Comparison Between Open Circuit Cooling Tower And Closed Circuit Cooling Tower For Central Air Conditioning System


There are many differences between Open Circuit Cooling Tower and Closed Circuit Cooling Tower, to help clients choose more suitable cooling towers, today we are doing a comparison for the two type of cooling towers .

ITEMSOpen Circuit Cooling TowerClosed Circuit Cooling Tower

Initial Investment 


Low investment cost. The open cooling tower equipment cost would be less than 1.5 million yuan for total cooling load of 23,000 KW.High investment cost,The cost is about 4 times as open cooling tower (6 million yuan) for the same cooling load.
Land OccupationBy direct heat exchange,the  efficiency is high and  tower body size is small, so the land occupation is small.Due to the indirect heat exchange, the efficiency is relatively low, and the tower body size is also large. Generally, the land occupation of closed tower is at least about 1.5 times that of the open tower.
Building LoadThe open tower is small and light in weight.The closed tower body is large and heavy, and the building structure must be strengthened, resulting in an increase in construction cost.

Cooling Water System 

Pump Power 


The pump lift of the open tower only needs about 4 to 5 meters,the power cosumption is low.Calculate by  a total water volume of 5000 m3/h for 10 hours operation per day, 1 yuan per kWh,then electricity consumption charge is 700 yuan per day, 21,000 yuan per month,thus every year operate 5 month in total is 10500 yuan. If actual load is 70%,the electricity cost still need about 70000 yuan.

Tower Body Electricity 


The open cooling tower only needs the fan motor power,generally need about 4KW for a water flow 34L/s.The closed tower not only needs the fan motor power, but also needs the spray pump motor power. For a water flow 34L/s,it needs 18.5KW and 4KW respectively, that is to say,18.5KW higher than open  cooling tower.Calculate by  a total water volume of 5000 m3/h for 10 hours operation per day, 1 yuan per kWh,then electricity consumption charge will be 7550 yuan higher,and over 1 million yuan per year for 5 moth's operation.
Water Consumptionabout 1%Almost the same
Operation NoiseThe required air volume is small, the fan consumes less power, and the noise is correspondingly small.The required air volume is large, the fan consumes a large amount of electricity, and the noise is correspondingly large.
MaintenanceRather simpleThe coil maintenance in the tower is very troublesome (such as scaling).
Impact on the HostSince the cooling water of the main system is  in direct contact with the air, the water quality is dirty, which is harmful to condenser, but even so,the life of main system could be 20 years generally.Since the cooling water of the main system is not in direct contact with the air, the water quality is clean, which is a advantage for extending the life of the main condenser.



Under normal circumstancesIt is especially suitable for environments where the plant has corrosive gases and dust.

Although the cost of closed cooling tower is higher than open cooling tower,it has its own special use.When the plant's enviroment rich of corrosive gases and dust, open cooling tower is not suitable,closed cooling tower will take responsibility well. So, choose a suitable one is better than choose a cheap one.

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