Abstract: Providing thermal comfort without excess space and conditioning costs is one of the primary requirements of buildings. Therefore, thermal control is an important aspect in almost all buildings. Understanding heat transfer and the temperature distribution through building materials and assemblies is also important for assessing energy use. Thermal comfort, thermal movements, durability, and the potential for moisture problems. The control of heat flow in buildings requires insulation layers compromised with few thermal bridges, an effective air barrier system, good control of solar radiation, and management of interior heat generation. Walls play a huge role in the heat gain and loss in buildings, thus, making wall an important subject in passive thermal control in buildings. This article is aimed at analyzing cavity walls and solid brick walls and comparing them for home construction in temperate regions. Temperate regions need good insulating walls, thus reducing heat loss via walls to its minimal, which in turn reduces the cost of active heating measures in buildings.
This document analyzes the feasibility of using insulated concrete forms (ICF) in hot and humid climates by comparing the thermal performance of an ICF building to a normal concrete building in Oman over three summer months. Data loggers recorded temperature and humidity inside and outside both buildings. Results showed the ICF building had lower indoor temperatures and humidity. Heat gain calculations also indicated less transmission through the ICF walls. Electricity bills revealed the ICF building consumed 20-40% less energy for cooling. Therefore, the study concludes ICF walls perform better than normal concrete in hot, humid climates and can lower energy use.
Building materials used for the walls of simple houses in lower-middle-class areas in Indonesia are currently dominated by brick. This study proposes that soil-paper blocks coated with calcium silicate board may be a suitable alternative, with high embodied energy and density. The research aims to obtain an optimal wall thickness to provide protection against cooling and embodied energy in low income houses, as well as against the temperature conditions in these buildings in highland and lowland areas. Determination of wall thickness is performed by simulation of a 9 m2 building model with thick variables. Cooling calculations involved the use of Archipak software. Temperature measurements were carried out using a data logger on a sample of soil-paper blocks. The results indicate that the optimal wall thickness for protection against cooling and embodied energy is 8 cm. Soil-paper block has a lower density than brick. The use of calcium silicate boards does not affect the internal temperature of a low income house, but they can be used as protection against rainwater and as a substitute for wall plastering.
This study developed a numerical model of a standard farm building to quantify the bill of materials for two construction types - steel and timber. The model was based on Irish legislation and divided the building into nodes to calculate material quantities. Estimates of thermal transmittance and energy consumption were also determined. The quantities of structural steel, roof sheeting, timber frames and plywood were calculated. Future work will involve validating the model and performing a life cycle assessment of the materials to compare their environmental impacts.
Heat discharge through forced cooling of phase change materials in concrete p...Kristin Kuckelkorn
This document discusses a study that aims to reduce energy consumption in buildings by optimizing the thermal mass capacity of concrete structures through the integration of phase change materials (PCMs). The study tests two concrete panel samples, a regular concrete mix and a PCM concrete mix containing microencapsulated paraffin, and measures their heat storage, natural drainage, and drainage with forced cooling via pipes. The results show that the PCM concrete achieved higher thermal storage but was slower to release heat, necessitating forced cooling through pipes to sufficiently cool the panel overnight and allow it to absorb heat the next day, improving indoor thermal comfort.
This document summarizes an experiment to measure the out-of-plane thermal conductivity of flexible substrate materials like polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET). A steady-state method is used where a heat flux is applied through one copper block in contact with the substrate, and the temperature difference across the substrate is measured. Thermal conductivity values are determined from the temperature differences and heat fluxes for substrates of varying thicknesses. The results indicate low thermal conductivity for flexible substrates, which could challenge thermal management in flexible electronics due to limited heat spreading and lack of active cooling options.
Thermal mass is the ability of a material to absorb and store heat energy. Materials with high thermal mass like concrete, brick and tiles require a lot of heat to raise their temperature but release heat slowly, while lightweight materials have low thermal mass. Thermal mass is important for passive solar design as it absorbs heat during the day and releases it at night, moderating indoor temperatures. Thermal mass works best in climates with large daily temperature swings but can exacerbate temperature extremes in constantly hot or cold climates. Effective use of thermal mass must be integrated with insulation and passive solar design techniques.
Investigation of Different Types of Cement Material on Thermal Properties of ...IJERA Editor
One of the challenges in sustainable development is to optimize the energy efficiency of buildings during their
lifespan. Nowadays the applying of different types of cements in modern concretes provide low embodied CO2
with the intrinsic property called “thermal mass” that reduces the risk of overheating in the summer and
provides passive heating in the winter. Thermal mass is affected by thermal properties of concrete which it is the
ability of the element to exchange heat with the environment and is based on thermal capacity, conductivity, and
density. Laboratory experiments measured density, specific capacity and thermal conductivity of sustainable
concrete mixes with various percentages of GGBS, PFA, SF. The results contribute to the investigation of the
performance of thermal properties performance in sustainable concrete.
This document analyzes the feasibility of using insulated concrete forms (ICF) in hot and humid climates by comparing the thermal performance of an ICF building to a normal concrete building in Oman over three summer months. Data loggers recorded temperature and humidity inside and outside both buildings. Results showed the ICF building had lower indoor temperatures and humidity. Heat gain calculations also indicated less transmission through the ICF walls. Electricity bills revealed the ICF building consumed 20-40% less energy for cooling. Therefore, the study concludes ICF walls perform better than normal concrete in hot, humid climates and can lower energy use.
Building materials used for the walls of simple houses in lower-middle-class areas in Indonesia are currently dominated by brick. This study proposes that soil-paper blocks coated with calcium silicate board may be a suitable alternative, with high embodied energy and density. The research aims to obtain an optimal wall thickness to provide protection against cooling and embodied energy in low income houses, as well as against the temperature conditions in these buildings in highland and lowland areas. Determination of wall thickness is performed by simulation of a 9 m2 building model with thick variables. Cooling calculations involved the use of Archipak software. Temperature measurements were carried out using a data logger on a sample of soil-paper blocks. The results indicate that the optimal wall thickness for protection against cooling and embodied energy is 8 cm. Soil-paper block has a lower density than brick. The use of calcium silicate boards does not affect the internal temperature of a low income house, but they can be used as protection against rainwater and as a substitute for wall plastering.
This study developed a numerical model of a standard farm building to quantify the bill of materials for two construction types - steel and timber. The model was based on Irish legislation and divided the building into nodes to calculate material quantities. Estimates of thermal transmittance and energy consumption were also determined. The quantities of structural steel, roof sheeting, timber frames and plywood were calculated. Future work will involve validating the model and performing a life cycle assessment of the materials to compare their environmental impacts.
Heat discharge through forced cooling of phase change materials in concrete p...Kristin Kuckelkorn
This document discusses a study that aims to reduce energy consumption in buildings by optimizing the thermal mass capacity of concrete structures through the integration of phase change materials (PCMs). The study tests two concrete panel samples, a regular concrete mix and a PCM concrete mix containing microencapsulated paraffin, and measures their heat storage, natural drainage, and drainage with forced cooling via pipes. The results show that the PCM concrete achieved higher thermal storage but was slower to release heat, necessitating forced cooling through pipes to sufficiently cool the panel overnight and allow it to absorb heat the next day, improving indoor thermal comfort.
This document summarizes an experiment to measure the out-of-plane thermal conductivity of flexible substrate materials like polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET). A steady-state method is used where a heat flux is applied through one copper block in contact with the substrate, and the temperature difference across the substrate is measured. Thermal conductivity values are determined from the temperature differences and heat fluxes for substrates of varying thicknesses. The results indicate low thermal conductivity for flexible substrates, which could challenge thermal management in flexible electronics due to limited heat spreading and lack of active cooling options.
Thermal mass is the ability of a material to absorb and store heat energy. Materials with high thermal mass like concrete, brick and tiles require a lot of heat to raise their temperature but release heat slowly, while lightweight materials have low thermal mass. Thermal mass is important for passive solar design as it absorbs heat during the day and releases it at night, moderating indoor temperatures. Thermal mass works best in climates with large daily temperature swings but can exacerbate temperature extremes in constantly hot or cold climates. Effective use of thermal mass must be integrated with insulation and passive solar design techniques.
