Fenestration systems are widely used across the world.There is expansive research on window configurations,frames,and glazing technology,but not enough research has been published on reducing window heat loss through ...Fenestration systems are widely used across the world.There is expansive research on window configurations,frames,and glazing technology,but not enough research has been published on reducing window heat loss through heat application to a pane.The presented study attempted to evaluate the performance of heated windows by developing an experimental setup to test a window at various temperatures by varying the power input to thewindow.Heated double pane window was installed in an insulated box.Atemperature gradient was developed across the window by cooling one side of the window using gel-based ice packs.The other face of the window was heated by enabling power at different wattages through the window.The temperature of the inside and outside panes,current and voltage input,and temperature of the room and box were recorded.The data was used to calculate the apparent effective resistance of the window when not being heated vs.when being heated.The study concluded that,when window temperature was maintained close to the room temperature,the heated double pane window is effective in reducing heat loss by as much as 50%as compared to a non-heated double pane window.When temperature of the window was much higher than the room temperature,the heat loss through the window increased beyond that of a non-heated window.The issues encountered during the current stages of experiments are noted,and recommendations are provided for future studies.展开更多
Accurate prediction of thermal radiation by applying rigorous model for the radiative heat transfer combined with the conduction and the convection has been performed for a single and double window glazing subjected t...Accurate prediction of thermal radiation by applying rigorous model for the radiative heat transfer combined with the conduction and the convection has been performed for a single and double window glazing subjected to solar and thermal irradiation. The glass window is analysed as a non-gray plane-parallel medium disctritized to thin layer as-suming the glass material as participating media in one-dimensional case, using the Radiation Element Method by Ray Emission Model (REM2). The model allows the calculation of the steady-state heat flux and the temperature distribution within the glass cover. The spectral dependence of the relevant radiation properties of glass (i.e. specular reflectivity, refraction angle and absorption coefficient) is taken into account. Both solar and thermal incident irradiations are applied at the boundary surfaces using the spectral solar model proposed by Bird and Riordan. The optical constant of a commercial clear glass material have been used. The calculation has been performed during winter period and the effect of the thickness of the glass for a single glazing and of the air layer between the two panels for double glazing has been studied. The result shows that increasing the air layer, the steady heat flux decreases and the temperature distribution within the glass changes.展开更多
Infrared window in hypersonic missile usually suffers complex aerodynamic force/heat during high-speed flight.A finite element method was adopted to simulate the thermal and stress response of microscale functional fi...Infrared window in hypersonic missile usually suffers complex aerodynamic force/heat during high-speed flight.A finite element method was adopted to simulate the thermal and stress response of microscale functional film for infrared window under different aerodynamic heats/forces conditions.Temperature and stress distribution were obtained with different heat fluxes.There is almost constant stress distribution along the film thickness except a sudden decrease near the substrate.The maximum stresses are located at the points which are 0.3 mm away from the edges.Different film materials result in different stress values.The temperature and stress in ZrN are larger than those in Y2O3.Besides the numerical simulation,an oxygen propane flame jet impingement test was performed to investigate thermal shock failure of the infrared window.Some place of the window surface has spots damage and some place has line crack damage after thermal shock.展开更多
Thermodel for Windows是一个在结构上由盆地尺度上的古温标热历史正、反演和岩石圈尺度上的盆地构造-热演化模拟两部分构成。通过对Thermodel for Windows系统模拟方法的研究及其主要组件的功能和数据的输入方法等的了解,分析了本系统...Thermodel for Windows是一个在结构上由盆地尺度上的古温标热历史正、反演和岩石圈尺度上的盆地构造-热演化模拟两部分构成。通过对Thermodel for Windows系统模拟方法的研究及其主要组件的功能和数据的输入方法等的了解,分析了本系统的优缺点。通过对沁水盆地Tl003号孔的实例研究,介绍了利用镜质体反射率(R0)反演非稳态热状态条件下盆地的热流史和地层的剥蚀量,进而重建盆地内地层热历史的工作方法和技巧。对盆地地热史软件的进一步开发和盆地地热演化史的研究具有较大的应用意义。展开更多
It is introduced the current situation and development for solar heating technology including passive solar heating and solar heating combisystems in China in this paper. Combined with the engineering application proj...It is introduced the current situation and development for solar heating technology including passive solar heating and solar heating combisystems in China in this paper. Combined with the engineering application projects, the author gave the technical and economic analysis of the passive solar and solar heating combisystems in China and summarized the developing obstacle and the spreading tactics for raising marketing of the solar heating in China.展开更多
