South Africa-based Booyco Engineering has upgraded the heating, ventilation and air conditioning (HVAC) system for a customer’s 8x8 armoured personnel carrier.

With almost 40 years of experience in custom designed robust HVAC solutions for the defence sector, the latest prototype is the third iteration of a bespoke unit for this longstanding export customer. According to Grant Miller, Executive Director at Booyco Engineering, the key advances in the latest system have been its integrated electronic control system and the addition of heating functionality.

“This version of the unit allows the driver two-way engagement with HVAC related information on the vehicle’s touchscreen dashboard consol, rather than via a standalone control panel,” says Miller. Using a controller area network (CAN bus) enabled controller, the HVAC’s control system is now fully integrated into the vehicle’s control communication network. The unit makes use of a micro-processor controller that was locally developed specifically for HVAC applications in military vehicles. The addition of heating to the system means that the vehicle can now be deployed in areas with colder climates.

Designed and manufactured in South Africa, the HVAC system is fully rated to stringent military standards. These include environmental specification MIL-STD-810G, MIL-STD-461C and MIL-STD-464C specifications on electromagnetic conformance and interference, and MIL-STD-1472F on general human engineering design. It was supplied to the customer in mid-2023 and has undergone extensive field testing under demanding conditions.

Ross Macphail, Engineering Manager at Booyco Engineering, highlights that the customer is also developing a hybrid electric-drive version of the same vehicle – in which the batteries will also require cooling.

“They intend to use our HVAC system for their new hybrid vehicle, where our equipment will be cooling not just the internal crew space but the batteries as well,” says Macphail. The large traction motor batteries on electric vehicles need to be actively cooled during operation.

He points out that this system also makes use of brushless DC compressors as opposed to a traditional engine driven compressor, which allows the HVAC system to be run independently of the vehicle engine.

Booyco Engineering’s HVAC equipment is designed to perform reliably in the high levels of shock, vibration and dust encountered in military applications. It also limits electromagnetic interference (EMI), which is unwanted electrical noise radiated and conducted from the equipment during operation. This aspect is particularly important in a military context, where EMI can negatively affect communication and other electronic equipment in the vehicle.