Ground energy options - Revision history

Editor at 16:50, 30 April 2021

2021-04-30T16:50:42Z

← Older revision		Revision as of 16:50, 30 April 2021
Line 88:		Line 88:
	* Heat gain.		* Heat gain.
	* Heat pumps.		* Heat pumps.
		+	* Ring circuit.
	* Thermal labyrinths.		* Thermal labyrinths.
	* Water source heat map.		* Water source heat map.

Designing Buildings at 08:36, 1 November 2020

2020-11-01T08:36:04Z

← Older revision		Revision as of 08:36, 1 November 2020
Line 97:		Line 97:
	* [http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].		* [http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].

−	[[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 18:15, 12 June 2019

2019-06-12T18:15:23Z

← Older revision		Revision as of 18:15, 12 June 2019
Line 81:		Line 81:
	* Dynamic thermal modelling of closed loop geothermal heat pump systems.		* Dynamic thermal modelling of closed loop geothermal heat pump systems.
	* Earth-to-air heat exchangers.		* Earth-to-air heat exchangers.
		+	* Environmental performance.
	* Geothermal energy.		* Geothermal energy.
	* Geothermal pile foundations.		* Geothermal pile foundations.
Line 96:		Line 97:
	* [http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].		* [http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].

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

Editor at 17:32, 19 February 2019

2019-02-19T17:32:11Z

← Older revision		Revision as of 17:32, 19 February 2019
Line 1:		Line 1:
−
	= Introduction =		= Introduction =

Line 12:		Line 11:
	== Horizontal – closed loop ==		== Horizontal – closed loop ==

−	[[File:~~Horizontal closed loop system~~.jpg\|~~520x235px~~\|~~alt~~=~~Horizontal closed loop system~~.jpg]]	+	[[File:Horizontal_closed_loop_system.jpg\|494px\|link=File:Horizontal_closed_loop_system.jpg]]

	With this variation, the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, pressure drops and to ensure an even heat extraction from the ground.		With this variation, the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, pressure drops and to ensure an even heat extraction from the ground.

	The useable amount of heat or energy is dependent on the following:		The useable amount of heat or energy is dependent on the following:
−	*Solar irradiation for the specific area.	+
−	*Moisture content.	+	* Solar irradiation for the specific area.
−	*Soil type.	+	* Moisture content.
−	*Size of pores.	+	* Soil type.
		+	* Size of pores.

	Extraction rates are generally in the order of 10 W/m2 for dry sandy soil, to over 30 W/m2 for wetter loamy soils. Relatively inexpensive earth moving equipment is required for installation, although costs increase with greater depths. This type of collector is generally used for applications with lower power outputs where there is a large undeveloped area that is easy to excavate.		Extraction rates are generally in the order of 10 W/m2 for dry sandy soil, to over 30 W/m2 for wetter loamy soils. Relatively inexpensive earth moving equipment is required for installation, although costs increase with greater depths. This type of collector is generally used for applications with lower power outputs where there is a large undeveloped area that is easy to excavate.
Line 28:		Line 28:
	A vertical closed-loop system utilises vertical ground heat exchangers or probes that are inserted into specially drilled boreholes up to depths of 150m.		A vertical closed-loop system utilises vertical ground heat exchangers or probes that are inserted into specially drilled boreholes up to depths of 150m.

−	[[File:~~Vertical closed loop system~~.jpg\|~~523x404px~~\|~~alt~~=~~Vertical closed loop system~~.jpg]]	+	[[File:Vertical_closed_loop_system.jpg\|460px\|link=File:Vertical_closed_loop_system.jpg]]

	Extraction rates generally vary between 20 W/m for loose dry substrate to ~80W/m for damper sandstones, granites and basalts.		Extraction rates generally vary between 20 W/m for loose dry substrate to ~80W/m for damper sandstones, granites and basalts.
Line 40:		Line 40:
	In this variation, ground water is extracted direct from the underground water aquifer, eliminating the need for a closed loop ground heat exchanger. The used cooled or heated water can then be returned to the ground via a return well.		In this variation, ground water is extracted direct from the underground water aquifer, eliminating the need for a closed loop ground heat exchanger. The used cooled or heated water can then be returned to the ground via a return well.

