An air jet at a temperature of 18 ° C passes into a non-isolated duct through a 32 ° C TBS environment and 60% relative humidity. Under these conditions will there be condensation on the duct?

To solve this type of question, simply use the psychrometric chart. Mark the point relative to the temperature and relative humidity of the external air and draw a horizontal line from right to left, check the point where there is intersection with the saturation line. The temperature found in this case is about 23 ° C. At this point, the dew temperature of the external air is located, ie if the air temperature is cooled below this value, there will be condensation. In this example the dew temperature is 23 ° C and the outside face temperature of the duct is practically 18 ° C (there is no insulation and the conductivity of the plate is high), which makes moisture condensation unavoidable. The solution to this problem is usually achieved by insulation of the duct. Conclusion: There will be condensation on the outer face of the duct because the temperature of the plate is less than the dew temperature of the external air.