1.tructurally dense with a lower occupying area, it is beneficial for the inadequate occupying space.
2.Due to the smaller volume and lower structural requirement, the initial setup costs are lower.
I. What is a cooling tower? What are its uses?
A cooling tower is also known as the heat dissipation tower. Cooling is required in many processes or equipment, with industrial applications accounting for more than 90%. Moreover, due to climatic factors, air cooling systems are no longer able to meet the need for higher water cooling efficiency (comparing air cooling and water cooling). One of the most common equipment is the cooling tower.
To put it simply, a cooling tower dissipates heat through heat transfer and exchange between water and air (outdoor air). Therefore, climate and water quality are major elements affecting the cooling tower, which also vary according to season, region, terrain, humidity, and temperature. Water is commonly divided into tap water and underground water, and pure water and brine water systems are set up in some venues.
A cooling tower structurally consists of:
Fan: The saturated moisture in water requiring cooling is removed by the wind generated from a running fan.
Water dispersion system: Evenly disperses water and increases the heat dissipation area.
Heat sink: Reduces the water sliding speed, generate water film, and extend the water film and air contact time in order to enhance cooling efficiency.
Water tank: Collect cooled water, which is sent to the process system or equipment through a pump.
Cooling tower operation principles:
The operation of a cooling tower involves a continuous circulation system.
Sequence of heat transmission with water as the medium: cooling tower→water storage equipment (as needed)→water cooled chiller (as needed)→process system or equipment→cooling tower
Fan: The saturated moisture in water requiring cooling is removed by the wind generated from a running fan.
Water dispersion system: Evenly disperses water and increases the heat dissipation area.
Heat sink: Reduces the water sliding speed, generate water film, and extend the water film and air contact time in order to enhance cooling efficiency.
Water tank: Collect cooled water, which is sent to the process system or equipment through a pump.
The operation of a cooling tower involves a continuous circulation system.
Sequence of heat transmission with water as the medium: cooling tower→water storage equipment (as needed)→water cooled chiller (as needed)→process system or equipment→cooling tower
| Counter flow | Cross flow | |
| Open type (conventional) | Counter flow-type open tower | Cross flow-type open tower |
| Closed type | Counter flow-type closed tower | Cross flow-type closed tower |
II. Major difference between closed towers and open towers
Closed-loop cooling tower (“closed tower”) Conventional cooling tower (“open tower”)
Extra circulation in the closed tower: We are all aware that the biggest problem of conventional open towers lies in scaling (calcium deposition), and impurities (minerals) in water and dust in the air that condenses due to heat will block the pipeline, resulting in reduced heat dissipation efficiency and the need for frequent cleaning. Most cleaning methods involve the use of pipeline cleaning agents, which are erosive ad may negatively impact efficacy in the long run. However, there is an additional heat exchange equipment (closed coil) in a closed tower, which is divided into internal circulation (primary side) and external circulation (secondary side). The cooling water entering the machine passes through the heat exchanger and is separated from external water to keep clean. The cooling efficiency of processes or equipment can in turn be maintained, thereby reducing the need to clean and maintain equipment pipelines.
Advantages and disadvantages
| Advantages | Disadvantages | |
| Open type (conventional) |
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| Closed type |
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III. The operational principles and types of closed-type cooling towers
Closed towers adopt the principle of internal circulating water and external circulating water separation to prevent the generation of scaling on equipment. The characteristic lies in adding a heat exchange device (our heat-dissipation coil) in the open tower. Using the heat-dissipation coil, the cooling system is divided into the internal circulating system (primary side system) and the external circulating system (secondary side system). The internal circulating system is in the closed tower and process system. The equipment end generates closed circulation to supply cooling water. The external circulating system uses the secondary side spray to spray the heat dissipation coil through the heat sink, indirectly cooling the internal circulating system and keeping the internal circulating water clean.