Investigation of Different Types of Cement Material on Thermal Properties of ...IJERA Editor
One of the challenges in sustainable development is to optimize the energy efficiency of buildings during their
lifespan. Nowadays the applying of different types of cements in modern concretes provide low embodied CO2
with the intrinsic property called “thermal mass” that reduces the risk of overheating in the summer and
provides passive heating in the winter. Thermal mass is affected by thermal properties of concrete which it is the
ability of the element to exchange heat with the environment and is based on thermal capacity, conductivity, and
density. Laboratory experiments measured density, specific capacity and thermal conductivity of sustainable
concrete mixes with various percentages of GGBS, PFA, SF. The results contribute to the investigation of the
performance of thermal properties performance in sustainable concrete.
This document summarizes previous research on thermal and moisture behavior in buildings. It discusses factors that influence indoor humidity levels and strategies to control humidity. The document also reviews numerical models that simulate coupled heat, air, and moisture transfer in buildings. It examines studies on natural convection in cavities, the effects of inclined lamellar structures, and correlations for heat and mass transfer. The research aims to numerically study the thermal and moisture behavior of a premise with walls equipped with inclined alveolar structures under variable climate conditions.
Strategies For Sustainable Building Envelopes Ventilation And Inertial Mass ...Andrea Ursini Casalena
1) The document discusses strategies for sustainable building envelopes, focusing on the importance of thermal inertia to reduce energy usage and improve indoor comfort.
2) It analyzes different wall typologies and their effects on indoor conditions, finding that high thermal inertia walls are better able to store heat and reduce temperature swings, improving comfort.
3) The document proposes adding a minimum required value for internal periodic heat capacity (Cip) to guidelines, in order to ensure walls can provide sufficient thermal storage and improve summer indoor comfort when faced with high internal heat loads.
Effect of High Temperature on Compressive Strength of ConcreteIOSR Journals
This document summarizes research on the effect of high temperatures on the compressive strength of concrete. Ninety concrete cubes were cast in three grades and subjected to temperatures from 200°C to 800°C for 1-2 hours. Testing found that strength was largely unaffected up to 350°C but started declining at 500°C, with over 30% reduction at 650°C. Beyond 650°C, concrete was largely decimated. Higher exposure times and temperatures led to greater strength reduction. The research adds to understanding concrete performance in fire conditions and suggests serviceability may be maintained up to 500°C but major repair is needed over 650°C.
The document contains three problems related to determining optimum conditions for heat exchanger design and insulation thickness:
1) It asks to determine the optimum thickness of insulation on a steam pipe given parameters like steam temperature, insulation conductivity, and insulation cost.
2) It asks to calculate the cooling water flow rate and exit temperature needed to optimally condense steam at a given rate and temperature difference, considering the heat exchanger cost and cooling water cost.
3) It asks to calculate the optimum exit temperature of cooling water and length of tubes needed to optimally cool air in a shell and tube heat exchanger, given parameters like air flow rate, temperature difference, heat transfer coefficients, cooling water cost, and exchanger
This document discusses thermal bridging in low energy buildings. Thermal bridging occurs where building materials with high thermal conductivity create paths of least resistance for heat transfer. This can occur at junctions where insulation is compromised. Infrared thermography is used to identify thermal bridges. While small bridges may have small impacts, larger bridges like uninsulated slabs can account for 20-70% of heat transfer. Proper design and insulation techniques can help mitigate thermal bridging to improve building energy efficiency.
This chapter discusses heat conduction through plane walls, cylinders, spheres, and multilayer geometries under steady conditions. It introduces the concept of thermal resistance networks to model conduction and convection resistances. Contact resistance is analyzed, and applications like insulation and fins are discussed. Fins enhance heat transfer by increasing surface area, and the fin equation models temperature variation along a fin.
Optimum insulation thickness for building envelope a revieweSAT Journals
Abstract Through this paper an important issue that what should be the level of insulation for energy conservation in conditioned building envelope is being address. It is well established from the earlier studies of heat transfer across the composite walls that as insulation thickness increases the corresponding resistance to heat flow increases so the rate of heat transfer decreases. The corresponding cost of maintain temperature through artificial means decreases but this is achieve at the cost of insulation which also increases as its thickness increases. The thickness of insulation where total cost of heating/ cooling and insulation cost over the life time becomes minimum is known as optimum insulation thickness. Answer to this question of thermal insulation level in the building envelope components like external wall or roof from economy point of view is being reviewed. Different angles of research in this field being discuss like methods of analyzing annual heating/ cooling loads, insulation material point of view, effect of climate, effect of energy source on optimum insulation thickness. Further different methods used for determination of optimum insulation thickness being reviewed. The effect of solar radiation on optimum insulation thickness is an area which needs further research in Indian context. There is a great need of not only insulating building envelope components like external wall or roof but from economical point of view there is a need to optimize insulation thickness. Further there is need to analyze two insulation materials in combination for maximizing savings. KeyWords- Optimum insulation thickness, Heating/cooling degree day, life cycle cost analysis, insulation material, external wall.
This document proposes modifying California's Title 24 building energy efficiency standards to include cool roofs as a prescriptive requirement for nonresidential buildings with low-sloped roofs. Cool roofs have high solar reflectance and thermal emittance, which helps reduce cooling energy usage and peak electricity demand. The proposal recommends establishing minimum solar reflectance requirements for roofs in each climate zone based on life cycle cost analysis showing savings. It outlines changes to the prescriptive, performance, and overall envelope compliance options to incorporate these requirements. Cool roof technologies are widely available for most low-sloped roofing materials at low additional cost.
Climatic Design of Vernacular Homes in Kenya to Meet Requirements of Modern L...paperpublications3
This document discusses the climatic design of traditional homes in Kenya and how their design principles can be applied to modern homes. It begins by outlining the problem of high energy consumption in modern Kenyan homes that do not consider local climate. It then examines the traditional housing styles of the Maasai, Rendile, and Taita ethnic groups, noting design features like natural ventilation, local materials, and passive cooling. A comparison is made between traditional and modern homes, showing how traditional designs were better adapted to the climate through layout, materials, ventilation and lighting approaches. The document concludes that Kenya's architecture should embrace traditional wisdom to improve thermal comfort and reduce energy use through climatically appropriate design.
This document provides an overview of thermal insulation in buildings. It discusses heat transfer mechanisms like conduction, convection, and radiation. It defines key terms like U-value and R-value and describes different types of thermal insulation materials. Benefits of insulation like reduced energy consumption and increased comfort are outlined. The significance of insulation for Saudi Arabian buildings given the hot climate is also reviewed. Finally, efforts by the Saudi government to promote energy efficiency and green building practices are briefly mentioned.
Benefits of the use of thermal insulation in a naturally ventilated residenti...IJERA Editor
The use of thermal insulation is not a common practice in civil construction in Brazil. The national standard for
thermal performance and the energy efficiency labeling program do not require the use of thermal insulation in
the building envelope, even for the hottest and for the coldest regions of the country. Brazil has a temperate
climate region that covers 7.2% of its territory and contains important and populous cities. This paper explores
the benefits of the use of thermal insulation in dwellings located in that climate. A heat balance analysis was
conducted in the computational model of a naturally ventilated single-family residential building. The simulation
task was carried out in the EnergyPlus software with the use of weather files of three cities, classified as
temperate climates. The main sources of heat transfer through the building envelope were identified and
subjected to a sensitivity analysis, seeking for the building performance optimization. Simulation results shows
that thermal insulation can be applied on building walls, roof and floor, with benefits measured as a reduction in
the heating degree hours along the year. Increase in cooling degree hours during the summer could be overcome
with strategies to control the solar heat gain on windows
The document contains three engineering design problems related to determining optimal conditions. Problem 1 involves calculating the optimum insulation thickness for a steam pipe. Problem 7 involves determining the cooling water flow rate and exit temperature for an optimal condenser design. Problem 13 involves calculating the optimum exit temperature of cooling water and optimal length of tubes for an air cooler design.
