One article showing you what’s a desiccant dehumidifier easily

What is a desiccant dehumidifier? How much do you know about this field? Can you briefly explain the

working principle of a desiccant dehumidifier? What are the core parameters of a desiccant dehumidifier?

How to choose a model? These questions that many people will encounter in interviews. For those who

have never been exposed to it, it is undoubtedly very complicated and will be confused when asked directly,

but don't be afraid, this article will show you a comprehensive understanding of industrial dehumidifiers!

1. Basic introduction

First, what is a desiccant dehumidifier?

Literally:, desiccant dehumidifier, also named as rotary dehumidifier, or adsorption dehumidifier, or wheel

dehumidifier, they express one same machine, and the desiccant dehumidifier is one more popular expression.

A desiccant dehumidifier is an air treatment device with a rotary wheel and better dehumidification effect than

an ordinary air conditioning unit. It can be directly understood as adding a rotary wheel and some other equipment to

the air conditioning unit.

Secondly, what is a rotary wheel and what is its function?

The rotary wheel is made of highly absorbent materials, usually silica gel, molecular sieve, alumina, etc. Its function

is to absorb moisture from the air after refrigeration and dehumidification, making the air drier. So how to remove the

moisture from the rotor after it absorbs the moisture? At this time, you need to know another thing that is different from

ordinary air conditioners - regeneration exhaust. The rotor continuously absorbs moisture from the air, and the

high-temperature regeneration heating air is continuously dried to exhaust the moisture in the rotor outside the unit.

2. General structure and working principle of desiccant dehumidifier

As mentioned earlier, the desiccant dehumidifier is an ordinary air conditioning unit + rotary wheel + regeneration

exhaust system, so it also has everything that the air conditioning unit has.

2.1. Air supply

Fresh air valve, return air valve: control the fresh air volume and return air volume through the valve opening;

Junior and middle school high-efficiency filters: needless to say, the previous article has a detailed introduction;

Fresh air pre-cooling (front surface cooling): the fresh air is subjected to the first freezing and dehumidification

to reduce the dew point temperature of the supply air (the degree of reduction is related to the chilled water supply

temperature);

The first rotor (front rotor): adsorbs and dehumidifies the air after freezing and dehumidification to further reduce the

dew point temperature of the air;

Return air fan (also known as air supply fan 1): provides power for fresh air and return air;

Middle surface cooling: freezes and dehumidifies the air again;

Rear rotor: further absorbs moisture in the air;

Air supply fan 2: provides air power and wind pressure.

Rear surface cooling: control the air supply temperature (under normal conditions of the unit, the air at the rear

surface cooling is very dry, the air dew point is very low, and no condensed water is precipitated);

Post-heating: control the air supply temperature;

The above is the air supply process.

2.2. Exhaust

Use a part of the air after the middle surface cooling as the air intake of the regeneration exhaust system,

because this part of the air is relatively dry, reducing the wet load brought to the regeneration system.

Regeneration heating 1: heat the air to increase the enthalpy value of the air;

The heated air contacts the rotor 2, and the high-temperature air evaporates the moisture in the rotor into the air,

so that the rotor restores its water absorption capacity, and the wet air enters the regeneration heating 2

Regeneration heating 2: heat the regeneration air after the rotor 1 again;

The heated air contacts the rotor 1, and the high-temperature air evaporates the moisture in the rotor into the air, so

that the rotor restores its water absorption capacity, and the wet air is discharged from the system and enters the outside air;

Regeneration fan: provide power for the regeneration exhaust system.

Regeneration exhaust heating is generally steam heating or electric heating. According to actual usage, steam heating

is more cost-effective if there are many units and large demand. Electric heating is more convenient if there are few units.

3. General parameter settings for dehumidifier operation

Front cooling temperature set to 7-10℃ Intercooling temperature set to 12-16℃ Supply air temperature set to 18℃

Regeneration temperature set to 100-150℃ When setting the regeneration temperature, pay attention to the regeneration

exhaust outlet temperature. If the outlet temperature is too high, it proves that there is a lot of energy waste, so it can be

set appropriately lower.

In general, the unit only needs to set the supply air temperature (23±2℃), dew point temperature (-40℃), and indoor

positive pressure (10-15Pa) to achieve automatic control. However, appropriate human intervention and regulation

can reduce the energy consumption of dehumidifier operation.

4, selection factors of desiccant dehumidifier

4.1. Air supply volume and fresh air volume

The air supply volume directly affects the indoor clean room conditions. According to the cleanliness level and the

parameters of the clean room such as air supply, exhaust, and fresh air, select a dehumidifier with appropriate air volume.

4.2. Dehumidification volume

The dehumidification volume represents the dehumidification capacity of the dehumidifier, which directly affects whether

the indoor humidity can meet the control requirements.

Note: It is necessary to calculate the indoor humidity production and select a matching dehumidifier. The larger the

better. Often, the larger the dehumidifier, the higher the cost and the higher the energy consumption.

Supply air humidity content < Indoor required humidity content - indoor humidity production

4.3. Supply air temperature and humidity

The supply air temperature and humidity of the dehumidifier directly affect the indoor temperature and humidity,

so the supply air temperature and humidity are also very important

4.4. Cooling capacity, heating capacity, rotor material, etc.

4.5. Heating method and energy consumption

Choose a heating method that meets the actual use needs and reduce the operating energy consumption as much

as possible.

5. Maintenance and care of desiccant dehumidifier

5.1. Replacement of primary and secondary high-efficiency filters According to the usage, the pressure difference

reaches twice the initial resistance, and it needs to be replaced

5.2. Coil purging and cleaning

Purge and clean the coil fins once every 3-6 months

Note: If there is no front heating at the front end of the front surface cooling, antifreeze must be added in winter

or the water in the coil must be drained and cleaned with compressed air, otherwise the coil may be frozen in winter!

5.3. Rotor maintenance

The rotor is purged and cleaned once every three months, the rotor drive is checked once a month, and the rotor seal

is checked once a month

5.4. Grease the fan bearings once every 3-6 months.

Well, till now, you may get a clear understanding for this device. If you want to learn more details , welcome to contact us directly.