Requirement of Maintaining Indoor Relative Humidity
Requirement of Maintaining Indoor Relative Humidity
(OP)
Presently, I am designing a HVAC system for the factory. It is strictly required to maintain indoor relative humidity between 55 % to 60 % in raw material processing area in a factory. There is no specific requirement of maintaining space temperature in that space. The factory is located in a desert where the ambient conditions are extremely hot and humid in summer. In peak summer, the outside relative humidity reaches to the saturation lavel.
I would like to know whether a normal split unit can meet the criteria or considering dehumidifiers would be the best option.
Please share your valuable advise.
I would like to know whether a normal split unit can meet the criteria or considering dehumidifiers would be the best option.
Please share your valuable advise.





RE: Requirement of Maintaining Indoor Relative Humidity
What desert are you in that is both hot and humid? how is winter? your system has to work in all seasons.
Keeping 55-60% accurately 24/7/365 will require more than a split system and possibly redundancy depending on if those levels can be exceeded for periods of time.
this is stricter than a museum, what factory is that?
RE: Requirement of Maintaining Indoor Relative Humidity
you cannot maintain humidity in ordinary residential space with "normal" split unit, and in situation where the whole your process depends on narrow range of humidity values, not only that you would need both humidification and dehumidification, but you would need lot of study about how to place sensors, how to separate process area from other areas, solve communications with other areas.
not a something to play with especially if you cannot run away from angry client as you are in a middle of a desert.
RE: Requirement of Maintaining Indoor Relative Humidity
This factory will be built in the Arabian desert where the temperature during the day time may reaches to 50 C and during the evening, the RH may reach to the saturation level but it cannot be hot and humid and the same time.The process area is an enclosed area where there is a requirement of maintaining RH between 55 % to 60 %.
Can we achieve this task by dehumidifiers. Please advise.
RE: Requirement of Maintaining Indoor Relative Humidity
And how does the material arrive, does it come in 55% RH railway cars? I mean does it come dryer or wetter? that also would generate or reduce humidity in the space.
and what place does not have ventilation and infiltration? Don't they open doors to bring hat material in?
you are aware by just getting colder/warmer in the space (even id you do nothing to add or subtract water), RH will change dramatically?
RE: Requirement of Maintaining Indoor Relative Humidity
if you heat this place by electrical heater (sensible heating) for example to 90F DB, the RH would be about 69%, if you heated to 95F db RH would be about 59%
check psychometric chart
RE: Requirement of Maintaining Indoor Relative Humidity
RE: Requirement of Maintaining Indoor Relative Humidity
Confirm the conditions required.
Is it ok if humidity goes down below 55%?
Otherwise you will need to install humidifiers.
For sure direct expansion splits are not an option.
RE: Requirement of Maintaining Indoor Relative Humidity
you need good psychrometric calculation to determine your unit size, as well as all other engineering work that makes ac design and cannot be covered in tip.
you certainly need at least some fresh air to be taken into account, even if there are no operators who permanently stay in space
RE: Requirement of Maintaining Indoor Relative Humidity
RE: Requirement of Maintaining Indoor Relative Humidity
By using deep cooling unit with humidity sensor that adjust the controller to the required humidity limit, if the RH exceeded the set point the controller will run all the cooling stages to reduce the humidity through deep cooling then after that it will run the heaters to maintain the required room temperature. This a a special unit to cater the requirement of maintaining space relative humidity.
Hope this is the unit which I am looking for.