The document discusses three chemical engineering problems involving heat exchanger design and optimization. Problem 3 involves determining the optimum insulation thickness for a steam pipe. Problem 9 involves determining the cooling water flow rate and exit temperature for a condenser. Problem 15 involves determining the optimum exit temperature of cooling water and length of tubes for an air cooler.
this power point discuses about pcm material s and recently applications on green house
and introduce kind of pcm system
this power point priority created by some other authors
A brief review on mixed convection heat transfer in channel flow with vortex ...IJERA Editor
In an effort to increase processor speeds, 3D IC architecture is being aggressively pursued by researchers and
chip manufacturers. This architecture allows extremely high level of integration with enhanced electrical
performance and expanded functionality, and facilitates realization of VLSI and ULSI technologies. However,
utilizing the third dimension to provide additional device layers poses thermal challenges due to the increased
heat dissipation and complex electrical interconnects among different layers. The conflicting needs of the
cooling system requiring larger flow passage dimensions to limit the pressure drop, and the IC architecture
necessitating short interconnect distances to reduce signal latency warrant paradigm shifts in both of their
design approach. Additional considerations include the effects due to temperature non-uniformity, localized
hot spots, complex fluidic connections, and mechanical design. This paper reviews the advances in electronic
chip cooling in the last decade and provides a vision for code signing integrated cooling systems. For various
heat fluxes on each side of a chip acting as discrete heat source, the current single-phase cooling technology is
projected to provide adequate cooling, albeit with high pressure drops. Effectively mitigating the high
temperatures surrounding local hot spots remains a challenging issue. Various forms of tabulators above the
chips, different geometric arrangements of the chips positioned top and bottom wall of the duct serves very
well in the heat augmentation technique with better performance
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy composites by adding boron nitride (BN) microparticles. Epoxy composites containing 0-11.3% BN by volume were prepared and their thermal conductivities were measured experimentally. Numerical simulations using ANSYS found the effective thermal conductivity increased by 27.82% for 11.3% BN and 440% for 30% BN, compared to neat epoxy. The results showed BN particles exhibited a percolation behavior, with a sudden jump in thermal conductivity occurring at 20% BN volume.
Application of Passive Cooling Techniques in Residential Buildings: A Case St...IJERA Editor
This document discusses passive cooling techniques that can be used in residential buildings in Northern Nigeria to reduce energy consumption and improve thermal comfort. It begins by providing background on the climate of Northern Nigeria and how current residential building designs do not consider energy efficiency. It then analyzes two main passive cooling approaches - reducing heat gain through design elements like orientation, insulation, shading and glazing selection; and dissipating heat using evaporative cooling techniques like vegetation, ventilation stacks, roof sprinklers and ponds. The document concludes that applying these passive cooling strategies can significantly decrease energy demands, lower cooling loads and provide a more sustainable and comfortable living environment.
This document discusses how the thermal conductivity and R-value of insulation materials are dependent on temperature and climate conditions, and can impact building durability. It notes that standardized testing may not accurately capture real-world performance, and that accounting for temperature-dependent properties is important for predicting condensation and durability. The document advocates for manufacturers providing tested data under various conditions, and considering insulation performance relative to specific project locations and environments.
This document proposes a methodology to investigate the effects of strategic vegetation planting on the thermal performance of housing in a tropical environment. The study aims to quantify the temperature reduction and energy savings potential of vegetation for the average tropical residence. The methodology involves examining different planting patterns and structures, quantifying the relationship between vegetation and building energy use through simulations and field measurements, and developing design guidelines based on the results. The research will be conducted on single-family homes in Kuala Lumpur, Malaysia to analyze the impacts of surrounding vegetation of different ages.
Comparison of Intelligent Façade’s Energy Efficiency in Hot and Humid Climate...paperpublications3
Abstract: Energy conservation and sustainable designs are very hot topics in the world today. Currently architects and building designers greatly influence the level of energy conservation in the world, since buildings are the highest energy consumers. Generally the use of passive heating and cooling systems has had a huge impact in energy conservation, especially in the warm and humid climate. This research will therefore focus on comparing intelligent skins (case in point: double skin façade), which are adaptive and/or responsive to the surrounding environment and how efficient they can be in their energy conservation on the principles of passive designs for warm and humid climate such as natural ventilation and free air movement, providing ample shading systems, glare control and so on.
This document provides a detailed review of zero energy building envelope components. It discusses various passive building strategies to improve energy efficiency, focusing on building envelope elements like insulation materials, walls, roofs, windows, and doors. Specific wall types are examined, like passive solar walls, walls with latent heat storage, and green walls. Roof types discussed include lightweight roofs, solar-reflective cool roofs, green roofs, and photovoltaic roofs. The integration of photovoltaics with building envelopes to generate on-site power is also covered. The goal of the review is to provide information on state-of-the-art zero energy building envelope components and developments to benefit building designers and constructors.
Improving envelope thermal insulation in construction projects using nanotech...eSAT Journals
Abstract
Conservation of energy consumption in the construction industry is becoming more important than ever due to global issues
related to the increased energy demand. Energy consumption in heating and cooling systemsfor commercial and residential
buildings is a major portion of the overall energy consumption. One important approach to respond to this type of consumption is
to enhance the thermal resistance (R value) of building envelopes with a special focus on the insulation materials.
Nanotechnology as an emergent science and engineering field is developing solutions to enhance the resistance value of different
building products withinnovative methodsincluding, reducing the pore size of insulation materials. This paper presents a review of
utilization of nano-enabled products to improve insulation materials. The research involves exploring the literatures that cover
area of technology application in addition to the commercial products currently being offered in the construction market.
Findings indicate that the relatively high cost of the nano-products is due to lack of both mass production and familiarity of public
to these products.
Key Words: Thermal Insulation, Nano Insulation, Envelope, Heat Resistance, Construction Projects.
This document summarizes previous research on thermal and moisture behavior in buildings. It discusses factors that influence indoor humidity levels and strategies to control humidity. The document also reviews numerical models that simulate coupled heat, air, and moisture transfer in buildings. It examines studies on natural convection in cavities, the effects of inclined lamellar structures, and correlations for heat and mass transfer. The research aims to numerically study the thermal and moisture behavior of a premise with walls equipped with inclined alveolar structures under variable climate conditions.
Strategies For Sustainable Building Envelopes Ventilation And Inertial Mass ...Andrea Ursini Casalena
1) The document discusses strategies for sustainable building envelopes, focusing on the importance of thermal inertia to reduce energy usage and improve indoor comfort.
2) It analyzes different wall typologies and their effects on indoor conditions, finding that high thermal inertia walls are better able to store heat and reduce temperature swings, improving comfort.
3) The document proposes adding a minimum required value for internal periodic heat capacity (Cip) to guidelines, in order to ensure walls can provide sufficient thermal storage and improve summer indoor comfort when faced with high internal heat loads.
Effect of High Temperature on Compressive Strength of ConcreteIOSR Journals
This document summarizes research on the effect of high temperatures on the compressive strength of concrete. Ninety concrete cubes were cast in three grades and subjected to temperatures from 200°C to 800°C for 1-2 hours. Testing found that strength was largely unaffected up to 350°C but started declining at 500°C, with over 30% reduction at 650°C. Beyond 650°C, concrete was largely decimated. Higher exposure times and temperatures led to greater strength reduction. The research adds to understanding concrete performance in fire conditions and suggests serviceability may be maintained up to 500°C but major repair is needed over 650°C.
The document contains three problems related to determining optimum conditions for heat exchanger design and insulation thickness:
1) It asks to determine the optimum thickness of insulation on a steam pipe given parameters like steam temperature, insulation conductivity, and insulation cost.
2) It asks to calculate the cooling water flow rate and exit temperature needed to optimally condense steam at a given rate and temperature difference, considering the heat exchanger cost and cooling water cost.
3) It asks to calculate the optimum exit temperature of cooling water and length of tubes needed to optimally cool air in a shell and tube heat exchanger, given parameters like air flow rate, temperature difference, heat transfer coefficients, cooling water cost, and exchanger
This document discusses thermal bridging in low energy buildings. Thermal bridging occurs where building materials with high thermal conductivity create paths of least resistance for heat transfer. This can occur at junctions where insulation is compromised. Infrared thermography is used to identify thermal bridges. While small bridges may have small impacts, larger bridges like uninsulated slabs can account for 20-70% of heat transfer. Proper design and insulation techniques can help mitigate thermal bridging to improve building energy efficiency.
