Student CD for Commercial Refrigeration for A/C Technicians Chapter 10 Supermarket Refrigeration

Copyright 2006 Thomson Delmar Learning 2 Learning Objectives Product visibility and customer access Multiple refrigerated cases and temperatures Parallel rack systems Controls and controllers Energy efficiency Mechanical subcooling Display case airflow Installation, service, and maintenance

Copyright 2006 Thomson Delmar Learning 3 Common Supermarket Product Temperatures 40° produce 36° dairy 34° deli 28° meat -5° frozen juice -10° frozen food -15° ice cream

Copyright 2006 Thomson Delmar Learning 4 Hussmann Training Center Open Front Refrigerated Dairy Case

Copyright 2006 Thomson Delmar Learning 5 Parallel Rack Systems Serve a group of different temperature cases Comprised of multiple compresses Share a common source of refrigerant and oil

Copyright 2006 Thomson Delmar Learning 6 at the Hussmann Training Center Parallel rack system

Copyright 2006 Thomson Delmar Learning 7 at the Hussmann Training Center End view of a rack system

Copyright 2006 Thomson Delmar Learning 8 Basic Parallel Rack System RECEIVER REFRIGERANT TO CASES AND WALK-INS LIQUID HEADER REFRIGERANT FROM CASES AND WALK-INS #1#2#3#4#5#6#7 #1#2#3#4#5#6#7 SUCTION FILTERS DISCHARGE HEADER OIL SEPARATOR LIQUID LINE FILTER DRIER TO CONDENSER FROM CONDENSER #1#2#3#4 OIL RETURN LINE SUCTION HEADER

Copyright 2006 Thomson Delmar Learning 9 Controls and sensors on a rack system

Copyright 2006 Thomson Delmar Learning 10 Multi-Compressor Lubrication All compressors share the same oil Oil separators return oil to compressors Oil level controls maintain sufficient oil and warn of loss of oil

Copyright 2006 Thomson Delmar Learning 11 Oil Separator and Oil Level Control Cutaway of an Oil SeparatorCompressor Oil Level Control

Copyright 2006 Thomson Delmar Learning 12 Oil Level control mounted next to the compressor

Copyright 2006 Thomson Delmar Learning 13 Oil Separator mounted on the end of the compressor rack

Copyright 2006 Thomson Delmar Learning 14 Maintaining case temperatures All cases on a specific suction line maintain the same temperatures An HPR valve is used to maintain a specific suction pressure in all the cases connected to that suction line A constant suction pressure results in a constant case temperature

Copyright 2006 Thomson Delmar Learning 15 Mechanical and Electronic EPR Valves Mechanical EPR valveElectronic EPR valve

Copyright 2006 Thomson Delmar Learning 16 Rack System Controllers Electronic control panels maintain parallel rack operation Inputs of temperature and pressure result in changes of valve and compressor operation This helps to increase system efficiency and to lower operation costs

Copyright 2006 Thomson Delmar Learning 17 Controller Cabinet Controllers respond to the input of sensors to operate the valves and compressors

Copyright 2006 Thomson Delmar Learning 18 Sensors on Discharge Line High and low temperature sensing thermistors send data to the controller

Copyright 2006 Thomson Delmar Learning 19 Pressure Controls Pressure controls cycle the compressors on and off

Copyright 2006 Thomson Delmar Learning 20 Sensors on Liquid Line Sensors attached to the liquid line monitor temperature and pressure

Copyright 2006 Thomson Delmar Learning 21 Hussmann Thermometer Properly Operating Controls Maintain Accurate Case Temperatures Courtesy of Jerry Meyer, Hussmann Training Center

Copyright 2006 Thomson Delmar Learning 22 Head pressure control Large remote condensers are often split into two sections Only one section is needed in the winter Both sections are needed in the summer

Copyright 2006 Thomson Delmar Learning 23 Courtesy of Jerry Meyer, Hussmann Training Center Hussmann Split Condenser

Copyright 2006 Thomson Delmar Learning 24 Courtesy of Jerry Meyer, Hussmann Training Center Discharge vapor into the condenser Condensed liquid out Refrigerant Flow in a Split Condenser

Copyright 2006 Thomson Delmar Learning 25 Mechanical Subcooling Approximately 1° of subcooling can increase system efficiency by ½% Normal single unit refrigeration subcooling is about 10° A plate subcooler can provide subcooling as high as 45°

Copyright 2006 Thomson Delmar Learning 26 Warm Liquid in Cool Liquid out From TEV To suction line Subcooler cutaway Subcooler

Copyright 2006 Thomson Delmar Learning 27 Mechanical subcooling 55  LIQUID OUT RECEIVER LIQUID HEADER PLATE SUBCOOLER SUCTION TEV 100  LIQUID IN

Copyright 2006 Thomson Delmar Learning 28 Heat Reclaim and Reheat Compressors send hot gas to the condenser to be de-superheated and condensed Heat reclaim de-superheats the hot gas before it reaches the condenser. This heat can be used to heat the store or the store’s domestic hot water

Copyright 2006 Thomson Delmar Learning 29 at the Hussmann Training Center Hot water heater Heat Reclaim 3-way Valves Heat reclaim for hot water

Copyright 2006 Thomson Delmar Learning 30 Display Case Airflow Open front cases make it easy for customers to choose the product they want Air curtains prevent ambient air from entering the case Improper product placement can disrupt the air pattern, pulling warm air into the case

Copyright 2006 Thomson Delmar Learning 31 Open Display Case Air Curtains

Copyright 2006 Thomson Delmar Learning 32 Case with Panels Removed Refrigerated case with bottom and back panels removed

Copyright 2006 Thomson Delmar Learning 33 Installation and Maintenance A correct installation can only be done by expert installation technicians A good maintenance program is essential to maintain efficient operation

Copyright 2006 Thomson Delmar Learning 34 Courtesy of Jerry Meyer, Hussmann Training Center Setting Refrigerated Cases in Place

Copyright 2006 Thomson Delmar Learning 35 Courtesy of Jerry Meyer, Hussmann Training Center Parallel Rack Equipment Room

Copyright 2006 Thomson Delmar Learning 36 Courtesy of Jerry Meyer, Hussmann Training Center Piping Above the Equipment Room

Copyright 2006 Thomson Delmar Learning 37 Courtesy of Jerry Meyer, Hussmann Training Center Piping Tunnels Beneath the Store

Copyright 2006 Thomson Delmar Learning 38 Courtesy of Jerry Meyer, Hussmann Training Center Installation tech brazing pipes

Copyright 2006 Thomson Delmar Learning 39 Courtesy of Jerry Meyer, Hussmann Training Center Sometimes it gets a little cramped

Copyright 2006 Thomson Delmar Learning 40 Courtesy of Jerry Meyer, Hussmann Training Center Hussmann Preassembled Equipment Rooms

Copyright 2006 Thomson Delmar Learning 41 Courtesy of Jerry Meyer, Hussmann Training Center The Rack System Inside the Equipment Room

Copyright 2006 Thomson Delmar Learning 42