Performance advantages of evaporative condensers in refrigeration systems
Time:
Nov 12,2021
The condenser is one of the main heat exchange devices in the refrigeration system. Its function is to cool the high-temperature superheated refrigeration medium vapor discharged by the compressor into a liquid state. Since the 1970s, developed countries have begun to replace water-cooled condensers with evaporative condensers. In recent years, my country has also begun to apply evaporative condensers to various refrigeration systems, including cold storage, central air conditioning, industrial refrigeration units, ammonia refrigeration systems, etc.
Performance advantages of evaporative condenser:
1. Save water
Evaporative condensers make full use of the latent heat of vaporization of water. The general water-cooled condenser can take away 16.75~ 25.12KJ of heat per 1Kg of cooling water, while 1Kg of water can take away about 2428KJ of heat when evaporated at room temperature. Therefore, the theoretical water consumption of evaporative condensers is only 1% of that of water-cooled condensers. Considering factors such as splash loss, sewage exchange and water exchange, the actual water consumption is about 5% to 10% of that of water-cooled condensers. Evaporative condensers greatly reduce water loss, which is of great significance to the northern region where water resources are seriously insufficient in my country.
2. Energy saving
The condensation capacity of the air-cooled condenser is limited by the ambient dry bulb temperature, while the evaporative condenser is limited by the ambient wet bulb temperature, which is 8~ 14 ° C lower than the general dry bulb temperature, plus the upper fan to the equipment. Therefore, compared with the air-cooled condenser, the condensation temperature of the evaporative condenser is lower. For every 1 ° C increase in the condensation temperature, the power consumption per unit cooling capacity will increase by 3% to 3.5%, so the total power consumption of the evaporative condenser will also be significantly reduced, and the energy saving effect is obvious. Compared with other condensers in the HVAC system, it can save energy by 20% to 40%.
3, compact structure
Since there is no need to set up a cooling tower, the entire device has a compact structure, small volume, small footprint, convenient installation and small daily maintenance workload.
4, do not pollute the environment
Many chemical plants used shell-and-tube or shower-type condensers in the past. In summer, due to the high condensing pressure, "venting and decompression" were often used, but each time the non-condensable gas was released, it contained a large amount of ammonia. According to the sampling and analysis of the relevant departments, it was sometimes as high as 90%, which not only caused serious ammonia loss, but also caused environmental pollution. But this phenomenon does not exist after using an evaporative condenser.
At present, evaporative condensers are widely used in western developed countries. In the application of the four nests, due to the lack of water in the northwest region, evaporative condensers are widely used in the northwest region. Hotels, office buildings, shopping malls and other civil buildings and workshops and cold storage, The cooling and air-conditioning equipment of greenhouses and the like basically adopts a energy-saving condenser.
For example, the 10,000-ton refrigerator of an aquatic product company was originally equipped with a vertical shell and tube condenser, and the cooling water was directly supplied with natural lake water, supporting three pumps. The condenser used is seriously corroded and the equipment maintenance is high. Later, the evaporative condenser was used to replace the original non-vertical shell and tube condenser, which saved about 300,000 in annual costs, and the equipment failure rate became smaller and the improvement effect was obvious in all aspects.