data from laboratory scale studies, swimming pools, and fuel pools in nuclear power plants. The data are from 25 sources. The range of data includes air temperatures from 6°C to 200°C, water temperatures from 7.1°C to 94.2°C, relative humidity from 0.21% to 98%, and air velocity from 0 to 8.5 m/s. The accuracy of prediction methods is examined for conditions in which natural convection dominates, that in which forced convection dominates, and that in which natural convection is absent. The results are reported and discussed. Recommendations are made for application.
{"title":"Evaluation of methods for prediction of evaporation from water pools","authors":"M. Shah","doi":"10.1177/17442591211034193","DOIUrl":"https://doi.org/10.1177/17442591211034193","url":null,"abstract":"Calculation of evaporation is needed in many applications including swimming pools, water reservoirs, nuclear fuel pools, pools for rejection of heat from refrigeration systems, process tanks, etc. Hence accurate methods for prediction of evaporation are needed. Many prediction methods have been published including analytical models and empirical correlations. In the present study, 18 published prediction methods are compared to a very wide-ranging database which includes data from laboratory scale studies, swimming pools, and fuel pools in nuclear power plants. The data are from 25 sources. The range of data includes air temperatures from 6°C to 200°C, water temperatures from 7.1°C to 94.2°C, relative humidity from 0.21% to 98%, and air velocity from 0 to 8.5 m/s. The accuracy of prediction methods is examined for conditions in which natural convection dominates, that in which forced convection dominates, and that in which natural convection is absent. The results are reported and discussed. Recommendations are made for application.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"77 4 1","pages":"629 - 648"},"PeriodicalIF":2.0,"publicationDate":"2021-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90855133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-01DOI: 10.1177/1744259120968586
A. Kubilay, A. Ferrari, D. Derome, J. Carmeliet
An urban microclimate model is used to design a smart wetting protocol for multilayer street pavements in order to maximize the evaporative cooling effect as a mitigation measure for thermal discomfort during heat waves. The microclimate model is built upon a computational fluid dynamics (CFD) model for solving the turbulent air, heat and moisture flow in the air domain of a street canyon. The CFD model is coupled to a model for heat and moisture transport in porous urban materials and to a radiative exchange model, determining the net solar and thermal radiation on each urban surface. A two-layer pavement system, previously optimized for maximal evaporative cooling applying the principles of capillary pumping and capillary break, is considered to design a smart wetting protocol answering the questions “when,” “how much,” and “how long” a pavement should be artificially wetted. It was found for the current optimized pavement solutions that a daily amount of 6 mm wetting over 10 min in the morning, preferentially between 8:00 and 10:00, guarantees a maximal evaporative cooling for 24 h during a heat wave.
{"title":"Smart wetting of permeable pavements as an evaporative-cooling measure for improving the urban climate during heat waves","authors":"A. Kubilay, A. Ferrari, D. Derome, J. Carmeliet","doi":"10.1177/1744259120968586","DOIUrl":"https://doi.org/10.1177/1744259120968586","url":null,"abstract":"An urban microclimate model is used to design a smart wetting protocol for multilayer street pavements in order to maximize the evaporative cooling effect as a mitigation measure for thermal discomfort during heat waves. The microclimate model is built upon a computational fluid dynamics (CFD) model for solving the turbulent air, heat and moisture flow in the air domain of a street canyon. The CFD model is coupled to a model for heat and moisture transport in porous urban materials and to a radiative exchange model, determining the net solar and thermal radiation on each urban surface. A two-layer pavement system, previously optimized for maximal evaporative cooling applying the principles of capillary pumping and capillary break, is considered to design a smart wetting protocol answering the questions “when,” “how much,” and “how long” a pavement should be artificially wetted. It was found for the current optimized pavement solutions that a daily amount of 6 mm wetting over 10 min in the morning, preferentially between 8:00 and 10:00, guarantees a maximal evaporative cooling for 24 h during a heat wave.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"190 1","pages":"36 - 66"},"PeriodicalIF":2.0,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79756799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-26DOI: 10.1177/17442591211017948
R. McLeod, C. Hopfe
This pedagogical note presents a novel learning activity (the icebox challenge) that was designed to facilitate deep learning of building physics energy transfer principles through a planning, prediction and analysis process following the Kolb learning cycle. The success of this strategy was evidenced by students relating and collating their knowledge and theoretical ideas and applying them to successfully solve a series of complex and inter-related practical building physics problems.