INTRODUCTION With respect to thermal performance, windows are the weakest component of the building envelope, essentially because the U-value is usually higher than the opaque envelope. This would allow the highest he...INTRODUCTION With respect to thermal performance, windows are the weakest component of the building envelope, essentially because the U-value is usually higher than the opaque envelope. This would allow the highest heat conductance of the building envelope. However, it also helps buildings to gain useful solar heat during winter. Therefore, it has been generally accepted that passive buildings would have small windows towards the poles and large windows facing the equator (Persson, Roos, and Wall 2006). In spite of this guideline, large or fully glazed facades have been used in modern architecture. The intensive use of air conditioning is the result of overheating and high thermal loss problems, which otherwise would lead to thermal discomfort. This extensive use of large windows associated with high energy consumption has motivated researchers to study this building component. Window areas were investigated by Persson et al. (Persson, Roos, and Wall 2006) on 20 terraced houses with larger windows facing the equator and built in Gothenburg. The building envelope was well insulated and fitted with energy efficient windows. It was found that energy efficient windows do not have a major influ-ence on the heating demand in the winter, but it is relevant for the cooling need in summer. Therefore, reduced indoor illuminance due to small windows can be solved by enlarging them in order to obtain relevant daylighting conditions. When efficient windows are designed for a warm climate, as in Mexico, reducing heat flux and solar transmittance indoors was the best option for energy savings (Aguilar et al. 2017). However, reducing solar transmittance influences the indoor illuminance, which was not analyzed.展开更多
INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same...INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same area of a typical 2×6 wall.It makes sense to upgrade or insulate windows in order to improve the thermal envelope of a home,especially in an area with a long heating season;however,windows are a very expensive component of the building envelope to replace.Replacing a single window can cost several hundred to more than a thousand dollars;therefore,people often resort to cheaper methods to reduce heat loss,such as shutters or curtains.Others may already have high-performance windows,but want to reduce heat loss even further by placing movable insulation over their windows during the cold winter nights.To help guide these decisions,the Cold Climate Housing Research Center(CCHRC)in Fairbanks,Alaska,conducted a study of common window insulation methods and compared them in terms of thermal effectiveness,affordability,ease of installation,durability,functionality,and condensation resistance.The purpose of the study was to inform homeowners about the various advantages and disadvantages of different window treatments.As part of the research,CCHRC studied a variety of methods and windows in volunteers’homes to understand how the methods work in real-life situations.CCHRC also modeled the retrofit window treatments with Therm 6.3,a modeling program,to help explain more generally how they can help homeowners.展开更多
基金This research work was funded in part by the Industrial Assessment Center Project,supported by grants from the US Department of Energy and by the West Virginia Development Office.
文摘Fenestration systems are widely used across the world.There is expansive research on window configurations,frames,and glazing technology,but not enough research has been published on reducing window heat loss through heat application to a pane.The presented study attempted to evaluate the performance of heated windows by developing an experimental setup to test a window at various temperatures by varying the power input to thewindow.Heated double pane window was installed in an insulated box.Atemperature gradient was developed across the window by cooling one side of the window using gel-based ice packs.The other face of the window was heated by enabling power at different wattages through the window.The temperature of the inside and outside panes,current and voltage input,and temperature of the room and box were recorded.The data was used to calculate the apparent effective resistance of the window when not being heated vs.when being heated.The study concluded that,when window temperature was maintained close to the room temperature,the heated double pane window is effective in reducing heat loss by as much as 50%as compared to a non-heated double pane window.When temperature of the window was much higher than the room temperature,the heat loss through the window increased beyond that of a non-heated window.The issues encountered during the current stages of experiments are noted,and recommendations are provided for future studies.
文摘Accurate prediction of thermal radiation by applying rigorous model for the radiative heat transfer combined with the conduction and the convection has been performed for a single and double window glazing subjected to solar and thermal irradiation. The glass window is analysed as a non-gray plane-parallel medium disctritized to thin layer as-suming the glass material as participating media in one-dimensional case, using the Radiation Element Method by Ray Emission Model (REM2). The model allows the calculation of the steady-state heat flux and the temperature distribution within the glass cover. The spectral dependence of the relevant radiation properties of glass (i.e. specular reflectivity, refraction angle and absorption coefficient) is taken into account. Both solar and thermal incident irradiations are applied at the boundary surfaces using the spectral solar model proposed by Bird and Riordan. The optical constant of a commercial clear glass material have been used. The calculation has been performed during winter period and the effect of the thickness of the glass for a single glazing and of the air layer between the two panels for double glazing has been studied. The result shows that increasing the air layer, the steady heat flux decreases and the temperature distribution within the glass changes.
