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The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required. [ 1 ] [ 2 ] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs.
The unit is operated 120 days each year for 8 hours per day (960 hours per year), and the electric energy cost is $0.10 per kilowatt-hour. What is its annual cost of operation in terms of electric energy? First, we convert tons of cooling to BTU/h: (4 tons) × (12,000 (BTU/h)/ton) = 48,000 BTU/h. The annual cost of the electric energy is:
Common absorption refrigerators use a refrigerant with a very low boiling point (less than −18 °C (0 °F)) just like compressor refrigerators.Compression refrigerators typically use an HCFC or HFC, while absorption refrigerators typically use ammonia or water and need at least a second fluid able to absorb the coolant, the absorbent, respectively water (for ammonia) or brine (for water).
Thermoelectric cooling uses the Peltier effect to create a heat flux at the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current.
A large domestic refrigerator stands as tall as a person and may be about one metre (3 ft 3 in) wide with a capacity of 0.6 m 3 (21 cu ft). Refrigerators and freezers may be free standing, or built into a kitchen. The refrigerator allows the modern household to keep food fresh for longer than before.
Kelvinator ad from 1920 Kelvinator refrigerator, c. 1926. The enterprise was established on September 18, 1914, in Detroit, Michigan, United States, by engineer Nathaniel B. Wales, who introduced his idea for a practical electric refrigeration unit for the home to Edmund Copeland and Arnold Goss. [1]
Propane refrigeration is a type of compression refrigeration. Propane (R290) has been used successfully in industrial refrigeration for many years, and is emerging as an increasingly viable alternative for homes and businesses.
However, below about 80 K the coefficient of performance is comparable with other coolers (compare equations and ) and in the low-temperature region the advantages get the upper hand. PTRs are commercially available for temperatures in the region of 70 K and 4 K.