Advantages And Disadvantages Of Cryocooler

Cryogenics comes from the combination of two different Greek words, namely “kryos”, which means very cold or freezing and “genes” means to produce. Cryogenics is thus defined as the branch of physics and engineering which deals with the study of very low temperature (below 123K), their production and the materials behavior at such low temperature.

1.1. Cryocooler

Cryocoolers are refrigeration machines/equipment having very low achievable refrigeration temperature (below 123K) and low refrigeration power (in the order of 5-500 Watts).

1.2. Classification of Cryocooler

Walker in 1983 classified cryocoolers on the basis of type of heat exchanger used into two types [1]:

1.2.1. Recuperative Cryocooler

The flow of the working fluid in this type of cryocooler is unique and hence they are analogous to direct current electrical systems. The compressor and expander have separate inlet and outlet valves for maintaining the flow direction. In rotary motion of components there’s a maximum chance for back flow because of which valves are necessary when the system has any rotary or turbine component [2]. The efficiency of the cryocooler depends a lot on the working fluid because it forms an important part of the cycle. The main advantage of recuperative cryocooler is that, that they can be scaled to any size for specific output. Joule Thomson cryocooler and Brayton cryocooler are few of the examples of recuperative type cryocooler.

1.2.2. Regenerative Cryocooler

The flow of working fluid in this type of cryocooler is oscillatory and hence have an analogy to alternative current electrical system. The working fluid inside this type of cryocooler oscillates in cycles and while passing through the regenerator exchanges heat with the wire m...

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...ponent of the pulse tube refrigeration system as it’s the one which is responsible for transferring heat from the cold heat exchanger to the hot heat exchanger by the enthalpy flow.

1.4.3.6. Hot End Heat Exchanger

Heat of compression in every periodic cycle is rejected through this heat exchanger.

1.5. Double Inlet Pulse Tube Refrigerator (DIPTR)

This configuration of the pulse tube refrigerator incorporates an orifice and a DI (double inlet) valve in the basic pulse tube refrigerator model. The need for employing an orifice and a DI valve was to improve the phase relation between the mass flow rate and the pressure oscillation. The following diagram shows a schematic view of a DIPTR.