−	[[File:~~Vertical open loop system~~.jpg\|~~519x441px~~\|~~alt~~=~~Vertical open loop system~~.jpg]]	+	[[File:Vertical_open_loop_system.jpg\|504px\|link=File:Vertical_open_loop_system.jpg]]

	Prior to the consideration of such a configuration, it is necessary to contact the Environmental Agency, initially to gain consent for a pumping test, then for a final abstraction licence for a pumping test, and finally for discharge consent. There is an additional requirement to consider the water quality of the water source, as this can have an adverse effect on the materials used within the heat exchanger.		Prior to the consideration of such a configuration, it is necessary to contact the Environmental Agency, initially to gain consent for a pumping test, then for a final abstraction licence for a pumping test, and finally for discharge consent. There is an additional requirement to consider the water quality of the water source, as this can have an adverse effect on the materials used within the heat exchanger.
Line 46:		Line 46:
	= Feasibility and Evaluation =		= Feasibility and Evaluation =

−	== ~~'''~~Generic guidelines for ground energy systems~~'''~~ ==	+	== Generic guidelines for ground energy systems ==

	=== Start considering the technology at an early stage in the project. ===		=== Start considering the technology at an early stage in the project. ===
−	*Complete a ground energy desktop survey to establish the suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.	+
−	*Establish the spatial limitations around the building.	+	* Complete a ground energy desktop survey to establish the suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.
−	*What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?	+	* Establish the spatial limitations around the building.
		+	* What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?

	=== Optimise the heating and cooling building circuits. ===		=== Optimise the heating and cooling building circuits. ===
−	*Use high temperature cooling where possible (eg chilled beams and air based systems with over sized heat exchangers).
−	*Use low temperature heat emitters (large radiators, underfloor heating and air based systems with oversized heat exchangers).
−	*Simultaneous heating and cooling can be provided from the same heat pump unit.

−	== ~~'''~~Closed loop do’s~~'''~~ ==	+	* Use high temperature cooling where possible (eg chilled beams and air based systems with over sized heat exchangers).
−	*For larger commercial systems, ie greater than ~100kW, a thermal conductivity test is advisable to confirm the insitu thermal properties.	+	* Use low temperature heat emitters (large radiators, underfloor heating and air based systems with oversized heat exchangers).
−	*Carry out a desktop simulation using recognised software to ensure long-term performance can be guaranteed.	+	* Simultaneous heating and cooling can be provided from the same heat pump unit.
−	*Ensure boreholes are spaced adequately to reduce thermal interference.	+
−	*Try to balance heat abstraction and rejection to the ground.	+	== Closed loop do’s ==
−	*Consider using less expensive conventional plant for infrequent heating and cooling loads and/or higher relative seasonal heating and cooling loads.	+
		+	* For larger commercial systems, ie greater than ~100kW, a thermal conductivity test is advisable to confirm the insitu thermal properties.
		+	* Carry out a desktop simulation using recognised software to ensure long-term performance can be guaranteed.
		+	* Ensure boreholes are spaced adequately to reduce thermal interference.
		+	* Try to balance heat abstraction and rejection to the ground.
		+	* Consider using less expensive conventional plant for infrequent heating and cooling loads and/or higher relative seasonal heating and cooling loads.
		+
		+	== Open loop do’s ==

−	~~== '''Open loop do’s''' ==~~	+	* For almost all open loop systems, Environment Agency (EA) approval is needed for both abstraction and discharge of ground or surface water.
−	*For almost all open loop systems, Environment Agency (EA) approval is needed for both abstraction and discharge of ground or surface water.	+	* A pumping test will be needed to confirm the yield and to get permission from the EA to abstract and discharge a specified volume of water per hour/day/year.
−	*A pumping test will be needed to confirm the yield and to get permission from the EA to abstract and discharge a specified volume of water per hour/day/year.	+	* Start the process to obtain an abstraction licence and discharge consent as early as possible, as this process can take eight to nine months in the UK.
−	*Start the process to obtain an abstraction licence and discharge consent as early as possible, as this process can take eight to nine months in the UK.	+

−	----	+	-----
		+	This article was created by --[[User:Buro_Happold\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.

