Electronics Heating and Cooling Overview

Why Is Heating of Electronics Necessary?

Electronic devices need to maintain the right temperature in order to work properly. Most of the time, this involves dissipating and reducing the temperature so the devices do not overheat. However, in environments with low temperatures, it is sometimes necessary to heat electronic components first so they can work properly and not malfunction.

Consider some of the different types of machines used daily in the outside environment, such as crosswalk signs, traffic signals, ATMs, and security cameras. The manufacturers create those machines to operate ideally at certain temperatures. When the temperature is too low, they will not operate properly. Thus, it becomes important to find ways to heat up the internal workings of those electronic devices so they can work. Of course, the temperature must never get too high, so there exist a number of ways to lower the temperature in electronics as well.

 

Why Is Cooling of Electronics Necessary?

Electronic devices of all types generate heat, and removing that heat is necessary so the components and device will not fail prematurely. The manufacturers of these devices provide ratings that detail the temperatures at which the devices will work optimally. They have a high temperature and a low temperature listed on their ratings, so the device needs to stay within this range for the best possible performance.

Unwanted heat causes the internal temperature within the enclosure to rise and exceed the manufacturer’s listed ratings for the device. The heat can come from internal sources or external sources. The heat the device generates from its electronic components is the internal heat source. This can include heat generated by batteries, power supplies, transformers, routers, switches, AC drives and inverters, and more. External heat sources can also cause an electronics device to fail. Devices used in foundries, engine rooms, under direct sunlight, and in hot climates can overheat and fail as well.

 

What Type of Heating and Cooling Devices Exist for Electronics?

In order to keep those electronics components at the proper temperature, the devices utilize a variety of different elements that will keep the temperatures in the right zone for quality performance. The following are the most commonly used elements for maintaining proper temperatures.

 

What Are Air to Air Heat Pumps?

Air to air heat pumps, or convection heat pumps, are a type of air source heat pump. They utilize outside air as the heat source, while using the air inside at the heat sink. Some of these systems are reversible as well, meaning you can use them for both heating and cooling. This is generally the case with the larger systems, such as the heating and cooling systems in homes and offices. They tend to be an efficient and cost effective way of cooling and heating, and they are the most common type of electric heat pump.

Inside smaller electronics, the air to air heat pumps will pump heat from one side of the thermoelectric device to the other part of the electronic device to dissipate it.

 

What Are Direct to Air Heat Pumps?

Direct to air heat pumps are a type of cooling assembly that cool down the unit through conduction. The electronic device will have the heat pump mounted to it. This pump then takes air from the cooler outside and pumps it into the device. The cooler external air will then cool down the internal temperature of the electronics.

 

What Are Enclosure Cooling Units?

Enclosure cooling units are helpful for getting the heat out from inside electronics enclosures. Several different methods are in use for enclosure cooling today. Natural convection cooling means the ambient outside temperature is cooler than inside of the enclosure. In those cases, the heat dissipates through the surface of the enclosure and through the grills and filters that it contains.

Some enclosure cooling units utilize forced convection. Forced air units are generally filter fans and cabinet cooling fans that can bring in the cooler outside air, which helps to cool the internal temperature within the enclosure. Closed loop cooling will keep the ambient air and the internal enclosure air separate, which can be helpful in cases where the external environment is harsh. Some of the common uses for enclosure cooling units today include machine tools, robotics, telecommunications, elevator controls and the transportation industry.

 

What Are Enclosure Heaters?

Enclosure heaters will help to keep the internal temperature of sensitive electronics warm enough to work regardless of the temperature outside. They are very useful for electronics that have to stay in the outside environment, and when that environment may reach very low temperatures. Some of the most common uses for enclosure heaters today include ATMs, control panels, switchgears, and traffic signal control boxes.

When choosing enclosure heaters, it is important to determine the lowest temperature in which the enclosure will have to work and then determine the ideal temperature at which the device needs to work. Different types of enclosure heaters are available for a variety of different purposes.

 

What Are the Elements for Enclosure Heating?

Enclosure heating devices generally have a number of different elements within them. They typically have mounting plates for mounting within the units, and some will have self-regulating thermostats within them to ensure proper performance at all times. Different types of heating elements are available as well, including ceramic heaters, silicone rubber heaters, tubular heaters, and finned strip heaters.

 

What Are Enclosure Thermo Hygrostats?

The enclosure thermo hygrostat works very similarly to a thermostat. The real difference is that the hygrostat will respond to the humidity in the device rather than the temperature of the device. These are popular in a variety of different types of devices today, including microwave ovens, humidifiers, and dehumidifiers, and are common in refrigerators and wherever there needs to be proper climate control, such as a climate controlled warehouse.

