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R.M.J. Bokel
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29 records found
1
Journal article
(2024)
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Qi Zhen, Anxiao Zhang, Regina Bokel, Yue Zheng, Jing Li, Yiming Du, Qi Zhang
Most respiratory infectious disease transmission events occur in indoor environments, and examining the infection risk in different types of multi-zone buildings is critical to the safe reopening and use of public buildings. Appropriate space design influences occupant behavior and virus spread, thereby aiding in mitigating indoor infection risk. This study aims to quickly evaluate the multi-route infection risk in multi-zone buildings with relatively stable occupant populations, and to quantify the effectiveness of spatial interventions at different levels. A Markov chain-based approach was proposed to characterize occupants' time-activity trajectories with low time cost and relatively high accuracy. Four transmission routes are considered, especially for the fine-grained characterization of close contact. A real university office building was selected as a case study to quantitatively evaluate the effects of three non-pharmacological interventions including spatial layout, ventilation, and occupant behavioral control. Results showed that short-range airborne transmission dominated, and optimized combination spatial design interventions reduced the indoor infection risk by up to 10 %. Zone layout intervention was the most effective, with the division of the open-plan office area into three subzones, reducing the risk by 9.6 %, which was superior to the intervention of maintaining a one-meter interpersonal distance. Followed by the furniture layout, without changing the seating capacity and without desktop baffles, the L-shaped table layout worked better reducing the risk by 2.78 %. This study can help architects and managers better understand the risk of indoor transmission in multizone buildings from a spatial design perspective, to select appropriate interventions to reduce the risk.
...
Most respiratory infectious disease transmission events occur in indoor environments, and examining the infection risk in different types of multi-zone buildings is critical to the safe reopening and use of public buildings. Appropriate space design influences occupant behavior and virus spread, thereby aiding in mitigating indoor infection risk. This study aims to quickly evaluate the multi-route infection risk in multi-zone buildings with relatively stable occupant populations, and to quantify the effectiveness of spatial interventions at different levels. A Markov chain-based approach was proposed to characterize occupants' time-activity trajectories with low time cost and relatively high accuracy. Four transmission routes are considered, especially for the fine-grained characterization of close contact. A real university office building was selected as a case study to quantitatively evaluate the effects of three non-pharmacological interventions including spatial layout, ventilation, and occupant behavioral control. Results showed that short-range airborne transmission dominated, and optimized combination spatial design interventions reduced the indoor infection risk by up to 10 %. Zone layout intervention was the most effective, with the division of the open-plan office area into three subzones, reducing the risk by 9.6 %, which was superior to the intervention of maintaining a one-meter interpersonal distance. Followed by the furniture layout, without changing the seating capacity and without desktop baffles, the L-shaped table layout worked better reducing the risk by 2.78 %. This study can help architects and managers better understand the risk of indoor transmission in multizone buildings from a spatial design perspective, to select appropriate interventions to reduce the risk.
Daylighting is desirable in classrooms but can pose a challenge to classroom illumination when there is a risk of discomfort from glare from windows and sunlight. There are several metrics in use for the evaluation of discomfort from glare from daylight, but none has yet been validated based on the field-of-view conditions of classrooms. A previous study found that Daylight Glare Probability (DGP) produced a relatively better predictive power of the reported discomfort from glare in a classroom compared to other metrics. However, the metric tended to correlate weakly with the reported glare in positions away from the window light source in a classroom. This prompted the current investigation
on the possibility of improving the DGP equation. The modified equation produced a significantly better fit to the subjective glare evaluations from a dataset comprising 184 evaluations from 49 participants collected in a classroom. The results suggest that DGP can be improved to predict the reported discomfort from glare for the conditions of board-based work in a classroom, particularly when a logarithmic form of the adaptation term is integrated in the equation. ...
on the possibility of improving the DGP equation. The modified equation produced a significantly better fit to the subjective glare evaluations from a dataset comprising 184 evaluations from 49 participants collected in a classroom. The results suggest that DGP can be improved to predict the reported discomfort from glare for the conditions of board-based work in a classroom, particularly when a logarithmic form of the adaptation term is integrated in the equation. ...
Daylighting is desirable in classrooms but can pose a challenge to classroom illumination when there is a risk of discomfort from glare from windows and sunlight. There are several metrics in use for the evaluation of discomfort from glare from daylight, but none has yet been validated based on the field-of-view conditions of classrooms. A previous study found that Daylight Glare Probability (DGP) produced a relatively better predictive power of the reported discomfort from glare in a classroom compared to other metrics. However, the metric tended to correlate weakly with the reported glare in positions away from the window light source in a classroom. This prompted the current investigation
on the possibility of improving the DGP equation. The modified equation produced a significantly better fit to the subjective glare evaluations from a dataset comprising 184 evaluations from 49 participants collected in a classroom. The results suggest that DGP can be improved to predict the reported discomfort from glare for the conditions of board-based work in a classroom, particularly when a logarithmic form of the adaptation term is integrated in the equation.
on the possibility of improving the DGP equation. The modified equation produced a significantly better fit to the subjective glare evaluations from a dataset comprising 184 evaluations from 49 participants collected in a classroom. The results suggest that DGP can be improved to predict the reported discomfort from glare for the conditions of board-based work in a classroom, particularly when a logarithmic form of the adaptation term is integrated in the equation.
