Evaporation cooling

Open steady-flow systems, which include almost all air conditioning processes, foUow this law. Examples include the energy flows in a cooling and dehurnidifying coil or an evaporative cooling system. 

Cooling. A compression refrigeration system, driven by an electric motor, suppHes cooling for either direct expansion or ice bank systems (Fig. 12). In the former, the milk is cooled by the evaporator (cooling cods) on the bulk tank liner opposite the milk side of the liner. The compressor must have the capacity to cool the milk as rapidly as it enters the tank. 

Order of preference adiabatic evaporation > isothermal evaporation > cooling >drown-out. 

Relative humidity at which water condenses on the apphed film as a result of evaporative cooling effects. 

Many organisms are exposed to some of the thermal, chemical, and physical stresses of entrainment by being mixed at the discharge with the heated water this is plume entrainment. The exact number exposed depends on the percentage of temperature decline at the discharge that is attributed to turbulent mixing rather than to radiative or evaporative cooling to the atmosphere. 

Cooling by means of evaporative cooling towers is required to maintain a constant temperature of 30—40°C. At higher temperatures, the deposit is rougher, impurity effects are more pronounced, lead codeposition is favored, and the manganese dioxide formed at the anode iacreases and tends to adhere rather than fall to the bottom of the cell. 

The specific enthalpies ia equation 9 can be determined as described earUer, provided the temperatures of the product streams are known. Evaporative cooling crystallizers operate at reduced pressure and may be considered adiabatic (Q = 0). As with of many problems involving equiUbrium relationships and mass and energy balances, trial-and-error computations are often iavolved ia solving equations 7 through 9. 

Predrag S. Hrnjak, F. C. Standiford, Klaus D. Timmerhaus Psychrometry Evaporative Cooling, and Solids Drying Charles G. Moyers, Glenn W. Baldwin... 

Glenn W. Baldwin, M.S., P.E., Staff Engineer, Union Carbide Corporation Member, American Institute of Chemical Engineers (Section 12, Psyclirometry Evaporative Cooling, and Solids Drying)... 

A nominal resiilt of this techniqne is that the reqnired airflow rate and eqnipment size is abont two-thirds of that when evaporative cooling is not nsed. See Sec. 20 for eqmpmeut available. 

Evaporative Cooling The process fluid can be cooled by using evaporative cooling with the sink temperature approaching the wet-bulb temperature. 

Example 4 Evaporative Cooling Air at 95 F dry-bulb temperature and 70 F wet-bulb temperature contacts a water spray, where its relative humidity is increased to 90 percent. The spray water is recirculated makeup water enters at 70 F. Determine exit dry-bulb temperature, wet-bulb temperature, change in enthalpy of the air, and quantity of moisture added per pound of dry air. 

The contrihiition of Robert W. Norris, Robert W. Norris and Associates, Inc., to material that was used from the sixth edition is acknowledged. (Evaporative Cooling)... 

---