Energy Conversion Units

In refrigeration work, three common forms of energy must be considered: me­chanical, electrical and heat.

The study of refrigeration deals mainly with heat energy, but it must be understood that heat energy is usually produced by utilizing a combination of electrical and 'mechanical energy. There is a re­lation that exists between these three forms of energy. In an electric refrigerating unit, electrical energy flows into an electric motor and this electrical energy is turned into mechanical energy. This mechanical energy is used to turn a compressor, and the compressor, in turn, compresses the gas to a high temperature. Energy con­version units are expressed as follows:

778 foot-pounds = 1 British thermal unit (Btu)

1 hp = 2545.6 Btu, hr.

1 hp = 746 watts

1 Btu/hr. = .000393 hp

1 Btu,/hr. = .293 watts

1 watt = .00134 hp

1 watt = 3.41 Btu/hr.

These conversion units will be used in Chapter 16 in calculating loads and deter­mining the capacity of equipment required for specific refrigeration applications.