In this paper, the energy efficiency potential of applying novel dynamic insulation systems to slab foundations is investigated for residential buildings. Specifically, dynamic insulation allows the foundation to change its thermal resistance to reduce both heating and cooling thermal loads compared to static insulation systems. The energy benefits for the dynamic insulation are evaluated using a validated numerical model integrated in state-of-art whole-building simulation tool. Specifically, optimal settings for slab-integrated the dynamic insulation are determined monthly to reduce heating and cooling thermal loads while maintaining thermal comfort for a prototypical house located in representative US climates. The analysis results indicate that the deployment of slab integrated dynamic insulation can reduce heating and cooling energy end-uses by up to 12% (1267 kWh) especially for homes located in cold climates.
{"title":"Impact of Dynamic Slab Insulation on Energy Performance of Residential Buildings","authors":"Roya Rajabi, Ammar H. A. Dehwah, M. Krarti","doi":"10.1115/1.4056168","DOIUrl":"https://doi.org/10.1115/1.4056168","url":null,"abstract":"\u0000 In this paper, the energy efficiency potential of applying novel dynamic insulation systems to slab foundations is investigated for residential buildings. Specifically, dynamic insulation allows the foundation to change its thermal resistance to reduce both heating and cooling thermal loads compared to static insulation systems. The energy benefits for the dynamic insulation are evaluated using a validated numerical model integrated in state-of-art whole-building simulation tool. Specifically, optimal settings for slab-integrated the dynamic insulation are determined monthly to reduce heating and cooling thermal loads while maintaining thermal comfort for a prototypical house located in representative US climates. The analysis results indicate that the deployment of slab integrated dynamic insulation can reduce heating and cooling energy end-uses by up to 12% (1267 kWh) especially for homes located in cold climates.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126004185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, three different approaches are investigated for keeping the roof cool and reducing the heat flow inside a building located in Kanpur, India. In the first approach, various reflective paints are investigated and their performance degradation over a year is examined along with the cost-benefit analysis. In the second approach, the roof surface is kept wet and due to water evaporation, the roof was kept cool. In the third approach, the effect of shading on the rooftop surface temperature is studied. It is observed that without any cooling, the rooftop temperature can rise about 20°C above the ambient air temperature. The application of white acrylic paints can reduce this temperature rise to about 5-7°C. However, after a year due to degradation, this temperature rise is about 10-12°C. Using evaporative cooling the rooftop temperature can be lowered even below the ambient air temperature by about 3°C. However, this approach will require active management of the system and consumption of water. The cost for the first two approaches is estimated to be about 5-6 Rs./sq.ft with a payback time of 2 years. Shading can reduce the temperature rise to about 5°C. Structures meant for other purposes such as photovoltaic panels can serve the additional benefit of cooling the roof. Shading seems to be a robust and low-maintenance option and cost analysis of structures meant primarily for shading the roof needs to be explored.
{"title":"Investigation of Cool Roof based on Reflective Paints, Evaporative Cooling and Shading","authors":"V. K. Arghode","doi":"10.1115/1.4056132","DOIUrl":"https://doi.org/10.1115/1.4056132","url":null,"abstract":"\u0000 In this study, three different approaches are investigated for keeping the roof cool and reducing the heat flow inside a building located in Kanpur, India. In the first approach, various reflective paints are investigated and their performance degradation over a year is examined along with the cost-benefit analysis. In the second approach, the roof surface is kept wet and due to water evaporation, the roof was kept cool. In the third approach, the effect of shading on the rooftop surface temperature is studied. It is observed that without any cooling, the rooftop temperature can rise about 20°C above the ambient air temperature. The application of white acrylic paints can reduce this temperature rise to about 5-7°C. However, after a year due to degradation, this temperature rise is about 10-12°C. Using evaporative cooling the rooftop temperature can be lowered even below the ambient air temperature by about 3°C. However, this approach will require active management of the system and consumption of water. The cost for the first two approaches is estimated to be about 5-6 Rs./sq.ft with a payback time of 2 years. Shading can reduce the temperature rise to about 5°C. Structures meant for other purposes such as photovoltaic panels can serve the additional benefit of cooling the roof. Shading seems to be a robust and low-maintenance option and cost analysis of structures meant primarily for shading the roof needs to be explored.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115862284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Smart cities will need collections of buildings that are responsive to the variation in renewable energy generation. However, an unprecedented level of renewable energy being added to the power grid compounds the level of uncertainties in making decisions for reliable grid operation. Making autonomous decisions regarding demand management requires consideration of uncertainty in the information available for planning and executing operations. Thus, this paper aims to quantitatively analyze the performances of supervisory controllers for multiple grid-integrative buildings with thermal energy storage depending on the quality of information available. Day-ahead planning and real-time model predictive controllers were developed and compared across 50 validation scenarios when given perfect information, deterministic forecasts, and stochastic forecasts. Despite the relatively large uncertainty in the stochastic forecasts, marked improvements were observed when a stochastic optimization was solved for both the day-ahead and real-time problems. This observation underscores the need for continued development in the area of stochastic control and decision-making for future grid-interactive buildings and improved energy management of smart cities.
