An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside di...An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external wall/roof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2.展开更多
Building energy efficiency is a key factor in reducing CO_(2) emissions.For this reason,European Union(EU)member states have developed thermal regulations to ensure building thermal performance.These results are often...Building energy efficiency is a key factor in reducing CO_(2) emissions.For this reason,European Union(EU)member states have developed thermal regulations to ensure building thermal performance.These results are often based on results achieved with building simulation software during the design stage.However,the actual thermal performance can deviate significantly from the predicted one,and this difference is known as the energy performance gap.Accurate indicators of the actual thermal performance are a valuable tool to guarantee building quality.These indicators,including the heat transfer coefficient(HTC)and the heat loss coefficient(HLC),can be estimated by the application of in situ methods.As multi-family housing and tertiary sector buildings are an important part of the building stock,mature methods to measure their thermal performance are needed.This paper presents a short-duration method for assessing the HTC in large building typologies using a sampling approach.The method was applied in a four-storey building model under different conditions to study the limits of the method and to improve indicator bias and uncertainty.Indicator quality was strongly influenced by the external weather conditions,the temperature variation during the protocol and the heat exchange with the adjacent apartments.Under winter conditions and with stable indoor temperatures,the method had a high accuracy when the protocol was applied for half a day.It is recommended that the protocol be used over two days to improve indicator quality under less favorable test conditions.展开更多
基金Project(51178201) supported by the National Natural Science Foundation of China Project(2011CDB292) supported by the Natural Science Foundation of Hubei Province,China
文摘An active pipe-embedded building envelope, which is an external wall or roof with pipes embedded inside, was presented. This structure may utilize the circulating water in the pipe to transfer heat or coolth inside directly. This kind of structure is named ＂active pipe-embedded building envelope＂ due to dealing with the thermal energy actively inside the structure mass by circulating water. This structure not only deals with thermal energy before the external disturbance becomes cooling/heating load by using the circulating water, but also may use low-grade energy sources such as evaporative cooling, solar energy, and geothermal energy. In the meantime, this structure can also improve the indoor thermal comfort by tempering the internal wall surface temperature variation due to the thermal removal in the mass. This work further presents the thermal performance of this structure under a typical hot summer weather condition by comparing it with that of the conventional external wall/roof with numerical simulation. The results show that this pipe-embedded structure may reduce the external heat transfer significantly and reduce the internal wall surface temperature for improving thermal comfort. This work also presents the effects of the water temperature and the pipe spacing on the heat transfer of this structure. The internal surface heat transfer may reduce by about 2.6 W/mE when the water temperature reduces by 1℃ as far as a brick wall with pipes embedded inside is concerned. When the pipe spacing reduces by 50 mm, the internal wall surface heat flux can also reduce by about 2.3 W/m2.
基金This work has received support from CSTB and the French PROFEEL program,which is under the Certificate of Energy Savings framework。
文摘Building energy efficiency is a key factor in reducing CO_(2) emissions.For this reason,European Union(EU)member states have developed thermal regulations to ensure building thermal performance.These results are often based on results achieved with building simulation software during the design stage.However,the actual thermal performance can deviate significantly from the predicted one,and this difference is known as the energy performance gap.Accurate indicators of the actual thermal performance are a valuable tool to guarantee building quality.These indicators,including the heat transfer coefficient(HTC)and the heat loss coefficient(HLC),can be estimated by the application of in situ methods.As multi-family housing and tertiary sector buildings are an important part of the building stock,mature methods to measure their thermal performance are needed.This paper presents a short-duration method for assessing the HTC in large building typologies using a sampling approach.The method was applied in a four-storey building model under different conditions to study the limits of the method and to improve indicator bias and uncertainty.Indicator quality was strongly influenced by the external weather conditions,the temperature variation during the protocol and the heat exchange with the adjacent apartments.Under winter conditions and with stable indoor temperatures,the method had a high accuracy when the protocol was applied for half a day.It is recommended that the protocol be used over two days to improve indicator quality under less favorable test conditions.