Conference paper
(2022)
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P.J.W. van den Engel, R.M.J. Bokel, E. Brembilla, L.A. de Araujo Passos, P.G. Luscuere
This research gives an overview of the current comfort and energy performance, and optional future design of highly transparent and lightweight buildings. The transparent Co-Creation Centre in the Green Village at the TU Delft, has a combination of active and passive climate control measures. The aim of the research is to show how transparent buildings with a high glass/floor percentage (here 122 %) perform and how these could be optimized. An overview of the research project and system integration is presented, with the focus on energy, comfort and working of the BMS-system. Energy and comfort performances are measured and simulated. Validation has been executed of daylight, solar heat access, and thermal performances. A large Phase Change Material (PCM) buffer in the air handling unit reduces the heating and cooling demand. Making use of passive qualities of the outdoor and indoor air temperature and solar energy requires a more complex control strategy than usual. A Model Predictive Control (MPC) strategy has been investigated and can optimize the energy consumption.
...
This research gives an overview of the current comfort and energy performance, and optional future design of highly transparent and lightweight buildings. The transparent Co-Creation Centre in the Green Village at the TU Delft, has a combination of active and passive climate control measures. The aim of the research is to show how transparent buildings with a high glass/floor percentage (here 122 %) perform and how these could be optimized. An overview of the research project and system integration is presented, with the focus on energy, comfort and working of the BMS-system. Energy and comfort performances are measured and simulated. Validation has been executed of daylight, solar heat access, and thermal performances. A large Phase Change Material (PCM) buffer in the air handling unit reduces the heating and cooling demand. Making use of passive qualities of the outdoor and indoor air temperature and solar energy requires a more complex control strategy than usual. A Model Predictive Control (MPC) strategy has been investigated and can optimize the energy consumption.
Naturally air-conditioned nearly zero-energy housing
The Earth, Wind & Fire Case Study
Dutch housing built before the 1990s consumes the highest percentage of
primary energy for heating and generally exhibits poor comfort. With the government targeting to convert 300,000 existing homes to become more energy-efficient every year, a renovation wave has started. How do we achieve this? This paper proposes a natural air-conditioning refurbishment strategy which not only provides energy savings but also contributes towards renewable energy harvesting to address the goal of a zeroenergy built environment. ...
primary energy for heating and generally exhibits poor comfort. With the government targeting to convert 300,000 existing homes to become more energy-efficient every year, a renovation wave has started. How do we achieve this? This paper proposes a natural air-conditioning refurbishment strategy which not only provides energy savings but also contributes towards renewable energy harvesting to address the goal of a zeroenergy built environment. ...
Dutch housing built before the 1990s consumes the highest percentage of
primary energy for heating and generally exhibits poor comfort. With the government targeting to convert 300,000 existing homes to become more energy-efficient every year, a renovation wave has started. How do we achieve this? This paper proposes a natural air-conditioning refurbishment strategy which not only provides energy savings but also contributes towards renewable energy harvesting to address the goal of a zeroenergy built environment.
primary energy for heating and generally exhibits poor comfort. With the government targeting to convert 300,000 existing homes to become more energy-efficient every year, a renovation wave has started. How do we achieve this? This paper proposes a natural air-conditioning refurbishment strategy which not only provides energy savings but also contributes towards renewable energy harvesting to address the goal of a zeroenergy built environment.
This paper describes a step-by-step approach for generating various energy concepts for neighbourhoods, based on local renewable resources. The approach is developed within the European research project ‘Smart Urban Isle’ (SUI). While much literature is focussed on comparison or optimization of predefined configurations, the SUI approach adds to the existing knowledge by introducing a systematic step-by-step approach that supports the first step of the development phase, i.e., the generation of various - potentially innovative - energy system configurations for neighbourhoods, which in the following phase can be optimized using optimization methods. First, the five steps of the approach are introduced, and secondly, these are applied to an existing residential neighbourhood in the Netherlands. The resulting preferred energy concept for the case study consists of a local, ultra-low temperature heat grid, heated by decentralised heat production from PV-thermal (PVT) collectors on individual roofs and connected to a collective seasonal underground storage (ATES). This paper demonstrates the usefulness of the approach for generating various alternative innovative energy concepts for neighbourhoods, based on the local demands and energy potentials, and also describes the resulting energy concept developed for the case study. This innovative energy concept can also be applied to similar residential neighbourhoods.