{"title":"Quantifying the value of stochastic supervisory controller for building thermal energy storage aggregators in two-settlement grid markets","authors":"Mingyung Yu, G. Pavlak","doi":"10.1115/1.4056023","DOIUrl":"https://doi.org/10.1115/1.4056023","url":null,"abstract":"\u0000 Smart cities will need collections of buildings that are responsive to the variation in renewable energy generation. However, an unprecedented level of renewable energy being added to the power grid compounds the level of uncertainties in making decisions for reliable grid operation. Making autonomous decisions regarding demand management requires consideration of uncertainty in the information available for planning and executing operations. Thus, this paper aims to quantitatively analyze the performances of supervisory controllers for multiple grid-integrative buildings with thermal energy storage depending on the quality of information available. Day-ahead planning and real-time model predictive controllers were developed and compared across 50 validation scenarios when given perfect information, deterministic forecasts, and stochastic forecasts. Despite the relatively large uncertainty in the stochastic forecasts, marked improvements were observed when a stochastic optimization was solved for both the day-ahead and real-time problems. This observation underscores the need for continued development in the area of stochastic control and decision-making for future grid-interactive buildings and improved energy management of smart cities.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121123151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Commercial buildings account for 18% of U.S. energy consumption, with 44% used for heating, ventilation, and air conditioning (HVAC). ASHRAE-90.1 requires HVAC systems to shut down fans and outdoor air ventilation during unoccupied times, only allowing fans to cycle on, without outdoor air, to maintain thermostat setpoints. However, it is minimally understood how often existing building operations align with energy code requirements and the energy implications of not doing so. This study used building automation system data from 843 buildings containing 5,706 AHUs to determine three unoccupied air handling unit (AHU) shutdown control schemes ranging in efficiency and then estimated their prevalence in the U.S. commercial building stock. ComStock was then used to analyze the energy savings potential of implementing the most energy efficient unoccupied shutdown control scheme in non-participating buildings across the U.S commercial building stock. Results show only 23% of AHUs align completely with the ASHRAE 90.1 requirement. ComStock modeling results show 4% annual stock energy savings by switching all non-participating buildings to the most efficient scheme, with 19% annual energy savings demonstrated for the median building switching from the least efficient scheme to the most efficient. Findings also show 114.5 TBtu electricity and 75.8TBtu natural gas savings when converting to the most efficient scheme. These findings help stakeholders understand the prevalence of buildings not aligning with the ASHRAE 90.1 requirements for unoccupied AHU shutdowns and the energy savings potential of utilizing the most efficient scheme.
