Secondary refrigerant

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. 

Secondary coolants frequently are called brines because such fluids originally were mixtures of salts and water. Common refrigeration brines are water solutions of calcium chloride or sodium chloride. These brines must be inhibited against corrosion. 

The secondaiy ejector systems used for removing air require steam pressures of 2,5 bar or greater. When the available steam pressure is lower than this, an electrically driven vacuum pump is used for either the final secondaiy ejector or for the entire secondaiy group. The secondary ejectors normally require 0,2-0,3 kg/h of steam per kW of refrigeration capacity,... 

Secondary refrigerants shown below, listed under their generic names, are sold under different trade names. Some other secondaiy refrigerants appropriate for various refrigeration application will be listed under their trade names. More data could be obtained from the manufacurer,... 

For many years, turboexpanders have been used in cryogenic processing plants to provide low-temperature refrigeration. Power recovery has been of secondary importance. Expander efficiency determines the amount of refrigeration produced and, in gas process plants, the amount of product usually depends on the available refrigeration. Accordingly, there is a large premium on efficiency and, of course, on reliability. 

The simplest air-cooled condenser consists of a plain tube containing the refrigerant, placed in still air and relying on natural air circulation. An example is the condenser of the domestic refrigerator, which may also have some secondary surface in the form of supporting and spacer wires. 

The cooling effect of a central refrigerating system can be distributed by a heat-transferring liquid or secondary refrigerant. 

Where a secondary refrigerant fluid is to be circulated, and the working temperatures are at or below 0°C, then some form of nonfreeze mixture must be used. These are collectively termed brines. 

The concentration of a solute has a considerable effect on the viscosity of the fluid and so on the surface convective resistance to heat flow. There is little published data on these effects, so applications need to be checked from basic principles. Industrial alcohol (comprising ethyl alcohol with a statutory addition of methyl alcohol to render it poisonous) may be used as a secondary refrigerant, either at 100% concentration or mixed with water. The fluid has a low viscosity and good heat transfer, but is nowlittle used on account of its toxicity and the fire risk in high concentrations. Other nonfreeze heat transfer fluids are used in specialist trades. 

A set of curved tube or coil in which refrigerant or glycol solution run is installed in a tank and cooled inside of the coil. Ice is formed on the surface of the coil and melted from boundary between ice and water. Stored heat is usually recovered by supplying water directly to secondary system. Some systems use heat exchanger to reduce water head loss. This type of ice storage... 

The main aims of this chapter are to provide estimates for the amounts of pollutants emitted from processed electronic waste (e-waste) and assess the magnitudes of human exposure to these pollutants. Specifically in this chapter, e-waste is defined as the sum of discarded personal computers, electronic/electrical equipment, electronic entertainment devices, cell phones, television sets, and refrigerators. In another word, e-waste explicitly refers to electronics at their end of life cycle and disposed by end users rather than surplus electronics (brand new products). In addition, e-waste also does not include reusable (e.g., repairable electronics or second hand electronics) and secondary scraps (e.g., noble metals, plastics, and rubbers). 

Secondary radiations, 21 312-313 Secondary recycling, 21 378-379, 449, 450 Secondary refrigerants, 21 525 Secondary slags, electric furnace for, 14 759-760... 

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