Heat gain - Revision history

Designing Buildings at 08:33, 2 November 2020

2020-11-02T08:33:48Z

← Older revision		Revision as of 08:33, 2 November 2020
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	* U-value.		* U-value.

−	[[Category:Theory]] [[Category:Design]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Theory]] [[Category:Design]]

Designing Buildings at 15:52, 10 February 2020

2020-02-10T15:52:56Z

← Older revision		Revision as of 15:52, 10 February 2020
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	* Heat stress.		* Heat stress.
	* Heat transfer.		* Heat transfer.
		+	* Incidental room heat gains.
	* Insulation.		* Insulation.
	* k-value.		* k-value.
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	* Trombe wall.		* Trombe wall.
	* U-value.		* U-value.
−	* U-value conventions in practice:

	[[Category:Theory]] [[Category:Design]]		[[Category:Theory]] [[Category:Design]]

62.255.8.59 at 10:49, 23 September 2019

2019-09-23T10:49:19Z

← Older revision		Revision as of 10:49, 23 September 2019
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	Heat gain is the term given to a temperature rise within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.		Heat gain is the term given to a temperature rise within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.

−	Heat gain can be positive, for example providing 'free' heating to spaces on sunny but cold days, or it can be negative, overheating spaces in the summer so that they are uncomfortable to ~~occuppy~~.	+	Heat gain can be positive, for example providing 'free' heating to spaces on sunny but cold days, or it can be negative, overheating spaces in the summer so that they are uncomfortable to occupy.

	= Contributory factors =		= Contributory factors =

Editor at 16:29, 1 April 2019

2019-04-01T16:29:44Z

← Older revision		Revision as of 16:29, 1 April 2019
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	= Introduction =		= Introduction =

−	Heat gain is the term given to a temperature rise ~~(or reduction in temperature fall)~~ within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.	+	Heat gain is the term given to a temperature rise within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.

	Heat gain can be positive, for example providing 'free' heating to spaces on sunny but cold days, or it can be negative, overheating spaces in the summer so that they are uncomfortable to occuppy.		Heat gain can be positive, for example providing 'free' heating to spaces on sunny but cold days, or it can be negative, overheating spaces in the summer so that they are uncomfortable to occuppy.

Designing Buildings at 10:14, 28 February 2019

2019-02-28T10:14:58Z

← Older revision		Revision as of 10:14, 28 February 2019
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	* Active thermal mass.		* Active thermal mass.
−	* ASHRAE
	* Ground energy options.		* Ground energy options.
	* Heat loss.		* Heat loss.
		+	* Heat stress.
	* Heat transfer.		* Heat transfer.
	* Insulation.		* Insulation.
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	* Passive building design.		* Passive building design.
	* Thermal admittance.		* Thermal admittance.
		+	* Thermal comfort.
	* Trombe wall.		* Trombe wall.
	* U-value.		* U-value.

Designing Buildings at 10:14, 28 February 2019

2019-02-28T10:14:30Z

← Older revision		Revision as of 10:14, 28 February 2019
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	Heat gain is the term given to a temperature rise (or reduction in temperature fall) within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.		Heat gain is the term given to a temperature rise (or reduction in temperature fall) within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.
		+
		+	Heat gain can be positive, for example providing 'free' heating to spaces on sunny but cold days, or it can be negative, overheating spaces in the summer so that they are uncomfortable to occuppy.

	= Contributory factors =		= Contributory factors =
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	A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the cooling systems.		A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the cooling systems.

−	In calculating the heat gain within a property, for instance when sizing an air conditioning system, engineers must assess the orientation of the building ~~and factor-in~~ the ~~specific solar heat gains (windows on the west~~ and ~~east elevations will receive more solar radiation than those on the north elevation)~~, type of occupation.	+	In calculating the heat gain within a property, for instance when sizing an air conditioning system, engineers must assess the orientation of the building, the nature of its construction, size and location of windows, type of occupation and so on.

