Condensing pressure and temperature

Condensing pressure and temperature

The refrigerant inside the condenser is usually in a saturated state, so its pressure and temperature can be searched for each other through the corresponding thermodynamic properties table of the refrigerant.

The condensation temperature of water-cooled units is generally 2 ℃ to 4 ℃ higher than the outlet temperature of cooling water. If it is too high, the copper pipes inside the condenser should be checked for scaling and cleaned.

The high or low condensation temperature, while keeping the evaporation temperature constant, has a decisive significance for the power consumption of the chiller unit. The increase in condensation temperature leads to an increase in power consumption. On the contrary, as the condensation temperature decreases, the power consumption also decreases. When air is present in the condenser, the temperature difference between the condensation temperature and the outlet of the cooling water increases, while the temperature difference between the inlet and outlet of the cooling water actually decreases. At this time, the heat transfer effect of the condenser is not good, and the outer shell of the condenser feels hot to the touch.

Scaling and sludge on the water side of condenser tubes also play a significant role in heat transfer. Therefore, during the operation of the chiller unit, attention should be paid to ensuring that the cooling water temperature, water quantity, water quality and other indicators are within the qualified range.

Pressure and temperature of chilled water

Air conditioning chillers are generally operated under the nominal operating conditions of a chilled water return temperature of 12 ℃, a supply temperature of 7 ℃, and a temperature difference of 5 ℃.

According to 【 Q=W × △ t 】, it can be seen that the flow rate of chilled water through the evaporator is inversely proportional to the temperature difference between the supply and return water, that is, the larger the chilled water flow rate, the smaller the temperature difference; On the contrary, the smaller the flow rate, the greater the temperature difference.

The principle of valve opening adjustment:

1. The evaporator outlet has sufficient pressure to overcome the resistance in the closed circulation pipeline of chilled water.

2. The chiller unit operates under the designed load, with a temperature difference of 5 ℃ between the inlet and outlet of the evaporator.

Although the chilled water system is enclosed, the scaling and corrosion inside the evaporator water pipes will not be as severe as in the condenser. However, starting from the requirements of equipment inspection and maintenance, the evaporator pipes and other pipes of the chilled water system should be cleaned every three years.

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