Refrigeration systems compressor/condenser

Fig. 1. Components of a refrigeration system A, condenser outlet B, evaporator inlet C, evaporator outlet D, compressor discharge.

When produced from natural gas the synthesis gas will be impure, containing up to 5 per cent inerts, mainly methane and argon. The reaction equilibrium and rate are favoured by high pressure. The conversion is low, about 15 per cent and so, after removal of the ammonia produced, the gas is recycled to the converter inlet. A typical process would consist of a converter (reactor) operating at 350 bar a refrigerated system to condense out the ammonia product from the recycle loop and compressors to compress the feed and recycle gas. A purge is taken from the recycle loop to keep the inert concentration in the recycle gas at an acceptable level. 

Demethanizer Overhead Expander and Multifeed Fractionation. Incorporation of an expander into the conventional high pressure demethanizer system eliminates bottlenecks in the refrigeration system, the demethanizer condenser, and charge gas compressor. It reduces the cost by lowering the refrigeration power. Multiple feed deethanization and ethylene fractionation debottlenecks the deethanizer, ethylene fractionator, and the refrigeration systems, thereby reducing power consumption. 

For the actual systems, compressor work will be higher than for ideal for the isentropic efficiency and other losses. In the case of hermetic or accessible compressors where an elec trical motor is cooled by the refrigerant, condenser capacity should be ... 

FIG. 11-98 Performance of complete refrigeration system (1), when there is reduction in heat load (2), and when for the same ambient (or inlet in evaporator) evaporation temperature is maintained constant hy reducing capacity of compressor/condenser part (3). 

During each of the three phases a refrigeration system, consisting of three (3) compressors, two (2) condensers and one (1) separation drum, ensures that the ammonia is at its storage temperature. 

To meet the 1993 Energy Standards, the industry undertook, at considerable cost, the optimization of the various refrigeration system components. The most significant improvement was the increase in compressor efficiency, from an EER of about 4 to about 5.5. Other system improvements included more efficient fan motors, more effective heat transfer by the evaporator and the condenser, and less defrost energy. In the early 1980s, both the Whirlpool Corporation and White Consolidate Industries introduced electronic defrost controls. Heretofore, an electric timer initiated the defrost cycle, typically every t A elve hours, whether the evaporator needed it or not. With the electronic control the defrost inteiwal is more a function of frost accumulation than of time, and thus referred to as a variable defrost control or as adaptive defrost. It saves energy by being activated only when needed. 

A refrigeration system requires that 52,400 Ib/hr of propylene refrigerant vapor from the compressors be desuperheated and then condensed. 

The refrigeration system is required to cool the ice condenser and the heat exchanger for the heat transfer medium. The system consists of four separate two-stage compressors with water-cooled liquehers. 

Now that the evaporator is cooler, we could increase the flow of warm process fluid to the evaporator. Thus, improving the efficiency of the condenser will increase the capacity of a refrigeration system to cool. This happens mainly by lowering the compressor discharge pressure rather than producing a colder condensed refrigerant. 

A very large percentage of refrigeration systems are not limited by either the compressor driver horsepower, the condenser, or the evaporator. Many refrigeration systems are limited by either ... 

There has been some innovative technology applied by some wineries to maintain the wines in a warm condition. Several wineries have been visited where small tanks, puncheons, or barrels were covered with electric blankets to maintain an adequate temperature for the malo-lactic fermentation. Larger wineries utilize an external heat source to warm the storage tanks in which the red wine is held. Where wineries are using ammonia refrigeration systems directly in the jacketed portion of the fermentors, these systems can be used as a heat pump. The hot ammonia gas from the compressors is desuperheated and the tank jacket used as a condenser to condense this gaseous ammonia. This has proven to be a very effective means of warming a tank. 

One refrigeration system is electrically driven a second is operated by a condensing turbine. High pressure steam from a power house is pressure-reduced for use by the plant as it passes through one air compressor turbine, one refrigeration machine turbine, and the high pressure section of the turbogenerator. 

A vapor-compression refrigeration system is conventional except that a countercurrent exchanger is installed to subcool the liquid from the condenser by heat exchange with the v stream from the evaporator. The minimum temperature difference for heat transfer is 10(°F). Amm is the refrigerant, evaporating at 22(°F) and condensing at 80(°F). The heat load on the evapo is 2,000(Btu)(s) . If the compressor efficiency is 75 percent, what is the power requirement ... 

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