	Various features can be used to limit solar heat gain, including:		Various features can be used to limit solar heat gain, including:

−	* ~~Horizontal shading~~	+	* Shading systems.
−	* Limiting the area of openings.	+	* Limiting the number or area of openings.
	* Orientating openings away from the sun path.		* Orientating openings away from the sun path.
	* Reducing solar transmittance through openings, for example, by reflective glazing.		* Reducing solar transmittance through openings, for example, by reflective glazing.
−	* ~~Using ventilation to lower heat gains~~.	+	* Ventilation.
	* Insulating the building envelope to prevent the transmission of indirect solar gains (ie through external walls).		* Insulating the building envelope to prevent the transmission of indirect solar gains (ie through external walls).
	* Reducing the solar absorptance of the building envelope (eg white-coloured surfaces can reduce heat transfer into buildings).		* Reducing the solar absorptance of the building envelope (eg white-coloured surfaces can reduce heat transfer into buildings).
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	* Planting to provide shading and to reduce the solar absorption of roofs.		* Planting to provide shading and to reduce the solar absorption of roofs.

−	In an office environment, calculating the mechanical cooling required will have to ~~predict~~ the ~~heat gains not only from solar radiation and people, but also from a potential~~ plethora of plug-in devices such as computers, monitors, photocopiers, projectors, electric kettles and ~~microwave ovens~~. The heat load from this sort of equipment (‘plug loads’) has been estimated by ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers) as constituting between 20-50% of the energy used by a building.	+	In an office environment, calculating the mechanical cooling required will have to consider the plethora of plug-in devices such as computers, monitors, photocopiers, projectors, electric kettles and microwaves and so on. The heat load from this sort of equipment (‘plug loads’) has been estimated by ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers) as constituting between 20-50% of the energy used by a building.

−	The opposite of heat gain is heat loss, which is the heat that is lost through the fabric of the building when the external air temperature is lower than inside the building. The heat is lost through the external walls, floors and roof (and through inefficient doors and windows~~) by a process called ‘heat transfer’~~. A similar process may be seen in adjacent apartments, where heat transfer will occur in winter through the party walls from one that is heated to an adjacent apartment that has been left unheated.	+	The opposite of heat gain is heat loss, which is the heat that is lost through the fabric of the building when the external air temperature is lower than inside the building. The heat is lost through the external walls, floors and roof, and through inefficient doors and windows and other openings. A similar process may be seen in adjacent apartments, where heat transfer will occur in winter through the party walls from one that is heated to an adjacent apartment that has been left unheated.
		+
		+	Part L of the building regulations, 'Conservation of fuel and power', sets liminting parameters on the construction of buildings, their airtightness, the amount of glazing, insulation, power consumption and so on to limit unwanted heat gains.

	= Related articles on Designing Buildings Wiki =		= Related articles on Designing Buildings Wiki =
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	* U-value.		* U-value.
	* U-value conventions in practice:		* U-value conventions in practice:
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−	{\|
−	\|
−
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	[[Category:Theory]] [[Category:Design]]		[[Category:Theory]] [[Category:Design]]

Designing Buildings at 10:04, 28 February 2019

2019-02-28T10:04:22Z

← Older revision		Revision as of 10:04, 28 February 2019
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	= Introduction =		= Introduction =

−	Heat gain is the term given to ~~the~~ temperature rise within a space ~~owing~~ to ~~the~~ heat from the sun (solar radiation) ~~and the~~ heat ~~radiated by~~ sources within the space, such as heating appliances, ovens, people, mechanical systems, lights and computers. ~~In other words, it~~ is the heat that is gained from ~~various~~ sources that ~~is added to~~ the prevailing temperature within the space~~. The exchange of heat seen in these examples will take place by conduction, convection and radiation~~.	+	Heat gain is the term given to a temperature rise (or reduction in temperature fall) within a space due to heat from the sun (solar radiation), heat from surfaces (long wave infrared radiation), heat originating from other sources within the space (such as heating appliances, ovens, people, mechanical systems, lights and computers) and so on. It is the heat that is gained from such sources that changes the prevailing temperature within the space.

	= Contributory factors =		= Contributory factors =

−	A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the ~~air conditioning system~~.	+	A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the cooling systems.