{"title":"Experiential learning in building physics: The icebox challenge","authors":"R. McLeod, C. Hopfe","doi":"10.1177/17442591211017948","DOIUrl":"https://doi.org/10.1177/17442591211017948","url":null,"abstract":"This pedagogical note presents a novel learning activity (the icebox challenge) that was designed to facilitate deep learning of building physics energy transfer principles through a planning, prediction and analysis process following the Kolb learning cycle. The success of this strategy was evidenced by students relating and collating their knowledge and theoretical ideas and applying them to successfully solve a series of complex and inter-related practical building physics problems.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"22 1","pages":"391 - 401"},"PeriodicalIF":2.0,"publicationDate":"2021-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87035185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-26DOI: 10.1177/17442591211017154
Hideya Yamamoto, D. Ogura
Vacuum insulation panels (VIPs) with a glass-fiber core has been considered to be difficult to operate for a long period of time, such as for building applications, because the thermal conductivity rises rapidly as the pressure increases. However, glass-fiber-core VIPs contain a material called a getter that continuously adsorbs permeated gas, and a theoretical model that considers the properties of the getter has not yet been developed. In this paper, the gas-adsorption mechanism by getters was investigated and a long-term-performance prediction model that considers the temperature dependence was proposed. Some gases were not adsorbed by the getter in the VIPs; however, a model was proposed that takes into account the non-absorbed gases by applying partial pressure to the adsorption isotherm in advance. The long-term performance of VIPs with different areas and volumes was compared with the measured values, and the validity of the calculation results was confirmed. These results show that the long-term performance of VIPs of different sizes can be accurately predicted when the getter performance is well understood.
{"title":"Dependence of gas permeation and adsorption on temperature in vacuum insulation panels (VIPs) containing getter materials","authors":"Hideya Yamamoto, D. Ogura","doi":"10.1177/17442591211017154","DOIUrl":"https://doi.org/10.1177/17442591211017154","url":null,"abstract":"Vacuum insulation panels (VIPs) with a glass-fiber core has been considered to be difficult to operate for a long period of time, such as for building applications, because the thermal conductivity rises rapidly as the pressure increases. However, glass-fiber-core VIPs contain a material called a getter that continuously adsorbs permeated gas, and a theoretical model that considers the properties of the getter has not yet been developed. In this paper, the gas-adsorption mechanism by getters was investigated and a long-term-performance prediction model that considers the temperature dependence was proposed. Some gases were not adsorbed by the getter in the VIPs; however, a model was proposed that takes into account the non-absorbed gases by applying partial pressure to the adsorption isotherm in advance. The long-term performance of VIPs with different areas and volumes was compared with the measured values, and the validity of the calculation results was confirmed. These results show that the long-term performance of VIPs of different sizes can be accurately predicted when the getter performance is well understood.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"106 1","pages":"604 - 628"},"PeriodicalIF":2.0,"publicationDate":"2021-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89169590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-10DOI: 10.1177/17442591211013449
Yiming Li, Xiang Yue, Lei Zhao, Huiyun Xu, Xingan Liu, T. Li
Chinese solar greenhouse (CSG) is an energy-saving agricultural building which is used to grow vegetables in winter. The north wall of CSG plays an crucial role in concerning the production yield and quality during the winter months. To improve the thermal performance of north wall, different internal surface structures (ISS) with same materials were compared. Based on the field experiment and the proposed valuation, the dynamic heat storage-release characteristics of the north walls have been analyzed and discussed. The results showed that compared with the flat wall and the striped wall, the alveolate wall has better properties of heat storage and thermal insulation. Moreover, relative humidity in this type of greenhouse is more suitable for growing crops. The alveolate wall can improve indoor thermal environment and reduce the sensitivity to external environment. The obtained results can provide a basis for the scientific construction of the CSG north wall. It has significant potential for the area in high latitude, high altitude and long winter.
{"title":"Effect of north wall internal surface structure on heat storage-release performance and thermal environment of Chinese solar greenhouse","authors":"Yiming Li, Xiang Yue, Lei Zhao, Huiyun Xu, Xingan Liu, T. Li","doi":"10.1177/17442591211013449","DOIUrl":"https://doi.org/10.1177/17442591211013449","url":null,"abstract":"Chinese solar greenhouse (CSG) is an energy-saving agricultural building which is used to grow vegetables in winter. The north wall of CSG plays an crucial role in concerning the production yield and quality during the winter months. To improve the thermal performance of north wall, different internal surface structures (ISS) with same materials were compared. Based on the field experiment and the proposed valuation, the dynamic heat storage-release characteristics of the north walls have been analyzed and discussed. The results showed that compared with the flat wall and the striped wall, the alveolate wall has better properties of heat storage and thermal insulation. Moreover, relative humidity in this type of greenhouse is more suitable for growing crops. The alveolate wall can improve indoor thermal environment and reduce the sensitivity to external environment. The obtained results can provide a basis for the scientific construction of the CSG north wall. It has significant potential for the area in high latitude, high altitude and long winter.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"30 1","pages":"507 - 527"},"PeriodicalIF":2.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84715099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-02DOI: 10.1177/17442591211009549
M. Ismaiel, Yuxiang Chen, C. Cruz-Noguez, M. Hagel
Increasing the thermal resistance of masonry wall systems is one of the effective ways to reduce energy consumption in the operation of masonry buildings. This increase is also demanded by newer, more stringent energy codes. However, the effective thermal resistance (R-value) of masonry walls is affected by many factors, such as thermal bridging, which occurs in places where highly conductive structural components penetrate insulating materials. Thermal bridging is common when connecting masonry veneers to structural backup walls. Furthermore, quick and precise methods for estimating the R-value are needed for thermal design improvements and code-compliance calculations. This study presents a comprehensive literature review on key factors that influence the overall thermal performance of masonry walls, methods to effectively estimate and measure R-values, and improvements in thermal design. In addition to identifying the main technical and practical challenges and the corresponding progress made on each front, key design considerations, such as code compliance, material properties, insulation types, and location, as well as special ties and shelf angles types, are also discussed. This study summarizes critical information and recommendations that will help improve the thermal design of masonry walls, hence reducing the energy consumption of buildings.
