Ground source heat pumps[1]sk


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DT117/4 Sustainable Build & Design - Class Presentations

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Ground source heat pumps[1]sk

  1. 1. Presented by Sean Keegan Suitable Build & Design Lecturer Sonya Daly GSHP Sustainable Build & Design Sean Keegan
  2. 2.  GSHP uses Geothermal Energy from heat exerted by the earths core  The ground maintains stable temperature between 11-13oC  Energy can be recovered from the ground, water or air but GSHP’s utilizes the stable ground temperature as its source of energy  Substitute for conventional heating systems  Can be a considered zero-carbon source of energy GSHP Sustainable Build & Design Sean Keegan
  3. 3.  Horizontal Collector system:  laid in trenches 0.5-1.8m  Vertical Collector system:  laid in bores 100- 150mm diameter & 20-150m deep  Direct expansion heat transfer- open loop  Indirect expansion heat transfer- closed loop GSHP Sustainable Build & Design Sean Keegan
  4. 4.  System consists of a ‘ground loop’ pipe  Filled with a mixture of water and antifreeze (Glycol) buried in a trench or borehole  Electric pump powered by electricity/solar /wind source circulates mixture in loop.  ‘Pump up’ collected heat at low temperature and release it at a higher temperature.  Transfers the heat collected to a hot water tank.  Heat is then used to supply under floor heating or radiators.  Indirect system uses secondary pipe work and closed loop.  Direct expansion heat transfer- open loop, more efficient but environmental issues and more system design needed because of inflexible copper work. GSHP- Sean Keegan
  5. 5.  Radiators, underfloor heating and hot water supply.  Recommended for newly constructed houses with adequate insulation and air-tightness that meet the latest building regulations.  Suited to homes with under-floor heating.  Not generally suitable for properties with existing gas-fired central heating systems.  Temperature delivered between 45-55oC for general use and 30-45oC for under floor heating.  Hot water in cylinder will be pumped up by an emersion to meet require temperature.  Can be incorporated in concrete piles. GSHP Sustainable Build & Design Sean Keegan
  6. 6. GSHP Sustainable Build & Design Sean Keegan  Materials ◦ Indirect Collector: highly-density polyethylene pipe; flexible closed loop ◦ Direct expansion: copper pipe; direct installation  Methods ◦ Horizontal: trenches 0.5-1.8m deep, excavated by a digger ◦ Vertical: bore holes 20-150m deep, excavated by a drilling rig
  7. 7.  Efficient performance needs good thermal contact with the ground- so ensure adequate backfill  Supplys30-50% of hot water demands- topped up electrical supply  Insulation costs vary depending on ground condition and choice of vertical or horizontal vertical €10,000-12,000  Payback 8-10 years, with a 20 year life expectancy  Every unit of electricity used by the pump, you get between 3-4 units of heat  You still need to use electricity to drive the pump, so a ground-source heat pump can’t be considered completely zero-carbon unless this is provided by a renewable source, such as solar power or a wind turbine. GSHP- Sean Keegan
  8. 8. GSHP Sustainable Build & Design Sean Keegan  15- 50% less than traditional electrical heating or oil heating costs  No extra maintenance needed same as typical annual boiler services  Low noise & good visual aesthetics; only pump visible but usually in garage  cheaper off peak rates can be used to maintain heat within cylinder  Can provide a well disturbed central heating system  Lower carbon emissions  Well suited for underfloor heating
  9. 9.  Initial insulation costs are high  Groundworks required to dig the trench & bore holes can be expensive and disruptive  Horizontal installation can be restricted by the size of the building plot  Not suitable for properties with existing gas- fired wet central heating as the technology works at lower temperatures, making it better suited to homes with under floor heating. GSHP Sustainable Build & Design Sean Keegan
  10. 10. The Sustainable Energy Authority Ireland operate a Greener Homes Scheme that provide grants to individuals who wish to make there homes more environmentally friend 23% of applications are for GSHP The average successful grant received is €2000 GSHP Sustainable Build & Design Sean Keegan
  11. 11.  GSHP’s provide an environmentally friendly heating source  Initial high investment with reduced utilities bills  Suitable for new well insulated homes GSHP Sustainable Build & Design Sean Keegan
  12. 12.  Sustainable Energy Authority Ireland website  ‘Ground Source Heat Pumps’ Home Heating Systems  ‘Assessment of Hybrid Geothermal Heat Pump Systems ‘(2001), Federal Energy Management Program, U.S. Department of Energy  ‘Ground Source Heat Pumps: A Technology Review’ (1999) by R. Rawling & J Sykulski, Department of Electrical Engineering, University of Southampton GSHP Sustainable Build & Design Sean Keegan