Thermal storage for cooling - Revision history

Designing Buildings at 08:01, 7 November 2020

2020-11-07T08:01:30Z

← Older revision		Revision as of 08:01, 7 November 2020
Line 59:		Line 59:
	* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]		* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.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]]

Designing Buildings at 10:40, 12 February 2020

2020-02-12T10:40:52Z

← Older revision		Revision as of 10:40, 12 February 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 ===	+

	* Dynamic thermal modelling of closed loop geothermal heat pump systems.		* Dynamic thermal modelling of closed loop geothermal heat pump systems.
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	* Thermal labyrinths.		* Thermal labyrinths.
	* Thermal mass.		* Thermal mass.
−	* ~~Valves~~.	+	* Thermal storage for cooling.

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

	* Calmac [http://www.calmac.com/ http://www.calmac.com/]		* Calmac [http://www.calmac.com/ http://www.calmac.com/]
Line 61:		Line 59:
	* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]		* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]

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

Designing Buildings at 15:33, 11 January 2018

2018-01-11T15:33:45Z

← Older revision		Revision as of 15:33, 11 January 2018
Line 60:		Line 60:
	* Cryogel [http://www.cryogel.com/ http://www.cryogel.com/]		* Cryogel [http://www.cryogel.com/ http://www.cryogel.com/]
	* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]		* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]
−	* Evapco [http://www.evapco.com/ http://www.evapco.com]

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

Editor at 12:32, 6 July 2017

2017-07-06T12:32:46Z

← Older revision		Revision as of 12:32, 6 July 2017
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−
	= Introduction =		= Introduction =

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	Chillers that will be used to build ice as well as directly cool loads should be specified with electronic expansion valves rather than mechanical thermal expansion valves to enable easy switching between evaporator temperature set points. This is a bigger issue with smaller, non-VFD chillers (variable frequency drive) and modular chillers where a TXV (thermal expansion valve) will be the standard.		Chillers that will be used to build ice as well as directly cool loads should be specified with electronic expansion valves rather than mechanical thermal expansion valves to enable easy switching between evaporator temperature set points. This is a bigger issue with smaller, non-VFD chillers (variable frequency drive) and modular chillers where a TXV (thermal expansion valve) will be the standard.

−	Wet bulb temperatures vary over a narrower range than dry bulb temperatures so with water-cooled systems the carbon benefits are seen on the electric utility side where efficient base load powerplants shoulder a higher load than inefficient "peaking" power plants.	+	Wet bulb temperatures vary over a narrower range than dry bulb temperatures so with water-cooled systems the carbon benefits are seen on the electric utility side where efficient base load powerplants shoulder a higher load than inefficient "peaking" power plants.

	Ice storage is not applicable to absorbers. Ice storage may however be applied in parallel with absorbers. Chilled water storage may be applicable to absorbers which are waste heat fired absorbers. Solar fired absorbers are probably not the best application for storage unless a design were to be considered without any other refrigeration technology. It might be more efficient to store the excess energy in such a system as heated fluid before it is used by the absorbers.		Ice storage is not applicable to absorbers. Ice storage may however be applied in parallel with absorbers. Chilled water storage may be applicable to absorbers which are waste heat fired absorbers. Solar fired absorbers are probably not the best application for storage unless a design were to be considered without any other refrigeration technology. It might be more efficient to store the excess energy in such a system as heated fluid before it is used by the absorbers.
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	The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night, this also simplifies control as there is no simultaneous ice building and direct cooling. An example of a load profile is shown below.		The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night, this also simplifies control as there is no simultaneous ice building and direct cooling. An example of a load profile is shown below.

−	[[File:~~Load profile building breakdown august~~.jpg\|~~707x429px\|alt~~=~~Load profile building breakdown august~~.jpg]]	+	[[File:Load_profile_building_breakdown_august.jpg\|link=File:Load_profile_building_breakdown_august.jpg]]

−	[[File:~~Thermal storage system operation~~.jpg\|~~730x443px\|alt~~=~~Thermal storage system operation~~.jpg]]	+	[[File:Thermal_storage_system_operation.jpg\|link=File:Thermal_storage_system_operation.jpg]]

	The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.		The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.
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	The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a 24 hour operating building it will be closer to 50%.		The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a 24 hour operating building it will be closer to 50%.

