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Products  |  Thermal Engineering and HVAC  |  Refrigeration and Air Conditioning Technology  |  ET 350
ET 350 Changes of State in the Refrigeration Circuit Show data sheet (pdf file) Print page
Technical Description

  In a compression refrigeration system a refrigerant flows through the refrigeration circuit and is subject to different changes of state. Here, the physical effect is used that during the transition of the refrigerant from a liquid to a gaseous state energy is required which is removed from the environment (evaporation enthalpy).
  The experimental unit ET 350 represents a typical refrigeration circuit consisting of a hermetic piston compressor, condenser, expansion valve and evaporator. The evaporator and condenser are transparent to provide good monitoring of the phase transition process during evaporation and condensation. The operation of the float valve as expansion valve is also easy to observe. Before the entry into the evaporator the aggregate state of the refrigerant can be monitored at a sight glass. A water circuit cools the condenser or supplies the cooling load for the evaporator. Cold and hot water and refrigerant flows are adjustable. The low pressure level of the refrigerant SES36 used permits the use of an evaporator and condenser out of glass. The refrigerant is CFC-free and environmentally friendly.
  Temperatures and pressures are recorded and displayed. The key points of the cyclic process can be read and entered into a log p-h diagram. The power of the compressor and flow rates of the water flows and the refrigerant are also indicated.
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- design and operation of a compression

  refrigeration system
- observe the evaporation and condensation of the

- represent and understand the refrigeration cycle in

  the log p-h diagram
- energy balances
- calculation of the coefficient of performance
- oil return in a flooded evaporator


* Refrigeration circuit demonstrated clearly1
* Transparent components offer insights into the

  changes of state1
* Energetic analyses of the refrigeration cycle

Alternative products
ET 352 -- Steam Jet Compressor in Refrigeration Engineering
ET 411C -- Compression Refrigeration System
[1] demonstration of the processes in a refrigeration circuit
[2] for better process monitoring the evaporator and condenser are of transparent design
[3] evaporator and condenser with pipe coil
[4] expansion valve in the shape of a float valve
[5] pressure switch to protect the compressor
[6] temperature sensor, power meter, manometer in the refrigeration circuit, flow meter for hot and cold water and refrigerant
[7] safety valves at the evaporator and condenser
[8] refrigerant Solkatherm SES36, CFC-free 
Technical Data

Hermetic piston compressor
- capacity: 18,3cm
Evaporator volume: approx. 2,8L
Condenser volume: approx. 2,8L
Measuring ranges
- temperature: 8x -20...200C
- pressure: 2x -1...1,5bar
- flow rate (water): 2x 0...800cm/min
- flow rate (refrigerant): 1x 0...700L/h
- power: 0...1.200W

Dimensions and Weight
LxWxH: 1.210x510x900mm
Weight: approx. 110kg
Required for Operation
230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase
Water connection, drain
Scope of Delivery
1 experimental unit
2L of refrigerant Solkatherm SES36
1 set of supply hoses
1 set of instructional material
Order Details

061.35000  ET 350  Changes of State in the

                                Refrigeration Circuit

© 2005 G.U.N.T. Gerätebau GmbH