{"title":"Thermal resistance of masonry walls: a literature review on influence factors, evaluation, and improvement","authors":"M. Ismaiel, Yuxiang Chen, C. Cruz-Noguez, M. Hagel","doi":"10.1177/17442591211009549","DOIUrl":"https://doi.org/10.1177/17442591211009549","url":null,"abstract":"Increasing the thermal resistance of masonry wall systems is one of the effective ways to reduce energy consumption in the operation of masonry buildings. This increase is also demanded by newer, more stringent energy codes. However, the effective thermal resistance (R-value) of masonry walls is affected by many factors, such as thermal bridging, which occurs in places where highly conductive structural components penetrate insulating materials. Thermal bridging is common when connecting masonry veneers to structural backup walls. Furthermore, quick and precise methods for estimating the R-value are needed for thermal design improvements and code-compliance calculations. This study presents a comprehensive literature review on key factors that influence the overall thermal performance of masonry walls, methods to effectively estimate and measure R-values, and improvements in thermal design. In addition to identifying the main technical and practical challenges and the corresponding progress made on each front, key design considerations, such as code compliance, material properties, insulation types, and location, as well as special ties and shelf angles types, are also discussed. This study summarizes critical information and recommendations that will help improve the thermal design of masonry walls, hence reducing the energy consumption of buildings.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"22 1","pages":"528 - 567"},"PeriodicalIF":2.0,"publicationDate":"2021-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77881213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-01DOI: 10.1177/17442591211009937
Klaas Calle, N. Van Den Bossche
Historical masonry constructions are difficult to mimic in hygrothermal models. The material properties of the walls are often highly uncertain due to the natural origin of the aggregates and the various, manual production processes used through time. Therefore, sensitivity analyses based on probabilistic simulations are powerful tools to indicate the risks on damage in masonry constructions. Damage criteria for relevant pathologies such as frost damage, potential decay of wooden beam heads and mould growth at the interior surface are used. The assessment methods (Scatter plots, Classification trees and Sobol indices) are based on 1D Heat, Air and Moisture simulations, including realistic variations on climate parameters and wall properties. These methodologies are applied to probabilistic simulations in which a potential damage risk is expected in historic masonries. The application of interior insulation, the use of hydrophobic treatments, and the impact of potential water infiltrations through cracks are discussed. In most of these situations a high dependency of each of the damage criteria on the rain intensity, the trend of the moisture retention/liquid conductivity curve and the absorption coefficient is evident, but also additional insights are found. For example, the thermal impact of interior insulation is negligible compared to its reduction of the first phase drying potential towards the interior. For hydrophobic treatments, the risk for damage typically decreases, but in combination with a rain water infiltration rate above approximately 5% of the wind driven rain the risk on mould growth at the interior surface significantly increases.
{"title":"Sensitivity analysis of the hygrothermal behaviour of homogeneous masonry constructions: Interior insulation, rainwater infiltration and hydrophobic treatment","authors":"Klaas Calle, N. Van Den Bossche","doi":"10.1177/17442591211009937","DOIUrl":"https://doi.org/10.1177/17442591211009937","url":null,"abstract":"Historical masonry constructions are difficult to mimic in hygrothermal models. The material properties of the walls are often highly uncertain due to the natural origin of the aggregates and the various, manual production processes used through time. Therefore, sensitivity analyses based on probabilistic simulations are powerful tools to indicate the risks on damage in masonry constructions. Damage criteria for relevant pathologies such as frost damage, potential decay of wooden beam heads and mould growth at the interior surface are used. The assessment methods (Scatter plots, Classification trees and Sobol indices) are based on 1D Heat, Air and Moisture simulations, including realistic variations on climate parameters and wall properties. These methodologies are applied to probabilistic simulations in which a potential damage risk is expected in historic masonries. The application of interior insulation, the use of hydrophobic treatments, and the impact of potential water infiltrations through cracks are discussed. In most of these situations a high dependency of each of the damage criteria on the rain intensity, the trend of the moisture retention/liquid conductivity curve and the absorption coefficient is evident, but also additional insights are found. For example, the thermal impact of interior insulation is negligible compared to its reduction of the first phase drying potential towards the interior. For hydrophobic treatments, the risk for damage typically decreases, but in combination with a rain water infiltration rate above approximately 5% of the wind driven rain the risk on mould growth at the interior surface significantly increases.","PeriodicalId":50249,"journal":{"name":"Journal of Building Physics","volume":"9 1","pages":"510 - 538"},"PeriodicalIF":2.0,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88078587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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