Cool roofs - Revision history

Editor: Reverted edits by 123.201.100.254 (talk) to last revision by Editor

2021-08-24T08:06:18Z

Reverted edits by 123.201.100.254 (talk) to last revision by Editor

← Older revision		Revision as of 08:06, 24 August 2021
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	Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.		Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.

−	~~According to [https://reportsanddata.com/report-detail/cool-roof-market ReportsAndData],~~ Cool Roof market is forecasted to grow at a rate of 5.5% from USD 20.49 Billion in 2020 to USD 31.58 billion in 2028. The general application of a roof in a building is that it provides protection from natural elements, but rooftops are becoming a significant source of excessive heat.This is leading to the increasing adoption of cool roofs around the world, as they solve the problem of excessive heat through roofs, which make up around 40% of a building\'s surface. It reflect sunlight and absorb relatively lesser heat than standard roofs.	+	Cool Roof market is forecasted to grow at a rate of 5.5% from USD 20.49 Billion in 2020 to USD 31.58 billion in 2028. The general application of a roof in a building is that it provides protection from natural elements, but rooftops are becoming a significant source of excessive heat.This is leading to the increasing adoption of cool roofs around the world, as they solve the problem of excessive heat through roofs, which make up around 40% of a building\'s surface. It reflect sunlight and absorb relatively lesser heat than standard roofs.

	= Other passive cooling systems =		= Other passive cooling systems =

123.201.100.254 at 07:45, 24 August 2021

2021-08-24T07:45:29Z

← Older revision		Revision as of 07:45, 24 August 2021
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	Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.		Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.

−	Cool Roof market is forecasted to grow at a rate of 5.5% from USD 20.49 Billion in 2020 to USD 31.58 billion in 2028. The general application of a roof in a building is that it provides protection from natural elements, but rooftops are becoming a significant source of excessive heat.This is leading to the increasing adoption of cool roofs around the world, as they solve the problem of excessive heat through roofs, which make up around 40% of a building\'s surface. It reflect sunlight and absorb relatively lesser heat than standard roofs.	+	According to [https://reportsanddata.com/report-detail/cool-roof-market ReportsAndData], Cool Roof market is forecasted to grow at a rate of 5.5% from USD 20.49 Billion in 2020 to USD 31.58 billion in 2028. The general application of a roof in a building is that it provides protection from natural elements, but rooftops are becoming a significant source of excessive heat.This is leading to the increasing adoption of cool roofs around the world, as they solve the problem of excessive heat through roofs, which make up around 40% of a building\'s surface. It reflect sunlight and absorb relatively lesser heat than standard roofs.

	= Other passive cooling systems =		= Other passive cooling systems =

Editor at 15:29, 23 August 2021

2021-08-23T15:29:30Z

← Older revision		Revision as of 15:29, 23 August 2021
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	* Tiwari, G. N., M. Upadhyay, et al. (1994). "A comparison of passive cooling techniques." Building and Environment 29(1): 21-31.		* Tiwari, G. N., M. Upadhyay, et al. (1994). "A comparison of passive cooling techniques." Building and Environment 29(1): 21-31.
	* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]		* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]
−	* Cool Roof Market By Product, By Type (Steep-Slope Roofs, Low-Slope Roofs), And By Application (Residential, Industrial, Commercial), Forecasts To 2028 by [https://reportsanddata.com/report-detail/cool-roof-market Reports and data]<br />
−

	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Sustainability]] [[Category:Products_/_components]]		[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Sustainability]] [[Category:Products_/_components]]

152.57.192.85 at 14:36, 23 August 2021

2021-08-23T14:36:02Z

← Older revision		Revision as of 14:36, 23 August 2021
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	Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.		Rosenfeld, Akbari et al. (1995) suggest that the costs of increasing the albedo of a city are quite low if performed during routine maintenance. Roofs are typically refinished every 10-20 years and cooler roofing material is either already available or can be developed at very little cost. Additionally, they suggest that light coloured surfaces suffer less damage from daily thermal expansion and contraction. UV damage is also reduced as this is caused by free radicals which interact more strongly the warmer the material. Rosenfeld, Akbari et al. (1995) suggest policy steps to implementing cool surfaces and shade trees, some of which have now been achieved with various levels of success since 1995.
		+
		+	Cool Roof market is forecasted to grow at a rate of 5.5% from USD 20.49 Billion in 2020 to USD 31.58 billion in 2028. The general application of a roof in a building is that it provides protection from natural elements, but rooftops are becoming a significant source of excessive heat.This is leading to the increasing adoption of cool roofs around the world, as they solve the problem of excessive heat through roofs, which make up around 40% of a building\'s surface. It reflect sunlight and absorb relatively lesser heat than standard roofs.

