Post on 05-Feb-2016
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JT Sorption Type Cryocooler
Operation of a sorption compressor is based on the principle that large amounts of gas can be adsorbed on certain solids such as highly porous carbon.The amount of gas adsorbed is a function of temperature and pressure.
JT Sorption Type Cryocooler
Absorption is a Chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase.
Adsorption is the adhesion of molecules of gas, liquid, or dissolved solids to a surface. This is physical effect.
Physical and Chemical effects on surface
Adsorption
JT Sorption Type Cryocooler
Typical gas - sorber combinations for sorption cryocoolers
JT Sorption Type Cryocooler
Working of Sorption Type Cryocooler
•By nature, a sorption compressor element is an intermittent system in which the sorbent bed alternates between gas generation and adsorption.
•By combining at least two sorbent beds in a single compressor and sequencing these sorbent beds out of phase, it is possible to produce a constant flow of gas through the cold stage and thus achieve continuous refrigeration.
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
Working of Sorption Type Cryocooler
• The compressor unit contains four sorption cells and two check valves fitted to each cell for controlling control the gas flows.
• Sorption compressor type J-T cryocooler essentially consists of
a) Sorption type compressorb) After coolerc) Return gas heat exchangerd) J-T expansion device
JT Sorption Type Cryocooler
Working of Sorption Type Cryocooler
•Usually, heating occurs with an electrical heater and cooling is done by circulating water in a coil around the sorption cell
JT Sorption Type Cryocooler
Valve position in JT cryocooler
JT Sorption Type Cryocooler
• The working fluid is initially heated in the Cell A for ¼ cycle.
• Inlet Valve of A and Outlet Valve of C are opened.
• The hot working fluid is cooled to room temperature in the after cooler.
• The high pressure working fluid at room temperature enters the recuperative heat exchanger, where, it is cooled by the return gas.
• The working fluid is then expanded Isenthalpically by passing through a J-T Valve. Resulting in reduction of temperature.
• The low temperature working substance evaporates as it takes the heating load and produces refrigeration.
• The working substance then enters the return gas heat exchange before getting adsorbed into the Cell C
Working of Sorption Type Cryocooler
A B C D
JT Sorption Type Cryocooler
• The type of compression employed in sorption compressor cell is
– Reciprocating type
– Rotary Compressor
– Adsorption type
– None of the above
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
• Pressure is developed due to
– Adsorption
– Absorption
– Desorption
– Sorption
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
• Heat exchanger prior to JT valve is used to
– Reduce the temperature before expansion
– To increase the cop
– To remove gaseous heat
– For refrigeration effect
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
• Adsorption is a ____?
– Physical effect
– Chemical effect
– mostly physical , but in certain cases it is chemical
– Neither physical nor chemical process
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
• Desorption in a cell comprises of ____?
– Compression
– Expansion
– Combined compression and expansion
– Refrigeration
JT Sorption Type Cryocooler
JT Sorption Type Cryocooler
Cryogenic Engineering By R Barrons
http://www.cryomech.com/
http://www.che.cemr.wvu.edu/publications/projects/large_proj/air.PDF