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Products | Thermodynamics, Heating and Sanitary Systems | Refrigeration and Air Conditioning | ET 426

ET 426

Capacity Control Methods in Refrigeration

Technical Description

This unit demonstrates several possible ways of regulating the capacity. The cooling capacity of the system with 2 separate evaporators can be changed by adjusting the speed of the open compressor. The compressor drive motor is controlled using a frequency converter. The evaporators are in individual insulated compartments. In the first compartment the temperature is regulated using an intake pressure controller and thermostat (mechanical regulation), in the second compartment using a case controller (electronic regulation). In both cooling compartments a cooling load can be generated using an electrical heater. Fans ensure even temperature distribution. A bypass capacity regulator is installed in the refrigerant circuit that connects the high and low pressure sides of the compressor. The system is equipped with temperature sensors at all relevant measuring points. The signals provided by these sensors are also used by the case controller.

Learning Objectives / Experiments

- Refrigerant circuit with two evaporators
- Effect of the compressor speed on the system
cooling capacity
- Various types of capacity regulation via temperature:
   + mechanical
   + electronic
- Function and operation of:
   + a case controller
   + an evaporator pressure regulator
   + a capacity controller

Features

* Familiarisation with various types of capacity control₁
* Clearly laid out on laboratory trolley

Alternative products

ET 165 -- Experimental Module Refrigeration System
ET 412C -- Industrial Refrigeration Trainer / PC
ET 422 -- Commercial Refrigeration Unit with Fault Simulation
ET 428 -- Multiple Compressor Refrigeration Control

Specification

[1] Mobile system for capacity control in refrigeration engineering
[2] 2 insulated cooling chambers with electric heater and evaporator with 2 fans
[3] Chamber 1 with mechanical temperature control (intake pressure controller + thermostat), chamber 2 with electronic temperature control (case controller)

[4] 1 evaporator with additional defrosting heater
[5] Compressor with adjustable speed, drive motor controlled via frequency converter
[6] Refrigerant R134a, CFC-free
[7] l x w x h 1100x750x1905mm, 150kg
[8] 230V, 50/60Hz, 1 phase

Technical Data

Condensing unit

- refrigerating capacity: 560W at -5/25°C

- drive motor: 550W
Cooling chamber

- heater: 500W

- evaporator with 2 fans

+ capacity: 78W at 5°C/ΔT=7K

+ heat exchanger surface area: 1.12m²

+ max. airflow rate: 2x 50m³/h
Defrosting heater: 75W
Intake pressure controller: 0...5.5bar
Capacity controller: 0.2...6bar
Case controller: 7 inputs, 7 outputs
Measuring ranges

- temperature: -60...50°C

- power: 0...10kW

- pressure: -1...9bar / -1...24bar

Dimensions and Weight

l x w x h : 1100 x 750 x 1905 mm
Weight : approx. 150 kg

Connections

230V, 50/60Hz, 1 phase

Scope of Delivery

1 refrigeration system

1 instruction manual

Order Details

061.42600 ET 426 Capacity Control Methods in

Refrigeration