|Have you ever put a stat-guard over a thermostat only to have to remove it later because it didn’t allow enough air flow? We’ve come across more than a few thermostats with the wall plate portion of the stat-guard still encircling them, but with the actual cover portion of the guard nowhere to be found. When a facility staff is asked about it, they invariably say they had to remove the guard because it choked off the air to the thermostat causing the room to get overly hot and then overly cold. A new technology on the market is aimed at eliminating this problem. It is called Computational Fluid Dynamics or CFD. It’s a way of analyzing the flow of fluid and air through an object by computer simulation. It works by taking a large complex system and breaking it down into thousands or even millions of small and simple systems. CFD is more precise than an actual air flow measurement because any tool used for measurement will itself affect the air flow. It can also measure all areas of an object including those that cannot be measured in the real world because of size or obstructions.
For the HVAC industry, this technology means that stat-guards can be designed, tested and perfected on the computer instead of sending out for prototype after prototype and then trying to simulate all possible air flow scenarios on each model. This gets an optimal design into the market much quicker while avoiding issues that might arise in the design after it’s created, such as lack of air flow.
CFD also means that sun shades for outdoor sensors can be designed to reduce solar heat gain without affecting the sensor measurement, and that can withstand extreme winds without snapping. And for the thermostats themselves, it means that manufacturers can locate the exact sweet spot for slots and openings in the enclosure that provide superior air flow. This will help prevent self-heating, which happens when the heat from other circuit board components affects the internal sensor readings. It can even improve thermostat performance to the point where they can be used in some non-ideal locations without compromising performance.
by Terry Noble, BAPI Technical Writer
Blogs stories provided by Building Automation Products, Inc.