This chapter discusses heat conduction through plane walls, cylinders, spheres, and multilayer geometries under steady conditions. It introduces the concept of thermal resistance networks to model conduction and convection resistances. Contact resistance is analyzed, and applications like insulation and fins are discussed. Fins enhance heat transfer by increasing surface area, and the fin equation models temperature variation along a fin.
Optimum insulation thickness for building envelope a revieweSAT Journals
Abstract Through this paper an important issue that what should be the level of insulation for energy conservation in conditioned building envelope is being address. It is well established from the earlier studies of heat transfer across the composite walls that as insulation thickness increases the corresponding resistance to heat flow increases so the rate of heat transfer decreases. The corresponding cost of maintain temperature through artificial means decreases but this is achieve at the cost of insulation which also increases as its thickness increases. The thickness of insulation where total cost of heating/ cooling and insulation cost over the life time becomes minimum is known as optimum insulation thickness. Answer to this question of thermal insulation level in the building envelope components like external wall or roof from economy point of view is being reviewed. Different angles of research in this field being discuss like methods of analyzing annual heating/ cooling loads, insulation material point of view, effect of climate, effect of energy source on optimum insulation thickness. Further different methods used for determination of optimum insulation thickness being reviewed. The effect of solar radiation on optimum insulation thickness is an area which needs further research in Indian context. There is a great need of not only insulating building envelope components like external wall or roof but from economical point of view there is a need to optimize insulation thickness. Further there is need to analyze two insulation materials in combination for maximizing savings. KeyWords- Optimum insulation thickness, Heating/cooling degree day, life cycle cost analysis, insulation material, external wall.
This document proposes modifying California's Title 24 building energy efficiency standards to include cool roofs as a prescriptive requirement for nonresidential buildings with low-sloped roofs. Cool roofs have high solar reflectance and thermal emittance, which helps reduce cooling energy usage and peak electricity demand. The proposal recommends establishing minimum solar reflectance requirements for roofs in each climate zone based on life cycle cost analysis showing savings. It outlines changes to the prescriptive, performance, and overall envelope compliance options to incorporate these requirements. Cool roof technologies are widely available for most low-sloped roofing materials at low additional cost.
Climatic Design of Vernacular Homes in Kenya to Meet Requirements of Modern L...paperpublications3
This document discusses the climatic design of traditional homes in Kenya and how their design principles can be applied to modern homes. It begins by outlining the problem of high energy consumption in modern Kenyan homes that do not consider local climate. It then examines the traditional housing styles of the Maasai, Rendile, and Taita ethnic groups, noting design features like natural ventilation, local materials, and passive cooling. A comparison is made between traditional and modern homes, showing how traditional designs were better adapted to the climate through layout, materials, ventilation and lighting approaches. The document concludes that Kenya's architecture should embrace traditional wisdom to improve thermal comfort and reduce energy use through climatically appropriate design.
This document provides an overview of thermal insulation in buildings. It discusses heat transfer mechanisms like conduction, convection, and radiation. It defines key terms like U-value and R-value and describes different types of thermal insulation materials. Benefits of insulation like reduced energy consumption and increased comfort are outlined. The significance of insulation for Saudi Arabian buildings given the hot climate is also reviewed. Finally, efforts by the Saudi government to promote energy efficiency and green building practices are briefly mentioned.
Benefits of the use of thermal insulation in a naturally ventilated residenti...IJERA Editor
The use of thermal insulation is not a common practice in civil construction in Brazil. The national standard for
thermal performance and the energy efficiency labeling program do not require the use of thermal insulation in
the building envelope, even for the hottest and for the coldest regions of the country. Brazil has a temperate
climate region that covers 7.2% of its territory and contains important and populous cities. This paper explores
the benefits of the use of thermal insulation in dwellings located in that climate. A heat balance analysis was
conducted in the computational model of a naturally ventilated single-family residential building. The simulation
task was carried out in the EnergyPlus software with the use of weather files of three cities, classified as
temperate climates. The main sources of heat transfer through the building envelope were identified and
subjected to a sensitivity analysis, seeking for the building performance optimization. Simulation results shows
that thermal insulation can be applied on building walls, roof and floor, with benefits measured as a reduction in
the heating degree hours along the year. Increase in cooling degree hours during the summer could be overcome
with strategies to control the solar heat gain on windows
The document contains three engineering design problems related to determining optimal conditions. Problem 1 involves calculating the optimum insulation thickness for a steam pipe. Problem 7 involves determining the cooling water flow rate and exit temperature for an optimal condenser design. Problem 13 involves calculating the optimum exit temperature of cooling water and optimal length of tubes for an air cooler design.
The document discusses three chemical engineering problems involving heat exchanger design and optimization. Problem 3 involves determining the optimum insulation thickness for a steam pipe. Problem 9 involves determining the cooling water flow rate and exit temperature for a condenser. Problem 15 involves determining the optimum exit temperature of cooling water and length of tubes for an air cooler.
this power point discuses about pcm material s and recently applications on green house
and introduce kind of pcm system
this power point priority created by some other authors
A brief review on mixed convection heat transfer in channel flow with vortex ...IJERA Editor
In an effort to increase processor speeds, 3D IC architecture is being aggressively pursued by researchers and
chip manufacturers. This architecture allows extremely high level of integration with enhanced electrical
performance and expanded functionality, and facilitates realization of VLSI and ULSI technologies. However,
utilizing the third dimension to provide additional device layers poses thermal challenges due to the increased
heat dissipation and complex electrical interconnects among different layers. The conflicting needs of the
cooling system requiring larger flow passage dimensions to limit the pressure drop, and the IC architecture
necessitating short interconnect distances to reduce signal latency warrant paradigm shifts in both of their
design approach. Additional considerations include the effects due to temperature non-uniformity, localized
hot spots, complex fluidic connections, and mechanical design. This paper reviews the advances in electronic
chip cooling in the last decade and provides a vision for code signing integrated cooling systems. For various
heat fluxes on each side of a chip acting as discrete heat source, the current single-phase cooling technology is
projected to provide adequate cooling, albeit with high pressure drops. Effectively mitigating the high
temperatures surrounding local hot spots remains a challenging issue. Various forms of tabulators above the
chips, different geometric arrangements of the chips positioned top and bottom wall of the duct serves very
well in the heat augmentation technique with better performance
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy composites by adding boron nitride (BN) microparticles. Epoxy composites containing 0-11.3% BN by volume were prepared and their thermal conductivities were measured experimentally. Numerical simulations using ANSYS found the effective thermal conductivity increased by 27.82% for 11.3% BN and 440% for 30% BN, compared to neat epoxy. The results showed BN particles exhibited a percolation behavior, with a sudden jump in thermal conductivity occurring at 20% BN volume.
Application of Passive Cooling Techniques in Residential Buildings: A Case St...IJERA Editor
This document discusses passive cooling techniques that can be used in residential buildings in Northern Nigeria to reduce energy consumption and improve thermal comfort. It begins by providing background on the climate of Northern Nigeria and how current residential building designs do not consider energy efficiency. It then analyzes two main passive cooling approaches - reducing heat gain through design elements like orientation, insulation, shading and glazing selection; and dissipating heat using evaporative cooling techniques like vegetation, ventilation stacks, roof sprinklers and ponds. The document concludes that applying these passive cooling strategies can significantly decrease energy demands, lower cooling loads and provide a more sustainable and comfortable living environment.
This document discusses how the thermal conductivity and R-value of insulation materials are dependent on temperature and climate conditions, and can impact building durability. It notes that standardized testing may not accurately capture real-world performance, and that accounting for temperature-dependent properties is important for predicting condensation and durability. The document advocates for manufacturers providing tested data under various conditions, and considering insulation performance relative to specific project locations and environments.
This document proposes a methodology to investigate the effects of strategic vegetation planting on the thermal performance of housing in a tropical environment. The study aims to quantify the temperature reduction and energy savings potential of vegetation for the average tropical residence. The methodology involves examining different planting patterns and structures, quantifying the relationship between vegetation and building energy use through simulations and field measurements, and developing design guidelines based on the results. The research will be conducted on single-family homes in Kuala Lumpur, Malaysia to analyze the impacts of surrounding vegetation of different ages.