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This paper describes a step-by-step approach for generating various energy concepts for neighbourhoods, based on local renewable resources. The approach is developed within the European research project ‘Smart Urban Isle’ (SUI). While much literature is focussed on comparison or optimization of predefined configurations, the SUI approach adds to the existing knowledge by introducing a systematic step-by-step approach that supports the first step of the development phase, i.e., the generation of various - potentially innovative - energy system configurations for neighbourhoods, which in the following phase can be optimized using optimization methods. First, the five steps of the approach are introduced, and secondly, these are applied to an existing residential neighbourhood in the Netherlands. The resulting preferred energy concept for the case study consists of a local, ultra-low temperature heat grid, heated by decentralised heat production from PV-thermal (PVT) collectors on individual roofs and connected to a collective seasonal underground storage (ATES). This paper demonstrates the usefulness of the approach for generating various alternative innovative energy concepts for neighbourhoods, based on the local demands and energy potentials, and also describes the resulting energy concept developed for the case study. This innovative energy concept can also be applied to similar residential neighbourhoods.
Green Architecture for Sustainable Communities (GASC) was a joint event organised by Dutch and Vietnamese universities with the aim of boosting sustainable development in the built environment of Vietnam. As a key activity of the event, the international student design workshop focused on renovation of typical Vietnamese row houses – aiming towards sustainable and energy efficient homes. This study reports an evaluation of the student workshop based on a post-workshop questionnaire and the outcomes of the student groups. Results showed that most activities were successful in transferring sustainable knowledge to the students. The students were capable of learning sustainable theory, analysing suitable design strategies in the specific cases and applying that knowledge into the design proposals. Students learned more about bioclimatic designs and related topics such as daylight, natural ventilation, indoor comfort and greenery. Sustainable aspects of energy efficiency and water usage were also of great interest. The student selection process was the main issue for this workshop. For future events, more involvement of architects with practice is recommended.
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Green Architecture for Sustainable Communities (GASC) was a joint event organised by Dutch and Vietnamese universities with the aim of boosting sustainable development in the built environment of Vietnam. As a key activity of the event, the international student design workshop focused on renovation of typical Vietnamese row houses – aiming towards sustainable and energy efficient homes. This study reports an evaluation of the student workshop based on a post-workshop questionnaire and the outcomes of the student groups. Results showed that most activities were successful in transferring sustainable knowledge to the students. The students were capable of learning sustainable theory, analysing suitable design strategies in the specific cases and applying that knowledge into the design proposals. Students learned more about bioclimatic designs and related topics such as daylight, natural ventilation, indoor comfort and greenery. Sustainable aspects of energy efficiency and water usage were also of great interest. The student selection process was the main issue for this workshop. For future events, more involvement of architects with practice is recommended.
This paper investigated the energy upgrade potentials of different facade refurbishment options in tube houses of Vietnam. A calibrated Design Builder model was created to simulate energy performance of different cases. Vietnamese technical regulation of energy efficiency building and Dutch standards were the two main guidelines for selection of refurbishing measures. The simulation results showed that applying Vietnamese technical regulation can save up to 9% of energy for heating and cooling. More interestingly, highly insulated facade that followed Dutch standards led to much more favourable results of 21% reduction in air conditioner consumption. It is worth to note that such improvement was by far only achieved with a night-time operation of air-conditioner, as how the system was working in the reference house. Shading devices were also tested on a southwest facade window. Horizontal overhang had very limited benefit of less than 6% reduction in cooling energy. An external blind could save up to 12.6% of cooling energy. However, as all three shading types had a negative effect in heating season, the maximum annual saving was only 7%.
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This paper investigated the energy upgrade potentials of different facade refurbishment options in tube houses of Vietnam. A calibrated Design Builder model was created to simulate energy performance of different cases. Vietnamese technical regulation of energy efficiency building and Dutch standards were the two main guidelines for selection of refurbishing measures. The simulation results showed that applying Vietnamese technical regulation can save up to 9% of energy for heating and cooling. More interestingly, highly insulated facade that followed Dutch standards led to much more favourable results of 21% reduction in air conditioner consumption. It is worth to note that such improvement was by far only achieved with a night-time operation of air-conditioner, as how the system was working in the reference house. Shading devices were also tested on a southwest facade window. Horizontal overhang had very limited benefit of less than 6% reduction in cooling energy. An external blind could save up to 12.6% of cooling energy. However, as all three shading types had a negative effect in heating season, the maximum annual saving was only 7%.