The types come in many patterns. The most common and the largest system consists of the following two types:
1.Counter flow closed tower
The air flow direction and water flow direction are in reverse flow. Due to the opposing direction, the cooling part can achieve the largest heat dissipation area. Conversely, a large amount of air is needed due to the great resistance. Therefore, the heat sinks and basin require a certain height.
Advantages:
Disadvantages:
1.Due to the structural support, the heat sink and closed coil have a limited capacity. Single units are less likely to be used as large units (except as multiple units connected in series).
2.Due to the great air inlet requirement, the inlet is higher with louder falling water sound (a noise-absorbing blanket may to reduce the falling water sound)
2.Due to the great air inlet requirement, the inlet is higher with louder falling water sound (a noise-absorbing blanket may to reduce the falling water sound)
2.Cross flow closed tower
The air flow and water flow direction are in vertical flow. The water flow direction is from top to bottom. The air flow from the side and the water flow direction are vertical. Since the air enters horizontally, the height of the heat sink and closed-type coil can be lowered to approximate the basin and reduce the large amount of falling water sound.
Advantages:
1. The design is simpler with a lower height and is easy to maintain (usually with a repair channel installed).
2. Since the height is lower, the water pressure and noise levels are extremely low.
3. Allows for heat sinks and heat dissipation coils, which are suitable for those with greater cooling needs.
2. Since the height is lower, the water pressure and noise levels are extremely low.
3. Allows for heat sinks and heat dissipation coils, which are suitable for those with greater cooling needs.
Disadvantages:
1. With the same tonnage, the lower height means a larger need for an occupying area.
2. Due to the larger volume and more numerous structures required, the initial setup costs are higher.
2. Due to the larger volume and more numerous structures required, the initial setup costs are higher.
IV. How do LYHO’s cooling towers differ? What are the advantages?
In response to the current adverse environmental needs, we have further upgraded efficiency, replacing manual operations with computerized control. With energy saving, environmental protection, and enhanced efficiency as the premises, we endeavor to better meet the needs of all.
(1) Closed coil: Switch from existing smooth pipes into thread pipes.
(2) Low-population and recoverable heat sinks: Increase surface contact area and recover old items, so as not to cause social burden.
(3) EC fans: Combine high-efficiency fans, motor, and inverter in one (complemented by fully automated control system).
(4) Automatic control system: Digital and intelligent control, real-time monitoring of equipment status (instant rotational speed, power consumption, temperature, etc.), easy-to-use smart functions.
(1) Closed coil: Switch from existing smooth pipes into thread pipes.
(2) Low-population and recoverable heat sinks: Increase surface contact area and recover old items, so as not to cause social burden.
(3) EC fans: Combine high-efficiency fans, motor, and inverter in one (complemented by fully automated control system).
(4) Automatic control system: Digital and intelligent control, real-time monitoring of equipment status (instant rotational speed, power consumption, temperature, etc.), easy-to-use smart functions.
V. Comparison between air cooling and water cooling:
What is air cooling? What is water cooling? What is the difference between air cooling and water cooling?
In general, the common heat exchange (heat sink) systems consist of two systems: air cooling and water cooling. Air cooling, as implied by the name, relies on air as the medium. Through the fan and heat exchanger (heat sinks), heat dissipation is achieved. Therefore, the air temperature becomes an important heat dissipation factor. For example, the atmospheric temperature in summer is high. In contrast, heat dissipation relies on the characteristics of “sensible heat”, while the level of “heat sensibility” depends only on the atmospheric temperature. However, water cooling has the physical characteristic of potential heat compared to air cooling. When water is subjected to heat and evaporated into water air, the heat exchange efficiency is staggering, several times higher than that of air cooling. Below is the comparison table of air cooling and water cooling.
| Air cooling | Water cooling | |
| Specific heat capacity (j/kg/k) | 1006 | 4179 |
| Heat transmission coefficient (W/m.k) (W/mk) | 0.024 | 0.58 |
| Conversion efficiency (%) | 25 | 75 |