dehumidifier evaporating temp

[crocens]

Hi all.

First of all, sorry for my english, i'm from Poland

My question is only teoretical. Let say we have an air dryer, power from 25kW to 100kW, air flow through evaporator about 16000 m3/h.Air temp. 14deg. C.

What is a good evaporating temperature? must it be above 0 deg. C to avoid evaporating freezing, or can it be for ex. -5 deg. C?

[NoNickName]

Temperature at any point of the coil shall never be below 0°C to avoid frosting.
The best temperature is a compromise between compressor efficiency and dehumidification capacity.
If you are designing a new system, you may need to tabulate compressor power input against dehumidification capacity, and find your best breakeven point.

[Sandro Baptista]

It also depends on what relative humidity you want for a specific air temperature of the medium.

The evaporating temperature could be a little below 0ºC with no problem giving you the possibility to increase the capacity of the cold coil.

[botrous]

The evaporation tempreture should be below the dew point of the air to be treated.
Depending on the design conditions, leave a deltaT of 5 degree between the dew point and the evaporation tempreture as a minimum difference , but make sure you are always positive.