Spatial configuration, building microclimate and thermal comfort
A modern house case
In this paper, the authors attempt to clarify the relationship between spatial configuration, building microclimate and thermal comfort through the investigation of a modern house in hot and humid climate with spatial diversity. Firstly, the spatial configuration of the house was analysed in detail. The spatial geometric features, spatial boundary conditions, and human activities in the building were categorised. Secondly, field measurements were conducted to investigate the microclimate of the house. The air temperature, relative humidity and wind velocity were monitored on typical summer days. Thirdly, a dynamic thermal simulation was performed to predict the thermal comfort performance of the building over the period of an entire summer. The simulated results were compared with the measurements, and the adaptive thermal comfort approach was used to evaluate the thermal comfort. The modern house studied was found to have a varied spatial configuration, similar to local vernacular buildings, which produces diverse thermal environments in the building. The microclimate of this specific building could provide considerable thermal comfort for the occupants in summer under the local climate conditions, although thermal comfort cannot be achieved through free-running model in the hottest days, mechanical cooling or mixed model are needed.
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In this paper, the authors attempt to clarify the relationship between spatial configuration, building microclimate and thermal comfort through the investigation of a modern house in hot and humid climate with spatial diversity. Firstly, the spatial configuration of the house was analysed in detail. The spatial geometric features, spatial boundary conditions, and human activities in the building were categorised. Secondly, field measurements were conducted to investigate the microclimate of the house. The air temperature, relative humidity and wind velocity were monitored on typical summer days. Thirdly, a dynamic thermal simulation was performed to predict the thermal comfort performance of the building over the period of an entire summer. The simulated results were compared with the measurements, and the adaptive thermal comfort approach was used to evaluate the thermal comfort. The modern house studied was found to have a varied spatial configuration, similar to local vernacular buildings, which produces diverse thermal environments in the building. The microclimate of this specific building could provide considerable thermal comfort for the occupants in summer under the local climate conditions, although thermal comfort cannot be achieved through free-running model in the hottest days, mechanical cooling or mixed model are needed.
Conference paper
(2019)
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Regina Bokel, Peter van den Engel, Annemarie Eijkelenboom, M.A. Ortiz Sanchez
For several years indoor comfort is measured in halls of hospitals by architecture students from the Delft University of Technology. Questionnaires and interviews have shows that patients and visitors have very few complaints about the indoor comfort in hospital halls. This, in hindsight, is not so very surprising. Patients and visitors usually come out of the cold into the hallway. A hallway which is at least marginally warmer, a hallway where it does not rain and hallway that is sheltered from the outside wind. Secondly, the indoor comfort is not the main concern of the patients and visitors entering the hospital. The patient’s and visitor’s upcoming consults with the doctors or nurses is much more important. Coming from the consult, patients and visitors always have the choice to immediately leave the hospital if they do not like the indoor comfort. Complaints from staff, however, are very common. Staff personnel usually complain about low temperatures and draught.
A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to
experience low temperatures and draught.
From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed.
Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems.
A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk. ...
A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to
experience low temperatures and draught.
From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed.
Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems.
A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk. ...
For several years indoor comfort is measured in halls of hospitals by architecture students from the Delft University of Technology. Questionnaires and interviews have shows that patients and visitors have very few complaints about the indoor comfort in hospital halls. This, in hindsight, is not so very surprising. Patients and visitors usually come out of the cold into the hallway. A hallway which is at least marginally warmer, a hallway where it does not rain and hallway that is sheltered from the outside wind. Secondly, the indoor comfort is not the main concern of the patients and visitors entering the hospital. The patient’s and visitor’s upcoming consults with the doctors or nurses is much more important. Coming from the consult, patients and visitors always have the choice to immediately leave the hospital if they do not like the indoor comfort. Complaints from staff, however, are very common. Staff personnel usually complain about low temperatures and draught.
A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to
experience low temperatures and draught.
From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed.
Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems.
A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk.
A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to
experience low temperatures and draught.
From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed.
Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems.
A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk.
In the early design stages, architects are in constant search of a design direction that can determine the success or failure of the final design. However, in real design practice, most of the prediction methods for building performances, in this paper energy and thermal comfort, are utilised in the later design stages. Spatial configuration is one of the most important issues for architectural design in the early design stage. This study investigates the correlations between the spatial indicators connected with architectural design and the building physics indicators ventilation performance and energy performance. The main objective is to explore the potential of applying spatial indicators using space syntax to predict ventilation performance and energy performance in order to support architects for the evaluation of their concepts and schemes in early design stages. The layout of a high-rise apartment in China in five different cities is chosen as a case study. The results show that the selected three indicators: connectivity value, air change rate and annual cooling saving ratio are linearly correlated, not just at building level but also at room level. R2, the correlation coefficient of determination, is between 0.53 and 0.90 (except for the case of Chongqing at building level).
...