基金Projects (51222205,51372053) supported by the National Natural Science Foundation of ChinaProject (JC201305) supported by Heilongjiang Provincial Science Fund for Distinguished Young Scholars,ChinaProject (20112302110036) supported by Ph.D. Programs Foundation of Ministry of Education of China
文摘Infrared window in hypersonic missile usually suffers complex aerodynamic force/heat during high-speed flight.A finite element method was adopted to simulate the thermal and stress response of microscale functional film for infrared window under different aerodynamic heats/forces conditions.Temperature and stress distribution were obtained with different heat fluxes.There is almost constant stress distribution along the film thickness except a sudden decrease near the substrate.The maximum stresses are located at the points which are 0.3 mm away from the edges.Different film materials result in different stress values.The temperature and stress in ZrN are larger than those in Y2O3.Besides the numerical simulation,an oxygen propane flame jet impingement test was performed to investigate thermal shock failure of the infrared window.Some place of the window surface has spots damage and some place has line crack damage after thermal shock.
文摘Thermodel for Windows是一个在结构上由盆地尺度上的古温标热历史正、反演和岩石圈尺度上的盆地构造-热演化模拟两部分构成。通过对Thermodel for Windows系统模拟方法的研究及其主要组件的功能和数据的输入方法等的了解,分析了本系统的优缺点。通过对沁水盆地Tl003号孔的实例研究,介绍了利用镜质体反射率(R0)反演非稳态热状态条件下盆地的热流史和地层的剥蚀量,进而重建盆地内地层热历史的工作方法和技巧。对盆地地热史软件的进一步开发和盆地地热演化史的研究具有较大的应用意义。
文摘It is introduced the current situation and development for solar heating technology including passive solar heating and solar heating combisystems in China in this paper. Combined with the engineering application projects, the author gave the technical and economic analysis of the passive solar and solar heating combisystems in China and summarized the developing obstacle and the spreading tactics for raising marketing of the solar heating in China.
基金supported by Portuguese national funds,namely FCT-Foundation for Science and Technology within the UID/ECI/04082/2013 project.
文摘INTRODUCTION With respect to thermal performance, windows are the weakest component of the building envelope, essentially because the U-value is usually higher than the opaque envelope. This would allow the highest heat conductance of the building envelope. However, it also helps buildings to gain useful solar heat during winter. Therefore, it has been generally accepted that passive buildings would have small windows towards the poles and large windows facing the equator (Persson, Roos, and Wall 2006). In spite of this guideline, large or fully glazed facades have been used in modern architecture. The intensive use of air conditioning is the result of overheating and high thermal loss problems, which otherwise would lead to thermal discomfort. This extensive use of large windows associated with high energy consumption has motivated researchers to study this building component. Window areas were investigated by Persson et al. (Persson, Roos, and Wall 2006) on 20 terraced houses with larger windows facing the equator and built in Gothenburg. The building envelope was well insulated and fitted with energy efficient windows. It was found that energy efficient windows do not have a major influ-ence on the heating demand in the winter, but it is relevant for the cooling need in summer. Therefore, reduced indoor illuminance due to small windows can be solved by enlarging them in order to obtain relevant daylighting conditions. When efficient windows are designed for a warm climate, as in Mexico, reducing heat flux and solar transmittance indoors was the best option for energy savings (Aguilar et al. 2017). However, reducing solar transmittance influences the indoor illuminance, which was not analyzed.
基金the Alaska Housing Finance Corporation,who provided the funding for this project.
文摘INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same area of a typical 2×6 wall.It makes sense to upgrade or insulate windows in order to improve the thermal envelope of a home,especially in an area with a long heating season;however,windows are a very expensive component of the building envelope to replace.Replacing a single window can cost several hundred to more than a thousand dollars;therefore,people often resort to cheaper methods to reduce heat loss,such as shutters or curtains.Others may already have high-performance windows,but want to reduce heat loss even further by placing movable insulation over their windows during the cold winter nights.To help guide these decisions,the Cold Climate Housing Research Center(CCHRC)in Fairbanks,Alaska,conducted a study of common window insulation methods and compared them in terms of thermal effectiveness,affordability,ease of installation,durability,functionality,and condensation resistance.The purpose of the study was to inform homeowners about the various advantages and disadvantages of different window treatments.As part of the research,CCHRC studied a variety of methods and windows in volunteers’homes to understand how the methods work in real-life situations.CCHRC also modeled the retrofit window treatments with Therm 6.3,a modeling program,to help explain more generally how they can help homeowners.
