Refrigerators, absorptive

Absorption Systems. Absorption refrigeration cycles employ a secondary fluid, the absorbent, to absorb the primary fluid, refrigerant vapor, which has been vaporized in the evaporator. The two materials that serve as the refrigerant—absorbent pair must meet a number of requirements however, only two have found extensive commercial use ammonia—water and water—Hthium bromide. 

Absorption Refrigeration Systems Two main absorption systems are used in industrial application lithium bromide-water and ammonia-water. Lithium bromide-water systems are hmited to evaporation temperatures above freezing because water is used as the refrigerant, while the refrigerant in an ammonia-water system is ammonia and consequently it can be applied for the lower-temperature requirements. 

Refrigerated Inlets for the Gas Turbines. The refrigerated inlets are more effeetive than the previous evaporative eooling systems as they ean lower the temperatures by about 45-55 °F (25-30 °C). Two teehniques for refrigerating the inlet of a gas turbine are vapor eompression (meehanieal refrigeration) and absorption refrigeration. 

Figure 2-37. Absorption refrigerated iniet eooiing system.

Steam and cooling water requirements for ammonia absorption refrigeration systems are shown in Table 1 for single-stage and two-stage units. The tables are based upon cooling water to the condenser of 85°F with 100°F condensing temperature. Water from the condenser is used in the absorbers. 

Steam and Cooling Water Required for Ammonia Absorption Refrigeration Systems... 

Vapor compression uses the highest form of energy, namely electrical energy. In absorption refrigeration, the energy input is any source of heat (e.g., electrical energy, bottled gas, kerosene, or solar energy). 

The first practical absorption refrigerator was developed in 1850 by Edmund Carre of France, who... 

Figure 11-18. Lithium bromide absorption refrigeration system concept water is the refrigerant. Actual commercial and industrial process flows reflect various heat recovery arrangements.

Figure 11-19. Lithium bromide hermetic absorption refrigeration system, double effect, liquid chiller/heater. As shown in chilling mode, water is the refrigerant under low absolute pressure (boiling at 40°F) (Used by permission Cat. 521-606, form 16DF-1 PD, 1994. Carrier Corporation, a United Technologies Company.)...

Figure 11-20. Sectional view of lithium bromide absorption refrigeration industrial unit. (Used by permission 1956. Carrier Corporation, a United Technologies Company.)...

Bogart, M., Ammonia Absorption Refrigeration in Industrial Process, Gulf Publishing Co., Houston, Texas (1981). 

Holldorff, G., Revisions Up Absorption-Refrigeration Efficiency, Hydrocarbon Processing, V. 58, p. 149 (1979). 

Absorption refrigeration (ammonia to -30°F, lithium bromide to -h45°F) Is economical when waste steam Is available at 12 psig or so. 

Compression refrigeration cycles are by far the most common and absorption refrigeration only applied in special circumstances. 

The features of absorption refrigeration are that there is a low power requirement relative to compression... 

The most common working fluids for absorption refrigeration are given in Table 24.5, together with the working range. 

When should absorption refrigeration be used rather than compression refrigeration There are two important criteria. The first is that absorption refrigeration can only be used... 

Table 24.5 Common working fluids for absorption refrigeration.

Absorption refrigeration is much less common than compression refrigeration. Absorption refrigeration powers by compressing the refrigerant fluid dissolved in a solvent using a pump. 

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