Comparison of Intelligent Façade’s Energy Efficiency in Hot and Humid Climate...paperpublications3
Abstract: Energy conservation and sustainable designs are very hot topics in the world today. Currently architects and building designers greatly influence the level of energy conservation in the world, since buildings are the highest energy consumers. Generally the use of passive heating and cooling systems has had a huge impact in energy conservation, especially in the warm and humid climate. This research will therefore focus on comparing intelligent skins (case in point: double skin façade), which are adaptive and/or responsive to the surrounding environment and how efficient they can be in their energy conservation on the principles of passive designs for warm and humid climate such as natural ventilation and free air movement, providing ample shading systems, glare control and so on.
This document provides a detailed review of zero energy building envelope components. It discusses various passive building strategies to improve energy efficiency, focusing on building envelope elements like insulation materials, walls, roofs, windows, and doors. Specific wall types are examined, like passive solar walls, walls with latent heat storage, and green walls. Roof types discussed include lightweight roofs, solar-reflective cool roofs, green roofs, and photovoltaic roofs. The integration of photovoltaics with building envelopes to generate on-site power is also covered. The goal of the review is to provide information on state-of-the-art zero energy building envelope components and developments to benefit building designers and constructors.
Improving envelope thermal insulation in construction projects using nanotech...eSAT Journals
Abstract
Conservation of energy consumption in the construction industry is becoming more important than ever due to global issues
related to the increased energy demand. Energy consumption in heating and cooling systemsfor commercial and residential
buildings is a major portion of the overall energy consumption. One important approach to respond to this type of consumption is
to enhance the thermal resistance (R value) of building envelopes with a special focus on the insulation materials.
Nanotechnology as an emergent science and engineering field is developing solutions to enhance the resistance value of different
building products withinnovative methodsincluding, reducing the pore size of insulation materials. This paper presents a review of
utilization of nano-enabled products to improve insulation materials. The research involves exploring the literatures that cover
area of technology application in addition to the commercial products currently being offered in the construction market.
Findings indicate that the relatively high cost of the nano-products is due to lack of both mass production and familiarity of public
to these products.
Key Words: Thermal Insulation, Nano Insulation, Envelope, Heat Resistance, Construction Projects.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
1. This project proposal outlines a study to assess the high temperature and innovative insulation performance of residential buildings.
2. The objectives are to resist heat transfer through walls and roofs and minimize energy losses. Two models will be constructed, one without insulation and one with various insulation materials, and their inner temperatures will be compared using a potentiometer.
3. A literature review found that materials like aerogel and vacuum insulation panels can provide high insulation with thinner layers than traditional materials like fiberglass or polystyrene. The study aims to demonstrate the need for thermal insulation in buildings.
A REVIEW ON ENERGY EFFICIENT BUILDINGS - USING PHASE CHANGE MATERIALS, GREEN ...IRJET Journal
This document reviews the use of various strategies to create more energy efficient buildings, including phase change materials (PCMs), green roofs, and heat reflective coatings. It summarizes several studies that have found incorporating PCMs into building materials like walls and roofs can significantly reduce temperature fluctuations and energy consumption for heating and cooling by absorbing and releasing thermal energy during phase changes. Green roofs are also highlighted as providing thermal benefits by keeping roof and indoor temperatures lower compared to bare roofs. Coatings that reflect infrared and sunlight are discussed as another method to decrease energy usage. The document then examines two specific studies in more depth, one analyzing the effects of different PCM variants installed in walls and roofs in Kuwait
International Journal of Engineering Research and Development (IJERD)IJERD Editor
The document discusses a study that assessed the performance of window films in reducing solar heat gain in buildings in Kurdistan, Iraq. A test wooden cabinet was constructed and measurements were taken over 9 hours both with and without a window film installed. Results showed that the window film reduced maximum indoor temperatures by 10°C and blocked 50-97% of solar radiation depending on weather conditions. Calculations estimated that applying the window film reduced the solar heat gain of the cabinet by 477.15 Watts, with the largest reduction due to decreased light transmission through the windows. The study demonstrates that window films can effectively support environmental protection by lowering energy use for cooling in hot climates like Kurdistan.
Abstract:
Introduction: The several ways that thermal energy is transferred from one place to another are referred to as the principle of heat transfer.
This process is known as radiation heat transfer.
The transfer of energy by thermal radiation, or electromagnetic waves, is known as radiant heat transfer.
A convection current is created when heated air rises and is replaced by colder air, transferring heat from the inner pane to the outside pane(s).
Heat is carried via the window frame in triple-glazing units; convection is minor in double-glazing units up to 20 mm, especially when argon gas is used, which is denser than air.
Heat transfer through buildings rooms and roofs: Even while convection often involves more variables than conduction, we are nevertheless able to characterize it and do some simple, accurate calculations to determine its effects.
Figure 7 illustrates each of the three heat transmission techniques in this portion of the attic.
This natural convection heating system, when correctly built, may be quite effective in heating a home evenly.
Environmental Heat Transfer
4
Introduction:
The several ways that thermal energy is transferred from one place to another are referred to as the principle of heat transfer. There are three main ways that heat travels through building assemblies: radiation, convection, and conduction. One or more of these mechanisms may be involved in a specific thermal energy transfer. Phase transitions also release or absorb heat through three processes: conduction, radiation, and convection. Examples of this include heat transfer from walls to rooms, from fluids to each other, between pipes, and from outside heat to dwellings. The types of heat transport are described in Figure 1. a (concept group LLC, 2023)
Figure 1: types of transferring heat. (energy saver, 2023)
Temperature and heat are not the same thing. Temperature is a measurement of the intensity of kinetic energy, which is what heat is. Consider two water containers, one holding 10 gallons and the other one holding 1 gallon, to demonstrate this. Both containers hold 50°F water. The bigger container retains ten times more heat than the smaller one, even if they are of the same temperature. Because it has a greater capacity, the larger container can hold more heat. (Clayton DeKorne, 2023)
Building heat transfer calculations are performed for different applications such as: (Kusuda T., 1977)
• heat transmission via the outer envelope, the basement walls, the slab-on-grade floor (to a semi-infinite zone),
• transmission, absorption, and reflection of short wavelengths (or solar heat) for openings.
• thermal storage in the external masses of structures.
Environmental Heat Transfer
5
• air leakage via outside envelopes as well as the interior partition walls, ceilings, and floors.
Interior environmental analyses-:
• radiant heat transfer between heat sinks or sources and interior surfaces,
• the transfer of heat convectively between interior surfaces an
This document discusses the importance of thermal management in telecommunications equipment. It notes that as power densities and loads have increased, thermal management has become a critical design consideration. Two novel air-cooled thermal architectures - 3D heat sinks and vortex generators - are presented that can provide enhanced heat transfer and energy efficiency over existing designs. Experimental arrangements and procedures for characterizing the thermal performance of these solutions are also overviewed.
FIRE RESISTANT ANALYSIS OF RC BEAM COLUMN JOINTIRJET Journal
This document summarizes a study that uses finite element analysis to analyze the fire resistant behavior of reinforced concrete beam-column joints. The study models beam-column joints exposed to fire based on the ISO 834 standard fire curve and analyzes the effects of different exposure conditions (2 sides, 3 sides, or 4 sides exposed). It finds that failure occurs more quickly when more sides of the joint are exposed to fire. The study concludes that the number of exposed sides significantly impacts a structure's ability to withstand fire, and that thermal failure criteria are more important than deflection criteria during a fire.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The document compares the thermal performance of Madras terrace roofing and concrete roofing (RCC) in the warm, humid climate of Coimbatore, India. An experiment was conducted on a residence with both roof types over 3 weeks in summer. Outdoor and indoor temperatures and humidity were recorded every 2 hours. Results showed RCC roofing gained more heat than Madras terrace roofing during the day. Peak indoor temperatures under RCC roofing were often 2-3°C higher. Therefore, Madras terrace roofing provided better thermal comfort for occupants in this climate compared to RCC roofing.
