Temperature V Relative Humidity

Air contains a certain amount of water vapour and the amount any mass of air can contain depends on the temperature of that air: The warmer the air is, the more water it can hold. A low relative humidity (% rH) means that the air is dry and could hold a lot more moisture at that temperature.

For example, at 20˚C a cubic meter of air can hold a maximum of 18 grams of water and at 25˚C it can hold 22 grams of water. If the temperature is 25˚C and a cubic meter of air contains 22 grams of water, then the relative humidity is 100%. If it contains 11 grams of water, the relative humidity is 50%. If it contains 0 grams of water, relative humidity is 0%.

The relative humidity plays a large role in determining our comfort level. If the relative humidity is 100%, it means that water will not evaporate - the air is already saturated with moisture. Our bodies rely on the evaporation of moisture from our skin for cooling and the lower the relative humidity is the easier it is for moisture to evaporate, making us feel cooler.

You may have heard of the heat index. The chart below lists how hot a given temperature will feel to us in various relative/humidity levels.

If the relative humidity is 100%, we feel much hotter than the actual temperature indicates because our sweat does not evaporate at all. If the relative humidity is low, we feel cooler than the actual temperature because our sweat evaporates easily; we can also feel extremely dry.

Low humidity has at least three effects on human beings:

·         It dries out your skin and mucous membranes. If your home has low humidity, you will notice things like chapped lips, dry and itchy skin, and a dry sore throat when you wake up in the morning. (Low humidity also dries out plants and furniture.)

·         It increases static electricity.

·         It makes it seem colder than it actually is. In the summer, high humidity makes it seem warmer than it is because sweat cannot evaporate from your body. In the winter, low humidity has the opposite effect. If you take a look at the chart above, you'll see that if it is 21˚C inside your home and the humidity is 10%, it feels like it is 18˚C. Simply by bringing the humidity up to 70%, you can make it feel 3˚C warmer.

For best indoor comfort and health, a relative humidity of about 45% is ideal. At temperatures typically found indoors, this humidity level makes the air feels approximately what the temperature indicates, and your skin and lungs do not dry out and become irritated.

Most buildings cannot maintain this level of humidity without help. In the winter, relative humidity is often much lower than 45%, and in the summer it is sometimes higher.

Why Is Dry Air A Problem?

When the outside temperature falls below the inside temperature, the cold and moist air that enters a heated building becomes hot and dry.

This happens due to an incident by which balance is established between the moisture in the objects inside the building and in the air that these are in contact with.

The reduction in the moisture in the air may cause well known problems, such as:

• dryness of the upper airways;
• cracks in wooden structures;
• electrostatic discharges.

Air-conditioning or refrigeration systems may also cause an increase in the dryness of the air, as they cool the air below its dew point, remove moisture (dehumidification) and subsequently reheat the air.

dew point: this is the temperature that air must reach (while maintaining a constant pressure and humidity) for the moisture to condense (saturation).

dehumidification: process by which the moisture in the air can be decreased or removed

By adding a commercial humidifier to the system, this problem can be overcome quite simply.  Either add the steam produced by the humidifier to the air handling system, or install the humidifier with a fan distribution unit directly in to the room that needs the extra humidity - problem solved.

Why Humidity Is Key To Bikram Yoga

The idea behind the unique style of hot yoga is to imitate the conditions in Calcutta, Indian, where it was first launched more than 40 years ago by renowned yoga master, Bikram Choudhury.

Bikram Choudhury

The difference between a room that just feels a little warm or a room that feels sweltering is the level of humidity. The more humidity there is in a space the more difficult it is for a person to remove heat from their body simply from evaporatively sweating.

A hot yoga room is kept at 40˚C and at a minimum of 40% humidity. This helps students to start sweating right away, sweating out the toxins in their body and stimulating their organs, glands and nerves. The hot, humid temperatures are also key in helping to relax the muscles so students can stretch without worrying about injuries. Without humidity the room can be very unpleasant. Your eyes and your skin can experience dryness and you don’t sweat in the same way. 

When supplying equipment for a hot yoga studio we recommend infrared heating, humidity, and airflow as these three combined offer a more comfortable environment rather than just a hot environment. 

If you're standing in a light breeze, even in a hot humid room, you can let your body cool itself naturally through sweating, through evaporation. The higher the humidity level, the less evaporative cooling you will feel because once the air becomes saturated with moisture it doesn't evaporate sweat from your body as quickly.

Usually the most uncomfortable experience in a hot yoga room is when you sweat, drip then cool. If you're sweating just to drip then cool, its can often leads to symptoms of heat stroke. You need to be very careful if you're going to heat a room and humidify it, if you find that students are not getting through class and they're laying down or getting the chills, then you need more airflow in the system. This can be achieved as simply as installing a few cross flow ventilation fans and should give relief straight away.

HumiSteam Operation

Carel humiSteam basic Operation Video

Carel have produced a video for the operation of the new humiSteam basic that we thought may be of interest.

Any questions please contact us.

www.humidifiers-uk.com

Attention All Air Con Installers, Facilities Managers

 CAREL humiSteam Installation

We thought it would be a good idea to share this cracking video from CAREL - a simple, easy to follow installation guide for the CAREL humiSteam humidifier.

Any questions?  Do get in touch.

(We digg the background music too!)

http://humidifiers-uk.com

Replacing A Carel HumiSteam Humidifier Cylinder

 

Easy guide to replacing your humiSteam cylinder

Important: The cylinder must only be replaced by qualified personnel, and with the humidifier unplugged from the power supply.

In normal conditions, the disposable cylinders should be replaced after one year (or 2500 hours of operation, if cleaned periodically), whilst the cleanable cylinders last 5 years (or 10,000 hours of operation, if cleaned periodically). They must be replaced immediately – even before the specified intervals – if any anomalies occur. For example, when the lime scale inside the cylinder prevents the correct flow of electric current. 

Replacement Procedure

• Firstly the humidifier needs to be turned off using the rocker switch on the front of the humidifier (0 = Off) and as a safety procedure the mains disconnect switch on the power supply need to be open;

• The cylinder then needs to be drained of water. To do this mechanically you need to make sure the humidifier is not powered and then activate the mechanical drain device under the cylinder (see figure below);

• Wait for the humidifer and cylinder to cool down and then disconnect the electrical cables and steam hose from the cylinder;

• Release the cylinder from the locking device and then lift it to remove it;

• Make sure the model and the power supply of the new cylinder corresponds to the rated data and then insert and fasten the new cylinder;

• Reconnect the electrical cables and steam hose to the new cylinder and replace the humidifier cover;

• Close the mains disconnect switch on the power supply and turn on the humidifier using the rocker switch on the front of the humidifier (1 = On);

• The cylinder operating hour counter now needs to be reset and the new cylinder flushed;

• To do this press the PRG button on the main screen to access the main menu;

• Using the down arrow scroll to the Maintenace Menu and press enter to access it;

• Press enter again and then use the up or down arrows to enter the password 77;

• Press enter to confirm and access the Maintenance Menu;

• Using the down arrow scroll to "4. Change cylinder" and press enter to access;

• Complete the following procedures;

Industrial | Opportunities | Heating and Ventilation News

Industrial | Opportunities | Heating and Ventilation News