{"title":"AIR HANDLING UNIT SHUTDOWNS DURING SCHEDULED UNOCCUPIED HOURS: U.S. COMMERCIAL BUILDING STOCK PREVALENCE AND ENERGY IMPACT","authors":"Christopher CaraDonna, Kelsea Dombrovski","doi":"10.1115/1.4055887","DOIUrl":"https://doi.org/10.1115/1.4055887","url":null,"abstract":"\u0000 Commercial buildings account for 18% of U.S. energy consumption, with 44% used for heating, ventilation, and air conditioning (HVAC). ASHRAE-90.1 requires HVAC systems to shut down fans and outdoor air ventilation during unoccupied times, only allowing fans to cycle on, without outdoor air, to maintain thermostat setpoints. However, it is minimally understood how often existing building operations align with energy code requirements and the energy implications of not doing so. This study used building automation system data from 843 buildings containing 5,706 AHUs to determine three unoccupied air handling unit (AHU) shutdown control schemes ranging in efficiency and then estimated their prevalence in the U.S. commercial building stock. ComStock was then used to analyze the energy savings potential of implementing the most energy efficient unoccupied shutdown control scheme in non-participating buildings across the U.S commercial building stock. Results show only 23% of AHUs align completely with the ASHRAE 90.1 requirement. ComStock modeling results show 4% annual stock energy savings by switching all non-participating buildings to the most efficient scheme, with 19% annual energy savings demonstrated for the median building switching from the least efficient scheme to the most efficient. Findings also show 114.5 TBtu electricity and 75.8TBtu natural gas savings when converting to the most efficient scheme. These findings help stakeholders understand the prevalence of buildings not aligning with the ASHRAE 90.1 requirements for unoccupied AHU shutdowns and the energy savings potential of utilizing the most efficient scheme.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114327233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khaled Hashad, Bo-Jei Yang, Vlad Isakov, K. M. Zhang
Near-road air pollution is worldwide public health concern, especially in urban areas. Vehicle Induced Turbulence (VIT) has a major impact on the initial dispersion of traffic-related pollutants on the roadways, affecting their subsequent near-road impact. The current methods for high-fidelity VIT simulations using computational fluid dynamics (CFD) are often computationally expensive or prohibitive. Previous studies adopted the TKE method, which models VIT as a fixed TKE volume source and produces turbulence uniformly in the computational traffic zones. This paper presents two novel methods, namely the Force method and the Moving Force method, to generate VIT implicitly by injecting a force source into the computational domain instead of physical vehicles in the domain explicitly, thus greatly reducing the computational burden. The simulation results were evaluated against experimental data collected in a field study near a major highway in Las Vegas, NV, which included collocated measurements of traffic and wind speed. The TKE method systematically overestimated the turbulence produced on the highway by converting the drag force completely into turbulence. This indicates that the TKE method, currently being used to implicitly model VIT in CFD simulations, requires major improvements. In comparison, the proposed Force and Moving Force methods preformed favorably and were able to capture turbulence anisotropicity and fluid convection. The Force method was shown to be a computationally efficient way to simulate VIT with adequate accuracy, while the Moving Force method has the potential to emulate vehicle motion and it is impact on fluid flow.
{"title":"A computationally efficient approach to resolving vehicle-induced turbulence for near-road air quality","authors":"Khaled Hashad, Bo-Jei Yang, Vlad Isakov, K. M. Zhang","doi":"10.1115/1.4055640","DOIUrl":"https://doi.org/10.1115/1.4055640","url":null,"abstract":"\u0000 Near-road air pollution is worldwide public health concern, especially in urban areas. Vehicle Induced Turbulence (VIT) has a major impact on the initial dispersion of traffic-related pollutants on the roadways, affecting their subsequent near-road impact. The current methods for high-fidelity VIT simulations using computational fluid dynamics (CFD) are often computationally expensive or prohibitive. Previous studies adopted the TKE method, which models VIT as a fixed TKE volume source and produces turbulence uniformly in the computational traffic zones. This paper presents two novel methods, namely the Force method and the Moving Force method, to generate VIT implicitly by injecting a force source into the computational domain instead of physical vehicles in the domain explicitly, thus greatly reducing the computational burden. The simulation results were evaluated against experimental data collected in a field study near a major highway in Las Vegas, NV, which included collocated measurements of traffic and wind speed. The TKE method systematically overestimated the turbulence produced on the highway by converting the drag force completely into turbulence. This indicates that the TKE method, currently being used to implicitly model VIT in CFD simulations, requires major improvements. In comparison, the proposed Force and Moving Force methods preformed favorably and were able to capture turbulence anisotropicity and fluid convection. The Force method was shown to be a computationally efficient way to simulate VIT with adequate accuracy, while the Moving Force method has the potential to emulate vehicle motion and it is impact on fluid flow.