 

What Are Enclosure Thermostats?

The enclosure thermostats are the devices within the enclosures used to measure the internal temperature of the device. These devices will help to regulate the fans and the heat exchangers. Some have switching signals for when the temperature in the enclosure is too high, which turns on the heat exchange, bringing cooler air into the enclosure or pumping the hot air outside.

 

What Are Heatsinks?

Heatsinks are extremely common in electronics today, and they are a part of most central processing units. Computers today would not be able to run at the speeds they do without heatsinks there to dissipate the buildup of heat within the units. Heatsinks are metal structures that disperse the heat buildup in electronics. In addition to being common for computers, they are also in use with cell phones, refrigerators, and a variety of other electronic devices.

A heat sink features a thermal conductor, and it is this conductor that will carry the heat away from the computer’s CPU and then into a series of fins that help to dissipate and cool that hot air as a means to eliminate the danger of overheating. This system cools the processor as well as the heatsink so it can work continuously. It has a fan that will help to move the air. Many different shapes and sizes of heatsink are available today for use with various applications, as mentioned above.

 

What Types of Mounting Accessories Exist for Heatsinks?

Since there are a number of different types of heatsinks, they have a variety of different types of mounting accessories to help attach them to different devices, computers, and other electronic units. Clips and spring clips help to attach the heatsink into different types of housings and assemblies with a simple click. Other types of mounting accessories include tape and double-sided tape. Some full mounting kits will include the various types of hardware needed, including screws, nuts, washers, and solder tags needed for mounting.

 

What Are Liquid Heat Exchangers?

A liquid heat exchanger will work by transferring thermal energy, or heat, from one liquid to another. They can transfer the heat through direct or indirect contact. With indirect contact, the exchanger includes a separator. This type of heat exchange is very common with refrigeration as well as with radiators. The systems feature pumps, to move the liquid from one area to the other, as well as tubing, a radiator heat exchanger, and some coolants. The liquid heat exchangers come in a variety of different sizes as well, including miniature cooling systems for use with smaller electronics units.

 

What Are Peltier Modules?

Peltier modules are generally used for cooling. However, by reversing the electric current flow, it is possible to use the modules for heating. They work by making use of the Peltier effect. This effect, named after Jean C. A. Peltier, is a temperature difference achieved by applying voltage to two electrodes connected to a semiconductor. In small electronics, the modules can be helpful for transferring heat from one area to another area. This method is often used for thermoelectric cooling with computers and other types of small electronic devices.

Some of the common areas where they are in use today include fiber optic lasers, microwave ICS, and infrared detector chips.

 

What Are Peltier Module Controllers?

The Peltier module controllers are useful for reversible thermoelectric assemblies for heating and cooling that require precision to maintain the proper temperature. The controllers will generally be able to provide programmable output for the fans, and an alarm output if the temperatures fluctuate too much.

 

What Is Rack Cooling?

Rack cooling systems are generally in use with servers and within data centers. They are able to replace the other methods of cooling down high temperatures in computer systems, or they could be used in addition to other cooling methods. They generally tend to be very efficient, especially when compared with devices and techniques used to cool an entire room rather than just a single part of the room, namely the server and computers.

The device generally features an enclosure system for one or two racks. They contain heat exchangers that cool the re-circulated air and then return that to the server or device. They will also contain fans or blowers. These elements provide the necessary flow of air across the heat exchanger.

 

What Are Thermal Conductive Pads?

A thermal conductive pad is a square or a rectangle usually made from silicone or paraffin wax, and they are on the bottom part of a heatsink. They help to conduct the heat away from the device or component that needs cooling, such as the central processing unit of a computer. Many different processors today, including those from Intel and AMD, have thermal pads already attached to the bottom of the heatsinks.

 

What Are Thermal Gap Pads?

The thermal gap pads are similar to conductive pads. They are solid while at room temperature, but as the heat rises, they grow softer and are able to fill gaps. Often, devices are not entirely flush with the heatsink, and when the pad grows soft, it can spread and fill that gap. Both the conductive pads and the gap pads are helpful for conducting and removing heat. However, they are not as effective as using thermal grease.

 

What Is Thermal Grease?

Thermal grease goes by many names. Some call it thermal gel or thermal paste, while others call it heat paste, heat sink paste, or thermal interface material. Regardless of what one calls it, the grease serves the same purpose. It improves the thermal conductivity of the interface similarly to how the aforementioned pads do it. The grease fills in the various gaps on the surface of the components to make the heat conduct and dissipate more efficiently.

One of the benefits to using the thermal grease is the fact that the conductivity is much greater than the air in those gaps. The grease is also more efficient than the thermal pads. A variety of different types of thermal grease are available including silicone and graphite filler.