Ground Source Heat Pump - Revision history

Trevor at 10:05, 1 August 2022

2022-08-01T10:05:04Z

Trevor: /* Solar Assisted Ground Source Heat Pump Systems */

2022-08-01T10:03:45Z

‎Solar Assisted Ground Source Heat Pump Systems

Trevor at 09:50, 1 August 2022

2022-08-01T09:50:30Z

Trevor at 15:32, 27 November 2019

2019-11-27T15:32:01Z

Trevor at 15:29, 27 November 2019

2019-11-27T15:29:06Z

Trevor at 15:27, 27 November 2019

2019-11-27T15:27:59Z

Trevor at 15:27, 27 November 2019

2019-11-27T15:27:02Z

Trevor at 15:09, 27 November 2019

2019-11-27T15:09:20Z

Trevor at 15:08, 27 November 2019

2019-11-27T15:08:08Z

Trevor at 15:03, 27 November 2019

2019-11-27T15:03:16Z

@@ Line 53: / Line 53: @@
 Further analysis carried out by Fluke in 2022 shows that a long term steady state system may be achieved by solar heat assistance. In this scenario, heat is recharged into the ground for part of the year to be extracted again during the heating season. The charging and discharging temperatures used in the model are 25°C and 5°C respectively.
-[[File:GSHP2.xlsm_-_Excel_2022-08-01_10-11-17.mp4|frameless|Multi-year temperature distribution, with solar assist]]<br style="clear:both;" />
+[[File:GSHP2.xlsm_-_Excel_2022-08-01_10-11-17.mp4|1600px|frameless|Multi-year temperature distribution, with solar assist]]<br style="clear:both;" />
 == Conclusions ==

@@ Line 53: / Line 53: @@
 Further analysis carried out by Fluke in 2022 shows that a long term steady state system may be achieved by solar heat assistance. In this scenario, heat is recharged into the ground for part of the year to be extracted again during the heating season. The charging and discharging temperatures used in the model are 25°C and 5°C respectively.
-[[File:GSHP2.xlsm_-_Excel_2022-08-01_10-11-17.mp4800px|frameless|Multi-year temperature distribution, with solar assist]]<br style="clear:both;" />
+[[File:GSHP2.xlsm_-_Excel_2022-08-01_10-11-17.mp4|frameless|Multi-year temperature distribution, with solar assist]]<br style="clear:both;" />
 == Conclusions ==

← Older revision		Revision as of 09:50, 1 August 2022
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	[[File:Qchart.png\|800px\|frameless\|Sub-surface temperature distribution, over time]]<br style="clear:both;" />		[[File:Qchart.png\|800px\|frameless\|Sub-surface temperature distribution, over time]]<br style="clear:both;" />
		+
		+	== Solar Assisted Ground Source Heat Pump Systems ==
		+
		+	Further analysis carried out by Fluke in 2022 shows that a long term steady state system may be achieved by solar heat assistance. In this scenario, heat is recharged into the ground for part of the year to be extracted again during the heating season. The charging and discharging temperatures used in the model are 25°C and 5°C respectively.
		+
		+	[[File:GSHP2.xlsm_-_Excel_2022-08-01_10-11-17.mp4800px\|frameless\|Multi-year temperature distribution, with solar assist]]<br style="clear:both;" />

	== Conclusions ==		== Conclusions ==

← Older revision		Revision as of 15:32, 27 November 2019
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	In urban settings the problem would be exacerbated due to the higher property density. In rural environments and for properties with extensive grounds, GSHP may be an appropriate solution		In urban settings the problem would be exacerbated due to the higher property density. In rural environments and for properties with extensive grounds, GSHP may be an appropriate solution

−	The working assumption is that solar gain during summer would be sufficient to recharge the ground with heat ready for the next heating season. This is by no means certain and further study must be made to check if there would be a multi year cooling effect from using GSHP technology	+	The working assumption is that solar gain during summer would be sufficient to "recharge" the ground with heat ready for the next heating season. This is by no means certain and further study must be made to check if there would be a multi year cooling effect from using GSHP technology