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123091503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims to research the energy performance comparison of two types of HVAC systems for subtropical regions. Two HVAC models are simulated using DesignBuilder: (1) Non Renewable Energy Source (Non-RES) based HVAC system, and (2) Renewable Energy Source (RES) based Grid-tied HVAC system. For simplicity of design, a three-story university building with multiple zones was built and the Bangladeshi weather condition was used for the simulation. The boiler and chiller are fueled by electricity and natural gas in a non-RES based HVAC model. Solar PV is installed on the rooftop of the university building as part of the RES-based HVAC design, while Ground Source Heat Pumps (GSHP) are employed to only supply heating. This study also demonstrates that RES-based HVAC models are preferable to non-RES-based models because it reduces the need for natural gas, which really is limited in the current world and produces greater CO2. Solar PV essentially lessens reliance on grid-fed electricity, which is essentially powered by natural gas. The RES based HVAC model is the most sustainable and appropriate choice for subtropical climate conditions also because of adequate renewable energy resources which apparently have a fixed cost but no variable or (Operation and Maintenance) O&M cost. Additional research in this work demonstrates that, in the case of RES-based design, photovoltaic-fed electricity can partially meet the cooling requirement, which is higher than the heating demand.
{"title":"COMPARATIVE STUDY BETWEEN ENERGY PERFORMANCES OF NON-RENEWABLE & RENEWABLE SOURCE BASED GRID-TIED HVAC SYSTEMS IN SUBTROPICAL CLIMATES","authors":"M. Rashid, Gulam Mahfuz Chowdhury, Tasnia Sultana","doi":"10.1115/1.4055639","DOIUrl":"https://doi.org/10.1115/1.4055639","url":null,"abstract":"\u0000 This paper aims to research the energy performance comparison of two types of HVAC systems for subtropical regions. Two HVAC models are simulated using DesignBuilder: (1) Non Renewable Energy Source (Non-RES) based HVAC system, and (2) Renewable Energy Source (RES) based Grid-tied HVAC system. For simplicity of design, a three-story university building with multiple zones was built and the Bangladeshi weather condition was used for the simulation. The boiler and chiller are fueled by electricity and natural gas in a non-RES based HVAC model. Solar PV is installed on the rooftop of the university building as part of the RES-based HVAC design, while Ground Source Heat Pumps (GSHP) are employed to only supply heating. This study also demonstrates that RES-based HVAC models are preferable to non-RES-based models because it reduces the need for natural gas, which really is limited in the current world and produces greater CO2. Solar PV essentially lessens reliance on grid-fed electricity, which is essentially powered by natural gas. The RES based HVAC model is the most sustainable and appropriate choice for subtropical climate conditions also because of adequate renewable energy resources which apparently have a fixed cost but no variable or (Operation and Maintenance) O&M cost. Additional research in this work demonstrates that, in the case of RES-based design, photovoltaic-fed electricity can partially meet the cooling requirement, which is higher than the heating demand.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131732020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ambient House is a building that maintains indoor temperature within a comfortable range by controlling gains and losses from ambient sources and utilizing thermal mass to moderate temperature changes when the sources are unavailable. Previously, necessary building characteristics were determined for passive solar as the heating source and ventilation as the cooling source in eleven US climate zones [1]. It was noted that in hot climates, such as Phoenix, AZ, there are long periods during which outdoor temperature is too warm for cooling, necessitating large thermal mass to avoid indoor overheating. In this paper, thermal mass requirements are compared between sky radiation and nighttime ventilation cooling in all sixteen US climate zones, including marine subzones 3C and 4C and very cold and subarctic zones 7 and 8. It is shown that sky radiation provides shorter intervals of cooling unavailability and allows much smaller thermal mass to achieve year-round indoor comfort in the hot climates of Las Vegas, Miami, New Orleans and Phoenix, while it provides no significant benefits in cool climates, where thermal mass is dictated more by the need to slow the decrease in indoor temperature during cloudy periods in the winter. In Fairbanks, AK (zone 8), in particular, the lack of significant solar gains for almost three months during the winter requires large thermal mass to maintain indoor comfort. Minimal thermal mass is needed to meet the small summer cooling demand and both sky and ventilation cooling are sufficient.