	= Other passive cooling systems =		= Other passive cooling systems =
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	* Tiwari, G. N., M. Upadhyay, et al. (1994). "A comparison of passive cooling techniques." Building and Environment 29(1): 21-31.		* Tiwari, G. N., M. Upadhyay, et al. (1994). "A comparison of passive cooling techniques." Building and Environment 29(1): 21-31.
	* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]		* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]
		+	* Cool Roof Market By Product, By Type (Steep-Slope Roofs, Low-Slope Roofs), And By Application (Residential, Industrial, Commercial), Forecasts To 2028 by [https://reportsanddata.com/report-detail/cool-roof-market Reports and data]<br />
		+

	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Sustainability]] [[Category:Products_/_components]]		[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Sustainability]] [[Category:Products_/_components]]

Editor at 17:06, 12 February 2021

2021-02-12T17:06:58Z

← Older revision		Revision as of 17:06, 12 February 2021
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	* Albedo.		* Albedo.
	* Brown roof.		* Brown roof.
		+	* Cool paint.
	* Designing green and blue roofs.		* Designing green and blue roofs.
	* Emissivity.		* Emissivity.

Editor at 17:05, 15 September 2020

2020-09-15T17:05:58Z

← Older revision		Revision as of 17:05, 15 September 2020
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	* Thermal comfort.		* Thermal comfort.
	* Thermal optical properties.		* Thermal optical properties.
		+	* Types of cool roofs.
	* Types of roof.		* Types of roof.
	* Urban heat islands.		* Urban heat islands.

−	=== External references ===	+	= External references =

	* Akbari, H. (2008). "Evolution of cool-roof standards in the United States." Advances in Building Energy Research.		* Akbari, H. (2008). "Evolution of cool-roof standards in the United States." Advances in Building Energy Research.

Designing Buildings at 11:22, 7 September 2020

2020-09-07T11:22:46Z

← Older revision		Revision as of 11:22, 7 September 2020
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	This article was created by --[[User:Buro_Happold\|Buro Happold]].		This article was created by --[[User:Buro_Happold\|Buro Happold]].

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Albedo.		* Albedo.
		+	* Brown roof.
	* Designing green and blue roofs.		* Designing green and blue roofs.
	* Emissivity.		* Emissivity.
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	* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]		* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]

−	[[Category:~~Sustainability~~]] [[Category:~~Products_/_components~~]] [[Category:DCN_Product_Knowledge]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Sustainability]] [[Category:Products_/_components]]

Editor at 17:31, 13 March 2018

2018-03-13T17:31:35Z

← Older revision		Revision as of 17:31, 13 March 2018
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	The main parameters which influence maximum roof surface temperatures are solar absorptance, infrared emittance, and the convection coefficient (Berdahl and Bretz 1997). Roofs that have high solar reflectance (high ability to reflect sunlight) and high thermal emittance (high ability to radiate heat) tend to stay cool in the sun (Akbari, Levinson et al. 2008).		The main parameters which influence maximum roof surface temperatures are solar absorptance, infrared emittance, and the convection coefficient (Berdahl and Bretz 1997). Roofs that have high solar reflectance (high ability to reflect sunlight) and high thermal emittance (high ability to radiate heat) tend to stay cool in the sun (Akbari, Levinson et al. 2008).

−	The colour of roofs can significantly influence the temperatures they reach. The term 'albedo' designates the total reflectance of a specific system. White can be effective in minimising heat transfer into buildings as it is a poor absorber of energy and a good emitter (Al-Homoud 2005). The general idea of white washing structures to reject heat has been known since antiquity (Berdahl and Bretz 1997). However, colour is not always a good indication of the albedo of a surface as it depends not only on visible reflectance but also reflectance of Infra Red (IR) light. For example commonly used 'white' coloured roofing shingles and galvanised steel run 35oC and 43oC hotter than air temperature on a sunny day. Conversely, surfaces painted with red or green acrylic paint run only 22oC hotter, even though they are not visibly bright (Rosenfeld, Akbari et al. 1995). Galvanised mild steel gets hot, not due to its low albedo but because of its low emissivities meaning it is slow to cool by radiation (Rosenfeld, Akbari et al. 1995).	+	The colour of roofs can significantly influence the temperatures they reach. The term 'albedo' designates the total reflectance of a specific system. White can be effective in minimising heat transfer into buildings as it is a poor absorber of energy and a good emitter (Al-Homoud 2005). The general idea of white washing structures to reject heat has been known since antiquity (Berdahl and Bretz 1997).
		+
		+	However, colour is not always a good indication of the albedo of a surface as it depends not only on visible reflectance but also reflectance of Infra Red (IR) light. For example commonly used 'white' coloured roofing shingles and galvanised steel run 35oC and 43oC hotter than air temperature on a sunny day. Conversely, surfaces painted with red or green acrylic paint run only 22oC hotter, even though they are not visibly bright (Rosenfeld, Akbari et al. 1995). Galvanised mild steel gets hot, not due to its low albedo but because of its low emissivities meaning it is slow to cool by radiation (Rosenfeld, Akbari et al. 1995).

