Detailed Operation of a Closed-Circuit Evaporative Cooler

A closed-circuit evaporative cooler is a highly efficient heat exchange device widely used in industrial cooling, air conditioning, and other applications. It achieves cooling through indirect contact between water and air, resulting in water and energy savings, as well as easy maintenance. Proper operation of a closed-circuit evaporative cooler not only improves its efficiency but also extends its lifespan. Below is a detailed operating guide.

1. Pre-Startup Preparation

Inspect the Cooler's Appearance

Ensure that the equipment has no obvious mechanical damage or corrosion. Check that the cooling coil, fan, water pump, and other components are securely installed.

Check the Water Tank Level

Open the water tank cap and confirm that the water level is between the minimum and maximum water levels. If the water level is too low, add clean, softened or deionized water to prevent scaling and corrosion.

Inspect the Piping System

Ensure that the inlet and outlet pipes are properly connected and that valves are properly open and closed. Inspect the pipes for leaks and tighten or replace seals if necessary.

Check the electrical system.

Confirm that the power supply voltage matches the rated voltage of the equipment. Check that the control cabinet wiring is secure and that protective devices (such as circuit breakers and thermal relays) are functioning properly.

Check the fan and pump.

Manually rotate the fan impeller and pump shaft to ensure there is no binding. Check the belt (if any) for proper tightness and adjust or replace it if necessary.

II. Startup Procedures

Starting the Circulating Water Pump

First, turn on the circulating water pump to ensure proper circulation in the water system. Observe the water level in the water tank to ensure that the water replenishment system (such as the automatic float valve) is functioning properly.

Starting the fan

After the pump is running steadily, start the fan. Observe the correct direction of rotation (usually marked on the fan) to ensure smooth air circulation.

Adjusting the water and air flow

Adjust the spray water volume and fan speed (if using variable frequency control) according to cooling requirements. During initial operation, increase the water volume slightly and then optimize after the temperature stabilizes.

Monitor Operating Parameters

After startup, monitor parameters such as inlet and outlet water temperature, water pressure, and air volume in real time to ensure they are within the rated range of the equipment. If any abnormalities are detected (such as excessively high temperatures or low water pressure), immediately shut down the unit for inspection.

III. Precautions During Operation

Regularly Check Water Level and Water Quality

During operation, regularly check the water level in the water tank to prevent low water levels due to evaporation. Also monitor water quality. If scale, algae, or corrosion are detected, promptly treat or replace the cooling water.

Observe the Spray System

Ensure that the spray nozzles are unblocked and that the spray water evenly covers the cooling coils. If the spray is uneven, clean the nozzles or adjust the water pressure.

Check Fan Operation

Observe the fan for abnormal noise or vibration, belt slack, or motor overheating. If any problems are detected, shut down the unit for maintenance.

Preventing Scaling and Corrosion

Add corrosion inhibitors or scale inhibitors, depending on the water quality, to extend the equipment's service life. Clean the coils and water tank regularly to prevent impurities from accumulating and affecting heat exchange efficiency.

IV. Shutdown Procedures

Stop the Fan

First, shut down the fan to stop air flow and prevent localized overheating of the coil due to sudden air interruption.

Stop the Water Pump

Run the water pump for a while (usually 5-10 minutes) to drain any remaining water from the pipes, then shut it down to prevent water hammer damage to the pipes.

Drain the System (If the equipment is to be shut down for an extended period)

If the equipment is to be shut down for an extended period, drain the water tank and pipes and clean the interior to prevent scale and corrosion.

Disconnect the Power

Ensure that all equipment has stopped operating before disconnecting the main power supply to prevent standby power consumption or electrical failures.

V. Maintenance and Care Recommendations

Regular Cleaning

Inspect and clean the sprinkler heads, filters, and cooling coils monthly to prevent blockages that could affect cooling efficiency.

Check Seals

Regularly inspect the seals at the water tank and pipe connections to prevent leaks.

Lubricate the Fan Bearings

Lubricate the fan bearings quarterly (if necessary) to extend their service life.

Winter Antifreeze Measures

In cold regions, drain the system or add antifreeze after shutdown to prevent the water tank and pipes from freezing and cracking.

Proper operation and maintenance procedures outlined above will ensure long-term stable operation of closed-loop evaporative coolers, ensuring efficient cooling while reducing energy consumption and maintenance costs.