In the early design stages, architects are in constant search of a design direction that can determine the success or failure of the final design. However, in real design practice, most of the prediction methods for building performances, in this paper energy and thermal comfort, are utilised in the later design stages. Spatial configuration is one of the most important issues for architectural design in the early design stage. This study investigates the correlations between the spatial indicators connected with architectural design and the building physics indicators ventilation performance and energy performance. The main objective is to explore the potential of applying spatial indicators using space syntax to predict ventilation performance and energy performance in order to support architects for the evaluation of their concepts and schemes in early design stages. The layout of a high-rise apartment in China in five different cities is chosen as a case study. The results show that the selected three indicators: connectivity value, air change rate and annual cooling saving ratio are linearly correlated, not just at building level but also at room level. R2, the correlation coefficient of determination, is between 0.53 and 0.90 (except for the case of Chongqing at building level).
Improving energy efficiency in Vietnamese tube houses
A survey of sustainable challenges and potentials
Purpose: Refurbishing houses is considered a key measure to improve the energy efficiency of the built environment. However, little is known about the implementation and outcome of housing renovation for energy upgrades in the Vietnamese practice. The purpose of this paper is to investigate the energy performance of the current housing stock in Vietnam and the potential to reduce energy use in households. Design/methodology/approach: The paper is based on a survey with 153 respondents in three major climatic regions of Vietnam. The survey focusses on building characteristics, environmental performance, energy performance and refurbishment activities. Data collected from the survey were statistically analysed to give insight into the current performance of the housing stock and its energy saving potential. Findings: This paper concludes that building design and construction, particularly the building envelope, have a significant influence on the occupants’ comfort. However, the energy consumption in houses is not statistically associated with building design and indoor environment. It is suggested that financial status and occupants’ behaviour currently have a strong influence on the household energy use. The survey also showed that refurbishment improves the housing performance, especially if improving the indoor environment was one of the drivers. Originality/value: There are very few studies on energy use in households in Vietnam, especially with regards to actual energy consumption. This paper brings insights into the actual energy consumption and reveals the “performance gap” in Vietnamese housing stock.
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Purpose: Refurbishing houses is considered a key measure to improve the energy efficiency of the built environment. However, little is known about the implementation and outcome of housing renovation for energy upgrades in the Vietnamese practice. The purpose of this paper is to investigate the energy performance of the current housing stock in Vietnam and the potential to reduce energy use in households. Design/methodology/approach: The paper is based on a survey with 153 respondents in three major climatic regions of Vietnam. The survey focusses on building characteristics, environmental performance, energy performance and refurbishment activities. Data collected from the survey were statistically analysed to give insight into the current performance of the housing stock and its energy saving potential. Findings: This paper concludes that building design and construction, particularly the building envelope, have a significant influence on the occupants’ comfort. However, the energy consumption in houses is not statistically associated with building design and indoor environment. It is suggested that financial status and occupants’ behaviour currently have a strong influence on the household energy use. The survey also showed that refurbishment improves the housing performance, especially if improving the indoor environment was one of the drivers. Originality/value: There are very few studies on energy use in households in Vietnam, especially with regards to actual energy consumption. This paper brings insights into the actual energy consumption and reveals the “performance gap” in Vietnamese housing stock.
Effects of a Vertical Green Façade on the Thermal Performance and Cooling Demand
A Case Study of a Tube House in Vietnam
Traditional architecture has often applied greenery in the design to improve the thermal performance of indoor spaces. Such a bioclimatic approach is not often seen in the contemporary tube houses of Vietnam. Vietnamese architects recently started to focus more on greenery solutions for housing projects. However, the quantitative effects of plants on the building performance has not yet been investigated in Vietnam. This paper reports on an experiment to quantify the benefits of a vertical greening system for thermal performance and energy saving. A typical tube house in Hanoi was selected and two similar rooms were monitored during July and August, 2018. One of the rooms’ façades was covered by the climbing plant Bougainvillea. Outdoor and indoor temperature and energy for air-conditioning were measured for the two rooms to quantify the effect of the greenery on the existing aluminium shading device and a bare window. Results for the green façade showed that the difference between outdoor and indoor temperature can be as high as 8°C. In addition, the climbing plants helped to reduce the indoor temperature by around 1°C and thus cooling energy was saved by up to 35%.
...
Traditional architecture has often applied greenery in the design to improve the thermal performance of indoor spaces. Such a bioclimatic approach is not often seen in the contemporary tube houses of Vietnam. Vietnamese architects recently started to focus more on greenery solutions for housing projects. However, the quantitative effects of plants on the building performance has not yet been investigated in Vietnam. This paper reports on an experiment to quantify the benefits of a vertical greening system for thermal performance and energy saving. A typical tube house in Hanoi was selected and two similar rooms were monitored during July and August, 2018. One of the rooms’ façades was covered by the climbing plant Bougainvillea. Outdoor and indoor temperature and energy for air-conditioning were measured for the two rooms to quantify the effect of the greenery on the existing aluminium shading device and a bare window. Results for the green façade showed that the difference between outdoor and indoor temperature can be as high as 8°C. In addition, the climbing plants helped to reduce the indoor temperature by around 1°C and thus cooling energy was saved by up to 35%.