−	In calculating the heat gain within a property, for instance when sizing an air conditioning system, engineers must assess the orientation of the building and factor-in the specific solar heat gains: windows on the west and east elevations will receive more solar radiation than those on the north elevation.	+	In calculating the heat gain within a property, for instance when sizing an air conditioning system, engineers must assess the orientation of the building and factor-in the specific solar heat gains (windows on the west and east elevations will receive more solar radiation than those on the north elevation), type of occupation.

	Various features can be used to limit solar heat gain, including:		Various features can be used to limit solar heat gain, including:

Editor at 17:37, 19 February 2019

2019-02-19T17:37:43Z

← Older revision		Revision as of 17:37, 19 February 2019
Line 6:		Line 6:

	Heat gain is the term given to the temperature rise within a space owing to the heat from the sun (solar radiation) and the heat radiated by sources within the space, such as heating appliances, ovens, people, mechanical systems, lights and computers. In other words, it is the heat that is gained from various sources that is added to the prevailing temperature within the space. The exchange of heat seen in these examples will take place by conduction, convection and radiation.		Heat gain is the term given to the temperature rise within a space owing to the heat from the sun (solar radiation) and the heat radiated by sources within the space, such as heating appliances, ovens, people, mechanical systems, lights and computers. In other words, it is the heat that is gained from various sources that is added to the prevailing temperature within the space. The exchange of heat seen in these examples will take place by conduction, convection and radiation.
		+
		+	= Contributory factors =

	A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the air conditioning system.		A south-facing conservatory, for instance, in an uninhabited house may see considerable solar heat gains on a daily basis, particularly in summer, but no heat gains from heating appliances and people. In contrast, a north-facing room in winter may receive very little solar heat gains but be warmed by considerable heat from central heating, lights and people. Generally, excessive heat gains will create overheating which may have to be tempered by opening a door or window or activating the air conditioning system.

Editor at 17:36, 19 February 2019

2019-02-19T17:36:04Z

← Older revision		Revision as of 17:36, 19 February 2019
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	{\|		{\|
−	\| [[File:~~Heat gain~~.jpg]]	+	\| [[File:Heat_gain.jpg\|link=File:Heat_gain.jpg]]
	\|}		\|}

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	* Planting to provide shading and to reduce the solar absorption of roofs.		* Planting to provide shading and to reduce the solar absorption of roofs.

−	In an office environment, calculating the mechanical cooling required will have to predict the heat gains not only from solar radiation and people, but also from a potential plethora of plug-in devices such as computers, monitors, photocopiers, projectors, electric kettles and microwave ovens. The heat load from this sort of equipment (‘plug loads’) has been estimated by ASHRAE as constituting between 20-50% of the energy used by a building.	+	In an office environment, calculating the mechanical cooling required will have to predict the heat gains not only from solar radiation and people, but also from a potential plethora of plug-in devices such as computers, monitors, photocopiers, projectors, electric kettles and microwave ovens. The heat load from this sort of equipment (‘plug loads’) has been estimated by ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers) as constituting between 20-50% of the energy used by a building.

	The opposite of heat gain is heat loss, which is the heat that is lost through the fabric of the building when the external air temperature is lower than inside the building. The heat is lost through the external walls, floors and roof (and through inefficient doors and windows) by a process called ‘heat transfer’. A similar process may be seen in adjacent apartments, where heat transfer will occur in winter through the party walls from one that is heated to an adjacent apartment that has been left unheated.		The opposite of heat gain is heat loss, which is the heat that is lost through the fabric of the building when the external air temperature is lower than inside the building. The heat is lost through the external walls, floors and roof (and through inefficient doors and windows) by a process called ‘heat transfer’. A similar process may be seen in adjacent apartments, where heat transfer will occur in winter through the party walls from one that is heated to an adjacent apartment that has been left unheated.

Editor at 17:29, 19 February 2019

2019-02-19T17:29:42Z

← Older revision		Revision as of 17:29, 19 February 2019
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	{\|		{\|
−	\|	+	\| [[File:Heat gain.jpg]]
−		+
	\|}		\|}