Cooling chilled-water

If suction load contains condensable vapour, installation of a trim condenser and separator using cooling/chilled water will be beneficial... 

Install pre-condensers cooled with cooling/chilled water. Use multi-stage steam ejectors arranged in series/series-parallel arrangement. Use liquid ring or dry vacuum pumps... 

A schematic diagram of the polymer precipitation process is shown in Figure 8. The hot polymer solution is cast onto a water-cooled chill roU, which cools the solution, causing the polymer to precipitate. The precipitated film is passed through an extraction tank containing methanol, ethanol or 2-propanol to remove the solvent. Finally, the membrane is dried, sent to a laser inspection station, trimmed, and roUed up. The process shown in Figure 8... 

Ejector (steam-jet) refrigeration systems are used for similar apph-cations, when chilled water-outlet temperature is relatively high, when relatively cool condensing water and cheap steam at 7 bar are available, and for similar high duties (0.3-5 MW). Even though these systems usually have low first and maintenance costs, there are not many steam-jet systems running. 

Evaporator is the heat exchanger where refrigerant (water) evaporates (being sprayed over the tubes) due to low pressure in the vessel. Evaporation chills water flow inside the tubes that bring heat from the external system to be cooled. 

Factors Affecting Capacity Ejec tor (steam-jet) units become attractive when cooling relatively high-temperature chilled water with a source of about 7 bar gauge waste steam and relatively cool condensing water. The fac tors involved with steam-jet capacity include the following ... 

Condenser cooling medium Brine Chilled water Tower water Chilled water... 

Stainless steel corrugated plates from a plate-and-frame heat exchanger. Closed chill water cooling loop used to cool continuous caster mold. 

Use cooling medium that will not cause freezing (e.g., tempered water instead of chilled water)... 

Example. To produce 20 tons of refrigeration while delivering 50°F chilled water, the steam consumption depends upon the quantity and temperature of the cooling... 

Chilled water Water that is cooler than ambient temperature, obtained from a refrigeration plant, cooling tower, or a well. 

Local cooling The cooling of a given area in a space by means of chilled air jets or chilled water panels. 

Refrigeration is needed for processes that require temperatures below those that can be economically obtained with cooling water. For temperatures down to around 10 0, chilled water can be used. For lower temperatures, down to -30°C, salt brines (NaCl and CaCF) are used to distribute the refrigeration" around the site from a central refrigeration unit. Vapor compression machines are normally used. 

Design a partial condenser to cool a mixture of hydrogen chloride-water vapor from 178°F to 90°F using 60 gal per min of chilled water at 70°F The unit is to have the acid mixture in the tubes, because this will allow for a cheaper construction than if this material were in the shell. The tube-side material is to be impervious graphite, and the shell and shell-side baffles are to be steel. The acid vapor is essentially at its dew point. 

A chlorine-air mixture is to be cooled and the water vapor condensed using chilled water. The design conditions are as follows ... 

Although it is usually not desired, water may be cooled to the freezing point, and ice has been formed in units. Chilling water less than 40°F becomes expensive. 

The utilities required for steam jet refrigeration operation often determine the selection of these units, between manufacturers and between types of refrigeration. As the chilled water temperature off of the unit approaches 32°F, the cost of the basic unit and its steam and cooling water requirements rise rapidly. 

For 40°F chilled water, 100 psig high-cost steam, 90°F cooling water to the barometric ... 

Closed Circuit. Approximate values between those in Figures 11-11 and 11-12 for 55°F chilled water temperature and 90°F cooling water. 

In this case water boils at approximately 40 F (4.4 C), thereby cooling the chilled water circulating through... 

The chilled water plant where the cold refrigerant first chills water (or other liquor), which is fed to the air-cooling coil. 

Of chilled water between the refrigerant and the air-cooling coil ... 

All electrical energy fed to the room will appear as heat. This presents a load to the plant unless power is conveyed out of the room by cable or hot items are physically removed. Parts of some large computers are cooled by a direct supply of chilled water presenting a load on the refrigeration plant but reducing the load on the airside. Cold outside conditions will result in some of the internal load being met by fabric loss. 

In chilled-water systems, pump shaft power adds to the heat of the circulating water. Similarly, if the chiller has a water-cooled condenser pump heat is added to that handled by the final cooler. Power is proportional to the flow and pressure ... 

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