	Whilst increasing roof albedo and infrared emittance can reduce energy consumption in hot climates, it may increase heating-energy consumption in winter months or in cooler climates (Akbari, Levinson et al. 2008).		Whilst increasing roof albedo and infrared emittance can reduce energy consumption in hot climates, it may increase heating-energy consumption in winter months or in cooler climates (Akbari, Levinson et al. 2008).
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	= Potential =		= Potential =

−	The focus of research to date has mostly been into the impacts of changing the thermal properties of a roof surface to improve building comfort or decrease building energy use. However, recently there has been interest on increasing world-wide urban albedos to offset CO2 emissions that contribute to global warming. The high albedo of roofs and paved surfaces have the potential to increase the albedo of urban areas by 10%. If this was implemented globally across all urban areas, there would be a negative radiative force equivalent to offsetting 44Gt of CO2 emissions (24Gt by roofs, 20Gt by pavements) (Akbari, Menon et al. 2009). Taking the rate that CO2 was traded at in Europe in 2009, (approximately $25/tonne), this offset would be worth $1,100 billion (Akbari, Menon et al. 2009).	+	The focus of research to date has mostly been into the impacts of changing the thermal properties of a roof surface to improve building comfort or decrease building energy use. However, recently there has been interest on increasing world-wide urban albedos to offset CO2 emissions that contribute to global warming. The high albedo of roofs and paved surfaces have the potential to increase the albedo of urban areas by 10%.
		+
		+	If this was implemented globally across all urban areas, there would be a negative radiative force equivalent to offsetting 44Gt of CO2 emissions (24Gt by roofs, 20Gt by pavements) (Akbari, Menon et al. 2009). Taking the rate that CO2 was traded at in Europe in 2009, (approximately $25/tonne), this offset would be worth $1,100 billion (Akbari, Menon et al. 2009).

	Additional benefits from reducing building temperature and energy use include a reduction in peak power demand meaning that fewer power stations are required. In Los Angeles peak cooling demand increases by 3.0% for every 1oC rise in air temperature above 18oC, and across the US, urban heat islands raise air conditioning demand by about 10GW annually (Rosenfeld, Akbari et al. 1995).		Additional benefits from reducing building temperature and energy use include a reduction in peak power demand meaning that fewer power stations are required. In Los Angeles peak cooling demand increases by 3.0% for every 1oC rise in air temperature above 18oC, and across the US, urban heat islands raise air conditioning demand by about 10GW annually (Rosenfeld, Akbari et al. 1995).
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	* Long span roof.		* Long span roof.
	* Overheating.		* Overheating.
		+	* Pitched roof.
	* Preventing overheating.		* Preventing overheating.
	* Rainwater harvesting.		* Rainwater harvesting.
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	* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]		* US Environmental Protection Agency. (2004). "Energy Star Roofing Comparison Calculator." Retrieved 06/07, 2009, from [http://roofcalc.com/ http://roofcalc.com/]

−	[[Category:Sustainability]] [[Category:Products_/_components]]	+	[[Category:Sustainability]] [[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Designing Buildings at 14:52, 31 October 2017

2017-10-31T14:52:32Z

← Older revision		Revision as of 14:52, 31 October 2017
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	* Albedo.		* Albedo.
		+	* Designing green and blue roofs.
	* Emissivity.		* Emissivity.
	* Flat roof.		* Flat roof.

Designing Buildings at 13:24, 10 January 2017

2017-01-10T13:24:21Z

← Older revision		Revision as of 13:24, 10 January 2017
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	* Thermal comfort.		* Thermal comfort.
	* Thermal optical properties.		* Thermal optical properties.
		+	* Types of roof.
	* Urban heat islands.		* Urban heat islands.