Transcript
Heat pump
W. HulshorstNov. 2008
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Agenda
1)Introduction
2) Overview of heatpumps (Europe)
3) Airsource heatpump technology
4) Coeffcient of performance
5) installation of heatpumps
6) case study with RETscreenBusiness Connecting and Development
What is a heatpump?
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• A device that transfers heat energy
• Examples: air conditioner; refrigerator
Bicycle pump
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Heat
P x V / T = C
Airco heat transfer
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Hot air
Cold air
Heat transfer
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1. Condensor2. Expansion3. Evaporator4. Compressor
Heating and cooling mode
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Air heat pumps are ideal for mild climates
Other types of heat pump
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Ground heat pumpIn this solution the heat pumpuses a pipe-loop buried abouta metre below ground.
Other types of heat pump
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Water heat pumps A water heat pump is a variantof the ground heat pump. The only difference is that it uses a hose on the lake floor (or otherwater source) instead of a pipe buried below ground.
Other types of heat pump
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Rock heat humpsA rock heat pump is another variant of ground heat pumps, and a very common one. Thesystem uses the solar energy stored in the rock shelf and the loop is lowered into a 100–150 metres bore hole in the rock.
Choice of technology
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Type of heat pump
Common capacity range
Application Dominant region
Air- Air 3 – 5 kW Heating + cooling
Southern Europe
Ground soil 5 – 25 kW Heating Northern + Central Europe
Ground rock 5 – 40 kW Heating + cooling
Northern + Central Europe
Lake water 15 – 40 kW Heating
Efficiency
Heat pump
3 – 5 kWhof heat
2 – 4 kWhof air heat
1 kWh electricity
Coefficient of performance (COP):
COP = Output/Input = 3 to 5
COP
• Larger temperature difference means less COP• Air type is less efficient at low ambient temperatures.
Design
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The design and installation of a heat pump system must also address:
• the duct system must be correctly designed to work with the heat pump equipment and to distribute conditioned air sufficiently throughout the house;
• the duct system must be properly installed and sealed to ensure its performance.
installation
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In general, correct heat pump installation can be achievedby addressing four critical areas:
1. the indoor air handler, especially the airflow over the fan-coil unit and through the forced air duct system;
2. the refrigerant system, especially the refrigerant charge;
3. the outdoor unit, especially its air supply; and
4. the control system, especially the thermostat that turns the equipment on and off.
Maintenance (1)
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In general: • Dirty filters, coils and fans reduce airflow through the system
• The fan should be cleaned
• Ductwork should be inspected and cleaned
Maintenance (2)
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Heat pump manufacturers recommend that homeowners consider the following operational and maintenance issues:• a heat pump works most efficiently when it maintains a constant room temperature; avoid large temperature changes overnight or during the day;• the system will periodically go into defrost mode to remove any ice build up on the outdoor coil in the winter;• the outdoor unit should be positioned above the prevailing snow-line, with suitable clearance around the unit maintained all year round;• expect the unit to run continuously in periods with low outdoor temperatures, or switch over to the supplementary heating system.
Thanks for your attention
Walter HulshorstEcon International B.V. PO box 50356802 EA ArnhemThe Netherlands
T: + 31 (0)61 047 45 77F: + 31 (0)26 381 64 82E: walter@econ-international.nlW: www.econ-international.nl
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Case Study
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• Residential Heat pump– 550 m2– Heating load: 18.4 W/m2– Cooling load: 28.4 W/m2
• Base Case– Diesel Boiler: 78% seasonal efficiency– AirCo: CoP 3
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