A dehumidifier is commonly used to decrease moisture and humidity in the air. The dehumidifiers accomplish their work with the help of different types of dehumidifiers. These systems can also achieve their goals by using chemicals which can absorb moisture. 

How Does a Dehumidifier Work?

A dehumidifier regulates the humidity in a room by removing the excess moisture from the air and creating a living environment that is inhospitable to dust, mould, moisture, etc. 

Steps that a dehumidifier takes during operations:

• Firstly, the air is drawn into the unit by a fan from the room
• Then the air is passed over the cold coils
• Air is cooled, and its moisture condenses
• After this step, the water falls into the drip pan 
• Then the air is reheated by a heat recovery system
• And simultaneously, the dry air goes into the room
• Lastly, the dehumidifier will automatically get off after the water is drained.

Types of Dehumidifiers

There are two types of dehumidifiers: Refrigerant dehumidifiers and Desiccant dehumidifiers.

Refrigerant Dehumidifiers:

The dehumidifier uses much similar process to a fridge at our home. The refrigeration process generally cools a metal plate, on which the moisture from the air liquidizes. In this process, a fan constantly draws the air through the dehumidifier and even over the cool metal plates. This process liquidates the moisture onto the plate and drips it into the dehumidifier's water tank. 

Refrigerant dehumidifiers are commonly effective at room temperatures and decline their performance dramatically in cooler conditions. The common reason for the declaration is ice formation on the metal plates. The dehumidifier can work efficiently at lower temperatures but requires higher-performing components to achieve its goals. 

Desiccant Dehumidifiers:

The desiccant dehumidifier is entirely different from the refrigerant dehumidifier. The dehumidifier absorbs water from the air using desiccants, like silica gel. A desiccant is commonly used for absorbing water and is found in small packs in the form of crystals or beads. 

How does the desiccant dehumidifier work?

In the dehumidifier, a wheel consisting of desiccants turns slowly through the incoming air and absorbs its moisture. During the process, a proportion of the wheel passes through the warm air steam, which reactivates the desiccant by absorbing all the moisture. Then the water is collected in the dehumidifier collection tank. This system tends to be relatively smaller and lighter than refrigerant dehumidifiers. The purpose is to choose dehumidifiers that operate at much lower temperatures, particularly in cool areas like garages, workshops, etc. 

The desiccant dehumidifiers generally use silica gel to absorb moisture and humidity. Silica gel makes the dehumidifier more active so that it can absorb more and more moisture and humidity. The silica gel is available in packets, pouches and bulk quantities according to the user's requirements.

Researchers convey that silica gel is a well-known desiccant and even a natural dehumidifier that absorbs moisture by reducing the humidity from the surrounding. Thus, silica gel is an effective desiccant in keeping away mould or mildew from essential products.

Different types of dehumidifiers used in Industrial and Commercial areas:

• Condensate Dehumidifier
• Electric Refrigeration Dehumidifier
• Spray Dehumidifier
• Ionic Membrane Dehumidifier
• Chemical Absorbent Dehumidifier

Condensate Dehumidifiers:

These dehumidifiers use cold devices to collect water from the air. This water is known as condensate, which is usually greywater. The dehumidifier is often used for industrial purposes. 

Electric Refrigeration Dehumidifiers:

It’s very commonly used and draws moist air from a refrigerated evaporator with the help of a fan. The evaporators have a coiled tube, a fin and a tube. The dehumidifier condenses the water, which is being removed, and then the air is reheated by a condenser coil. The preheated air is then released into the room. The dehumidifiers are best at higher ambient temperatures, with high dew points. 

Spray Dehumidifiers:

In spray dehumidifiers, the cold water to a temperature that is below the atmospheric dewpoint. Due to this, the water condenses into it faster than water evaporates. Therefore, the system mixes cold water and air sprays to capture moisture. 

Ionic Membrane Dehumidifiers:

These dehumidifiers use an ionic membrane to remove humidity in or out of a sealed enclosure. These systems mostly use a solid polymer electrolyte membrane (SPE). As a disadvantage, these don't have high dehydration capacities. Dehumidifiers are often used to protect sensitive electrical components, medical equipment, etc., from humidity. 

Chemical Absorbent Dehumidifiers:

The absorbent dehumidifiers, also known as desiccant dehumidifiers, use hydrophilic materials like silica gel to dry the air. Silica gel is one of the best practical solutions for absorbing moisture. The process of removing the moisture from the air is the same as the desiccant dehumidifiers. These dehumidifiers can be used in both commercial and industrial applications. 

Common features of dehumidifiers:

Frost-control sensor: This sensor turns off the dehumidifier if frost begins to form in the coils. This senses the frost and keeps the application free from racking up your energy bills. 

