bl2707-hvac-enclosures-a

PROTECT YOUR ELECTRONICS IN HARSH ENVIRONMENTS

HVAC, climate and environmental technology can face a hard life because the environments it operates in are inherently challenging. The extreme temperatures and windblown moisture of the great outdoors are seldom merciful.

Even supposedly comfortable indoor settings can take their toll. Devices often reside in the ‘backstage’ areas of buildings: plant rooms, rooftops, duct spaces, basements and external walls – far from controlled environments like an office or laboratory.

Temperatures can fluctuate significantly. Even ambient indoor spaces may create microclimates inside enclosures, due to heat generated by relays, power supplies or processors. Temperature swings can cause condensation inside enclosures. If the housing is fully sealed but not pressure equalised, internal condensation can form and drip on to the electronics.

Air carries particles – dust, fibres and spores. Electronics in or near ductwork, filters, fans and blowers get exposed to this build-up over time. Filtration systems and air quality control units can be especially vulnerable. If the enclosure isn’t well sealed or properly vented, fine particles can penetrate and build up conductive paths across PCB traces.

That’s not all: in commercial or industrial settings, equipment may be cleaned aggressively with solvents, detergents or disinfectants. Airborne chemical vapours can attack plastics, seals and coatings. Some air filtration or pollution-control systems also deliberately introduce reactive chemicals (such as ozone) into the air. This can degrade plastics and seals over time. Furthermore, outdoor or near-window installations expose electronics to ultraviolet radiation. Many common plastics such as ABS degrade under UV rays: they discolor and crack.

Plant rooms and rooftop installations can be subject to constant low-level vibration from compressors, pumps, fans and external wind forces. Mobile units face even harsher mechanical stress. PCB solder joints, connectors and internal mounting points suffer fatigue if enclosures are not designed properly.

Incoming or outgoing EMI/RFI can also be an issue, especially if the device is housed in a non-conductive plastic enclosure. HVAC systems in particular are full of high-current motors, compressors and switching relays. These generate electromagnetic interference. Wireless IIoT devices, controllers and sensitive data-acquisition electronics can suffer communications dropouts, data corruption or even full hardware failure if not shielded properly.

DIVERSE APPLICATIONS CALL FOR VERSATILE ENCLOSURES

Climate and environmental technology covers a broad spectrum of applications. Heating, ventilation and air conditioning are obvious requirements for most end users. But the need for environmental monitoring and control is growing as climate change makes the planet an increasingly unpredictable place.

This in turn is creating ever more applications, each of which places unique demands on the plastic enclosures needed to safeguard the electronics. Applications can include wind turbine controllers, air quality meters, Geiger counters, agricultural climate control systems, inspection cameras and leak detection.

Meeting these requirements calls for a very wide range of versatile standard plastic enclosures that can be supplied fully customized – even in low volumes to suit niche applications.

For indoor systems, an ingress protection rating of IP 54 to IP 65 is often sufficient to protect against dust and splashes. For outdoor systems, much greater protection is needed – typically IP 66.

A common pitfall is that designers assume that indoor environments are benign – forgetting that condensation, cleaning fluids and accidental splashes are frequent. It is better to prepare for the worst possible conditions and specify the enclosure accordingly. ABS has long been a popular plastic for enclosures but HVAC, climate and environmental applications often call for something tougher such as UV-stable ASA+PC or robust PC+ABS.

Given the increasing use of wireless communications in these smart devices, electromagnetic compatibility (RFI/EMI) shielding is critical. Standard plastic provides no inherent shielding against electromagnetic interference. To mitigate this, enclosures can be designed with internal metallic coatings. An all-too-easy mistake is believing that – because a device performs well in a laboratory environment – it will do so in situ. But this ignores the large electromagnetic fields generated by HVAC motors, compressors or rooftop communications arrays.

For IIoT integration, enclosures must accommodate external antenna mounts, sealed cable glands and interfaces such as LEDs or touchscreens without compromising environmental protection. Failing to plan properly for external connectivity can result in water ingress around poorly fitted connectors. Established best practices include using IP 68 cable glands and gasketed viewing windows for displays.

View examples of customized enclosures for HVAC, climate and environmental electronics here...

OKW’S ENCLOSURES AND TUNING KNOBS FOR THESE APPLICATIONS: