| A | B |
|---|
| Air, dry | air without contained water vapor; air only |
| Air, standard | dry air at a pressure of 760 mm(29.92 in.) Hg at 21 C (69.8 F) temperature and with a specific volume of 0.833mJ/kg (13.33 ft3/lb.). |
| Capillary tube | In refrigeration practice, a tube of small internal diameter used as a liquid refrigerant flow control or expansion debvice between high and low sides; also used to transmit pressure from the sensitive bulb of some temperature controls to the operating element. |
| Calorie | heat required to raise the temperature of 1 gram of water 1 C, actually from 4 C to 5 C. Mean calorie = 1/100 part of the heat required to raise 1 gram of water from 0 to 100 C. |
| Change of air | introduction of new, cleansed or recirculated air to conditioned space, measured by the number of complete changes per unit time |
| Change of state | change from one phase, such as solid, liquid or gas, to another state. |
| Coefficient of performance, compressor, heat pump | the ratio of the compressor heating effect (heat pump) to the rate of energy input to the shaft of the compressor, in consistent units, in a complete heat pump, under designated operating conditions. |
| Compression ratio | ratio of absolute pressures after and before compression |
| Counter flow | In heat exchange between two fluids, oppopsite directionof flow, coldest portion of one meeting coldest portion of the other. |
| Cutting room | cold roomin which animal carcasses are cut up into commercial sizes such as rib roast, legs, etc. |
| Cycle defrosting | the portion of a refrigeration operation which permits the cooling unit to defrost. |
| Cycle, refrigeratng | a sequence of thermodynamic processes through which a refrigerant passes, in a closed or open system, to absorb heat at a relatively low temperature level and reject heat at a higher temperature level |
| Drier | a manufactured device containing a dessiccant (water absorbing material) placed in the refrigerant circuit, its primary purpose being to collect and hold within the dessiccant all water in the system in excess of the amount which can be tolerated in the circulating refrigerant. |
| Enthalpy | the sum of the internal energy of a body and the product of its volume multiplied by the pressure. Occasionally called heat content. |
| Equalizer, external | in a thermostatic expansion valve, a tube connection froma selected control point in the low-sied circuit to the pressure sensing sideo f the control element such that the controll point pressure is transmitted to the actuating element (diaphragm or bellows). This connection provides a means for compensating for the pressure drop through the accessories and the evaporator. |
| Equalizer, Internal | thermostatic expansion valve, an integral internal part of passage, which provides exposure of the actuating element (diaiphragm or bellows) to pressure leaving the valve. |
| Flash gas | the gas resultng from the instantaneous evaporationo f refrigerant in a pressure reducing device to cool the refrigerant to the evaporation temperature obtained at the reduced pressure. |
| Foaming | the formation of a foam or froth of an oil-refrigerant mixture due to rapid boilingo ut of the refrigerant dissolved in the oil when the compressor starts operating and,if large quantities of refrigerant were dissolved, large quantities of oil may boil out and be carried through the refrigerant lines. |
| Freeze-up | failure of a refrigerating unit to operate nomrally due to formationof ice at the expansion device. A val e may freeze shut or open, causing improper refrigeration in either case. On a coil, frost formation to the extent that air flow stops or is severely restricted. |
| Freezing point | temperature at which a given liquid substance will solidify or freeze upon removal of heat. Freezing pointof owater is 32 F. |
| Motor, capacitor | a singlel-phase induction motor with a main winding arranged for direct connection to a source of power and an auxiliary winding connected in series with a capacitor |
| Pressure drop | static pressure loss in fluid pressure, as from one end to the other, due to friction, etc. |
| Pressure regulator, evaporator (back-pressure valve) | an automatic valve located between the evaporator outlet and compressor inlet that is responosive to its own inlet pressure or to the evaporator or refrigerator temperature and functions to throttle the vapor flow when necessary to prevent the evaporator pressure from falling below a selected value. |
| Pump down (refrigeration system) | the operation by which the refrigerant in a charged is pumped into the liquid receiver. |
| Thrust Bearing | a bearing the has a pushing pressure to the side and that therefore needs an additonal surface to absorb the push. Most motor shifts cradle in their bearings because they operate in a horizontal mode, like holding a stick inthe palm of your had. When a shaft is turnedto the vertical mode, a thrust surfae must support the weight of the shaft along with the load the shaft may impose on the thrust surface. The action of a vertical fan shaft that pushed air up is actually pushing the shaft downward. |