−	[[File:~~Ice storage operation load profile~~.jpg\|~~441x356px\|alt~~=~~Ice storage operation load profile~~.jpg]]	+	[[File:Ice_storage_operation_load_profile.jpg\|link=File:Ice_storage_operation_load_profile.jpg]]

	In terms of overall energy savings, they are most effective when using air cooled chillers when there is a peak diurnal range of at least 10°C. Another good way to improve efficiency is to harness a large delta T; use the chillers to precool the water at a higher than usual temperature 15-8° and then go through ice to go from 8-3. This means that the chiller operates at more favourable conditions. Then consider the operating savings connected to fans and pumps. This means the overall savings are not easy to predict without a significant amount of detail, but with air cooled chillers there will be savings.		In terms of overall energy savings, they are most effective when using air cooled chillers when there is a peak diurnal range of at least 10°C. Another good way to improve efficiency is to harness a large delta T; use the chillers to precool the water at a higher than usual temperature 15-8° and then go through ice to go from 8-3. This means that the chiller operates at more favourable conditions. Then consider the operating savings connected to fans and pumps. This means the overall savings are not easy to predict without a significant amount of detail, but with air cooled chillers there will be savings.
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	All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.		All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.

−	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which would be difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.~~<br/>~~	+	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which would be difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.

−	----	+	-----
−		+	This article was created by --[[User:Buro_Happold\|Buro Happold]].
−	This article was created by --[[User~~%3ABuro%20Happold~~\|Buro Happold]].	+

	= Find out more =		= Find out more =

	=== Related articles on Designing Buildings Wiki ===		=== Related articles on Designing Buildings Wiki ===
−	*Dynamic thermal modelling of closed loop geothermal heat pump systems.	+
−	*Earth-to-air heat exchangers.	+	* Dynamic thermal modelling of closed loop geothermal heat pump systems.
−	*Geothermal energy.	+	* Earth-to-air heat exchangers.
−	*Geothermal pile foundations.	+	* Geothermal energy.
−	*Ground energy options.	+	* Geothermal pile foundations.
−	*Ground pre-conditioning of supply air.	+	* Ground energy options.
−	*Ground source heat pumps.	+	* Ground pre-conditioning of supply air.
−	*Night-time purging.	+	* Ground source heat pumps.
−	*Phase change materials.	+	* Night-time purging.
−	*Thermal labyrinths.~~<br/>~~	+	* Phase change materials.
−	*Thermal mass.	+	* Thermal labyrinths.
		+	* Thermal mass.
		+	* Valves.

	=== External references ===		=== External references ===
−	*Calmac [http://www.calmac.com/ http://www.calmac.com/]
−	*Cryogel [http://www.cryogel.com/ http://www.cryogel.com/]
−	*Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]
−	*Evapco [http://www.evapco.com/ http://www.evapco.com]

−	[[Category:Sustainability]]	+	* Calmac [http://www.calmac.com/ http://www.calmac.com/]
−	[[Category:Products_/_components]]	+	* Cryogel [http://www.cryogel.com/ http://www.cryogel.com/]
		+	* Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]
		+	* Evapco [http://www.evapco.com/ http://www.evapco.com]
		+
		+	[[Category:Sustainability]] [[Category:Products_/_components]]

Designing Buildings at 10:25, 3 November 2014

2014-11-03T10:25:12Z

← Older revision		Revision as of 10:25, 3 November 2014
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	----		----

−	This article was created by --[[User~~:Buro_Happold~~\|Buro Happold]].	+	This article was created by --[[User%3ABuro%20Happold\|Buro Happold]].

	= Find out more =		= Find out more =
Line 50:		Line 50:
	*Ground pre-conditioning of supply air.		*Ground pre-conditioning of supply air.
	*Ground source heat pumps.		*Ground source heat pumps.
−	*Phase change materials	+	*Night-time purging.
−	*Thermal labyrinths<br/>	+	*Phase change materials.
		+	*Thermal labyrinths.<br/>
		+	*Thermal mass.