Natural summer ventilation strategies for energy-saving in high-rise buildings
A case study in the Netherlands
This paper investigates the potential use of natural ventilation strategies to reduce the energy demand for cooling and mechanical ventilation for high-rise buildings in summer. A 21-storey office building was selected to represent a mechanically ventilated high-rise design in temperate climates. Six natural ventilation scenarios were developed for the base design and the CFD package in DesignBuilder was used to predict their flow pattern under two summer conditions. Afterwards, the Operative temperature and the total fresh air changes per hour were calculated with EnergyPlus and were compared accordingly with European comfort standards. The percentage of discomfort hours indicates when a natural ventilation system would need active cooling or mechanical ventilation. Natural ventilation strategies can provide comfort conditions for up to 90% of the occupancy time in summer and therefore can save a significant amount of energy that is generally needed for the operation of traditional mechanical ventilation and air-conditioning systems.
...
This paper investigates the potential use of natural ventilation strategies to reduce the energy demand for cooling and mechanical ventilation for high-rise buildings in summer. A 21-storey office building was selected to represent a mechanically ventilated high-rise design in temperate climates. Six natural ventilation scenarios were developed for the base design and the CFD package in DesignBuilder was used to predict their flow pattern under two summer conditions. Afterwards, the Operative temperature and the total fresh air changes per hour were calculated with EnergyPlus and were compared accordingly with European comfort standards. The percentage of discomfort hours indicates when a natural ventilation system would need active cooling or mechanical ventilation. Natural ventilation strategies can provide comfort conditions for up to 90% of the occupancy time in summer and therefore can save a significant amount of energy that is generally needed for the operation of traditional mechanical ventilation and air-conditioning systems.
The research question of this report is “Is it possible to save energy by lowering the bedroom temperatures in winter”. In this paper first the literature on optimum sleeping temperatures is investigated. Then bedroom temperatures and CO2 levels in a cold week in March 2018 are investigated in 16 bedrooms of students of the Master course Technoledge Climate Desing in 2017-2018 of the faculty of Architecture and the Built Environment of the Delft University of Technology. This study shows that it must be possible to save energy by lowering the bedroom temperature in winter. The measured indoor temperatures were much higher than the 16-18°C recommended by several authors, and with appropriate bed covering and bed clothing could be much lower than 18°C and a period of lower temperatures could be more healthy. The thermal sensation of the occupants also suggest that lower temperatures are possible as more occupant perceive the indoor temperature as slightly warm or warm then slightly cool or cold, even when the outside temperatures are below 10 °C.
The amount of energy that can be saved depends on the ‘home’ climate of the occupants, with occupants with a warmer ‘home’ climate preferring higher temperatures. The amount of energy that can be saved also depends on
the energy label of the building. A better energy label means that there is less energy necessary to heat the room.
A better scheduling or control system might supply healthier and lower temperatures as night due to a longer time that the heating is turned of. Opening windows to lower the indoor temperature, which might have health benefits, was not preferred by the students because the room would cool down to much, due to safety concerns or due to noise from outside.
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The research question of this report is “Is it possible to save energy by lowering the bedroom temperatures in winter”. In this paper first the literature on optimum sleeping temperatures is investigated. Then bedroom temperatures and CO2 levels in a cold week in March 2018 are investigated in 16 bedrooms of students of the Master course Technoledge Climate Desing in 2017-2018 of the faculty of Architecture and the Built Environment of the Delft University of Technology. This study shows that it must be possible to save energy by lowering the bedroom temperature in winter. The measured indoor temperatures were much higher than the 16-18°C recommended by several authors, and with appropriate bed covering and bed clothing could be much lower than 18°C and a period of lower temperatures could be more healthy. The thermal sensation of the occupants also suggest that lower temperatures are possible as more occupant perceive the indoor temperature as slightly warm or warm then slightly cool or cold, even when the outside temperatures are below 10 °C.
The amount of energy that can be saved depends on the ‘home’ climate of the occupants, with occupants with a warmer ‘home’ climate preferring higher temperatures. The amount of energy that can be saved also depends on
the energy label of the building. A better energy label means that there is less energy necessary to heat the room.
A better scheduling or control system might supply healthier and lower temperatures as night due to a longer time that the heating is turned of. Opening windows to lower the indoor temperature, which might have health benefits, was not preferred by the students because the room would cool down to much, due to safety concerns or due to noise from outside.
