Dehumidification

Dehumidification

A dehumidifier is a household appliance that reduces the level of humidity in the air, usually for health reasons, as humid air can cause mold and mildew to grow inside homes, which has various health risks. Relative humidity is preferably 30 to 50%.[1] Very high humidity levels are also unpleasant for human beings, can cause condensation and can make it hard to dry laundry or sleep.

Processes:

Mechanical/refrigerative

Mechanical/refrigerative dehumidifiers, the most common type, usually work by drawing moist air over a refrigerated coil with a small fan. Since the saturation vapor pressure of water decreases with decreasing temperature, the water in the air condenses, and drips into a collecting bucket. The air is then reheated by the warmer side of the refrigeration coil. This process works most effectively with higher ambient temperatures with a high dew point temperature. In cold climates, the process is less effective.[2] They are most effective at over 45% relative humidity, higher if the air is cold. [3]

Desiccative 

A desiccant dehumidifier is a device that employs a desiccant material to produce a dehumidification effect. As they are more effective for low-temperature and low (relative) humidity levels, they are generally used for these conditions instead of mechanical/refrigerative dehumidifiers - or are used in tandem with them.[3]
Desiccant materials have a high affinity for water vapor. An example of dessicant material is silica gel. Typically their moisture content is a function of the relative humidity of the surrounding air. Exposed to low relative humidities desiccant materials come to equilibrium at low moisture contents and exposure to high relative humidities results in equilibrium at high moisture contents. The process involves exposing the desiccant material to a high relative humidity air stream, allowing it to attract and retain some of the water vapor and then exposing the same desiccants to a lower relative humidity air stream which has the effect of drawing the retained moisture from the desiccant. The first air stream is the air that is being dehumidified while the second air stream is used only to regenerate the desiccant material so that it is ready to begin another cycle. Note that the first air stream's water vapor content is reduced while the second air stream's water vapor content is increased. Typically the low relative humidity air stream is air taken from any available source and heated to reduce its relative humidity. Hence
desiccant dehumidifiers consume heat energy to produce a dehumidifying effect.

In general a desiccant dehumidifier comprises four major components:
the component that holds the desiccant, of which there are several types;
1. a fan to move the air to be dehumidified (process air) through the desiccant holder;

2. a heater to heat the air that will be used to dry the desiccant (regeneration air);

3. a fan to move the low humidity air for drying the desiccant through the desiccant holder.

There are many different companies who have create dehumidifier like as Aprilaire.

Why Do I Need a Whole-House Dehumidifier?

Have you ever experienced any of the following uncomfortable and/or unhealthy conditions:

· Do you have trouble sleeping at night due to clammy skin or stuffiness in the air?

· Have you ever reduced the temperature setting because you're uncomfortable with the stuffy feeling?

· Have your floors or other surfaces ever felt sticky or “sweaty”?

· Are you concerned with mold and mildew growth in your home?

· Do you have musty odors or smells in any area of your home?

· Do you have condensation on your water pipes?

· Have you seen wet stains on walls or ceilings?

· Do you or a family member have allergies (over-moist air can encourage the growth of mold, bacteria, and dust mites—three commonly known household allergens).

Core Benefits

Every Aprilaire product provides important key benefits for your family and home.

Health

Excess indoor humidity provides the perfect breeding ground for mold, mildew, dust mites, bacteria and more. An Aprilaire Whole-House Dehumidifier combats these nasty home invaders, which are linked to asthma, allergies and other serious respiratory problems.

Comfort

Few things impact your home’s comfort more than excess indoor humidity. When you turn up your air conditioner to try and get rid of indoor stickiness, you’re really just making your home uncomfortably cool. An Aprilaire Dehumidifier allows you to wipe out that clammy feeling and say goodbye to musty odors. Plus optional built-in ventilation allows you to bring in conditioned, fresh outside air - ensuring your home remains properly ventilated.

Protection

Excess indoor humidity allows mold and mildew to thrive—ruining carpets, draperies, furniture and even clothing. It also can cause condensation build-up on windows, destroying their finishes and structural integrity. An Aprilaire Whole-House Dehumidifier helps protect your home and its contents by removing unnecessary moisture from your home’s air whenever it rises to an inappropriate and harmful level.

Energy Savings

Many homeowners turn up their air conditioning to get rid of the stickiness or clammy-feeling caused by high indoor humidity. An Aprilaire Whole-House Dehumidifier eliminates the need to over-cool, allowing for a higher thermostat setting for the same comfort level. And because it is more energy efficient than portable dehumidifiers, it uses less energy for the same amount of moisture removed.

Aprilaire Whole-House Dehumidifier Models There are two different models of Aprilaire Whole-Home Dehumidifiers that can solve your home’s excess humidity problems.

· Aprilaire Models 1710 Free Standing Dehumidifier

· Aprilaire Models 1750/1770 Whole-House Dehumidifiers The only truly effective solutions for total home excess moisture control.