Units for Refrigerant-Based Systems

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  • Topic: Heat pump, HVAC, Conversion of units
  • Pages : 2 (529 words )
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  • Published : February 25, 2013
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The chiller efficiency depends on the energy consumed. Absorption chillers are rated in fuel consumption per ton cooling. Electric motor driven chillers are rated in kilowatts per ton cooling. • KW/ton = 12 / EER

• KW/ton = 12 / (COP x 3.412)
• COP = EER / 3.412
• COP = 12 / (KW/ton) / 3.412
• EER = 12 / KW/ton
• EER = COP x 3.412
If a chillers efficiency is rated at 1 KW/ton,
• COP = 3.5
• EER = 12

Cooling Load in - kW/ton

The term kW/ton is commonly used for larger commercial and industrial air-conditioning, heat pump and refrigeration systems. The term is defined as the ratio of energy consumption in kW to the rate of heat removal in tons at the rated condition. The lower the kW/ton the more efficient the system. KW/ton = Pc / Er         (1)

Where Pc = energy consumption (kW)
Er = heat removed (ton)

Coefficient of Performance - COP

The Coefficient of Performance - COP - is the basic parameter used to report efficiency of refrigerant based systems. The Coefficient of Performance - COP - is the ratio between useful energy acquired and energy applied and can be expressed as COP = Eu / Ea         (2)

Where COP = coefficient of performance
Eu = useful energy acquired (btu in imperial units)
Ea = energy applied (btu in imperial units)
COP can be used to define either cooling efficiencies or heating efficiencies as for heat pumps. • Cooling -  COP is defined as the ratio of heat removal to energy input to the compressor • Heating - COP is defined as the ratio of heat delivered to energy input to the compressor COP can be used to define the efficiency at single standard or non-standard rated conditions, or as a weighted average of seasonal conditions. The term may or may not include the energy consumption of auxiliary systems such as indoor or outdoor fans, chilled water pumps, or cooling tower systems. • higher COP - more efficient system

COP can be treated as an efficiency where COP of 2.00 =...
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