New passively cooled enclosure from Intertec

Sept. 19, 2008

Intertec launches a passively cooled enclosure that exploits a novel phase-change material to maintain the temperature of electronics equipment at 10 degrees lower than peak ambient temperatures. Requiring no power supply to operate, the standard cooling enclosure has enough internal space to meet common application requirements, such as the pressure transmitters and process analyzers used on oil and gas pipelines running through desert environments. Intertec believes this to be the first application of phase- change materials to process instrumentation. 

"Protecting sensitive electronics equipment against very high temperatures has traditionally been an expensive exercise, especially if the application also demands explosion-proof protection, or involves a location that is not served by an electricity infrastructure" says Martin Hess of Intertec.  "This new type of passive enclosure gives remote equipment developers a valuable new option, providing a very simple and cost- effective means of protecting smaller-scale electronics equipment in environments with temperature swings, such as deserts."

PCMs can provide a cooling mechanism by absorbing and storing the large quantity of energy needed to change the material's state from solid to liquid as the melting point is passed — during the normal daytime temperature rise. This energy is then released as the PCM re-solidifies during cooler periods, making it ideal for use in desert locations with their cold night time temperatures.  For this application, Intertec has chosen a PCM with a phase-change temperature of 34 degrees C. 

The first enclosure produced by Intertec, the PCM Passive Cooling System, provides approximately 25 litres of usable space for mounting electronics equipment and will dissipate up to 10 W of heat. Moreover, there is no need to add fans or vents, so an enclosure's environmental ingress protection (IP rating) against dust and water remains unchanged.

The phase change material is located at the back of the enclosure, behind a mounting panel. The electronics device or equipment to be protected is attached to this panel with as large a contact area as possible to aid heat conduction. Intertec offers ready-to-use pipe clamp-like accessories for mounting process transmitters and will also fabricate simple mechanical panel-mounting accessories for other equipment shapes, such as small electronics modules. 

The enclosure itself is fabricated using special insulated construction principles developed and field-proven by Intertec over many years. The basic material used is long- fiber-reinforced, glass-reinforced polyester (GRP) sheeting, which provides great structural strength, combined with high resistance to weather and the corrosive effects of aggressive chemicals. Special mounting and construction principles for the internal components then ensure that the very high degree of thermal insulation provided by this shell is not compromised by providing a path for heat conduction. The enclosure is also compatible with Intertec's standard range of accessories, including sun shades to protect the top and/or sides, to provide further optimization of the enclosure for use in hot environments.

Intertec's new enclosure can deliver major reductions in system building costs. Alternative cooling mechanisms such as air conditioning and vortex coolers usually involve thousands of dollars of extra hardware costs, as well as the need for a local power supply to power the pumps/compressors required. These costs can escalate again if explosion-proof protection is required, as is typically the case for pipeline equipment.  Peltier coolers are an alternative for smaller-scale electronics, but their relatively low efficiency means that a substantial local power supply can be required. Such cooling methods typically necessitate connections between the internal and external environments as well, such as vents or fans, complicating the provision of protection against dust and rain.

Intertec's unpowered PCM Passive Cooling System costs typically less than $1,500 and has zero running costs and no regular maintenance requirements. A range of other enclosure and PCM material block sizes are optionally available to suit larger or smaller electronics equipment and varying heat dissipation requirements.