Sustainable design for building envelope in hot climates; a case study for t...IJAEMSJORNAL
Architectural design is influenced by the actual thermal behaviour of building components, and this in turn depends not only on their steady and periodic thermal characteristics, but also on exposure effects, orientation, surface colour, and climatic fluctuations at the given location. Design data and environmental parameters should be produced in an accurate way for specified locations, so that architects and engineers can confidently apply them in their design calculations that enable precise evaluation of the influence of various parameters relating to each component of the envelope, which indicates overall thermal performance of building. The present paper will be carried out with an objective of thermal behaviour assessment and characteristics of the opaque and transparent parts of one of the very unique components used as a symbolic distinguished element of building envelope, its thermal behaviour under the impact of solar temperatures, and its role in heat exchange related to a specific U-value of specified construction materials alternatives. The research method will consider the specified Hot-Dry weather and new mosque in Baghdad, Iraq as a case study. Also, data will be presented in light of the criteria of indoor thermal comfort in terms of design parameters and thermal assessment for a“model dome”. Design alternatives and considerations of energy conservation, will be discussed as well using comparative computer simulations. Findings will be incorporated to outline the conclusions clarifying the important role of the dome in heat exchange of the whole building envelope for approaching an indoor thermal comfort level and further research in the future.
The document discusses several methods to reduce operational energy in buildings, including:
1. Using energy efficient building envelopes with high insulation to control air, water, and heat flow. This includes roofs, walls, foundations, and thermal barriers.
2. Considering the solar heat gain coefficient and U-values of facade materials like windows to reduce unwanted solar heat gain and heat loss.
3. Implementing efficient lighting technologies, energy efficient appliances, renewable energy sources, and energy monitoring systems to reduce overall energy usage.
This document summarizes research on the effect of high temperatures on the compressive strength of concrete. Ninety concrete cubes were cast in three grades and subjected to temperatures from 200°C to 800°C for 1-2 hours. Testing found that strength was largely unaffected up to 350°C but started declining at 500°C, with over 30% reduction at 650°C. Beyond 650°C, concrete was largely decimated. Higher exposure times resulted in greater damage. The research adds to understanding concrete performance during fires and suggests structures may require repair after 500°C exposure but major work after 650°C.
The present work shows the importance of using thermal insulation for new building walls. To decrease cooling and heating load, so the electric power consumption for air-conditioning equipment drop to more than 50% of that without insulation. The experimental work includes building of two models of (1X1X1) m width, length and height located at (32.5 latitude) kut city, Iraq. The model is set to be each wall faced south, east, north and west direction exactly. The models built from brick (24cm), thermo-stone (20cm) and sandwich panel (5cm). Another type of insulation material were tested and compared with normal brick wall is styropor. The heat gain was calculated for all the above insulations compared with brick model. The results showed that the best model in energy saving is the sandwich panel model with about 70% energy save, while the thermo-stone model gives 33% and outside styropor 54.28%.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Proper ventilation in one of the primary requirements of any domestic or commercial buildings. The conventional method employs usage of air conditioning or air cooling systems which requires high power consumption. The solar driven ventilation systems can be used in buildings which doesn’t require any external power. The current research reviews various researches conducted in improving system of passive ventilation along use of phase change material as energy storage system. Passive design of buildings does not use the electrical and mechanical systems in providing comfortable indoor environment. Prem Shankar Sahu | Praveen Kumar | Ajay Singh Paikra "Review on Solar Chimney Ventilation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd42427.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/42427/review-on-solar-chimney-ventilation/prem-shankar-sahu
This document discusses heat and moisture transfer through building envelopes. Section 3.1 defines the key components of a building envelope, including exterior walls, roofs, windows, ceilings and floors. Section 3.2 covers heat transfer fundamentals, discussing conductive, convective and radiative heat transfer. Section 3.3 discusses heat transfer coefficients. Section 3.4 covers moisture transfer, including sorption isotherms and moisture migration in building materials. Section 3.5 discusses condensation in buildings.
The need for vernacular mud huts of Ranchi to re-adapt in response to the cha...Janmejoy Gupta
presented at conference in SPA BHOPAL in Dec 2015...on vernacular architecture...
under the sub-head....Adaptation and innovation in Techniques of Construction for the Future of Vernacular Architecture.
Similar to PASSIVE THERMAL CONTROL FOR BUILDINGS IN TEMPERATE REGIONS-COMPARISON OF CAVITY WALLS AND CONVENTIONAL WALLS (20)
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Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
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Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
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PASSIVE THERMAL CONTROL FOR BUILDINGS IN TEMPERATE REGIONS-COMPARISON OF CAVITY WALLS AND CONVENTIONAL WALLS
1. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
Page | 64
Paper Publications
PASSIVE THERMAL CONTROL FOR
BUILDINGS IN TEMPERATE REGIONS-
COMPARISON OF CAVITY WALLS AND
CONVENTIONAL WALLS
1
Ibibia Ajubo Jamabo, 2
Assist. Prof. Dr. Halil Zafer Alibaba
Department of Architecture, Faculty of Architecture, Eastern Mediterranean University, Famagusta, Turkish Republic of
North Cyprus
Abstract: Providing thermal comfort without excess space and conditioning costs is one of the primary
requirements of buildings. Therefore, thermal control is an important aspect in almost all buildings.
Understanding heat transfer and the temperature distribution through building materials and assemblies is also
important for assessing energy use. Thermal comfort, thermal movements, durability, and the potential for
moisture problems. The control of heat flow in buildings requires insulation layers compromised with few thermal
bridges, an effective air barrier system, good control of solar radiation, and management of interior heat
generation. Walls play a huge role in the heat gain and loss in buildings, thus, making wall an important subject in
passive thermal control in buildings. This article is aimed at analyzing cavity walls and solid brick walls and
comparing them for home construction in temperate regions. Temperate regions need good insulating walls, thus
reducing heat loss via walls to its minimal, which in turn reduces the cost of active heating measures in buildings.
Keywords: walls, masonry wall, cavity wall, solid brick wall, insulation, thermal resistance, thermal insulation.
1. INTRODUCTION
Building construction in temperate regions requires good passive insulation and thermal control systems to reduce the
excessive cost of active heating. Heat loss and transfers in buildings occur in three ways; conduction, convection and
radiation. Heat can be lost in a building through various building assemblies; roof, slabs, openings and walls. It is also
important to note that walls are the highest medium in which heat is lost in a building. Thus, it is very important to choose
a good wall type to reduce heat loss to its minimal. We will take two wall types into consideration; Cavity wall and Solid
Brick wall, which are the two major typologies we see in temperate regions for home construction. Both wall types have
their advantages and disadvantages, heat resistance abilities and insulation cost.
2. METHOD
This study analyses the modern construction material for wall assembly in temperate regions and focusing on the United
Kingdom (UK) as a case study. It aims at comparing between cavity walls and solid brick walls, their advantages and
disadvantages, aesthetics, price and efficiency. This study acquires material resistance and assembly data from Francis
D.K. Ching (1943). Building construction illustrated. New Jersey, cost analysis from the Energy Saving Trust UK (2012).
Save energy at home. Retrieved from. http://www.energysavingtrust.org.uk/, and energy consumption data from Paula
Owen (2010). Powering a nation. Retrieved from. http://www.energysavingtrust.org.uk/sites/default/files/reports
/PoweringthenationreportCO332.pdf. All data will be analyzed and applied for this comparative study to draw a
2. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
Page | 65
Paper Publications
reasonable conclusion for preferable wall choice assembly in temperate region. The Energy Saving Trust UK is a non-
governmental organization (NGO) which works in partnership with the government and local authorities to help reduce
carbon emissions.
2.1. Building in temperate regions
Building in temperate regions require the maximum passive thermal control measures. Many authors have carried out
quantitative studies on the behavior of traditional and modern buildings in different seasons, showing the capacity of these
buildings to secure indoor comfort by means of passive thermal control systems (Cardinale & Al. 2009). Some authors
have experimentally compared the behavior of traditional and modern buildings, not only showing how the former are
preferable but from the point of view of comfort in terms of both comfort and energy saving (Martin and Al. 2010) but
also identifying the limitations of energy legislation which tends to encourage the latter (Yilmaz 2007; C. Di Perna and
Al; 2009)
2.2. Building construction in the United Kingdom (UK)
The English national survey (EHS) 2008 report covers several thousand dwellings in the country. The survey covers a
whole range of attributes from whether the dwelling has a cavity wall to the income of the homeowner. The survey does
not explicitly record specific type of cavity wall. Information is acquired by qualified surveyors physically surveying a
dwelling and interviewing the homeowners/occupiers. EHS contains data from around 16,000 dwellings. Each dwelling in
the survey is considered to be a single data point for purpose of this study. The report shows that only 20% of houses use
cavity wall for construction, while solid walls of either brick or concrete constitutes of about 65%. An increased in the use
of cavity walls should be achieved in other to reduce the annual CO2 emission.
