Heat Stratification: Floors and Walls
by Tom Costello, Technical Director
April 29, 2018
Physics dictates heat rises
When heated air overlies cooler air within the structure, conditions may result that inhibit an effective treatment. This condition is heat stratification and often occurs due to a lack of air circulation in a given area. Heat stratification is particularly evident in higher-temperature applications when warm, energized air is ducted into a room at the ceiling level, and the room has a cold floor. This produces stable temperature layers. The stratification is caused by differences in the density of layers of air of different temperatures.
Mitigation of stratification problems involves three basic tasks:
1. Mixing energized air by using fans.
2. Mixing energized air by means of duct placement.
3. Mixing energized air by venting.
Fans are been particularly effective and are essential to ensure a successful GreenTech Heat treatment with portable bed bug heaters. The exact placement of fans in a particular treatment depends on the configuration of the area being treated. There is no one rule on how may many fans should be used in every treatment. One advantage of fans is they can be placed in each area where mixing is needed. Fans also move large volumes of air, thus maximizing convective heat transfer. Generally a GreenTech Heat technician can mix energized air by opening windows or doors. This type of venting can also create a condition of air currents that mixes the air during open system treatments.
Heat Stratification for Bed Bug Treatments
Heat stratification is a valid concern when treating bed bug infestations. These insects do not fly and may inhabit areas close to the floor. If heated air is not properly circulated to heat carpeting, carpet padding, coving, and floor surfaces, the technician is not likely to achieve a kill. Bed bug treatments with portable electric heaters and fans direct the air close to the floor and around their harborages.
Use the spectrometer to check temperatures at the ceiling. The 4,000 cfm fans generate enough air flow that air directed at walls and furniture in the treatment area usually breaks heat stratification.