{"title":"Sky radiation decreases thermal mass requirements to achieve 100% ambient cooling in hot US climates","authors":"M. Sharp","doi":"10.1115/1.4055110","DOIUrl":"https://doi.org/10.1115/1.4055110","url":null,"abstract":"\u0000 Ambient House is a building that maintains indoor temperature within a comfortable range by controlling gains and losses from ambient sources and utilizing thermal mass to moderate temperature changes when the sources are unavailable. Previously, necessary building characteristics were determined for passive solar as the heating source and ventilation as the cooling source in eleven US climate zones [1]. It was noted that in hot climates, such as Phoenix, AZ, there are long periods during which outdoor temperature is too warm for cooling, necessitating large thermal mass to avoid indoor overheating. In this paper, thermal mass requirements are compared between sky radiation and nighttime ventilation cooling in all sixteen US climate zones, including marine subzones 3C and 4C and very cold and subarctic zones 7 and 8. It is shown that sky radiation provides shorter intervals of cooling unavailability and allows much smaller thermal mass to achieve year-round indoor comfort in the hot climates of Las Vegas, Miami, New Orleans and Phoenix, while it provides no significant benefits in cool climates, where thermal mass is dictated more by the need to slow the decrease in indoor temperature during cloudy periods in the winter. In Fairbanks, AK (zone 8), in particular, the lack of significant solar gains for almost three months during the winter requires large thermal mass to maintain indoor comfort. Minimal thermal mass is needed to meet the small summer cooling demand and both sky and ventilation cooling are sufficient.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130205456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this note a brief survey is given to the possibility for a thermo ducted kitchen hood where exhaust fan or other mechanical devices are no longer needed and then, in addition, no sound is generated. The aim of this thermo ducted kitchen hood is a device self-powered by its own wasted heat produced from the simmering or cooking process by re-injecting properly this heat at the top of the hood and then exacerbating an induced thermal convective loop able to extract moisture, odors and oils generated.
{"title":"A short survey for a thermo ducted kitchen hood wasted heat self-powered","authors":"S. de las Heras, F. Arias","doi":"10.1115/1.4055030","DOIUrl":"https://doi.org/10.1115/1.4055030","url":null,"abstract":"\u0000 In this note a brief survey is given to the possibility for a thermo ducted kitchen hood where exhaust fan or other mechanical devices are no longer needed and then, in addition, no sound is generated. The aim of this thermo ducted kitchen hood is a device self-powered by its own wasted heat produced from the simmering or cooking process by re-injecting properly this heat at the top of the hood and then exacerbating an induced thermal convective loop able to extract moisture, odors and oils generated.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"36 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131727173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the energy performance of dynamic instead of static shading devices is investigated for prototypical US office spaces. Specifically, six dynamic shading systems are considered to assess their ability to reduce heating and cooling thermal loads, total building energy use, and electrical peak demand. The most promising dynamic shading is the rotating overhang and is evaluated further using a wide range of design and operation conditions. It is found that rotating overhangs can provide effective and easily controllable dynamic shading systems for windows to reduce energy consumption of US office buildings by up to 39% especially for mild US climates. Moreover, the rotating overhangs have the added benefit to support PV panels for on-site electricity generation. A series of sensitivity analysis results indicate that performance of the dynamic external shading systems depend on its depth and orientation, the location climate, the window size, and the glazing type have significant impacts. For instance, the dynamic shading device can reduce annual heating and cooling energy end-use for an office space located in Boulder, CO, compared to no shading case by 19% for a window-to-wall ratio (WWR) of 15% and by 31% for a WWR of 30%.