3. HEAT TRANSFER IN BUILDINGS
Heat can be gained or lost in a building by Conduction, Convection, and Radiation. Although, heat transfer occurs on
various building assemblies; walls play a huge role in this respect due to their large surface areas, about 35% of heat loss
or gain via uninsulated walls. Thus, wall choice is a very important subject when it comes to thermal control.
Buildings lose sensible heat to the environment (or gain sensible heat from it) in three principal ways:
I) Conduction: The transfer of heat between substances which are in direct contact with each other. Conduction occurs
when heat flows through a solid.
II) Convection: The movement of gases and liquids caused by heat transfer. As a gas or liquid is heated, it warms,
expands and rises because it is less dense resulting in natural convection.
III) Radiation: When electromagnetic waves travel through space, it is called radiation. When these waves (from the sun,
for example) hit an object, they transfer their heat to that object.
Figure 3.a. conduction, convection and radiation
Images retrieved from: http://auworkshop.autodesk.com/library/building-science/heat-energy-flows-buildings
Figure 3.a. conduction, convection and radiation illustrated with above images.
Conduction, convection, and radiation heat transfer take place almost everywhere we look. In a building envelope,
conduction primarily takes place through opaque envelope assemblies, convection is usually the result of wind or
3. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
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Paper Publications
pressure-driven air movement, and radiant heat transfer is primarily from the sun through fenestrations. Building HVAC
systems are typically designed to provide comfort using convective or radiant modes of heat transfer.
3.1. Thermal resistance
The tables below can be used to estimate the thermal resistance of a construction assembly. For specific R-values of
materials and building components such as windows, consult the product manufacturer.
R=Fo
/Btu/hr .
sf, where:
• R is a measure of thermal resistance of a given material. It is expressed as the temperature difference required to cause
heat flow through a unit area of material at the rate of one heat unit per hour.
• U=1/Rt, where:
• Rt is the total thermal resistance for a construction assembly and is simply the sum of the individual R-value of the
component materials of an assembly.
• U is a measure of the thermal transmittance of a building component assembly. It is expressed as the rate of heat
transfer through a unit area of a building component or assembly caused by a difference of one degree between the air
temperatures on the two sides of the components or assembly. The U-value for a component or assembly is the
reciprocal of its R-value.
• Q=U x A x (ti - to), where:
• Q is the rate of heat flow through a construction assembly and is equal to:
• U=overall coefficient of assembly
• (ti - to) = difference between the inside and outside air temperatures
Francis D.K. (1943). Building construction illustrated.
Figure 3.1.a. Thermal resistance of materials.
Image retrieved from: Francis D.K. (1943). Building construction illustrated.
4. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
Page | 67
Paper Publications
3.2. Thermal insulation
The primary purpose of thermal insulation is to control the flow or transfer of heat through the exterior assemblies of a
building and thereby prevent excessive heat loss in cold seasons and heat gain in hot weather. This control can effectively
reduce the amount of energy required by heating and cooling equipment to maintain conditions for human comfort in a
building. Francis D.K. (1943). Building construction illustrated.
Figure 3.2.a Recommended thermal insulation in a building.
Image retrieved from: Francis D.K. (1943). Building construction illustrated.
3.3. Insulating materials
Almost all building materials offer some resistance to heat flow. To achieve the desired Rt value, however, walls, floor
and roof assemblies usually require the addition of an insulating material. Below is an outline of the basic materials used
to insulate the components and assemblies of a building. Note that all effective insulating materials usually incorporate
some form of captured dead air space.
• Batt insulation consists of flexible, fibrous thermal insulation of glass or mineral wool, made in various thicknesses
and lengths and in 16’’ or 24” (406 or 610) widths to fit between studs, joists and rafters in light wood frame
construction, sometimes faced with a vapor retarded of Kraft paper, metal foil or plastic sheet. Batt insulation is also
as a component in sound-insulating construction.
• Rigid foam insulation is a performed, nonstructural insulating board of foamed plastic or cellular glass. Cellular glass
insulation is fire-resistant, impervious to moisture and dimensionally stable, but has a lower thermal-resistance value
5. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
Page | 68
Paper Publications
than foamed plastic insulations, which are flammable and must be protected by a thermal barrier when used on the
interior surfaces of a building. Rigid insulations have closed-cell structures, such as extruded polystyrene and cellular
glass, are moisture-resistant and may be used in contact with the earth.
• Foamed-in-place insulation consists of a foamed plastic, as polyurethane, that is sprayed or injected into a cavity
where it adheres to the surrounding surfaces.
• Loose-filled insulation consists of mineral wool fibers, granular vermiculite or perlite or treated cellulosic fibers,
poured by hand or blown through a nozzle into a cavity or over a supporting membrane.
• Reflective insulation uses a material of high reflectivity and low emissivity, as paper-backed aluminum foil or foil-
backed gypsum board, in conjunction with a dead air space to reduce transfer of heat by radiation.
Francis D.K. (1943). Building construction illustrated.
Figure 3.3.a. Insulating materials with Rt Values
Image retrieved from: Francis D.K. (1943). Building construction illustrated.
3.4. Wall insulation
Figure 3.4.a. Insulating wall techniques: masonry cavity wall, cast concrete wall and wood stud frame wall.
Image retrieved from: Francis D.K. (1943). Building construction illustrated.
6. ISSN 2393-8471
International Journal of Recent Research in Civil and Mechanical Engineering (IJRRCME)
Vol. 3, Issue 2, pp: (64-73), Month: October 2016 – March 2017, Available at: www.paperpublications.org
Page | 69
Paper Publications
4. WALLS
Walls are the vertical constructions of a building that enclose, separate and protect its interior spaces. They may be
loadbearing structures of homogeneous or composite construction designed to support imposed loads from floor to roofs,
or consist of a framework of columns and beams with nonstructural panels attached to or filling in between them. The
pattern of these loadbearing walls and columns should be coordinated with the layout of the interior spaces of the building
Francis D.K. (1943). Building construction illustrated.
Figure 4.a. wall Figure 4.b. wall efficiency
Image retrieved from: Francis D.K. (1943). Building construction illustrated
4.1. Masonry walls
Masonry walls consist of modular building blocks bonded together with mortar to form walls that are durable, fire-
resistant and structurally efficient in compression. The most common types of masonry units are bricks, which are heat-
hardened clay units and concrete blocks, which are chemically hardened units. Other types of masonry units include
structural clay tile, structural glass block and natural or cast stone.
• Masonry walls may be constructed as solid walls, cavity walls or veneered walls.
• Masonry walls may be unreinforced or reinforced.
• Unreinforced masonry walls, also called plain masonry, incorporate horizontal joint reinforcement and metal wall ties
to bond the wythes of a solid or cavity wall.
• A wythe refers to a continuous vertical section of a wall that is one masonry unit in thickness.
• Reinforced masonry walls utilize steel reinforcing bars embedded in grout-filled joints and cavities to aid the masonry
in resisting stresses.
• Masonry bearing walls are typically arranged in parallel sets to support steel, wood or concrete spanning systems.
• Common spanning elements include open-web steel joist, timber or steel beams and site-cast or precast concrete slabs.
• Pilasters stiffen masonry walls against lateral forces and buckling and provide support for large concentrated loads.
• Openings may be arched or spanned with lintel.
• Exterior masonry walls must be weather-resistant and control heat flow.
• Water penetration must be controlled through the use of tooled joints, cavity spaces, flashing and caulking.
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• Differential movements in masonry walls due to changes in temperature or moisture content or to stress concentrations
require the use of expansion and control joints.
Francis D.K. (1943). Building construction illustrated.
Figure 4.1.a. concrete masonry wall. Figure 4.1.b. brick masonry wall.
