Purchaser's Specifications
Purchaser's Specifications must clearly outline all conditions which are applicable to the installation so taht economical cooling tower selection can be made based on a total coat evaluation including not only capital investment but also operationg costs. Items which should be given consideration for inclusion in specifications are listed below :
- Design Conditions
- 1. Total Heat Load:Kca/Hr
2. Circulating Water Flow :M3/Hr
3. Pump Head Required :M
4. Water Inlet Temp : ํC
5. Water Outlet Temp : ํC
6. Ambient Wet Bulb Temp : ํC
7. Average Wind Velocity and Direction
8. Available Installation Area
9. Electrical Voltage and Frequency
10. Conditions of Area Surrounding installation
- Design Conditions
-
1. Mechanical Equipment Material Including fan, Reducer & Drive shaft
2. Meterials of Framework (H.D.G.S / FRP) and Casing
3. Materials and treatment of structure Connectors
4. Materials and treatment of piping systems.
- Other Items
-
1. Purpose of tower usages
2. Location of piping
3. Capacity of cold water basin
4. Time of Delivery
Advantages and features
- 1. Highest Performance
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Provide with more wetted surface for uniform water distribution and higher heat transfer efficiency. The filling and drift eliminator allow the maximum air volume through the cooling tower.
- 2. Lowest Maintenance
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Construct with durable materials for Cooling Tower is H.D.G.S (Standard : ASTM A123)
- 3. Economical Operation
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Optimize with special axial fans, speed reducer and drift eliminator etc. It is maximized the cooling performance at lower energy.
- 4. Noise Level
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Design with large fans at low speed opertion to minimize noise pollution. The venturi fan cylinder will be added on larger Cooling Tower for low noise level.
Recommened Installation area
1. A drafty site is needed for installation.
2. The installation site should be distant from places that are full of dust and acid air.
3. The location should keep aloof from chimney or other heat source areas.
4. Enough space should be made for connection of pipe to main machine.
5. Be sure to keep the tower vertically when installing it, the anchor bolt and steel support of water basin should be locked closely.
6. In design, the air will be sucked in through inlet louver into the tower so the proper distance between louvers and surrounding objects should be kept to avoid air deficiency due to the excessive resistance.
*Please refer to table for the details
| LEC | L |
|---|---|
| 100-125 | More than 2.0 M |
| 150-200 | More than 2.5 M |
| 225-350 | More than 3.0 M |
| 400-600 | More than 3.5 M |
| 700-800 | More than 4.0 M |
| 900-1500 | More than 5.0 M |
make up water
The calculation of make-up water
The gradual loss of circulation water during operation is caused by the following factors :
- During the heat exchange contact of cold air and hot water part of water will be transferred into vapor flowing out of the cooling tower.
- In the situation od large air volume, part of gravitating water will be carried out of the cooling tower due to the cold air being driven by mechanical power (motor and fan)
- When the water is cirulating fo rsame long time, the concentration of solids will increase and water quality will be affected by the grawth of scales so that part of water should be let out and replaced with fresh water.
- 1. The calculation formula of evaporation loss
-
E = Q / 600 = (T2 - T2 ) / 600 x L
*E = Evaporation water (Kg/h)
*Q = Heat load (Kcal/h)
*600 = Water evaporation heat (Kcal/h)
*T1 = Inlet water temperature (°C)
*T2 = Outlet water temperature (°C)
*L = Circulating water flow (Kg/h)
- 2. The loss of carry over.
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The loss of carry-over depends on the design of cooling, velocity, etc. Generally speaking the loss is equal to 0.1% to 0.3% circulation water.
- 3. The loss of regular blow-down
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To decrase the loss of regular blow-down, please follow the procesures below:
- The drain on cold water basin should be opened a little bit when the cooling tower is in operation.
- The operational water level should be increased tolet the water anytime flow out of the overflow outlet
- The water in the cold water basin and pipes should be replaced seasonally. The loss of regular blow-down is determined by the water quality and its concentration of solids. Generally, the loss is about 0.3% of circulating.
- 4. Make-up water
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The total make-up water of cirlating water is equal to :
M = E + C + D
M = Make-up water
E = Evaporation loss
C = Carry-over
D = Regular blow-down loss
when the cooling tower is rigged on air conditioner, its cooling range is set up at 5 °C in this case, The make-up water needed for cooling tower is about 2% of circulation water.
Referance
