Heat Pump

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This minute lecture introduces heat pumps as a best practices for heating and cooling buildings. According to UIE, more widescale use of heat pumps could save 1,200 million tonne of greenhouse gas emissions per year on a global scale, and represents one of the largest potential savings that any single technology can offer.

Published in: Business, Technology

Heat Pump

  1. 1. Heat Pumps
  2. 2. What is a heat pump? <ul><li>A heat pump enables energy-efficient heating </li></ul><ul><li>It does not produce energy </li></ul><ul><li>It ‘pumps’ heat at a relatively lower temperature from air, water, or soil and gives it off at a higher temperature into a building </li></ul>
  3. 3. Pros and Cons <ul><li>Advantages </li></ul><ul><ul><li>Lower life cycle cost due to high efficiency </li></ul></ul><ul><ul><li>Reduction of final energy demand by a factor 3 </li></ul></ul><ul><ul><li>Reduction of CO2 emissions by 25 – 65% (depending on baseline) </li></ul></ul><ul><ul><li>Business opportunity for contractors </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>To be combined with low-temperature heating in a well-insulated building </li></ul></ul><ul><ul><li>High initial investment cost </li></ul></ul><ul><ul><li>Requires large soil surface or water volume (in case of a high efficiency water or soil heat pump) </li></ul></ul>
  4. 4. Basic principle (1/2) <ul><li>Refrigerator: </li></ul><ul><li>Heat is withdrawn from inside a refrigerator (low temperature) </li></ul><ul><li>Temperature inside refrigerator drops </li></ul><ul><li>Extracted heat is given off to environment (higher temperature) </li></ul><ul><li>Negligible temperature rise of the environment </li></ul><ul><li>Heat pump: </li></ul><ul><li>Heat is withdrawn from environment: air, soil, or water (low temperature) </li></ul><ul><li>Negligible temperature drop of the environment </li></ul><ul><li>Extracted heat is given off into building (higher temperature) </li></ul><ul><li>Temperature of building’s interior rises </li></ul>Principle is similar to refrigerator:
  5. 5. Basic principle (2/2)
  6. 6. Four main components <ul><li>Evaporator: </li></ul><ul><ul><li>contains work fluid at lower temperature than environment. Heat is extracted from ground, air, or water. Pressure is low, so the work fluid evaporates </li></ul></ul><ul><li>Compressor: </li></ul><ul><ul><li>brings gas to higher pressure, the temperature rises </li></ul></ul><ul><li>Condenser: </li></ul><ul><ul><li>gas temperature is higher than fluid temperature of heating system. Excess heat is transferred to fluid. The gas cools and condenses </li></ul></ul><ul><li>Pressure relief valve: </li></ul><ul><ul><li>causes pressure reduction, the temperature drops, and the cycle begins again </li></ul></ul>
  7. 8. Also used for cooling <ul><li>Has to be equipped with reverse valve to change circulation of the work fluid </li></ul><ul><li>This application is becoming popular </li></ul>
  8. 9. High efficiency <ul><li>To obtain 100% useful energy: </li></ul><ul><li>Traditional system on fossil fuel: </li></ul><ul><ul><li>120% combustion heat (paid for) </li></ul></ul><ul><ul><li>Coefficient of performance = 0.8 </li></ul></ul><ul><li>Heat pump: </li></ul><ul><ul><li>30% electrical energy to drive compressor (paid for); 70% taken from nature </li></ul></ul><ul><ul><li>Coefficient of performance = 3 </li></ul></ul>
  9. 10. Competitive life cycle cost
  10. 11. Should be combined with low-temperature heating <ul><li>Lower temperature of heating fluid </li></ul><ul><li>Compensated by larger heating surface </li></ul><ul><li>Large radiators </li></ul><ul><li>Floor heating </li></ul><ul><li>Wall heating </li></ul><ul><li>Ceiling heating (ideal in combination with reversible heat pump for cooling) </li></ul>
  11. 12. Round-up <ul><li>Transfers available heat from air, water, or soil at lower temperature into higher temperature for a building </li></ul><ul><li>Also used for cooling </li></ul><ul><li>High efficiency </li></ul><ul><ul><li>Competitive life cycle cost </li></ul></ul><ul><ul><li>Lower environmental impact </li></ul></ul><ul><li>Only effective in combination with low-temperature heating and adequate insulation </li></ul><ul><li>Investment cost is still high </li></ul>
  12. 13. Further information <ul><li>Heat Pump Centre: www.heatpumpcentre.org </li></ul><ul><li>Green Building: www.greenbuilding.com </li></ul>

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