Module 3

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Module 3

• Ground Source Heat Pumps

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Plan

• Intro Why and what is a Ground Source Heat Pump
  (GSHP)?
• Advantages of GSHPs
• How a fridge works?
• How a liqui/water heat pump works?
• Works
• Co-efficient of preformance (COP)
• Effficiencies
• Sizing
• Futher information
• Micro CHP

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Why Ground Source Heat Pumps ?

• Relies on fairly constant temperature of the
  ground
• Can be used for heating and cooling
• High capital costs, very low running costs

4
Ground and Air Temperatures
Source Geoscience
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What is a Ground Source Heat Pumps ?
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Advantages of GSHPs

• high reliability (few moving parts, no exposure
  to weather)
• high security (no visible external components to
  be damaged or vandalised)
• long life expectancy (typically 20-25 years and
  up to 50 years for the ground coil)
• low noise
• low maintenance costs (no regular servicing
  requirements)
• no boiler or fuel tank
• no combustion or explosive gases within the
  building
• no flue or ventilation requirements
• no local pollution.

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How a fridge works
Diagram BBT Thermotechnology UK
8
How a liquid/water heat pump works

• Diagram BBT Thermotechnology UK

9
Ground Source Heat Pumps

• Horizontal collectors can be less expensive to
  install but require an area of approximately
  120-150 of the floor area to be heated
• Capital cost around EUR 6 000 per household
  (depending on civils)

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A Typical drilling rig for a borehole based GSHP
installation

• Photo Geoscience

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Trench for a ground loop heat exchanger

• Photo
• Geoscience

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Co-efficient of Performance (COP)
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Efficiencies

• Heat pump efficiencies improve as the temperature
  differential between source and demand
  temperature decreases
• Therefore a low temperature heat distribution
  system is required

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BRE Good Practice Guide 339
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Sizing

• Crucial to operation
• Energy efficiency very important
• Usually designed to meet 50 of peak demand and
  80-85 of heat demand over the year
• Usually pre-heats hot water, electrical immersion
  heater used for top up heating

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Further Information

• IEA Heat Pump Centre www.heatpumpcentre.org
• Canadian Earth Energy Association
  www.earthenergy.ca
• www.earthenergy.co.uk

17
Micro CHP

• CHP (Combined Heat and Power)
• Replaces gas boiler and also produces electricity
• Whispergen
• 3000 VAT
• Available from Powergen in East Anglia, East
  Midlands, Yorkshire, the North West and London
  regions
• 150 savings per year (EST report, 3-4 bedroom
  house)
• CO2 savings of 1.5 tonnes a year
• Floor mounted, against an outside wall
• Microgen
• Similar system, to be launched in the UK in 2007
• Further info at www.chpa.co.uk