@@ Line 23: / Line 23: @@
 &alpha; = 0.0647 m²/day the Thermal Diffusivity for "Coal Measures Group" geology (GeoReports, British Geological Survey)
-Additionally, the house is on a 12 metre x 18 metre plot and has a heating requirement of 12,000 kW-h per year equivalent to the OFGEM Typical Domestic Consumption Value (TDCV) for ''gas'', for a medium size household (the GSHP is providing space heating and domestic hot water in place of a gas boiler). 12,000 kW-h equates to a year-round average demand of 1,370 W; the demand model was further refined to reflect varying seasonal requirements using a 'degree-days' method, explained elsewhere. Also it was assumed that for every 3.5 kW of heat delivered to the house, 2.5 kW came from the ground and 1 kW from the electrical energy to drive the heat pump (coefficient of performance  / COP = 3.5). The case study covers an eight month 'heating season' from October to May. It is a fairly trivial exercise to create a spreadsheet from scratch using the information given above and then one can compare, for example, the times for the subsoil to cool to 7°C at depths 0.5m, 1m, 2m are 7 days, 28 days and 112 days respectively. At 5m depth the temperature never goes below 8°C and at 10m the sub-soil barely drops ½°C. Here is a graph of the results:
+Additionally, the house is on a 12 metre x 18 metre plot and has a heating requirement of 12,000 kW-h per year equivalent to the OFGEM Typical Domestic Consumption Value (TDCV) for ''gas'', for a medium size household (the GSHP is providing space heating and domestic hot water in place of a gas boiler). 12,000 kW-h equates to a year-round average demand of 1,370 W; the demand model was further refined to reflect varying seasonal requirements using a 'degree-days' method, explained elsewhere. Also it was assumed that for every 3.5 kW of heat delivered to the house, 2.5 kW came from the ground and 1 kW from the electrical energy to drive the heat pump (coefficient of performance  / COP = 3.5). The case study covers an eight month 'heating season' from October to May. It is a fairly trivial exercise to create a spreadsheet from scratch using the information given above and then one can compare, for example, the times for the subsoil to cool to 7°C at depths 0.5m, 1m, 2m: 7 days, 28 days and 112 days respectively. At 5m depth the temperature never goes below 8°C and at 10m the sub-soil barely drops ½°C. Here is a graph of the results:
 [[File:TDchart.png|800px|frameless|Sub-surface temperature distribution, over time]]<br style="clear:both;" />

@@ Line 53: / Line 53: @@
 Mass deployment of Ground Source Heat Pumps in a suburban setting would result in inadequate space heating and domestic hot water for the households in the scheme. The area available per property is simply too small
-The findings can be understood in qualitative terms. Initially, at the start of the heating season ground heat is close to the surface but as time progresses the shallower sub-soil cools close to the extraction temperature and heat must then be obtained from deeper into the ground making it harder to extract - just at the same time demand is reaching its winter peak
+The findings can be understood in qualitative terms. Initially, at the start of the heating season demand is low and ground heat is close to the surface, easy to extract. But as time progresses the shallower sub-soil cools close to the extraction temperature and heat must then be obtained from deeper into the ground making it harder to extract - just at the same time demand is reaching its winter peak
 In urban settings the problem would be exacerbated due to the higher property density. In rural environments and for properties with extensive grounds, GSHP may be an appropriate solution
 The working assumption is that solar gain during summer would be sufficient to recharge the ground with heat ready for the next heating season. This is by no means certain and further study must be made to check if there would be a multi year cooling effect from using GSHP technology

@@ Line 51: / Line 51: @@
 == Conclusions ==
-Mass deployment of Ground Source Heat Pumps in a suburban setting would result in inadequate space heating and domestic hot water for the households in the scheme. The area available per property is simply too small.
+Mass deployment of Ground Source Heat Pumps in a suburban setting would result in inadequate space heating and domestic hot water for the households in the scheme. The area available per property is simply too small
 The findings can be understood in qualitative terms. Initially, at the start of the heating season ground heat is close to the surface but as time progresses the temperature profile migrates deeper into the ground making it harder to extract at the same time demand is reaching its winter peak