What is the difference between indirect and direct cooling system?

- Mar 13, 2020-

Chiller is a kind of refrigeration equipment that can provide industrial chilled water. It is widely used in electroplating, plastics, electronics, food, card manufacturing, chemical, machining, laser and other industries. When the chiller is working, it can choose its freezing method according to customer needs: direct freezing and indirect freezing. Maybe many customers don't understand this very well, we will explain it in detail below.

What I want to analyze today is the difference between direct cooling and indirect freezing of water-cooled chiller in the electroplating industry.

I. Indirect freezing method

The working principle of indirect freezing of water-cooled chiller: Water-cooled chiller needs to use cooling water tower and circulating chilled water pump. The water in the basin at the bottom of the cooling water tower is transferred to the condenser of the water-cooled chiller through the circulating chilled water pump. Cool down. Then it flows back to the interior of the cooling water tower for spraying down, cools the water through the cooling water tower's sprinkler system, and then flows back to the water basin at the bottom of the cooling water tower, so that it runs repeatedly.

While the condenser is dissipating heat, the refrigerant R22 inside it is liquefied, and then flows into the evaporator in the water tank of the water-cooled chiller to evaporate, and to absorb heat during evaporation, the temperature in the water tank is cooled, and the cooled water passes through the circulation The water pump sends it to the heat exchanger (separated in the middle, with water and sulfuric acid), and then the sulfuric acid is cooled by the process of heat transfer. The advantage of this chiller is that it is easy to install, its service life is longer than that of directly frozen chiller, and acid and alkali are not easy to corrode the chiller.

2 、 Direct freezing method

Working principle of direct cooling of water-cooled chiller: Similarly, water-cooled chiller needs to use a cooling water tower and a circulating chilled water pump. The water in the bottom of the cooling tower is transferred to the condenser of the water-cooled chiller through the circulating chilled water pump, so When the device cools down, and then flows back to the interior of the cooling water tower to spray down, the water is cooled by the cooling tower's sprinkler system, and then flows back to the water basin at the bottom of the cooling water tower, so that it runs repeatedly.

While the condenser is radiating heat, the refrigerant R22 inside it is liquefied, and then flows into the evaporator for evaporation. The heat needs to be absorbed during evaporation, so the sulfuric acid (tank solution) is cooled. The cooled sulfuric acid is sent to the electroplating tank by the water pump. It is the working principle of direct cooling of water-cooled chiller in the electroplating industry.

From the above comparison, we can see that direct cooling and indirect freezing of water-cooled chiller have the same effect, but it is obvious:

1. The direct freezing chiller is not as safe as the indirect freezing chiller, and the direct freezing equipment is easy to corrode, and the life is short compared to that;

2, the direct freezing chiller only has a slight advantage in terms of price, but the price difference is not great;

3. Comparing the service life of the chiller, the indirect refrigeration chiller is several times longer than the direct refrigeration chiller.