> Contents1 Reading (UK), 24-25 February 2011

EUROPEAN REGIONALDEVELOPMENT FUND

GROMIT project: GROund coupled heat pumps MITigation potential

Partner 6, Reading Borough Council

Anne Verhoef, on behalf of the GROMIT team

Soil Research Centre, University of Reading

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UoR/NCAS-Climate (Land surface modelling & Fieldwork): Raquel Garcia-Gonzalez, Bruce Main, Pier Luigi Vidale, Anne Verhoef

Nottingham University (Modelling of GCHPs): Guohui Gan, Yupeng Wu

BGS (Groundwater modelling): Majdi Mansour & Andrew Hughes

CEH-Wallingford (UK 1 km driving data): Eleanor Blyth & Jon Finch

EarthEnergy Ltd (GCHP expertise): Robin Curtis

Aim: To investigate and optimise the CO2 mitigation potential of horizontal GCHPs under current and future UK environmental conditions

GROMIT project team

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Infiltration Rates / Evaporation

Energy balance/ground water level; (vary in time and space)

Water (vapour) flux, induced by

heat extraction/rejection

Thermal regime

Thermal soil properties

Soil water freezing/melting

3

Primary source of energy, Rn

Top Boundary conditionRn –(H+LE) = G

Net Thermal Recharge

Ground water Flow

~1.5 m

Heat pump

Horizontal GCHPHeat extraction / Cooling

Lower Boundary conditionFh=0 (T=constant)

Diagram: Heat and water exchange processes near GCHP

G, soil heat flux

H, sensibleheat flux

E, evaporation

Key variables: soil moisture contentand soil temperature

Largely affected by climate, soil texture & vegetation

GCHPs and environmental interactions

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• Model development (combined Land surface-Groundwater-GCHP model

• Experimental campaigns (UK field sites)• Model simulation

– Driving variables (UK 1 km grid)– Verification– Sensitivity - Varying model parameters – Climate change impact – COP under future

environmental conditions– Climate change scenarios (UKCIP)

• Dissemination

Project approach

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Land surface model

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The National soil map, NATMAP (NSRI)

Soil properties such as:

Dry bulk density Hydraulic properties Thermal properties

Soil texture

UK texture maps

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Rainfall Rate (kg m-2 d-1), 1 January 2003

Air Temperature (K) 1 January 2003

Courtesy of: Tongfei Zhang, CEH-Wallingford

UK driving variables

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2 Profiles:-GSHP profile-Reference profile

Measurements:- Bulk density- Water retention curve- Soil temperature- Soil moisture content- Thermal properties)- Inlet/outlet data

slinky

Field measurements

Cooling near the slinky due to heat extraction… how will this affect the water and heat transfer and hence the performance of GSHP

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Some results

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• Long-term performance of horizontal GSHP systems can only be assesed through fully mechanistic models

• This also allows the effect of Climate Change to

be taken into account

• We aim to apply the GROMIT approach on a European-wide scale in a follow-up project

Conclusions/Outlook