{"title":"A Comparative Energy Analysis of Dynamic External Shadings for Office Buildings","authors":"M. Krarti","doi":"10.1115/1.4054775","DOIUrl":"https://doi.org/10.1115/1.4054775","url":null,"abstract":"\u0000 In this paper, the energy performance of dynamic instead of static shading devices is investigated for prototypical US office spaces. Specifically, six dynamic shading systems are considered to assess their ability to reduce heating and cooling thermal loads, total building energy use, and electrical peak demand. The most promising dynamic shading is the rotating overhang and is evaluated further using a wide range of design and operation conditions. It is found that rotating overhangs can provide effective and easily controllable dynamic shading systems for windows to reduce energy consumption of US office buildings by up to 39% especially for mild US climates. Moreover, the rotating overhangs have the added benefit to support PV panels for on-site electricity generation. A series of sensitivity analysis results indicate that performance of the dynamic external shading systems depend on its depth and orientation, the location climate, the window size, and the glazing type have significant impacts. For instance, the dynamic shading device can reduce annual heating and cooling energy end-use for an office space located in Boulder, CO, compared to no shading case by 19% for a window-to-wall ratio (WWR) of 15% and by 31% for a WWR of 30%.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125705686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The insulated glass unit (IGU) system is widely used in the Northern Hemisphere to improve the energy performance of buildings and the thermal comfort of their occupants. However, it has been introduced in the Brazilian market without a proper thermal assessment. Proper glass choice is essential to reduce energy consumption, as the most intense heat exchange occurs through the windows. This research aimed to investigate the influence of IGU use on conditioned office buildings’ energy performance for nine different climates in Brazil, including tropical (Aw, Af, and As) and temperate (Cfa and Cfb) climates. The energy consumption using air-filled IGU was compared to its non-insulated version through computer simulation in EnergyPlus. This sample demonstrated that IGU could generate annual savings in cooling consumption in tropical climates (up to 2.8%) when the outside temperature is constantly higher than the thermostat temperature. However, IGU models resulted in annual cooling consumption up to 9.3% higher in temperate climates by hindering the thermal load dissipation through the façade. The observed sample demonstrated that the IGU could inhibit the dissipation of the indoor thermal load through the façade, which increases energy consumption for cooling compared to models with the same glass but non-insulated. Either in the tropical or the temperate climates analyzed, the use of IGU seems not to be the ideal approach to improve the thermal performance and reduce the cooling energy consumption of highly glazed office buildings in Brazil.
{"title":"Insulated Glass Unit in High-Glazed Office Buildings in Brazil: Comparative HVAC Consumption Analyses","authors":"Mônica Martins Pinto, Fernando Simon Westphal","doi":"10.1115/1.4054894","DOIUrl":"https://doi.org/10.1115/1.4054894","url":null,"abstract":"\u0000 The insulated glass unit (IGU) system is widely used in the Northern Hemisphere to improve the energy performance of buildings and the thermal comfort of their occupants. However, it has been introduced in the Brazilian market without a proper thermal assessment. Proper glass choice is essential to reduce energy consumption, as the most intense heat exchange occurs through the windows. This research aimed to investigate the influence of IGU use on conditioned office buildings’ energy performance for nine different climates in Brazil, including tropical (Aw, Af, and As) and temperate (Cfa and Cfb) climates. The energy consumption using air-filled IGU was compared to its non-insulated version through computer simulation in EnergyPlus. This sample demonstrated that IGU could generate annual savings in cooling consumption in tropical climates (up to 2.8%) when the outside temperature is constantly higher than the thermostat temperature. However, IGU models resulted in annual cooling consumption up to 9.3% higher in temperate climates by hindering the thermal load dissipation through the façade. The observed sample demonstrated that the IGU could inhibit the dissipation of the indoor thermal load through the façade, which increases energy consumption for cooling compared to models with the same glass but non-insulated. Either in the tropical or the temperate climates analyzed, the use of IGU seems not to be the ideal approach to improve the thermal performance and reduce the cooling energy consumption of highly glazed office buildings in Brazil.","PeriodicalId":326594,"journal":{"name":"ASME Journal of Engineering for Sustainable Buildings and Cities","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127198350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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