Seeking guidance on calculations for converting air-cooled to water-cooled compressors
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This post was last edited by wwn10 on 2021-3-9 22:21. Our company has three screw air compressors, model: D110W-8； Parameters: volumetric flow rate of 20.6 m3/min, operating pressure of 0.8 MPa, power of 110 KW, oil volume of approximately 72 liters (other parameters are unknown) ； It was originally designed to be water-cooled; however, due to issues such as water shortages and poor water quality (as recycled wastewater was used), the oil coolers accumulated scale frequently, resulting in poor heat exchange performance. The exhaust temperature of the air compressor reached 110°C, causing the machine to shut down. Even after acid cleaning, the coolers developed scale again within less than half a month, so the performance was not satisfactory. (These are the reasons, but they’re not what I want to ask about.) I now wish to convert the air compressor to an air-cooled version. The manufacturer’s proposal is to add 2 fans with a power of 2.2 KW each (see the attached diagram). I would like to ask: 1. How was the required amount of cooling air specified in the table calculated? 2. How is the heat transfer power calculated? 3. How is motor power calculated?
It’s better to address this issue from the perspective of changes in water quality. If it is air-cooled, it is greatly affected by changes in the atmospheric environment, and energy consumption also needs to be taken into account. Considering the joint construction of water treatment facilities using other equipment is also a common approach these days, for your reference.
Both the air volume and heat transfer capacity are determined through thermal balance calculations. The motor power is selected based on the fan diameter, air volume, and wind pressure. I’m not sure whether this air cooling system uses a plate-fin design or a tube-in-fin design; my home unit uses the tube-in-fin type
Heat transfer rate (Kcal/h): Q = m × C × t1, where m is the mass, C is the specific heat, and t1 is the temperature difference. Air volume (m3/h) = Q / (p × c × t1), where p is the density. Knowing the air volume allows one to select the appropriate fan
We can use our family’s cooling cycle water scale removal equipment to remove some of the scaling ions from the water, thereby achieving a scale prevention effect. If you need it, feel free to contact me at 13484284917