• Clean-filter Alert: The importance of cleaning and maintaining the dehumidifier is to operate it properly. This filter is responsible for cleaning up the air that flows through the system. 

• Water tank size: When choosing a dehumidifier, it is very important to look for a water tank with comfortable handles so that you can remove and carry water easily. 

• Timer: The timer is generally programmed automatically and switches on and off when the work is done. 

What Makes Indicating Silica Gel Stand-Out From Other Desiccants?

Indicating silica gel is unique because it is treated chemically to make the transition possible from one color to another. It absorbs moisture and gradually becomes absolutely drenched in it. This characteristic of indicating silica gel makes it remarkable for absorbing moisture from the surrounding environment it is placed in. Their colors change when the Indicating desiccants are soaked with the surrounding moisture. Hence, indicating to the user that it is high time to replace or recharge the desiccants.

Not only this but Indicating silica gel also has the feature of a rapid detection process that makes it easy for the user to determine the life of desiccants instantly. You can recharge or replace the indicating silica gel when it is out of working efficiency.

And, as the name suggests, non-indicating desiccants do not have this quality to change their color. That is why it makes it difficult for the user to determine the quantity of moisture absorbed by their desiccants. There are two types of indicating silica gel.

Orange Indicating Silica Gel

Orange Indicating silica gel appears orange or yellow when dry or fresh before using it. When the desiccant is completely soaked with moisture and has gained 15 percent more weight, it appears green. Moreover, Orange silica gel is not toxic and is 100% pollution-free. It is environment-friendly and self-sufficient to fulfill all the requirements as a desiccant.

The Orange silica gel is applicable in all the professional sector and domestic requirements where the monitoring of visual control of moisture is a must. For example, its use in compressed air dryers and transformer breathers for the protection and safety of packed goods that are non-consumable. Orange silica gel also plays an important role in drying the flowers and seeds and keeping them safe for a long period.

Precaution: Orange silica gel should be kept away from consumable products and items. It should also be kept away from medications and pharmaceuticals.

The Use Of Orange Indicating Silica Gel

Orange Silica Gel is easily available in the market, and anyone can access it. It has a high rate of absorption. It can also tolerate high temperatures and can be working 65°C.

• Cleansing the Industrial gases
• Drying the industrial gases
• Prevent moisture from packaging material during export consignments
• Transporting electrical appliances
• Storage and transportation of leather
• dehumidification of synthesis products
• Use in science laboratories
• Packaging of optical devices and instruments

Blue Indicating Silica Gel

Blue Silica Gel has a translucent to semi-transparent appearance. It looks like a glassy substance. The Blue Indicating Silica Gel is a granule that has been dipped or washed with concentrated cobalt chloride. Cobalt chloride is a very heavy metal salt. Cobalt blue has a deep-blue color when it is dry. When the granule of Blue Indicating Silica Gel is completely soaked with the moisture surrounding the environment, its color changes from blue to pink silica gel desiccant. This transformation indicates that this silica gel must be replaced with the new one or recharged.

This Blue Silica Gel has the same application as the Orange Silica Gel. And it should never be placed in close contact with the consumption items. It should also be kept away from pharmaceuticals and medications.

The Use of Blue Indicating Silica Gel

Blue Silica gel is limited in the market because the European Union bans it. It is banned because of the presence of cobalt, which tends to be toxic in certain environments. Although it has a lower cost than Orange Silica gel, it has an equal performance standard. In addition, other than in European countries, it is accessible.

• Refrigerating goods
• Gas drying in the industrial sector
• Leather and textile goods
• Purifying natural gases in the industrial sector
• Storage and transportation of electrical appliances
• Air- conditioners

Sorbead India is a leading company manufacturing Indicating Silica Gel beads. Silica gel beads of both orange and blue are available in different sizes in millimeters and have the liberty to be present in two or three different shapes. It is also present in mesh. Both silica gels have high absorption power that is quite useful in professional and industrial sectors. 

An efficient active packaging solution is quintessential for extending a product's lifetime for every manufacturer and distributor. Desiccants are compounds that are used in facilitating low humidity environments. By reducing moisture-induced degradation, desiccants play a key role in enhancing product shelf-life without compromising safety and efficacy. Hence, it is vital to select the right desiccant. Desiccants are often used to develop, transport, maintain, or store various materials and products.

The cheapest or the most convenient option doesn't lead you to the most valuable solution. The poor quality and wrong quantity of desiccant can result in over or under-desiccation, which can impact your product's life span and efficacy. This could be detrimental to both the company and the end-users. Hence, investing the time in selecting the right quality and quantity of desiccants in the development and packaging of your product will not only increase the chances of the product's success in the market and ensure the product's efficacy for end-users.