Journal article
(2017)
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Anxiao Zhang, Regina Bokel, Andy van den Dobbelsteen, Yanchen Sun, Q Huang, Qi Zhang
A high demand for heating energy in winter, overheating in summer and visual discomfort are important issues in school buildings in the cold climate of China. This study presents the use of simulation–optimization tools to find the optimal trade-off between minimizing energy use for heating and lighting, reducing summer discomfort time and maximizing the Useful Daylight Illuminance (UDIavg, between 100 and 2000 lx). Different spatial configurations were investigated, including a single-sided open corridor type, a single-sided enclosed corridor type and a double-sided corridor type school. The following passive design parameters were considered in the optimization analysis: orientation, room depth and corridor depth, window-to-wall ratio of different interfaces, glazing materials and shading types. The results of the optimization study show that the energy demand for heating and lighting can be reduced by 24–28% and summer thermal discomfort by 9–23% while the UDIavg (100–2000 lx) can simultaneously increase by 15–63%. Considering all three aspects, the double-sided enclosed corridor type performs best due to its energy performance while the one-sided enclosed corridor type is the least suitable for the cold climate because of its relatively poor visual comfort quality. In addition, the passive design parameters should be carefully considered as each spatial configuration has its own optimal passive design parameters.
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A high demand for heating energy in winter, overheating in summer and visual discomfort are important issues in school buildings in the cold climate of China. This study presents the use of simulation–optimization tools to find the optimal trade-off between minimizing energy use for heating and lighting, reducing summer discomfort time and maximizing the Useful Daylight Illuminance (UDIavg, between 100 and 2000 lx). Different spatial configurations were investigated, including a single-sided open corridor type, a single-sided enclosed corridor type and a double-sided corridor type school. The following passive design parameters were considered in the optimization analysis: orientation, room depth and corridor depth, window-to-wall ratio of different interfaces, glazing materials and shading types. The results of the optimization study show that the energy demand for heating and lighting can be reduced by 24–28% and summer thermal discomfort by 9–23% while the UDIavg (100–2000 lx) can simultaneously increase by 15–63%. Considering all three aspects, the double-sided enclosed corridor type performs best due to its energy performance while the one-sided enclosed corridor type is the least suitable for the cold climate because of its relatively poor visual comfort quality. In addition, the passive design parameters should be carefully considered as each spatial configuration has its own optimal passive design parameters.
Conference paper
(2017)
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Anxiao Zhang, Yanchen Sun, Qiong Huang, Regina Bokel, Andy van den Dobbelsteen
This paper discusses the energy impact of corridor design for school buildings in the cold climate of China. Local school buildings were classified into three types in terms of the corridor design patterns. Architectural related parameters of corridors which could have a potential impact on the energy consumption were summarized and discussed, including form and orientation, temperature control, opaque envelope components, glazing, ventilation and infiltration. The annual heating, cooling, lighting and total energy consumption were compared. Results showed that form and orientation have the most significant influence on building energy consumption while opaque envelope insulation of corridors shows the least effect on energy demand. By combining the most beneficial strategies at each step, this study resulted in a better performing corridor design that increases the energy-saving by around 6% for the double-sided corridor building type and 17% for the one-sided enclosed corridor type of school building respectively.
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This paper discusses the energy impact of corridor design for school buildings in the cold climate of China. Local school buildings were classified into three types in terms of the corridor design patterns. Architectural related parameters of corridors which could have a potential impact on the energy consumption were summarized and discussed, including form and orientation, temperature control, opaque envelope components, glazing, ventilation and infiltration. The annual heating, cooling, lighting and total energy consumption were compared. Results showed that form and orientation have the most significant influence on building energy consumption while opaque envelope insulation of corridors shows the least effect on energy demand. By combining the most beneficial strategies at each step, this study resulted in a better performing corridor design that increases the energy-saving by around 6% for the double-sided corridor building type and 17% for the one-sided enclosed corridor type of school building respectively.
The housing stock in Vietnam faces the challenge of becoming sustainable,provide a healthy living environment and reduce its energy consumption. The challenge lies not only in new buildings but also in existing houses. Nevertheless, little is known whether the new tube houses, the most dominant housing typology in Vietnam, can be renovated to offer adequate living conditions for the occupants, can tackle the issue of energy shortage, and can adapt to climate change. This paper introduces the potential of refurbishment design for energy efficiency. Although both passive and active approaches are encouraged, traditional bioclimatic design strategies, including solar control, natural ventilation and thermal insulation,are more popular because of their low cost and high efficiency. This paper concludes that solar energy has large potential in Vietnam because it can be used passively in sun space or actively in photovoltaics and solar thermal collectors. However, as these refurbishment measures require investments and careful design, the actual benefit in Vietnamese context has not yet been verified.