−	~~This article was created by --[[User%3ABuro%20Happold\|Buro Happold]], 17 March 2013, based~~ on ~~a 2008 article in 'Patterns'.~~	+	= Related articles on Designing Buildings Wiki =

−	~~= Find out more =~~	+	* Dynamic thermal modelling of closed loop geothermal heat pump systems.
		+	* Earth-to-air heat exchangers.
		+	* Geothermal energy.
		+	* Geothermal pile foundations.
		+	* Ground preconditioning of supply air.
		+	* Ground source heat pumps.
		+	* Heat gain.
		+	* Heat pumps.
		+	* Thermal labyrinths.
		+	* Water source heat map.
		+	* Water source heat pump.

−	==~~= Related articles on Designing Buildings Wiki ===~~	+	= External references =
−	*Dynamic thermal modelling of closed loop geothermal heat pump systems.	+
−	*Earth-to-air heat exchangers.	+
−	*Geothermal energy.	+
−	*Geothermal pile foundations.	+
−	*Ground preconditioning of supply air.	+
−	*Ground source heat pumps.	+
−	*Heat pumps.	+
−	*Thermal labyrinths.	+
−	*Water source heat map.	+
−	*Water source heat pump.	+

−	~~=== External references ===~~	+	* [http://www.icax.co.uk/Heat_Pumps.html icax, Heat Pumps].
−	*[http://www.icax.co.uk/Heat_Pumps.html icax, Heat Pumps].	+	* [http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].
−	*[http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].	+

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

Designing Buildings at 15:43, 10 October 2014

2014-10-10T15:43:59Z

← Older revision		Revision as of 15:43, 10 October 2014
Line 83:		Line 83:
	*Ground preconditioning of supply air.		*Ground preconditioning of supply air.
	*Ground source heat pumps.		*Ground source heat pumps.
		+	*Heat pumps.
	*Thermal labyrinths.		*Thermal labyrinths.
−	*Water source heat map.~~External references~~	+	*Water source heat map.
		+	*Water source heat pump.

−	[http://www.icax.co.uk/Heat_Pumps.html Heat Pumps]	+	=== External references ===
−		+	*[http://www.icax.co.uk/Heat_Pumps.html icax, Heat Pumps].
−	[http://www.icax.co.uk/Mean_Annual_Air_Temperature.html Mean annual air temperature]	+	*[http://www.icax.co.uk/Mean_Annual_Air_Temperature.html icax, Mean annual air temperature].

	[[Category:Sustainability]]		[[Category:Sustainability]]
	[[Category:Products_/_components]]		[[Category:Products_/_components]]

Edward Thompson at 08:18, 23 September 2014

2014-09-23T08:18:23Z

← Older revision		Revision as of 08:18, 23 September 2014
Line 2:		Line 2:
	= Introduction =		= Introduction =

−	Below a depth of approximately ~~7-10m~~, the temperature of ~~the~~ ground remains fairly constant at the mean ~~ambient~~ air temperature ~~regardless of~~ the ~~time of~~ year. Depending on the location and depth this temperature is typically between 7 and ~~13ºC~~ in the UK. This means that it can be used to as a heat source in the winter and as a source of coolth in the summer.	+	Below a depth of approximately 6m, the temperature of undisturbed ground remains fairly constant at the mean annual air temperature throughout the year. Depending on the location and depth this temperature is typically between 9 and 12ºC in the UK. This means that the ground can be used to as a heat source in the winter and as a source of coolth in the summer.

	In general, the use of ground energy to provide heating and cooling in buildings requires equipment (heat pumps). The energy can be transferred to this equipment using a ground heat exchanger (closed loop system). This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates the possibility of freezing at the lower end of the application’s seasonal temperature range. An alternative system is to abstract and discharge ground water (open loop systems) from an aquifer beneath the building.		In general, the use of ground energy to provide heating and cooling in buildings requires equipment (heat pumps). The energy can be transferred to this equipment using a ground heat exchanger (closed loop system). This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates the possibility of freezing at the lower end of the application’s seasonal temperature range. An alternative system is to abstract and discharge ground water (open loop systems) from an aquifer beneath the building.
Line 84:		Line 84:
	*Ground source heat pumps.		*Ground source heat pumps.
	*Thermal labyrinths.		*Thermal labyrinths.
−	*Water source heat map.	+	*Water source heat map.External references
		+
		+	[http://www.icax.co.uk/Heat_Pumps.html Heat Pumps]
		+
		+	[http://www.icax.co.uk/Mean_Annual_Air_Temperature.html Mean annual air temperature]

