Heaters: A Hot Topic

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How many times have you ordered coffee and instantly got what you wanted?

Not often, I’d bet. That’s not surprising, since there are 80,0000 ways to drink coffee at the world’s largest chain of coffee shops. Given that, how is the server supposed to know which one you want?

The world of heat control isn’t that complex but it also isn’t simple. However, armed with some knowledge and general rules you can make sure that you get what you want.

Before going over the guidelines, though, let’s first define the problem. In seven out of ten cases for our customers the reason for heating is to get rid of condensation in an enclosure.

Condensation is often a concern for facilities that shut down for the night. As the heat inside an enclosure drains away, dew can form. Also, if the cabinet is outdoors in an area where relative humidity is 70% or greater, then the risk that inner metallic surfaces will hit the dew point is high.

What about the other 30% of customers? Well, sometimes the reason for heating is to fight the cold, with this a concern when temperatures range from 5 to 15o C (41 to 59o F). When conditions are even colder, there’s often some other form of heating protection for the electronics. But even then, heating inside the cabinet may be required.

As for solutions, here’s a basic guideline to keep in mind. In general, you need to know the environmental specifications for the electronics and other components you’re protecting. You can find the working temperature and humidity ranges in equipment manuals and other documentation. That will tell you what conditions the inside of the cabinet must satisfy.

With regard to heating solutions, they come in four general types, each with its own benefits and disadvantages. They are:

  • Aluminum resistance heater. These consume 10-150 watts and provide heat in all directions. However, their heating speed is slow.
  • Insulated resistance heater. These also use 10-150 W and also offer a slow heating speed. But, because they’re insulated, they predominantly provide heating in one direction only.
  • Insulated and aluminum resistance heater with fan. These can guzzle up to 400 W and offer fast, multidirectional heating.
  • Ultrathin resistance heater. These require anywhere from 10 to 200 W and provide multidirectional heating. As for speed, they’re average, falling between the first two and the third types above.

To give you an idea how these technologies might be applied, let’s look at some examples. Take the case where installation is in cold country, with variable speed drives moving a crane around and requiring rapid heating. Then heaters with a fan combined with an accurate electronic thermostat provide a good solution, one that can handle temperatures as low as -40o C (-40o F).Screen Shot 2016-03-01 at 1.27.13 PM

For another example, consider equipment located close to salt and marine environments. Then my recommendation would to be to go with a Spacial CRS (commonly known as an ultrathin resistance heater) teamed up with a humidity measuring hygrostat or humidistat as a controller.

A variation of the same problem can sometimes appear in very specific areas, such as metal parts, trays and so on. The solution there is to make surface temperature measurements on the problem spots and warm them up as needed with an ultrathin resistance heater.

A final example is a situation where sensitive equipment sits are various spots in a large control cabinet. Here, use insulated resistance heaters in those specific spots. That protects the sensitive gear without heating up the entire enclosure.

A final solution tip is that you use our free ProClima thermal calculation software. It will help you determine which heat resistance approach and what control device is most appropriate for your particular situation.

In the end, making the right choice of heater can be as satisfying as getting the right cup of coffee. For more information on the leading cause for heater use, please read our “Technical Guide-Preventing Condensation” and visit our ClimaSys CR solutions page.

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  • Thaddeus Matonya

    7 years ago

    I always consider your electrical designs systematically the best and reliable Schneider your sill the best

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