Heat pump Refrigerator and Air conditioner

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Heat pump Refrigerator and Air conditioner

• ESM288
• Li-Chin Huang
• Takehiko Nagai

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Theory of Heat pump

• Electrical Energy gt Kinetic Energy gt Heat
  energy
• When refrigerants change from vapor to liquid,
  heat is discharged.
• On the contrary, changing from liquid to vapor,
  heat is absorbed

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Diagram of Refrigerator
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Diagram of air-conditioner
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Efficiency of Heat pump
Desired output/removed Required energy Input

• COP (Coefficient of performance)
• For a heater, COP
• For a cooler, COP

TH TH-TL
QH QH Wnet QH-QL
QL QL Wnet QH-QL
TL TH-TL
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Example of Calculation

• A refrigerator is removing heat at a rate of 6
  kJ.
• The required power input to the refrigerator is
  2kJ.
• (a) COP 3
• (b) QH QL Wnet,in
• 6kJ 2kJ 8 kJ

QL
6 kJ
25?
Wnet
2 kJ
5?
QH 8kJ
QL 6kJ

• COP of an electric heater 1,
• because the electricity is totally
• converted to heat

Wnet 2kJ
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Improvement of Energy consumption
Technical Breakthrough for energy savings

• Start using an inverter in 1997
• Change Refrigerants in 2000
• R134a(HFC) to R600a(HC)
• Improvement of insulator in 2003
• Poly-urethane to Vacuum insulator

• Brushless DC compressor in 1992
• Start using an inverter in 1996
• Continual improvement of heat exchanger and
  Magnetic motor

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Type of refrigerants