According to different cooling media, the condensers of Dongguan water chillers can be divided into three categories: water cooled, air cooled, and evaporative.
（1） Water cooled condenser
Water cooled condensers use water as the cooling medium, and the temperature rise of water takes away the condensation heat. Cooling water is generally recycled, but a cooling tower or cooling pool is required in the system. According to its structure, water cooled condensers can be divided into shell and tube condensers and sleeve condensers,
A common type is a shell and tube condenser.
1. The main characteristics of a vertical shell and tube condenser are:
Due to the large cooling flow rate and high flow rate, the heat transfer coefficient is relatively high, generally K=600~700 (kcal/m2 · h · ℃).
The 2 ° vertical installation has a small footprint and can be installed outdoors.
"The 3 ° cooling water flows directly and has a large flow rate, so it does not require high water quality. Generally, water sources can be used as cooling water.".
The scale in the 4 ° pipe is easy to remove, and it is not necessary to stop the refrigeration system.
"However, since the temperature rise of cooling water in vertical condensers is generally only 2-4 ℃, and the logarithmic average temperature difference is generally around 5-6 ℃, the water consumption is relatively high.". Due to the equipment being placed in the air, the pipes are prone to corrosion and leakage is more easily detected.
2. Horizontal shell and tube condenser
It has a similar shell structure to a vertical condenser, with the main differences being the horizontal placement of the shell and the multi-channel flow of water. Horizontal condensers are widely used not only in ammonia refrigeration systems, but also in freon refrigeration systems, with slightly different structures. The cooling pipes of ammonia horizontal condensers are made of smooth seamless steel pipes, while the cooling pipes of Freon horizontal condensers are generally made of low rib copper pipes. This is due to the low heat release coefficient of Freon. It is worth noting that some Freon refrigeration units generally do not have a liquid storage tank, and only use a few rows of tubes at the bottom of the condenser to serve as a liquid storage tank.
3. Tubular condenser
The refrigerant vapor enters the cavity between the inner and outer tubes from above, condenses on the outer surface of the inner tube, and the liquid sequentially flows downward at the bottom of the outer tube, flowing from the lower end into the reservoir. The cooling water enters from below the condenser and flows out from above through each row of inner pipes in turn, in a countercurrent manner with the refrigerant. The advantage of this type of condenser is that it has a simple structure and is easy to manufacture. Due to the single tube condensation and the opposite flow direction of the medium, the heat transfer effect is good. When the water flow rate is 1 to 2 m/s, the heat transfer coefficient can reach 800 kcal/(m2 · h · ℃). The disadvantage is that the metal consumption is large, and when the number of longitudinal tubes is large, the lower tubes are filled with more liquid, making it impossible to fully utilize the heat transfer area. In addition, the compactness is poor, cleaning is difficult, and a large number of elbows need to be connected. Therefore, this type of condenser has been rarely used in ammonia refrigeration devices.
Air cooled condenser
Air cooled condensers use air as the cooling medium, taking away condensation heat by the temperature rise of the air. This type of condenser is suitable for situations where water is extremely scarce or unavailable, and is commonly used in small Freon refrigeration units. According to different air flow modes, it can be divided into two types: natural convection type and forced convection type.
（2） Evaporative condenser The heat exchange of an evaporative condenser is mainly carried out by evaporating cooling water in the air to absorb the latent heat of gasification. According to the air flow mode, it can be divided into suction type and pressure type, as shown in the figure. The evaporative condenser consists of a cooling pipe group, water supply equipment, a ventilator, a water baffle, and a box body. The cooling pipe group is a serpentine coil group made of seamless steel pipes, which is installed in a rectangular box made of thin steel plates. Ventilators are provided on both sides or top of the box, and the bottom of the box doubles as a cooling water circulating pool. Parallel connection of evaporative and shell and tube condensers:
（3） The air cooled condenser uses air as the cooling medium, and the condensation heat is carried away by the temperature rise of the air. This type of condenser is suitable for situations where water is extremely scarce or unavailable, and is commonly used in small Freon refrigeration units. According to different air flow modes, it can be divided into two types: natural convection type and forced convection type.