	[[Category:Sustainability]]		[[Category:Sustainability]]
	[[Category:Products_/_components]]		[[Category:Products_/_components]]

Designing Buildings at 10:19, 29 August 2014

2014-08-29T10:19:10Z

← Older revision		Revision as of 10:19, 29 August 2014
Line 72:		Line 72:
	----		----

−	This article was created by --[[User~~:Buro_Happold~~\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.	+	This article was created by --[[User%3ABuro%20Happold\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.

	= Find out more =		= Find out more =
Line 84:		Line 84:
	*Ground source heat pumps.		*Ground source heat pumps.
	*Thermal labyrinths.		*Thermal labyrinths.
		+	*Water source heat map.

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

Designing Buildings at 05:49, 26 May 2014

2014-05-26T05:49:30Z

← Older revision		Revision as of 05:49, 26 May 2014
Line 72:		Line 72:
	----		----

−	This article was created by [[User~~%3ABuro%20Happold~~\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.	+	This article was created by --[[User:Buro_Happold\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.

	= Find out more =		= Find out more =

Designing Buildings at 13:23, 18 March 2013

2013-03-18T13:23:10Z

Alex Harvie at 11:31, 18 March 2013

2013-03-18T11:31:42Z

← Older revision		Revision as of 11:31, 18 March 2013
Line 2:		Line 2:
	= Introduction =		= Introduction =

−	Throughout the year the ground absorbs solar energy ~~and below~~ a depth of approximately 7-10m the temperature remains fairly constant at the mean ambient air temperature regardless of the time of year. Depending on the location and depth this temperature can vary, typically, ~~from~~ 7-13ºC in the UK. In general, the use of ground energy to provide heating and cooling in building requires equipment (heat pumps) to upgrade the temperature of the source temperature to a more useful temperature level using additional energy.	+	Throughout the year the ground absorbs different amounts of solar energy, however it is only the upper level of the ground which is affected. Below a depth of approximately 7-10m, the temperature remains fairly constant at the mean ambient air temperature regardless of the time of year. Depending on the location and depth this temperature can vary, typically, between 7 and 13ºC in the UK.

−	~~The~~ energy ~~can be transferred~~ to ~~this~~ equipment ~~using a ground~~ heat ~~exchanger (closed loop systems~~)~~. This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates~~ the ~~possibility~~ of ~~freezing within~~ the ~~application’s seasonal~~ temperature ~~range. The alternative is~~ to ~~abstract and discharge ground water (open loop systems) from an aquifer beneath the building~~.	+	In general, the use of ground energy to provide heating and cooling in building requires equipment (heat pumps) to upgrade the temperature of the source temperature to a more useful temperature level using additional energy.

−	In the case of the closed loop system the energy in the ground is, if the ground loop is sized appropriately, replenished by solar irradiation, rain and, sometimes, for deeper vertical collector systems, underground water flow. With open loop systems it is necessary to consider the sustainable yield available from the wells.	+	The energy can be transferred to this equipment using a ground heat exchanger (closed loop system). This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates the possibility of freezing at the lower end of the application’s seasonal temperature range. An alternative system is to abstract and discharge ground water (open loop systems) from an aquifer beneath the building.
		+
		+	In the case of the closed loop system, the energy in the ground is (if the ground loop is sized appropriately) replenished by solar irradiation, rain and, sometimes, for deeper vertical collector systems, underground water flow. With open loop systems it is necessary to consider the sustainable yield available from the wells.

	= Variations of ground energy =		= Variations of ground energy =
Line 14:		Line 16:
	[[File:Horizontal closed loop system.jpg\|520x235px\|alt=Horizontal closed loop system.jpg]]		[[File:Horizontal closed loop system.jpg\|520x235px\|alt=Horizontal closed loop system.jpg]]

−	With this variation the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, pressure drops and to ensure an even heat extraction from the ground.	+	With this variation, the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, eliminate pressure drops and to ensure an even heat extraction from the ground.

