17 Nov 2020

How do ComNet products work in excessive temperatures?

Operational temperature range covers the breadth of ambient temperatures over which a product will work. Ambient temperature is the air temperature of an environment. So, this relates to the exact location of the equipment. This is important as various factors will affect that temperature. For example, if you stand close to an air-conditioning condenser unit, you will feel the heat that it gives off. As such, any product placed in the vicinity of an air-conditioning condenser unit would have to deal with a higher ambient temperature than the air temperature provided in your daily regional weather forecast.

So, how do ComNet products work in excessive temperatures?

ComNet product is rated operationally up to 75°C or 167°F. This is very hot for standard electronic equipment but ComNet products are designed to be tough or hardened. All components used in ComNet devices are rated for high-temperature operation. They are in fact rated across a wide high and low-temperature range as they must do both. So component selection is crucial in ensuring that devices operate at temperature extremes but what else is required to ensure operation?

A fundamental problem of operating anything electrical is that it generates heat. Modern electronics compacts more into a smaller space, and this increases the heat that is generated. ComNet’s methods to control and remove this unwanted heat are covered under the banner of Thermal Management.

To minimize generated heat, ComNet layout components on circuit boards in specific designs and reduce the transmission path length between those components. Electrical power in a product is your heat enemy and, more specifically, the electrical current that flows within a device.

To describe in layman’s terms how this works, think of an electric kettle. In the bottom is a heating element that acts as a resistor. This is a device that prevents the current flowing. When the current flow is prevented by the resistance, heat is generated. In the case of the kettle we want the element to get hot as it makes the water boil.

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In ComNet products, there is resistance in every electrical path and component, and as a result, heat is generated. However, unlike the example of the electric kettle, ComNet products do not want to generate heat…we are not a kettle. It is a by-product created by the current flow that is needed for the electronics to operate.

So, in order to remove this unwanted heat, ComNet use heatsinks to pull heat from components and pass that unwanted heat to the surrounding air. Heatsinks tend to be flat on the side that mates with the component and then has a fin arrangement on the other side. The fin arrangement is to increase the amount of heatsink surface area that touches the air to maximize heat transfer.

ComNet also use the product enclosure as a heatsink, and this will explain the strange appearance of some of ComNet’s products. The fins on the outside are functional and certainly not there purely for cosmetic reasons. On the inside of the product, the circuit boards bond with the enclosure to dissipate heat.

Unlike all commercial-grade products, ComNet industrial-grade units do not contain fans that keep new cooler air flowing over the components and heatsinks. It might sound crazy that fans are not employed, but they create too many issues. Firstly, they have moving components, and that is not good in hot environments as they are subject to failure. Secondly, most unconditioned environments are not clean environments, and so fans or fan filters will get blocked quickly and break as a result. Therefore, good high-temperature operational design calls for great Thermal Management without the assistance of forced air cooling.

Finally, ComNet’s product design must show respect for other nearby products. If this is not considered, then the heat that is generated will be dissipated to the surrounding environment without a care. This simply puts strain, not just on our ComNet transmission equipment, but on every other device close by. More importantly, that nearby product could be the power supply for a ComNet device and if that gets hot, it becomes inefficient.

So, ComNet’s good design really is crucial when considering how to make their products and associated systems operational in excessive temperature conditions.