In the early days, evaporative condensers were mainly used in areas with high temperatures, humid heat, and high air humidity in summer. Nowadays, evaporative condensers are widely used in chemical industries, such as methanol distillation, methanol conversion, toluene, chloromethane, and other production processes.
- Selection of evaporative condensers in different regions
Among the various factors that affect the heat load per unit area, condensation temperature and air inlet temperature are the most significant, followed by frontal wind speed, and the spray water volume has the least impact.
The calculation formula for the condensation temperature tk of an evaporative condenser is:
Tk=ts+/t
In the formula, ts represents the wet bulb temperature of the inlet air of the condenser, ℃;
△ t - The temperature difference between the inlet and outlet of the cooling medium, generally ranging from 8 ℃ to 15 ℃. The smaller value is taken in dry areas and the larger value is taken in humid and hot areas;
The wet bulb temperature is determined by local meteorological conditions, and the condensation temperature is selected during design. The higher the condensation temperature, the lower the refrigeration capacity. The lower the condensation temperature, the higher the refrigeration capacity; When the wet bulb temperature exceeds 25 ℃, the condensation temperature should be 5 ℃~15 ℃ higher than the wet bulb temperature; When the wet bulb temperature is less than 25 ℃, the condensation temperature should be 8 ℃~15 ℃ higher than the wet bulb temperature, and the higher the wet bulb temperature, the smaller the temperature difference with the condensation temperature can be taken. The lower the wet bulb temperature, the larger the temperature difference with the condensation temperature can be taken. Therefore, it is particularly important to choose different types of evaporative condensation correctly according to different regions.
- Matching of evaporative condenser and compressor
The total heat dissipation of the system is the sum of the cooling capacity of the compression mechanism and the power consumption of the motor. The total condensing area of the condenser should be able to meet the maximum load requirements of actual operation, with a certain margin. In actual construction, the correction coefficient of the condenser should also be considered (the correction coefficient represents the standard heat dissipation capacity coefficient of the equipment corresponding to the required heat dissipation of the system under operating conditions. The larger the coefficient, the greater the corresponding standard heat dissipation of the equipment to be selected, and the lower the standard heat dissipation of the equipment; otherwise, the smaller the coefficient, the smaller the corresponding standard heat dissipation of the equipment to be selected, and the higher the standard heat dissipation capacity of the equipment).
- Tubing method for evaporative condensers (single or multiple in parallel)
The installation form of the piping in an evaporative condenser has a significant impact on the operating efficiency of the condenser. Especially when multiple evaporators are connected in parallel, if the installation is not reasonable, the pressure drop in one coil is greater than that in another coil, resulting in different outlet pressures of the coil. As a result, the liquid refrigerant will be forced into the coil with the maximum pressure drop. Therefore, a reasonable piping method is also a key focus of condenser operating efficiency research.
