This ammonia refrigeration system services a food distribution facility in Sydney. The plant is designed by Scantec Refrigeration Technologies as a dual compression stage plant with one dedicated low-temperature screw compressor package, one, second stage compressor package and one dual-duty standby compressor.
All medium temperature services are designed for connection to a secondary refrigerant loop. The primary refrigerant for the secondary refrigerant circuit is ammonia. The semi-welded cassette plate heat exchanger between the primary and the secondary refrigerant streams is arranged for gravity flooded refrigerant feed and is located in close proximity to the intercooler in the engine room.
The freezer is serviced by two insulated air cooling units (evaporators) with fans within the insulated enclosures. Each insulated cooler has motorized baffles for automatic ambient air defrost and are fitted with individual, dedicated valve stations.
A feature of the insulated coolers is total separation on the airside from the refrigerated warehouse. This means that during defrost there is no exchange of air between the insulated evaporator enclosure and the warehouse. This minimizes heat flow from the cooling coils into the warehouse during defrost.
The separation of the cooler from the warehouse also means that all maintenance activities on the evaporator take place outside the refrigerated space. In the event of a refrigerant leak, the evaporator, when programmed accordingly, will enter into defrost mode thereby preventing the refrigerant from entering the refrigerated space for extra safety.
The evaporators employ the “cold lake” air distribution principle requiring no ducts within the refrigerated environment. This air distribution concept utilizes the fact that colder air is heavier, flows along the floor of the warehouse and rises to return to the air cooler. At the time of construction, this facility was the first in Australia to employ insulated coolers with automatic ambient air defrost and cold lake air distribution.
The compressors, condenser fans, warehouse air cooler/evaporator fans and main glycol pumps are connected to variable frequency drives for maximization of energy savings.
Scantec, are experts in refrigeration design, installation and servicing. To enquire about a refrigeration plant design for a new site or for a retrofit click here to contact us today or call 07 3890 9400.