Refrigeration cycle absorption

Soave modification of, 491-492 Reduced coordinates, 85, 477 Refrigeration, 274-290 Refrigeration cycles absorption, 288-289 Carnot, 275-276 cascade, 286-287... 

There are many means to obtain refrigerating effect, but here three will be discussed mechanical vapor refrigeration cycles, absorption and steam jet cycles due to their significance for industry. 

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. 

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

Absorption Air-Conditioning Brayton Gas Refrigeration Cycle Stirling Refrigeration Cycle Ericsson Cycle Liquefaction of Gases Nonazeotropic Mixture Refrigeration Cycle Design Examples Summary... 

Absorption chillers may operate either a one or two stage absorption refrigeration cycle, using water as the refrigerant (typically inhibited by molybdate) and lithium bromide as the absorbent. Depending on design, heat exchangers may include ... 

The word refrigeration implies the maintenance of a temperature below that of the surroundings. This requires continuous absorption of heat at a low temperature level, usually accomplished by evaporation of a liquid in a steady-state flow process. The vapor formed may be returned to its original liquid state for reevaporation in either of two ways. Most commonly, it is simply compressed and then condensed. Alternatively, it may be absorbed by a liquid of low volatility, from which it is subsequently evaporated at higher pressure. Before treating these practical refrigeration cycles, we consider the Carnot refrigerator, which provides a standard of comparison. 

Absorption chillers use heat as the primary source of energy for driving an absorption refrigeration cycle. These chillers require very little electric power (0.02 kW/ton) compared to electric chillers that need 0.47-0.88 kW/ton, depending on the type of electric chiller. Absorption chillers have fewer and smaller moving parts and are quieter during operation than electric chillers. These chillers are also environment-friendly in that they use non-CFC refrigerants. 

The flow diagram of the absorption scheme is shown in Fig. 4. An ammonia/water refrigeration cycle is used both to boil up the bottom column outlet stream and to condense the top column outlet stream. 

Besides above, there are some other absorption refrigeration cycles in order to make use of the energy more efficiently and completely, for example, the triple-effect absorption refrigeration cycle, the GAX cycle and the absorption/ compression refrigeration cyde. 

The heat capacity of traditional working pair LiBr-H20 is very low, which is only 2 J g-i K-i at 373.15 K with the mass fraction of 55%. The heat capacities of binary system [MMIm]DMP-methanol and [BMIm]Cl-methanol on the same condition is close to that of LiBr-H20 solution. This means that the evaporating of methanol out of solution requires only a small amount of heat, which is favorable for enhancing COP of absorption refrigeration cycle. 

S Q Liang, J Zhao, L Wang, et al. Absorption refrigeration cycle utilizing a new working... 

Natural gas Hquids are recovered from natural gas using condensation processes, absorption (qv) processes employing hydrocarbon Hquids similar to gasoline or kerosene as the absorber oil, or soHd-bed adsorption (qv) processes using adsorbants such as siHca, molecular sieves, or activated charcoal. Eor condensation processes, cooling can be provided by refrigeration units which frequently use vapor-compression cycles with propane as the refrigerant or by... 

Coefficient of performance of the absorption cycle is defined on the same principle as for the mechanical refrigeration ... 

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