PLC-TRCAC PLC Industrial Process Control for TRCAC



The Computer Controlled Refrigeration Circuit with Variable Load, "TRCAC", has been designed to carry out basic tests for the study of a vapor-compression refrigeration cycle with a thermal adjustable load.

See general description

General Description

The Computer Controlled Refrigeration Circuit with Variable Load, "TRCAC", is a unit designed for the study of a refrigeration cycle with an thermal adjustable load.

The unit includes all the components required for a fully operational refrigeration circuit, such as hermetic compressor, condenser, evaporator and a thermostatic expansion valve.

The condenser consists of a tube exchanger with a fan where the working fluid, in vapor phase, transfers heat while passing through the tubes. Therefore, the working fluid undergoes a phase change, to liquid state, through a condensation process.

In the evaporator, heat is exchanged from a water circuit (thermal load) to the refrigeration circuit. The evaporator consists of a tube exchanger where the working fluid changes phase until it reaches the saturated vapour state. The water circuit consists of a tank with a computer controlled heating element , allowing the water temperature in the tank to be controlled. The water at a certain temperature is driven to the evaporator by a computer controlled circulatory pump.

The main factors involved in the cycle can be measured: coolant flow, compressor power and pressure and temperature in key points of the cycle.

The circuit also includes a sight glass to observe the state of the coolant fluid, a filter, a storage vessel to ensure a proper flow of coolant in the circuit and a liquid separator to prevent liquid from entering the compressor. As a safety measure, the circuit includes a high pressure switch and a low pressure switch.

This Computer Controlled Unit is supplied with the EDIBON Computer Control System (SCADA), and includes: The unit itself + a Control Interface Box + a Data Acquisition Board + Computer Control, Data Acquisition and Data Management Software Packages, for controlling the process and all parameters involved in the process.

Exercises and guided practices


  1. Study of the refrigeration process.
  2. Study of a refrigeration circuit under an adjustable load.
  3. Study and familiarisation with each of the components of a refrigeration system (compressor, condenser, evaporator, expansion valve, pressure switches, etc).
  4. Determination of the cooling power (refrigeration capacity).
  5. Determination of the performance coefficient.
  6. Study of the operating behaviour under load.
  7. Preparation of performance curves.
  8. Determination of the compressor pressure ratio.
  9. Measurement of the electrical power.
  10. Representation of the thermodynamic cycle in a P-H diagram.
  11. Measurement of the temperature in the main points of the refrigeration process.
  12. Sensors calibration.


  1. Many students view results simultaneously. To view all results in real time in the classroom by means of a projector or an electronic whiteboard.
  2. Open Control, Multicontrol and Real Time Control. This unit allows intrinsically and/or extrinsically to change the span, gains, proportional, integral, derivative parameters, etc, in real time.
  3. The Computer Control System with SCADA and PID Control allow a real industrial simulation.
  4. This unit is totally safe as uses mechanical, electrical and electronic, and software safety devices.
  5. This unit can be used for doing applied research.
  6. This unit can be used for giving training courses to Industries even to other Technical Education Institutions.
  7. Control of the TRCAC unit process through the control interface box without the computer.
  8. Visualization of all the sensors values used in the TRCAC unit process.
  9. By using PLC-PI additional 19 more exercises can be done.
  10. Several other exercises can be done and designed by the user.



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