Latent Heat: How Heat Exchange Affects High Volume, Low Speed Fan Technology

April 24, 2013 by Eddie
Latent Heat Effects HVLS Fan Technology

A diagram of a column of air as created by HVLS technology. (Above) An 3-dimensional view of the diagram and how air travels out and up 360 degrees using balloons to be able to identify the pattern.

Air quality is important wherever you work. Indoor air, when it isn’t continuously mixed with fresh air, becomes stuffy and smelly, and temperatures can increase quickly if not checked. For building owners or facility managers depending on a human workforce, indoor air quality and temperature can affect employee comfort, and ultimately productivity.

Workplaces that are in constant flux due to production, stock movement, distribution even regional weather patterns face ongoing indoor air quality and temperature battles. Large size high volume, low speed (HVLS) fans can make a big impact on air quality battles due to a small principle of thermodynamics of which the technology was developed latent heat.

To fully understand how latent heat affects HVLS fans the superior complement to traditional HVAC systems, one must first understand how heat can be exchanged through objects and materials typically found in industrial or commercial work environments.

MacroAir HVLS Cooling Fans Balloon Demo

Sensible heat, Latent Heat and traditional HVAC technology

Sensible heat is heat exchanged when the temperature changes, for example, in a room. When an object is heated its temperature rises as heat is added. The increase in heat is called sensible heat. Similarly, when heat is removed from an object and its temperature falls, the heat that is removed is also called sensible heat. For example, it takes one Btu (British thermal unit measurement) to heat one pound of water by one degree.

Latent heat is the exchange of heat that occurs with a change of a state of matter. All pure substances in nature are able to change their state. Solids can become liquids (ice to water) and liquids can become gases (water to vapor), but changes such as these require the addition or removal of heat.  The heat that causes these changes is called latent heat.

The heat released when water vapor condenses to water (changes state) is about 1,060 Btu, a thousand times greater than the one Btu sensible heat example above.

Evaporation and air movement with HVLS Fans

Latent heat of vaporization can’t happen if the moisture is not allowed to evaporate. Stagnant humid air on moist skin hinders evaporation and therefore reduces the latent heat absorbed. The sweat on an employee’s skin just can’t evaporate as easily, contributing to a less than desired work environment for everyone involved.

Think about it: moisture on your skin is like potential energy (heat) waiting to be used to help cool your body. The introduction of moving air, through HVLS fans, removes the stagnant, humid air from moist skin, allowing evaporation to take place, thus increasing the latent heat absorbed (in this way, the potential energy is released). The old air near our bodies is replaced by drier air that can continue to absorb evaporating sweat. HVLS fans use this powerful principle of latent heat to comfort people in a room and not just the room itself. By continuously mixing incoming fresh air with stale air, HVLS fans minimize the total amount of ventilation required to achieve adequate air quality, and use less energy, which can help lower HVAC costs.

For businesses that depend on a productive workforce, HVLS technology also helps keep employees comfortable, safe and productive. With balanced and controlled temperatures, product and machinery are also within an optimal environment a win-win for any business.

As featured in Indoor Comfort New April 2013


One comment on “Latent Heat: How Heat Exchange Affects High Volume, Low Speed Fan Technology

  1. Divyesh, Mehta Forgings, India on

    This is very useful article. I have a forging unit. A 75 KW induction furnace to heat steel. All forged pieces are also kept inside workshop to be cooled from 1000 c to room temperature. Average temperature is 35 c and maximum is 45 c.

    Workshop is 40′ x 40′ with 2 doors of 10’x8′, 2 doors of 10’x3′ and 3 windows of 4’x3′. Roofing is corrugated cement sheet with 3 turbo ventilators. Roofing height is 20′ at wall and 25′ at center.

    How your hvls fan and which model is useful for me.


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