 What do You Need to Know Before Selecting the Desiccant?

When deciding on the proper desiccant, you must examine various parameters, such as LOD (loss on drying), and MAC (Moisture Adsorption Capacity) at low relative humidity and high temperatures. The container in which the product will be packaged, shipped, stored, and packaging headspace is also vital in determining how much of a particular desiccant you need and in what packaging form.

 It would be best if you also considered the temperature and relative humidity to which the product will be exposed.

 Each issue is best dealt with by a specific type or combination of different desiccants. An effective desiccant will absorb the water vapor in the air, lowering the relative humidity to the point where water cannot condense, i.e., the dew point.

Use a desiccant tailored to your requirements.

At Sorbead India, we understand just how important choosing the right desiccant is!

For this reason, we offer a diverse array of desiccants that can be customized to fit a variety of design and manufacturing parameters. 

The key to ensuring product stability and integrity is the incorporation of a structural desiccant during the initial design and storage phase. By comparing the properties and capabilities of each desiccation product, you can identify the suitable desiccant for your needs and make a clear choice. Some of these desiccants are as follows.

Types of Desiccants

1)Silica Gel

Silica gel is a popular desiccant choice in the food and drug (pharmaceutical and nutraceutical) industry due to its inert, non-toxic, and highly stable properties. Silica gel is a partially dehydrated form of polymeric colloidal silicic acid. Silica gel has an amorphous micro-porous structure. Its interconnected pore opening sizes of roughly 3-60 angstroms form a vast surface area that attracts and retains water by adsorption and capillary condensation, allowing silica gel to adsorb up to 40% of its weight in water. Silica gel is the most suitable desiccant for products with stable storage temperatures and high relative humidity. It is seen that silica gel is highly efficient at a temperature below 25°C (77°F) at a relative humidity of 40% (Fig. 1 & 2). However, caution must be exercised; as the temperature rises, the desiccant will desorb water or lose a part of its adsorption capacity like clay (Fig. 3). 

Figure 1: Adsorption Rate (H?O) of Various Adsorbents

Figure 2: Equilibrium Capacity (H?O) of Various Adsorbents

2) Molecular Sieve

Molecular sieves (also known as Synthetic Zeolite or aluminosilicates) adsorb moisture more strongly and rapidly than silica gel or clay (Fig. 2), making them ideal for products requiring instant protection from moisture degradation. 

Molecular sieves have a distinctive feature in the uniformity of the pore size openings in their crystal lattice structure. Due to this uniformity, molecular sieves have a high adsorption capacity even at low relative humidity, making them an economical choice of desiccants. This uniform structure of the molecular sieve does not allow it to desorb moisture into the package as readily as silica gel or clay would as temperature increases (Fig. 3). This is particularly important for packaged products that can experience a wide range of environmental conditions. However, caution should be exercised when selecting the proper dosage for products with specific RH requirements.Choosing the right specific desiccant within the desiccant range is as important as selecting the right type of desiccant. Molecular sieves come in various styles, such as, type 3A, 4A, 5A, 13X, carbon molecular sieve, and molecular sieve powder. Similarly, there are different varieties of silica gels. Silica gel blue, silica gel white and silica gel orange. Each of these types has specific properties for specific uses per your products' requirements. 

Both desiccants, i.e., silica gel and molecular sieve, are used to protect drugs, active pharmaceutical ingredients (APIs), diagnostic kits, and medical devices from the harmful effects of hydrolytic degradation triggered by unbound water in packaging headspace.

Figure 3: Equilibrium H?O Capacity in reference with temperature

3) Montmorillonite Clay

Montmorillonite Clay is a naturally occurring, porous adsorbent that is mined and then dried for use as a desiccant. One of the biggest advantages of the clay is that the clay can be successfully regenerated for repeated use at very low temperatures without substantial deterioration or swelling. However, this also causes the clay to desorb moisture into the container as temperatures rise. Clay is an inexpensive and an effective desiccant within the normal temperature and relative humidity ranges (Table 1).

                                                                         Table 1: Properties of Adsorbents

 4) Calcium Oxide (CaO)

Calcium oxide (CaO) is a cost-effective desiccant that you should use if your product is stored or transported in areas with high temperatures. The substance, also known as quick lime, is distinguished by its ability to absorb much greater water at low relative humidity than other materials (Fig. 2). Calcium oxide is used mainly in packaging dehydrated foods where a low critical relative humidity is necessary.

Users can select the right desiccants based on the abovementioned factors and requirements. 

Looking to buy high-grade desiccants? Sorbead India is your place to go. Remember, help is just an email away! For more information on the best desiccants suitable for your products, our technical sales representative would be more than happy to help you.