	=== External references ===		=== External references ===
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	*Evapco [http://www.evapco.com/ http://www.evapco.com]		*Evapco [http://www.evapco.com/ http://www.evapco.com]

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

Designing Buildings at 06:31, 28 May 2014

2014-05-28T06:31:21Z

← Older revision		Revision as of 06:31, 28 May 2014
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	----		----

−	~~[[File:Buro-happold-logo.jpg\|139x180px]]<br/>~~	+	This article was created by --[[User:Buro_Happold\|Buro Happold]].
−		+
−	This article was created by [~~http~~:~~//www.burohappold.com/~~ Buro Happold]. ~~<br/>~~	+

	= Find out more =		= Find out more =

Designing Buildings at 14:05, 23 July 2013

2013-07-23T14:05:38Z

← Older revision		Revision as of 14:05, 23 July 2013
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	All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.		All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.

−	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which would be difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.	+	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which would be difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.<br/>
		+
		+	----
		+
		+	[[File:Buro-happold-logo.jpg\|139x180px]]<br/>
		+
		+	This article was created by [http://www.burohappold.com/ Buro Happold]. <br/>

	= Find out more =		= Find out more =

Designing Buildings at 07:57, 23 July 2013

2013-07-23T07:57:19Z

← Older revision		Revision as of 07:57, 23 July 2013
Line 54:		Line 54:
	*Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]		*Balitomore Air Coil [http://www.baltimoreaircoil.com/ http://www.baltimoreaircoil.com/]
	*Evapco [http://www.evapco.com/ http://www.evapco.com]		*Evapco [http://www.evapco.com/ http://www.evapco.com]
−	*Ice Energy [http://www.-ice-energy.com/ http://www.-ice-energy.com] (DX ice storage for packaged DX rooftop units)

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

Designing Buildings at 07:56, 23 July 2013

2013-07-23T07:56:32Z

← Older revision		Revision as of 07:56, 23 July 2013
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	= Ice storage sizing =		= Ice storage sizing =

−	The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night ~~where there need for thermal storage for cooling (~~this also simplifies control as there is no simultaneous ice building and direct cooling). An example of a load profile is shown below.	+	The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night, this also simplifies control as there is no simultaneous ice building and direct cooling. An example of a load profile is shown below.

	[[File:Load profile building breakdown august.jpg\|707x429px\|alt=Load profile building breakdown august.jpg]]		[[File:Load profile building breakdown august.jpg\|707x429px\|alt=Load profile building breakdown august.jpg]]
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	The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.		The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.

−	In this case, there were four ice chillers each at around 3800kW arranged in modules, which is how they achieve the simultaneous cooling and ice building at 0:00. Thus the ice chillers ran during the day; the glycol did not affect the COP (coefficient of performance) too much as they ran at normal temperatures during the day. The capacity was derated due to the heat transfer reduction of the glycol, but the actual efficiency may only have reduced by about 10%. When they reduced to operate in night mode the output was always be derated, usually around 60% but the efficiency again was still be good because of the cooler night time temperatures.	+	In this case, there were four ice chillers each at around 3800kW arranged in modules, which is how they achieve the simultaneous cooling and ice building at 0:00. Thus the ice chillers ran during the day; the glycol did not affect the COP (coefficient of performance) too much as they ran at normal temperatures during the day. The capacity was derated due to the heat transfer reduction of the glycol, but the actual efficiency may only have reduced by about 10%. When they reduced to operate in night mode the output was always derated, usually around 60% but the efficiency again was still good because of the cooler night time temperatures.

−	The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a ~~24hour~~ operating building it will be closer to 50%.	+	The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a 24 hour operating building it will be closer to 50%.

	[[File:Ice storage operation load profile.jpg\|441x356px\|alt=Ice storage operation load profile.jpg]]		[[File:Ice storage operation load profile.jpg\|441x356px\|alt=Ice storage operation load profile.jpg]]
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	All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.		All of this assumes the use of a peak lopping system which gives optimum capital expenditure (capex). Using a full storage system is more efficient as all cooling occurs at night but the capex is much higher as there will generally need to be more chillers than a conventional system in addition to the ice.

−	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.	+	Finally in terms of space, ice storage systems don’t save huge amounts on the central plant, the ice tanks do need space but the chiller farm size is reduced (which would be difficult to hide architecturally). This is particularly true for large air-cooled plants. There are then space savings from the large delta T and low temperature which reduces ducts/pipes and airhandling plant.