Image retrieved from: Francis D.K. (1943). Building construction illustrated
4.2. Solid brick walls
Solid brick wall is exactly like it sounds. Typically, two bricks wide, with each row of bricks interlocking to form a
completely solid 9-inch brick wall. There is no gap between the bricks to insulate, and so you must either add insulation
to the inside of the property, or do so externally. In constructing solid brick walls, bricks are typically held together by
mortar. In most cases either the interior or exterior is usually coated with gypsum plaster. Solid brick wall can either be
structural or non-structural members of a building. They are considerably cheap in the construction industry. Solid walls
tend to need insulation due to their high level of conductivity and thus, could prove very expensive and may also require
active heating in temperate regions, insulating your solid walls could cut your heating costs considerably, because solid
walls let through twice as much heat as cavity walls do. The good news is they can be insulated.
Figure 4.2.a. solid brick wall.
Image retrieved from: http://www.insulationireland.net/solid_walls.htm
4.3. Cavity walls
A cavity wall is made up of two masonry brick walls running parallel to one another with a space (cavity) between them
of at least 50mm. Masonry bricks are very absorbent, so moisture absorbed by the outer wall as well as from the inside of
the house as from outside. The cavity serves to drain water back out through weep holes at the base of the wall system or
above windows. The weep holes allow wind to create an air stream through the cavity and the stream removes evaporated
water from the cavity to the outside. Usually weep holes are created by intentionally leaving several vertical joints, also
open head joints, open about two meters apart at the base of in every story. Weep holes are also placed above windows to
prevent dry rot of a wooden window frame. A cavity wall with masonry as both inner and outer skins is more commonly
referred to as a double Wythe masonry wall. Typically drains through the cavity, rather than coming into the home,
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helping to prevent damp issues. This type of wall construction became the norm in the 1930s superseding solid walls and
as time has gone on, the size of the cavity between the two skins of brick has continued to grow – a typical cavity wall
now is between 280-300mm thick.
The skins are commonly masonry such as brick or concrete block. Masonry is an absorbent material, and therefore will
slowly draw rainwater or even humidity into the wall, A home can lose as much as 35% of its heat through uninsulated
external walls. Therefore, if these can be insulated, the home retains heat better, which means lower energy bills. The
concept of insulating a cavity wall is really very simple – it involves filling the cavity between the two skins of
masonry bricks with an insulating material, which slows the movement of heat through the wall.
Figure 4.3.a. cavity wall. Figure 4.3.b. insulation of cavity wall.
Images retrieved from: http://www.iqbuildersmerchant.com/ursa-fg-032-cavity-insulation-2023-p.asp & http://www.keep
warmltd.co.uk/cavity-wall-insulation.html
5. COMPARISON
5.1. Results
What is the cost difference?
Many people get a shock when they hear the cost of solid wall insulation. It is a very labor intensive, material rich job that
takes weeks rather than hours to properly install. Cavity wall insulation can be done in a few hours on an equivalent
property, and the cost is an order of magnitude lower. £5-8 per square meter for cavity wall compared to £100 per square
meter for solid wall insulation. Unfortunately, you can’t choose between the two, it depends on the build type of your
property as to the type of insulation you will need. Below is a typical example of the cost of installing insulation for
Cavity wall and Conventional solid wall in the United Kingdom;
SOLID BRICK WALL
Table 5.1.a. typical gas-heated home. All data obtained from the energy saving trust (EST).
Solid wall insulation
Type of property Insulation cost Savings per year CO2 savings per year (kg)
Detached house (4
bedrooms)
Between £ 5,000 and £
18,000
£ 455 1,900
Semi-detached house (3
bedrooms)
Between £ 5,000 and £
18,000
£ 260 1,100
Mid-terrace house (3
bedrooms)
Between £ 5,000 and £
18,000
£ 175 720
Detached bungalow (2
bedrooms)
Between £ 5,000 and £
18,000
£ 180 740
Mid-floor flat (2
bedrooms)
Between £ 5,000 and £
18,000
£ 145 610
Table retrieved from: http://www.which.co.uk/reviews/insulation/article/solid-wall-insulation/solid-wall-insulation-costs-
and-savings.
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CAVITY WALL
Table 5.1.b. typical gas-heated home. All data obtained from the energy saving trust (EST).
Cavity wall insulation
Type of property Insulation cost Savings per year CO2 savings per year (kg)
Detached house (4 bedrooms) £ 720 £ 272 1,100
Semi-detached house (3
bedrooms)
£ 475 £ 160 650
Mid-terrace house (3 bedrooms) £ 370 £ 105 430
Detached bungalow (2
bedrooms)
£ 430 £ 110 450
Mid-floor flat (2 bedrooms) £ 330 £ 90 360
Table retrieved from: http://www.which.co.uk/reviews/insulation/article/cavity-wall-insulation/cavity-wall-insulation-
costs-and-savings
5.2. Advantages and disadvantages
Advantages:
Solid brick walls
• Economical (raw material is easily available).
• Durable.
• Low maintenance required.
• Easy demolition when required.
• Reusable and recyclable.
• High fire resistance.
• Produces less environmental pollution during manufacturing process.
Cavity wall
• Diameter size advantage.
• Heat loss reduction.
• Mold prevention.
• Lower energy bills.
• There is no possibility of the moisture travelling from the outer wall to the inner wall.
• These have good sound insulation property.
Disadvantages:
Solid brick wall
• Time consuming construction.
• Cannot be used in high seismic zones.
• Since bricks absorb water easily, it causes fluorescence when not exposed to air.
• Very less tensile strength.
• Rough surfaces of bricks may cause mold growth if not properly cleaned.
• Cleaning brick surfaces is a hard job.
• Color of low quality brick changes when exposed to sun for a long period of time.
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Cavity wall
• Construction cost.
• Shoddy work.
• Possible insulation restriction.
• Not applicable to all construction types.
• Heavy in weight.
• Can only be used in exterior walls.
6. CONCLUSION
Wall insulation is always worth it in the long term, once you factor in the savings you will make annually on cooling and
heating. From all the above data, analysis, research, study and comparison, cavity walls are more ideal when constructing
a building in temperate regions. Cavity walls are more thermal resistant in comparison to solid brick walls. Solid walls in
temperate regions are less ideal due to their less thermal resistance and prom to moisture plus easy weathering of wall
assembly. Solid walls in temperate regions still need a form of thermal control which will result in either extra cost of
insulation installation or active thermal control measures (HVAC) which incurs high heating costs. Therefore, when it
comes to building construction in temperate regions, cavity walls are a better option, cavity walls insulate not just
thermally by also acoustically. Cavity walls are also more feasible and cost effective because they slash active thermal
control cost by over 65% annually. The UK government through the energy saving trust (EST) is holding seminars to
advice on the issue of energy efficient buildings to reduce the rate of carbon emission and the ideal walls for buildings are
also cavity walls. Cavity walls are the ideal choice when it comes to building construction in the UK which is a temperate
region and all other temperate regions too.
REFERENCES
[1] Francis D.K. Ching (1943). Building construction illustrated, fifth edition, Hoboken, New Jersey, Published by John
Wiley & Sons, Inc. ISBN 978-1-118-45834-1 (pbk.)
[2] Z. Yilmaz (2007) Evaluation of energy efficient design strategies for different climate zones; comparison of thermal
performance of buildings in temperate-humid and hot-dry climates. Energy and Building 39 (2007)
[3] N. Cardinale, G. Rospi & A. Stazi (2010) Energy and Microclimatic performance of restored hypogenous buildings
in south Italy; the “Sassi” district of Metera. Building and Environment. (2010)
[4] F. Stazi, C. Di Perna & P. Munafo (2009) Durability of 20-years-old external insulation and assessment of various
types of retrofitting to meet new energy regulations. Energy and Building 41 (2009)
[5] Energy Saving Trust UK (2012). Save energy at home. Retrieved from. http://www.energysavingtrust.org.uk/
[6] Paula Owen (2010). Powering a nation. Dartmouth, London Retrieved from. http://www.energysaving
trust.org.uk/sites/default/files/reports/PoweringthenationreportCO332.pdf
[7] S. Martin, F. R. Mazarron & I. Canas (2010) Study of thermal environment inside rural houses of Navapalos
(Spain); The advantages of reuse buildings of high thermal inertia. Construction and Building Materials 24 (2010)
[8] English Housing Survey (2012) English Housing Survey Headline Report 2012-2013, Department for Communities
and Local Government. Eland House Bressenden Place, London. SW1E 5DU. ISBN: 978-1-4098-4152-4