Acpac Semi Hermetic Packaged Condensing Unit, Custom Buffalo Air Handler, Carel Expansion Valve, Vacon Variable Speed Drive
When a major air conditioning contracting business was looking for refrigeration equipment to suit a highly specialized close control storage room for float glass manufacture they came to Actrol. The close controlled 14°C low humidity glass storage room was required as part of a multi-million dollar fully automated float glass assembly line. The design specification required a constant 14°C to be maintained despite the varying heat loads that would be encountered manufacturing different float glass types.
Actrol Applications Engineer Anthony Chandler offered a suite of refrigeration equipment comprising a dedicated air handling unit incorporating a direct expansion evaporator coil to operate with refrigerant R134a, an Acpac semi hermetic packaged condensing unit coupled to a Vacon variable speed drive and a Carel electronic expansion valve.
The air handler was designed and supplied by Buffalo Trident in Melbourne. The Acpac packaged condensing unit is speed controlled between 30Hz and 70Hz using a Vacon variable speed drive using a suction pressure transducer as the control input. The suction temperature is maintained at a constant 0°C by varying the compressor speed. The Carel electronic expansion valve supplies accurate superheat across the widely variable room load and the generous condenser size of the Acpac condensing unit keeps control of the condensing temperature even at the highest compressor speed of 70Hz.
This system has been maintaining the critical float glass storage room within the close control performance requirements of the specification since being commissioned in November 2012.