Cooling in remote underground locations need no longer be a challenge. “Whether cooling capacity is either inadequate or inefficient or additional cooling capacity is required, the mobile Enerflow Underground Air Cooling Unit (ACU) can create a comfortable working environment with a temperature of between 26° and 28°C,” Dion Booyens, General Manager of Mine Support Products (MSP), a company within the DCD-Dorbyl Group, which supplies the unit, says. Developed by M-Tech Industrial in conjunction with MSP, the Enerflow ACU has a high positional efficiency, with a construction configuration which facilitates transport and installation, making it ideal for remote underground areas where temperatures hover around the critical 32.5°C wet bulb limit. Its size allows it to fit into a mine cage and it can be moved easily as mining activities expand.“Based on field-tested heat pump technology, the unit accommodates a water inlet temperature of up to 35°C,” Booyens continues. “The compressor, air evaporator and water condenser that make up the vapour compression cycle are housed within a single mobile, modular unit that can be mounted on a tracked unit, have its own undercarriage or can be wheel-mounted. There are currently two layout configurations to fit inside different cages. It weighs less than two tonnes and uses the environmentally-friendly refrigerant, R407c.”Easily connected to all services such as water, electricity and fan, the Enerflow ACU draws hot air in, cycles it through the air evaporator with a standard mine ventilation fan to cool it, and feeds the cooled air back into the environment. Depending on the air volume flow rate through the unit, the temperature drop on the air side through the unit ranges between 5° and 10°C wet bulb. The unit can also be customised to suit specific underground conditions.“Energy extracted from the air is transferred via the compressor to the water in the condenser which is then expelled into the mine’s wastewater reticulation system. This discharge volume is minimal, depending on specific application circumstances and the temperature of the supply water, with a flow of about 1 litre/s. Maximum flow rate is about 2 litres/s,” Booyens says.In the event of additional cooling requirements, the Enerflow ACU can be installed in series or in parallel. Water connection requires one inlet and one outlet using 50 mm flexible hoses. Electricity supply required is 525 V 50 A/phase. The unit uses either a 406 mm mine ventilation fan with a 4 kW capacity or a 572 mm (7.5 kW) fan. It is energy efficient, with a nominal cooling capacity of 100 kW which requires little electrical input, helping reduce cooling costs.