THARA2C/1 Computer Controlled Capacity Control Methods in Refrigeration

The Computer Controlled Capacity Control Methods in Refrigeration, "THARA2C/1", allows to study and to investigate several methods of capacity control. For this purpose a refrigeration circuit with two refrigeration chambers is available in which a cooling load is generated using adjustable heating elements. Several fans in both refrigeration chambers ensure an even temperature distribution.

The refrigeration capacity of the refrigeration can be adjusted via the speed of the compressor (computer controlled). There also is the option to adjust the refrigeration capacity with the capacity controller situated in the compressor bypass. The unit includes a computer controlled air condenser, two evaporators in insulated refrigeration chambers, an accumulator, a filter, a flow sensor and a high and low pressure control. Each refrigeration chamber includes an adjustable heating element (computer controlled), a thermostatic expansion valve, a sight glass and a set of fans (computer controlled).

In the first refrigeration chamber (refrigeration) a solenoid valve (computer controlled) and an evaporation pressure regulator control the flow and the pressure of the coolant in the evaporator of the chamber and thereby the temperature.

In the second refrigeration chamber (freezing) a solenoid valve (computer controlled) control the flow of the coolant in the evaporator of the chamber and thereby the temperature. This refrigeration includes a check valve and a defrost heating element (computer controlled).

Both refrigeration chambers feature a window to be able to monitor the fans operation and formation of ice.

A flow sensor measures the coolant flow at the inlet of the refrigeration chambers, and several temperature sensors record the temperature of the coolant upstream and downstream of the evaporators and inside of the refrigeration chambers. Manometers and pressure sensors enable the easy reading of pressures at the relevant points.

Two PID controls enable constant temperature operation by controlling the open or close of the solenoid valves.

The software incorporates a "Defrost Process" to defrost the layer of frost of the second refrigeration chamber (freezing).

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.