Humidity Control 101: How Humidity Chambers Work

Temperature and humidity-controlled chambers provide stabilized storage environments that can manipulate those two principal factors (temperature and humidity), which can help customers study and analyze the durability of their products.

The humidity control chamber environment to be conditioned is controlled at a targeted dew point temperature and then reheated to a specified air temperature. Maintaining a constant dew point and air temperature will produce a very constant relative humidity(RH).

(A) Air introduced to water spray

A portion of the air returning from the conditioned area is directed through a water spray area with a closely controlled temperature. The water spray is adjusted to maintain the dew point temperature of the targeted condition. As the air passes through the water spray, it is cooled down to the temperature of the water and approaches saturation.

(B) Air leaves spray chamber

The air then leaves the spray chamber through a mist eliminator, which removes any excess water vapor, and is next mixed with air that has bypassed the spray area.

(C) Air is returned to the conditioned space

After passing over an electric heater, to heat the air back to the desired dry bulb temperature, the air is returned to the conditioned space.

Utilizing the above humidity control method, a very precise level of humidity is achieved. The system does not distinguish between humidifying and dehumidifying; it is always setting a dew point and reheating.

The temperature of the water spray is automatically adjusted by the feedback from an RH sensor in the controlled space. If the set point is lower than the actual condition, the temperature of the water spray will gradually decrease until the RH set point is achieved. On the other hand, when the relative humidity set point is above the actual condition, the water spray temperature is incrementally increased until the RH set point is achieved.

For conditions that require a below-freezing dew point, a desiccant dryer is utilized until the desired humidity level is achieved.

FAQs

What is humidity control?

Humidity control is the process of managing and regulating the moisture content in the air to achieve optimal levels for comfort and various applications. Humidity control systems ensure that the relative humidity stays within defined ranges by modifying the presence of water vapor in the air. Proper humidity control is essential in maintaining indoor air quality, preventing mold and mildew growth, and preserving sensitive materials like artwork and electronic equipment.

What are the uses of a humidity chamber?

A humidity chamber is used for product testing at different setpoints, including maintaining controlled humidity and temperature conditions for drug storage in the pharmaceutical industry, circuit board testing in the electronics industry, and paper testing in the Paper industry.

Can chambers control humidity without temperature control?

Chambers like ours control both humidity and temperature because relative humidity takes temperature into account. The relative humidity is essentially a ratio between how much moisture the air is actually holding compared to how much moisture the air is capable of holding. The temperature has a very strong effect on how much moisture air is able to hold, with higher temperatures generally allowing for more moisture capacity. Humidity is always relative to temperature, therefore to be able to control humidity accurately and precisely, you need to control the temperature as well.

Are humidity chambers difficult to maintain?

As with any large machinery, there are some maintenance requirements that you should take into account to ensure a well functioning humidity chamber:

• Be sure that the facility in which you plan to house the chamber can meet your humidity chamber’s utility needs, including any electrical, water, and venting requirements.
• Chambers should have at least a yearly service for calibration and preventative maintenance. The PM schedule should however be based on usage of the chamber and also water quality.
• It’s best to use water with the proper purity to keep inner tubing from degrading too quickly. This also plays a large role in deciding on your PM schedule.
• If any upgrades are required down the road, be sure they are completed by a certified engineer. This is important because it might void the warranty and have other impacts on control and stability.

Humidity chamber vs. stability chamber

Stability chambers create specific conditions to check stability and verify optimal shelf life for products. The term “stability” refers to the usage of the chamber in the pharmaceutical and some other industries. Essentially, a Humidity chamber can be a stability chamber but it can also do a lot of other things in a lot of other industries. A stability chamber is a humidity chamber testing the stability of a product.

Reach-in vs. walk-in chambers

As the name suggests, reach-in chambers are generally smaller, easier to place in tight spaces, and have a lower up-front cost. Walk-in rooms require a lot more planning on the front end and are more expensive. However, walk-ins are more cost-effective per cubic foot of storage space making them a great alternative, especially if you are planning to test large quantities of product.

What is accelerated stability?

Accelerated stability testing is used to learn about a product’s life span or expiration date in instances where we do not have real time data available. This is a modified version of regular stability testing that puts the product under heightened levels of stress compared to the standard stability test. This enables companies to gain approval much quicker to place products out on the market for sale compared to the 3 years of long-term testing that needs to be done.