	= Find out more =		= Find out more =

Designing Buildings at 07:50, 23 July 2013

2013-07-23T07:50:53Z

← Older revision		Revision as of 07:50, 23 July 2013
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	= Introduction =		= Introduction =

−	Ice can be used as an effective means of thermal storage, storing ‘coolth’ in colder parts of the day to ~~be used~~ during warmer parts of the day. Thermal storage for cooling can be a useful way of achieving efficiency and carbon ~~emissions~~ reductions in climates with wide daily temperature variations, especially in areas where water is not available for heat rejection. It can also be a useful way of gaining utility incentives and reducing peak demand charges.	+	Ice can be used as an effective means of thermal storage, storing ‘coolth’ in colder parts of the day to provide cooling during warmer parts of the day. Thermal storage for cooling can be a useful way of achieving efficiency and carbon emission reductions in climates with wide daily temperature variations, especially in areas where water is not available for heat rejection. It can also be a useful way of gaining utility incentives and reducing peak demand charges.

	= Design considerations =		= Design considerations =
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	Ice storage is not applicable to absorbers. Ice storage may however be applied in parallel with absorbers. Chilled water storage may be applicable to absorbers which are waste heat fired absorbers. Solar fired absorbers are probably not the best application for storage unless a design were to be considered without any other refrigeration technology. It might be more efficient to store the excess energy in such a system as heated fluid before it is used by the absorbers.		Ice storage is not applicable to absorbers. Ice storage may however be applied in parallel with absorbers. Chilled water storage may be applicable to absorbers which are waste heat fired absorbers. Solar fired absorbers are probably not the best application for storage unless a design were to be considered without any other refrigeration technology. It might be more efficient to store the excess energy in such a system as heated fluid before it is used by the absorbers.

−	= Ice storage sizing~~: suggested methodology / practical example~~ =	+	= Ice storage sizing =

	The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night where there need for thermal storage for cooling (this also simplifies control as there is no simultaneous ice building and direct cooling). An example of a load profile is shown below.		The total installed chiller capacity (both glycol and conventional) for an ice system should be around 65% of the total peak cooling load. This will however depend entirely on the load profile. The purpose of using conventional chillers is to meet the base load ie the consistent load that exists right through the night where there need for thermal storage for cooling (this also simplifies control as there is no simultaneous ice building and direct cooling). An example of a load profile is shown below.

−	[[File:Load profile building breakdown august.jpg\|707x429px]]	+	[[File:Load profile building breakdown august.jpg\|707x429px\|alt=Load profile building breakdown august.jpg]]

−	[[File:Thermal storage system operation.jpg\|730x443px]]	+	[[File:Thermal storage system operation.jpg\|730x443px\|alt=Thermal storage system operation.jpg]]

	The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.		The blue represents the baseload chiller. The nature of the buildings means that the night time load is a very small percentage of the peak load and so in this case, there is only one conventional baseload chiller rated at 3900kW. The purple/mauve colour represents the glycol (ice) chillers in charging mode, building ice. The light blue represents the glycol chillers operating in direct cool mode, the dark blue is then the ice being harvested to meet the peak load.
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	The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a 24hour operating building it will be closer to 50%.		The split between baseload and ice chillers is highly dependent upon load profile but it will range typically from around 25-50% baseload chiller. For a 24hour operating building it will be closer to 50%.

−	[[File:Ice storage operation load profile.jpg\|441x356px]]	+	[[File:Ice storage operation load profile.jpg\|441x356px\|alt=Ice storage operation load profile.jpg]]

	In terms of overall energy savings, they are most effective when using air cooled chillers when there is a peak diurnal range of at least 10°C. Another good way to improve efficiency is to harness a large delta T; use the chillers to precool the water at a higher than usual temperature 15-8° and then go through ice to go from 8-3. This means that the chiller operates at more favourable conditions. Then consider the operating savings connected to fans and pumps. This means the overall savings are not easy to predict without a significant amount of detail, but with air cooled chillers there will be savings.		In terms of overall energy savings, they are most effective when using air cooled chillers when there is a peak diurnal range of at least 10°C. Another good way to improve efficiency is to harness a large delta T; use the chillers to precool the water at a higher than usual temperature 15-8° and then go through ice to go from 8-3. This means that the chiller operates at more favourable conditions. Then consider the operating savings connected to fans and pumps. This means the overall savings are not easy to predict without a significant amount of detail, but with air cooled chillers there will be savings.