Cooling Water System Design

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1. Cooling water circulation system

The outlet temperature of the cooling water of the condenser can generally reach above 37°C. The high-temperature water is cooled by the cooling tower to the inlet water temperature required for cooling the condenser of the chiller, and then sent to the chiller for recycling through the cooling water pump. Since the cooling water system is an open system, the cooling water is easily polluted by external dirt. In addition, the cooling water is mainly evaporative cooling, the amount of water evaporation is large, and the salt substances in the water continue to concentrate and deteriorate the water quality. Therefore, in the cooling water system, it is required to install water filtration and water quality treatment devices.

2. How to choose a cooling tower

★ Directly check the required cooling water volume value according to the refrigerator sample, multiply it by a certain safety margin (1.1~1.2) to calculate the cooling tower water volume value, and then select the model and specification from the product sample according to the cooling tower water volume value.

★The cooling tower can be selected according to the cooling water volume, supply and return water temperature and temperature difference. However, the working principle of the cooling tower mainly relies on the evaporation of water to absorb heat to achieve the purpose of water cooling. It can be seen that the cooling effect of cooling water mainly depends on the air wet bulb temperature, so the technical data of cooling tower products are all data under the established air wet bulb temperature, and the technical data of the product need to be corrected.

★Simple experience value calculation formula:

The total cooling capacity of the equipment (KW) × 860 (kcal) ÷ 3000 = cooling tower water flow, but on this basis, add 25T ~ 100T = cooling tower actual specification flow or cooling tower water flow × 1.2 ~ 1.3 = cooling tower actual Specification flow.

3. Cooling Tower Selection Considerations

(1) If the noise is required to be strict, the ultra-low noise cooling tower can be selected. When the cooling tower also needs to run at night, the cooling tower with variable speed fan can also be selected. At night, the fan runs at a low speed.

(2) When the requirements for aesthetics are high, square towers should be used. Square towers can be used in combination, easy to adjust, and conducive to energy-saving operation, but the investment is high, and the color should be coordinated with the main building.

(3) Ensure good ventilation conditions and rationally organize the airflow of the cooling tower.

(4) Prevent floating water from affecting the surrounding environment.

(5) Consider with or without fire protection requirements.

4. Precautions for the layout of cooling towers

(a) The cooling tower should be installed in a place where the air is smooth and there are no obstacles at the outlet of the fan. If the appearance of the building requires, when the cooling tower needs to be enclosed by louvers, the wind speed at the static hole area of the louver should be less than 2m/s to ensure that there is enough opening surface;

(b) Cooling towers should be located where noise requirements are low and splashing of water droplets is allowed. When there are residences or other buildings nearby and there are certain noise requirements, noise reduction and vibration isolation measures should be considered;

(c) If the cooling tower is installed on the roof or floor, the compressive strength of the structure should be checked;

(d) Cooling towers and refrigerators are generally arranged in a single unit, which is convenient for management;

(e) The make-up water volume of the cooling tower is generally 1∽3% of the circulating water volume of the cooling tower;

(f) In order to prevent the corrosion of the condenser and the cooling water pipeline system, the water quality of the cooling water and the make-up water should reach a certain standard, and if necessary, a dosing device should be installed to treat the cooling water;

(g) When multiple cooling towers are used in parallel, special attention should be paid to avoid uneven distribution of water due to unbalanced resistance of parallel pipelines or overflow of water in the bottom pool of cooling towers. For this reason, valves must be set on each water inlet pipe to adjust the amount of water inlet; at the same time, between the bottoms of each cooling tower, a pressure equalizing pipe (balance pipe) with the same diameter as the water inlet main pipe is connected. In addition, in order to balance the water output of each cooling tower, the water outlet main pipe should be a header that is two sizes larger than the water inlet main pipe and connected with each cooling tower water outlet pipe with a 45º elbow.

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