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Refrigeration Learning System (DAI)



Learn the thermodynamics fundamentals and main components of the refrigeration cycle in a compact workstation

This system is designed to teach the fundamentals of refrigeration to students starting their learning in HVAC/R. With a data acquisition interface (DAI), parameters are shown live, making abstract notions such as enthalpy or COP much easier to grasp.

A refrigeration system is often a “magic” piece of equipment that generates cold for the non-specialists. The Refrigeration Learning System (DAI) includes a software that shows the components of the system along with pressure and temperature readings at key locations.

A pressure/enthalpy diagram provides a real-time plot of the refrigeration cycle, making it possible to observe the effects of a given parameter on the overall performance of the system. For example, the system can be tested under various heat load conditions. One heat source, located in the cooling chamber, can be turned on and off, while the rotation speed of the evaporator and condenser fans can be varied.

In terms of hardware, components common to most refrigeration and air conditioning installations are included, making this system a must for beginners. Instructors can also insert faults to teach basic troubleshooting.

The learning system consists mainly of a hermetic-type compressor with thermal protection, forced-air coil evaporator and condenser, and three types of expansion (metering) devices selectable using manual valves: a thermostatic expansion valve and two capillary tubes of different lengths. One of the capillaries is designed to allow observation of the system operation under normal conditions; the other capillary is designed to simulate the effect of a partially obstructed capillary.

Features & Benefits

  • Compact design
  • Powerful data acquisition system and software for real-time monitoring
  • Variable heat load and fans speed
  • Includes fault-insertion switches for teaching troubleshooting
  • Protection against high pressure to preserve the integrity of the system

Topic Coverage

  • Identify the main components of a typical refrigeration cycle and briefly explain their role
  • Verify the pressure-temperature relationship of R-134a using the DAI, determine the COP and NRE
  • Describe and configure the pressure and temperature controllers
  • Vary the load, fan speed or expansion device and observe the effect on the other parameters of the system using the software
  • Perform various electrical measurements and troubleshoot faults

Optional Equipment

Qty DescriptionModel Number
1 Refrigeration Charging Equipment 3440-5
1 Refrigerant Recovery Unit 3445-1
1 Refrigeration Training System (Manuals on CD-ROM) 37869-A


Figure 5. The System Information panel displays in real time the values of variables used to assess the performance of the system.
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Figure 6. The Pressure/Enthalpy Diagram provides a real-time plot of the refrigeration cycle.
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Figure 7. The Trend Recorder provides a graph over time of the pressures, temperatures, and compressor data at the system test points.
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Figure 1. Three expansion (metering) devices are available.
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Figure 2. The electronic pressure controller, with LCD display and adjustable cut-in and cut-out pressures.
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Figure 3. An electrical control panel with silk-screened diagram and banana jacks allows students to develop troubleshooting skills through the insertion of fault switches.
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Refrigeration Training System
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Figure 4. The LVHVAC software Refrigeration Diagram shows the main components of the system and displays in real-time the temperatures, pressures, and compressor data measured at the various test points.
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