	The useable amount of heat or energy is dependent on the following:		The useable amount of heat or energy is dependent on the following:
	*Solar irradiation for the specific area.		*Solar irradiation for the specific area.
	*Moisture content.		*Moisture content.
−	*Soil type	+	*Soil type.
	*Size of pores.		*Size of pores.

Line 34:		Line 36:
	The useable heat or energy is dependent on similar factors to the horizontal system although more specialist geological analysis is generally needed. Deeper test-bores can ascertain the type and depth of each soil/rock layer, the heat transfer potential for the different layers over the length of the borehole, the presence and height of water table and underground water flow.		The useable heat or energy is dependent on similar factors to the horizontal system although more specialist geological analysis is generally needed. Deeper test-bores can ascertain the type and depth of each soil/rock layer, the heat transfer potential for the different layers over the length of the borehole, the presence and height of water table and underground water flow.

−	Due to the requirement for a test bore this type of system lends itself to larger applications where the initial testing costs can be justified. The data gathered ~~help~~ to reduce risk during the design stage as non-optimum sizing has serious cost implications.	+	Due to the requirement for a test bore, this type of system lends itself to larger applications where the initial testing costs can be justified. The data gathered helps to reduce risk during the design stage as non-optimum sizing has serious cost implications.

	== Vertical – open loop ==		== Vertical – open loop ==

−	In this variation ground water is extracted direct from the underground water aquifer, eliminating the need for a closed loop ground heat exchanger. The used cooled or heated water can then be returned to the ground via a return well.	+	In this variation, ground water is extracted direct from the underground water aquifer, eliminating the need for a closed loop ground heat exchanger. The used cooled or heated water can then be returned to the ground via a return well.

	[[File:Vertical open loop system.jpg\|519x441px\|alt=Vertical open loop system.jpg]]		[[File:Vertical open loop system.jpg\|519x441px\|alt=Vertical open loop system.jpg]]

−	Prior to the consideration of such a configuration it is necessary to contact the Environmental Agency, initially to gain consent for a pumping test, ~~and~~ then for a final abstraction licence for a pumping test, and ~~then~~ for discharge consent. There is an additional requirement to consider the water quality of the water source as this can have an adverse effect on the materials used within the heat exchanger.	+	Prior to the consideration of such a configuration, it is necessary to contact the Environmental Agency, initially to gain consent for a pumping test, then for a final abstraction licence for a pumping test, and finally for discharge consent. There is an additional requirement to consider the water quality of the water source, as this can have an adverse effect on the materials used within the heat exchanger.

	= Feasibility and Evaluation =		= Feasibility and Evaluation =
Line 49:		Line 51:

	=== Start considering the technology at an early stage in the project. ===		=== Start considering the technology at an early stage in the project. ===
−	*Complete a ground energy desktop survey to establish the suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.	+	*Complete a ground energy desktop survey to establish the relative suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.
	*Establish the spatial limitations around the building.		*Establish the spatial limitations around the building.
	*What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?		*What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?
Line 55:		Line 57:
	=== Optimise the heating and cooling building circuits. ===		=== Optimise the heating and cooling building circuits. ===
	*Use high temperature cooling where possible (eg chilled beams and air based systems with over sized heat exchangers).		*Use high temperature cooling where possible (eg chilled beams and air based systems with over sized heat exchangers).
−	*Use low temperature heat emitters (large radiators, underfloor heating and air based systems with ~~over sized~~ heat exchangers).	+	*Use low temperature heat emitters (large radiators, underfloor heating and air based systems with oversized heat exchangers).
	*Simultaneous heating and cooling can be provided from the same heat pump unit.		*Simultaneous heating and cooling can be provided from the same heat pump unit.

Line 66:		Line 68:

	== '''Open loop do’s''' ==		== '''Open loop do’s''' ==
−	*For almost all open loop systems Environment Agency (EA) approval is needed for both abstraction and discharge of ground or surface water.	+	*For almost all open loop systems, Environment Agency (EA) approval is needed for both abstraction and discharge of ground or surface water.
	*A pumping test will be needed to confirm the yield and to get permission from the EA to abstract and discharge a specified volume of water per hour/day/year.		*A pumping test will be needed to confirm the yield and to get permission from the EA to abstract and discharge a specified volume of water per hour/day/year.
−	*Start the process to obtain an abstraction licence and discharge consent as early as possible (this process can take ~~from~~ eight to nine months in the UK).	+	*Start the process to obtain an abstraction licence and discharge consent as early as possible, as this process can take eight to nine months in the UK.

