Cooling towers efficiency

The giant natural-draft towers are used in Europe and in nuclear power plants in the United States. I ve only worked with these towers in one refinery in Lithuania, and their performance was poor. Air flow is generated by the air inside the tower being heated by the warm cooling water. Also, the molecular weight of the evaporated water is less than the molecular weight of air. A few tenths of an inch of water draft may be developed. 

The much smaller induced-draft cooling towers are used in process plants throughout the Gulf Coast of Texas and Louisiana. Air flow is generated by large induced-draft fans. 

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Cooling tower blowdown can be reduced by improving the energy efficiency of processes, thus reducing the thermal load on cooling towers. Alternatively, cooling water systems can be switched to air coolers, which eliminates the problem altogether. 

Provision of efficient drift eliminators of water cooling towers consideration of replacement by air cooling systems. Thermal insulation to protect personnel from contact with hot or cold surfaces prevention of water supply disruption by freezing. 

Rate of evaporation (cooling tower), gpm Ot eraU column efficiency, %... 

While the majority of cooling tower installations work efficiently, the normal requirements of maintenance and good efficiency practice have still to be applied. This may not always be the case. Time for maintenance is limited, and plant engineers have other pressing problems or, as is well known, forget about the towers With the increasing economic and environmental pressures on the use of water, this situation must change. 

Regular checks and an efficient logging system will ensure that the cooling tower, correctly planned, efficiently installed and adequately maintained, will give valuable service for many years. The economic returns justity a little more thought and attention than has been given to the subject in the past. 

There are several measure sets with immediate payback SE, SF, SH, SI. Measures SE and SF are radiant panel systems with displacement ventilation. These systems have a similar cost to the base case, but they offer energy savings. Furthermore, significant sizing reductions, mainly in the cooling tower and chiller sizes, offset the incremental cost of the envelope and heat recovery measures. Because the elevator efficiency measures offer a net savings in capital cost, the capital cost of the other measures is further offset. 

Decreasing the heat duty on evaporative cooling tower circuits by better energy efficiency to decrease the evaporation from the cooling tower and hence, decrease the makeup requirements. 

Cooling towers vary dramatically in their size, with some able to handle no more than about 2,000 gallons per minute (7,500 liters per minute), and the largest able to process more than 100,000 gallons per minute (400,000 liters per minute). The least efficient of such plants reduce the temperature of the water they process by less than 10°F (5°C), and the most efficient, by more than SOT (16°C). 

Gas ejectors (an ejector is a vent for removing non-condensable gases from the condensing unit located downstream from the turbine. Condensate from the cooling towers is pumped to the condenser unit to condense the steam leaving the turbine. In this way, low pressure is created downstream from the turbine, which leads to improved efficiency to generate electric... 

Details of the thermodynamic basis of availability analysis are dealt with by Moran (Availability Analysis, Prentice-Hall, Englewood Cliffs, NJ, 1982). He applies the method to a cooling tower, heat pump, a cryogenic process, coal gasification, and particularly to the efficient use of fuels. 

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