mech enginnering

1. “Theoritical analysis of cascade refrigeration system
for cooling application”
PRESENTED BY:-
Ashok kumar singh
Uid- k10798
course – B.tech
Branch –mechanical
Year/Sem- 3rd/6th
PRESENTED TO:-
Mr. Aditya Mishra
Assistant professor
Mechanical Deptt.
CAREER POINT UNIVERSITY, KOTA
MAJOR ASSIGNMENT OF RAC

2. CONTENT
1. Introduction.
2. Types.
3. Description.
4. Assumptions.
5. Graphs.
6. Conclusion.
7. References.

3. • It is a freezing system
• Two kinds of refrigerants
are used having different
boiling points
• Both refrigerants run in
their own independent
freezing cycle
• Both cycles are joined by
heat exchanger
INTRODUCTION

4. • Natural refrigerant have
low ODP and GWP in
nature
• Low temperature cycle
R744
• High temperature cycle
R134a,R290,R717,
R404a
TYPES OF REFRIGERANT S

5. During process 1-2 the low temperature
cycle refrigerant is compressed
isentropically.
It is then passes through cascade
condenser where it gives heat to
refrigerant of higher temperature cycle
(process 2-3).
It is expands in throttling device
(process 3-4) and further passes to
evaporator (process 4-1) to produce
necessary refrigerating effect.
In higher stage refrigerant is
compressed in high temperature cycle
compressor (process 5-6), then it passed
through condenser where it rejects heat
(process 6-7).
It expands isentropically in throttling
device (process 7-8) further passes to
cascade condenser where heat transfer
between two refrigerants takes place.
DESCRIPTION

6. DESCRIPTION

7. • Adiabatic and irreversible compression
• Negligible pressure and heat drop in the piping or
system components.
• Isenthalpic expansion of refrigerants in expansion
valves.
• Heat transfer process in heat exchanger is isobaric.
• Changes in kinetic and potential energy are negligible.
ASSUMPTIONS

8. EQUATIONS

9. Low evaporating temperature range
(TE,LT) of -55˚C to -30˚C
Increasing the higher stage temperature of
cascade system (TC,HT) from 30˚C to 55˚C
GRAPHS

10. Cascade condenser temperature
(ΔTCC) is increased from 1˚C to 13˚C
Condensing temperature (TC,LT)
increases from -30°C to 10°C
GRAPHS

11. • From the comparative assessment of different cascade
refrigeration pairs; the R744-R717 pair has the maximum
COP
• The cascade refrigerant pair R744-R717 has higher COP
as compared to other refrigerants pairs R744-R134a,
R744-R290 and R744-R404A for the same TC, TE and
TCASC; other parameters remain constant
• R744-R717 pair has the higher COP as compared to other
refrigerant pairs for cooling application
CONCLUSION

12. • World Academy of Science, Engineering and Technology International Journal of
Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8,
No:8, 2014[A. D. Parekh, P. R. Tailor]
• International Journal of Innovative Research in Science, Engineering and
Technology(An ISO 3297: 2007 Certified Organization) Vol. 4, Special Issue 6, May 2015.
[ Gajendrasinh G. Parmar , Dr. R. G. Kapadia
• Applied Thermal Engineering, Elsevier, 2009, 29 (8-9), pp.1577.
<10.1016/j.applthermaleng.2008.07.006>. <hal-00581928>
• GOOGLE SEARCH ENGINE
• WIKIPAEDIA
REFERENCES