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The housing stock in Vietnam faces the challenge of becoming sustainable,provide a healthy living environment and reduce its energy consumption. The challenge lies not only in new buildings but also in existing houses. Nevertheless, little is known whether the new tube houses, the most dominant housing typology in Vietnam, can be renovated to offer adequate living conditions for the occupants, can tackle the issue of energy shortage, and can adapt to climate change. This paper introduces the potential of refurbishment design for energy efficiency. Although both passive and active approaches are encouraged, traditional bioclimatic design strategies, including solar control, natural ventilation and thermal insulation,are more popular because of their low cost and high efficiency. This paper concludes that solar energy has large potential in Vietnam because it can be used passively in sun space or actively in photovoltaics and solar thermal collectors. However, as these refurbishment measures require investments and careful design, the actual benefit in Vietnamese context has not yet been verified.
Journal article
(2017)
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Anxiao Zhang, Regina Bokel, Andy van den Dobbelsteen, Yanchen Sun, Qiong Huang, Qi Zhang
This paper discusses the role of geometry parameters including building shape, window to wall ratio, room depth, and orientation on the energy use and thermal comfort of school buildings in cold climates of China. The annual total energy demand and summer thermal discomfort time were compared through computer simulations with DesignBuilder. Furthermore, a questionnaire was conducted that related to the students’ subjective preference for various building geometry parameters. Results showed that a maximum of 13.6% of energy savings and 3.8% of thermal comfort improvement when compared to the reference case could be achieved through variations in geometry parameters. The H shape performed the best when the building thermal performance and students’ preferences were considered, as well as the various design options for rchitects. Window to wall ratio, room depth, and orientation should also be carefully addressed in terms of different building types. The results of this study can serve as a reference for architects and school managers in the early design stages of schools in cold climates of China.
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This paper discusses the role of geometry parameters including building shape, window to wall ratio, room depth, and orientation on the energy use and thermal comfort of school buildings in cold climates of China. The annual total energy demand and summer thermal discomfort time were compared through computer simulations with DesignBuilder. Furthermore, a questionnaire was conducted that related to the students’ subjective preference for various building geometry parameters. Results showed that a maximum of 13.6% of energy savings and 3.8% of thermal comfort improvement when compared to the reference case could be achieved through variations in geometry parameters. The H shape performed the best when the building thermal performance and students’ preferences were considered, as well as the various design options for rchitects. Window to wall ratio, room depth, and orientation should also be carefully addressed in terms of different building types. The results of this study can serve as a reference for architects and school managers in the early design stages of schools in cold climates of China.
The traditional way of supplying energy to the built environment is no longer suitable: New buildings with high energy performance and decentralised renewable energy generation, together with the desire to become fossil-free, involve the need for new, more flexible and more integrated energy systems. The district of Buiksloterham was a test case to develop feasible and potentially desirable energy supply scenarios for the built environment at district level. It is not possible to develop Buiksloterham, and similar areas with high density, into an energy neutral area within the current legal framework (without wind energy it is not possible). About 1/3 of the energy use in buildings (building-related and user-related) can be supplied by renewable energy. In Buiksloterham a low temperature supply of heat is essential for a maximised use of renewable input. A fourth, low temperature, energy concept, consisting of local heat generation from solar and waste, thermal storage, and heat pumps, seems the best integrated energy system. The non-technical lesson learned is that new energy-efficient energy systems require very good, early planning, appointments, and cost and support of existing energy suppliers. Extracting a CO₂ neutral society by 2050 also depends on implementation aspects i.e. not only CO₂ and costs but also circularity parameters such as the use of resources for equipment, water, biodiversity, health, adaptability and resilience must be considered.
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The traditional way of supplying energy to the built environment is no longer suitable: New buildings with high energy performance and decentralised renewable energy generation, together with the desire to become fossil-free, involve the need for new, more flexible and more integrated energy systems. The district of Buiksloterham was a test case to develop feasible and potentially desirable energy supply scenarios for the built environment at district level. It is not possible to develop Buiksloterham, and similar areas with high density, into an energy neutral area within the current legal framework (without wind energy it is not possible). About 1/3 of the energy use in buildings (building-related and user-related) can be supplied by renewable energy. In Buiksloterham a low temperature supply of heat is essential for a maximised use of renewable input. A fourth, low temperature, energy concept, consisting of local heat generation from solar and waste, thermal storage, and heat pumps, seems the best integrated energy system. The non-technical lesson learned is that new energy-efficient energy systems require very good, early planning, appointments, and cost and support of existing energy suppliers. Extracting a CO₂ neutral society by 2050 also depends on implementation aspects i.e. not only CO₂ and costs but also circularity parameters such as the use of resources for equipment, water, biodiversity, health, adaptability and resilience must be considered.