Types and characteristics of condensers

According to different cooling media, condensers can be divided into three categories: water-cooled, air-cooled, and evaporative.
（1） Water-cooled condenser
A water-cooled condenser uses water as the cooling medium, and the condensation heat is carried away by the temperature rise of the water. Cooling water is generally recycled, but a cooling tower or cooling water tank is required in the system. Water cooled condensers can be further divided into shell and tube condensers and sleeve condensers according to their structural forms,
A common type is a shell and tube condenser.
1. The main characteristics of a vertical shell and tube condenser are:
1 ° Due to the large cooling flow and high flow rate, the Heat transfer coefficient is high, generally K=600~700 (kcal/m2 · h · ℃).
2 ° vertical installation has a small footprint and can be installed outdoors.
The 3 ° cooling water flows directly and has a high flow rate, so the water quality requirements are not high. Generally, the water source can be used as cooling water.
The scale inside the 4 ° pipe is easy to remove and there is no need to stop the refrigeration system.
5 ° But because the temperature rise of cooling water in the vertical condenser is generally only 2-4 ℃, and the Logarithmic mean temperature difference is generally about 5-6 ℃, the water consumption is large. Moreover, due to the equipment being placed in the air, the pipes are prone to corrosion and leaks are more easily detected.
2. Horizontal shell and tube condenser
It has a similar shell structure to a vertical condenser, with the main difference being the horizontal placement of the shell and the multi-channel flow of water. Horizontal condenser is not only widely used in ammonia refrigeration system, but also in Freon refrigeration system, but its structure is slightly different. The cooling pipe of ammonia horizontal condenser adopts smooth seamless steel pipe, while the cooling pipe of Freon horizontal condenser generally adopts low rib copper pipe. 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 cylinder, but only use a few rows of tubes at the bottom of the condenser to serve as a liquid storage cylinder.
3. Sleeve condenser
The vapor of the refrigerant enters the cavity between the inner and outer tubes from above, condenses on the outer surface of the inner tube, and the liquid flows down in sequence at the bottom of the outer tube, flowing into the reservoir from the bottom. Cooling water enters from below the condenser and flows out from above through each row of inner pipes in reverse flow with the refrigerant. The advantages of this condenser are simple structure, easy to manufacture, and good heat transfer effect due to single tube condensation and opposite medium flow direction. When the water flow rate is 1~2m/s, the Heat transfer coefficient can reach 800 kcal/(m2 · h · ℃). Its disadvantage is that the metal consumption is high, and when there are many longitudinal pipes, the lower pipes are filled with more liquid, which makes the heat transfer area unable to be fully utilized. In addition, the compactness is poor, cleaning is difficult, and a large number of elbows need to be connected. Therefore, this type of condenser is rarely used in ammonia refrigeration devices.
Air-cooled condenser
Air cooled condensers use air as the cooling medium, and the condensation heat is carried away by the temperature rise of the air. This kind of condenser is suitable for occasions where water is extremely scarce or cannot be supplied. It is commonly used in small Freon refrigeration units. According to different air flow modes, it can be divided into Natural convection type and forced convection type.