Refrigerator Training System

1. Scope of Supply

The Contractor shall supply, deliver, install, test, commission, and hand over complete Refrigerator Training System, including:

• Training bench with full refrigeration circuit
• Integrated data acquisition system
• Licensed data acquisition software
• RFID power management system
• Branded desktop computer
• Offline UPS
• All instruments, accessories, and documentation

The system shall be complete, fully operational, and ready for instructional use.

2. General Description

The Refrigerator Training System shall be a desktop-type educational unit designed for laboratory study of refrigeration thermodynamics and system performance analysis.

The system shall enable students to:

• Observe and analyze refrigeration cycle stages
• Plot and interpret pressure–enthalpy (P–h) diagrams
• Determine superheating and subcooling
• Calculate coefficient of performance (COP)
• Compare actual cycle performance with inverse Carnot cycle
• Evaluate compressor efficiencies

The refrigerant shall be R134a or equivalent environmentally acceptable refrigerant.

3. Mechanical Construction

3.1 Training Bench

• Movable aluminum profile structure
• Dimensions (Minimum)
  1200 (L) × 700 (W) × 1600 (H) mm
• Mounted on four (4) castors:
  • Two (2) with brakes
  • Two (2) without brakes
• Front demonstration board:
  • Silkscreened refrigeration circuit diagram
  • Clearly labeled components
  • Color-coded refrigerant piping (red/blue)

4. Electrical Requirements

• Power Supply: 220V ±10%, Single Phase, 50Hz
• Rated Current: 10A (Minimum)
• Residual Current Circuit Breaker (16A) (Minimum)
• Key switch (self-locking)
• Emergency stop button (self-locking)
• Overload protector (5A) (Minimum)
• Indicator lights (minimum 5 pcs)
• Power monitoring module

5. Refrigeration System Components

The system shall include, but not be limited to, the following:

5.1 Compressor

• Capacity: 1/8 HP (Minimum)
• Displacement: approx. 4 cm³
• Cooling capacity: approx. 329W (per EN 12900 standard)

5.2 Condenser with Water Tank

• Spiral copper coil (12–14 turns)
• Minimum1/4-inch outer diameter tubing
• Submerged in water tank
• Heat transfer area approx. 0.082 m²

5.3 Evaporator with Water Tank

• Spiral copper coil (7–9 turns)
• Minimum 1/4-inch outer diameter tubing
• Submerged in water tank
• Heat transfer area approx. 0.049 m²

5.4 Circulating Pumps

• Voltage: 220V ±10%
• Power: 165W (Minimum)
• Adjustable (three power settings)
• Flow rate: approx. 80 L/min
• Quantity: 2 pcs

5.5 Expansion Valve

• Internal balance thermostatic expansion valve (TEV)

5.6 Filter-Dryer

• Minimum 1/4" service connections

5.7 Service and Manual Valves

• Flared thread connection
• Minimum 1/4" pipe diameter

5.8 Sight Glasses

• Installed on liquid line, suction line, and evaporator inlet (3 pcs)

6. Instrumentation and Sensors

The system shall include:

• Low-pressure gauge: -30 ~ 260 psi
• High-pressure gauge: -30 ~ 550 psi
• Pressure transmitters: 0–2 MPa (4–20 mA output) – 2 pcs
• Temperature transmitters (PT100) – 4 pcs
• Digital thermometers (-40°C to +90°C) – 4 pcs
• Pointer voltmeter (0–250V)
• Pointer ammeter (0–5A)
• LCD display for real-time measurement display
• Analog input module
• Power monitoring module
• High/low pressure controller

Pressure and temperature shall be measurable at multiple points throughout the refrigeration circuit.

7. Water Tank and Heat Exchange System

• Evaporator and condenser coils shall be submerged in separate water tanks.
• Water tank temperature sensor shall be provided.
• Circulating system shall allow water circulation between tanks during steady-state experiments.
• System shall allow demonstration of cooling and heat pump cycles.

8. Integrated Data Acquisition System

The system shall include a built-in multi-functional data acquisition system with the following minimum specifications:

• USB interface connection to computer
• Real-time data acquisition
• High-precision measurement capability
• Manual and automatic data recording
• Configurable sampling intervals (time or interval-based)
• Digital and analog instrument display modes
• User-friendly graphical interface
• Customizable layout and display

All necessary USB cables shall be supplied.

9. RFID Power Management System (Mandatory)

The equipment shall include an integrated RFID-based power control system with:

• Operating frequency: 13.56 MHz (high frequency)
• Communication via RS485 (Standard)
• OLED display for RFID card information
• Audible status prompts
• LED indicators
• Data verification capability
• Parameter configuration via software
• ISO-15693 protocol compliance
• Support for ModBus_TCP and ModBus_RTU

The RFID system shall control power activation via card authentication.

10. Additional Equipment

10.1 Branded Desktop Computer

Brand: HP, Dell or equivalent approved brand
Manufacturer reference:

Minimum specifications:

• Processor: Intel Core i5 (10th Generation or higher)
• Cache: Minimum 12MB
• Base frequency: 2.5 GHz or higher
• RAM: 8GB DDR4
• Storage: 1TB SATA HDD or better
• Graphics: Integrated
• Monitor: 21.5-inch minimum
• Resolution: Minimum 1366 × 768
• Interfaces: VGA ×1, HDMI ×1
• Keyboard and mouse: USB, same brand
• Operating system: Free-DOS or equivalent

10.2 Uninterruptible Power Supply (UPS)

• Type: Offline UPS
• Capacity: Minimum 650VA
• Backup time: Minimum 10 minutes at full load
• Support: 1 computer + 1 monitor

11. Learning Capabilities

The system shall support the following laboratory exercises:

• Use of pressure–enthalpy charts
• Determination of superheat and subcooling
• Refrigeration energy balance
• Calculation of Coefficient of Performance (COP)
• Determination of isentropic and volumetric efficiencies
• Influence of heat source and sink temperatures on COP
• Comparison between actual cycle and inverse Carnot cycle