Question

1. Compare between, single simple refrigeration cycle, two-stage cascade refrigeration cycle, and a two-stage compression refrigeration cycle with a flash chamber all between both between same pressure limits.

Answer 1

- Simple Vapour compression system of a two-pressure System. Systems with more than two pressured may be of two types: mult pression Systems D Compound compression 2) Mult' evaporator byteros Systems which employ more than one refrigerant 18 known as Cascade Systems. It has also multi- pressux System but each refrigerant circuit operates on a two-press core System Only. Simple Vaporer Compression system - Condens or OK и0 Verpancion device CO presion Evaporates! It consists of Ø 1 Compressor 2) Condresor 3) expansion device 4) evaporates, presswe-Sthalpy diagram Cycle :- for simple vapor Compression Cop= hi-he ha-hi р 1-2 2-3 Isentropic compression Constant pressure heat rejection Isenthalpic expansion Constant pressure heat addition 3-4 4-

Two stage compression refrigeration cycle with a flash chamber. It is an effective method of reducine work of compression by working on isentropics closer to the Saturation cave. S2 - ibentropica =ی ر Wiz 2 Wolai Compous Works only when and evaporator Compound compression is employed parus ure ratio between condenser Ad greater than 4 of 5. Ich multi detaging two types of Stages is employed - water inter cooling 2 flash stercooling cooling between two stage compression with Schematic diagram of flash chamber. condersos ts +4 mm, Flash Chamber tz Lot Evaporator

pressure enthalpy diagram for redrigeration System with two stage compression flash intercooling Pk Condense Sm 34 Tee intermediak) ----- I Po Evaporator Flash Chamber enables highes h Stage compression to takes place along the striper is entropic nearer to the Saturated vapour One. The compressed vapour in lower stage are bubbled through the liquid in the flash chamber. And the vapours are then cooked to the Saturation temperature at the pruss ure of flash chamber. The liquid which evaporats goes to figher stage.

Two Setage Cascade refrigeration cycle Liontating factors of surgle refrigerant in simple VERS (2 very high pressure ratio leads to low cop (1) High pressure in condenson may ocear it low boiling refrigerant is wed. () Solidification temperature of refrigerant. (v) If high bobing refrigerant is selected then extremely low pressure in the evaporator and large suction Volumes. Schematic diagram of Cascade System Confersen High temperature Cascade system o Evaporator how tempoature Cas cade system, high boiling The high temperation cascade uses retrigeants leg: NH₂ R22 The cow temperature cascade uses a refrigerant such as CO CHq etc.. low boiline