In this article, we are going to learn briefly how to do dehumidifier sizing of different types of dehumidification units. In other words, we are going to do the moisture load calculation and accordingly select dehumidifiers. Here, I would like to mention that this article will explain the dehumidifier calculation of a refrigerant-based dehumidifier only.
There will be a separate article on desiccant dehumidifier calculation. We will see how to do the calculation for three different types of dehumidifiers and those are home dehumidifier, industrial dehumidifier, and swimming pool dehumidifier. In every case, humidity contributing factors are different, and hence, we need to consider all those factors while making the moisture load calculation sheet.
For example, in a swimming pool application pool surface is the biggest moisture contributing factor, while at home might be fresh air or air from outside due to the opening of doors and windows. Hence, we will see all three calculations separately.
Home dehumidifier sizing
At home, humidity is generated due to outside air entering through the open door, window, and the fresh air taken by the air conditioner. It can also be due to the water work in the kitchen area. It means that only the volume of air is the main moisture contributing factor. This is reason by home dehumidification load calculation is simpler than commercial dehumidifier sizing.
This widely used method is recommended by the Association of Home Appliances Manufacturers (AHAM), which is also known as the AHAM dehumidifier sizing guide. This method basically sizes a dehumidifier on the basis of two factors. The first one is the area of the room, and the other is the humidity level in the room.
This method divides the humidity level into four types, i.e., extremely wet area, very wet area, very damp area, and moderately damp area in descending order of humidity level in the room. Also, it provides a table that gives the liters per day capacity required for different sizes of rooms under those humidity levels. Hence, one can easily calculate the size of the home dehumidifier. Please refer to this article for more details.
Industrial Dehumidifiers Capacity Selection
For a commercial dehumidifier, other than the size of the room, we need to consider the temperature of the room and different moisture contributing factors, as per the application. Also, since these units are required to use a certain humidity which is needed for industrial processes, the required humidity level or the humidity level to be achieved plays an important role in the sizing of industrial dehumidification units.
The moisture contribution factor can be different in different applications. For example, in the laboratory, which requires 100% fresh air, moisture is contributed by outside air. While in the case of a commercial catering kitchen, the moisture load is due to water vapor during cooking.
Hence, for commercial dehumidifier capacity calculation, we need to consider different moisture loads at the site and also the number of people working at the site. You need to have a different approach for each site. There is no fixed dehumidifier calculation chart for industrial dehumidifiers.
Moisture load calculation for Swimming pool Dehumidifier
An indoor swimming pool is the worst kind of load for any dehumidifier. While calculating swimming pool dehumidification, we need to consider five factors, which are as follows are surface area of swimming pool, volume of indoor pool room, maximum water temperature of swimming pool water, room temperature, and type of swimming pool.
Moisture load will be higher if the surface area of the indoor pool and the pool water temperature are higher. While the type of pool decides the activity factor in a pool. This activity factor varies from o.5 to 1. For example, for a home swimming pool, use is limited, hence the activity factor is lowest, that is 0.5, while for a sport complex swimming pool used continuously by many swimmers simultaneously, hence activity factor going to to height and that is 1. I hope this article will help to understand dehumidifier calculation.
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