	----		----

−	This article was created by [[User~~:Buro_Happold~~\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.	+	This article was created by [[User%3ABuro%20Happold\|Buro Happold]], 17 March 2013, based on a 2008 article in 'Patterns'.

	= Find out more =		= Find out more =

← Older revision		Revision as of 13:23, 18 March 2013
Line 2:		Line 2:
	= Introduction =		= Introduction =

−	~~Throughout the year the ground absorbs different amounts of solar energy, however it is only the upper level of the ground which is affected.~~ Below a depth of approximately 7-10m, the temperature remains fairly constant at the mean ambient air temperature regardless of the time of year. Depending on the location and depth this temperature ~~can vary,~~ typically, between 7 and 13ºC in the UK.	+	Below a depth of approximately 7-10m, the temperature of the ground remains fairly constant at the mean ambient air temperature regardless of the time of year. Depending on the location and depth this temperature is typically between 7 and 13ºC in the UK. This means that it can be used to as a heat source in the winter and as a source of coolth in the summer.

−	In general, the use of ground energy to provide heating and cooling in ~~building~~ requires equipment (heat pumps) ~~to upgrade the temperature of the source temperature to a more useful temperature level using additional energy~~.	+	In general, the use of ground energy to provide heating and cooling in buildings requires equipment (heat pumps). The energy can be transferred to this equipment using a ground heat exchanger (closed loop system). This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates the possibility of freezing at the lower end of the application’s seasonal temperature range. An alternative system is to abstract and discharge ground water (open loop systems) from an aquifer beneath the building.
−		+
−	The energy can be transferred to this equipment using a ground heat exchanger (closed loop system). This usually comprises a number of pipe loops, vertical or horizontal, with a primary process medium of water, or more normally a glycol solution which eliminates the possibility of freezing at the lower end of the application’s seasonal temperature range. An alternative system is to abstract and discharge ground water (open loop systems) from an aquifer beneath the building.	+

	In the case of the closed loop system, the energy in the ground is (if the ground loop is sized appropriately) replenished by solar irradiation, rain and, sometimes, for deeper vertical collector systems, underground water flow. With open loop systems it is necessary to consider the sustainable yield available from the wells.		In the case of the closed loop system, the energy in the ground is (if the ground loop is sized appropriately) replenished by solar irradiation, rain and, sometimes, for deeper vertical collector systems, underground water flow. With open loop systems it is necessary to consider the sustainable yield available from the wells.
Line 16:		Line 14:
	[[File:Horizontal closed loop system.jpg\|520x235px\|alt=Horizontal closed loop system.jpg]]		[[File:Horizontal closed loop system.jpg\|520x235px\|alt=Horizontal closed loop system.jpg]]

−	With this variation, the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, ~~eliminate~~ pressure drops and to ensure an even heat extraction from the ground.	+	With this variation, the energy or heat is transferred to the building using a series of ground collectors, laid horizontally at a depth of 1.5-2m. Each pipe run should be limited to 100m to avoid the need for more powerful circulation pumps. Pipe runs would normally be the same length to guarantee similar flow conditions, pressure drops and to ensure an even heat extraction from the ground.

	The useable amount of heat or energy is dependent on the following:		The useable amount of heat or energy is dependent on the following:
Line 51:		Line 49:

	=== Start considering the technology at an early stage in the project. ===		=== Start considering the technology at an early stage in the project. ===
−	*Complete a ground energy desktop survey to establish the ~~relative~~ suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.	+	*Complete a ground energy desktop survey to establish the suitability of the geology and hydrogeology underneath the site to different types of ground energy systems. Suitable sources include the British Geological Survey and site specific Geotechnical Investigation reports.
	*Establish the spatial limitations around the building.		*Establish the spatial limitations around the building.
	*What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?		*What is the indicative foundation design and is it suitable to act as part of the ground energy heat exchanger?