Project On using LPG as a refrigerant and the process involved in the design and development

1. LPG REFRIGERATION SYSTEM
DESIGN AND FABRICATION OF
PROJECT WORK
ANTO SAJU RA1411002020132
R KRISHNADEV RA1411002020158
SARATH S RA1411002020161
KALATHIL SHIVLAL RA1411002020193
B-TECH –(MECHANICAL)
Under the guidance of
Mr. David Andrews
Department of Mechanical Engineering
Faculty of Engineering And Technology
SRM University, Ramapuram

2. ABSTRACT
Slide 1
In this project we have designed and analysed a refrigerator using
LPG as refrigerant. LPG is available in cylinders at high pressure.
When this high pressure LPG is passed through the capillary tube
of small internal diameter, the pressure of LPG is dropped due to
expansion and phase change of LPG occurs in an isoenthalpic
process.
Due to phase change from liquid to gas latent heat is gained by
the liquid refrigerant and the temperature drops. In this way LPG
can produce refrigerating effect for a confined space.

3. INTRODUCTION
Slide 2
It works on the principle that during the conversion of LPG into
gaseous form, expansion of LPG takes place. Due to this expansion
there is a pressure drop and increase in volume of LPG that results
in the drop of temperature and a refrigerating effect is produced.
This refrigerating effect can be used for cooling purposes. So this
work provides refrigeration for socially relevant needs as well as
replaces global warming creator refrigerants.

4. Slide 3
LITERATURE SURVEY
The energy crisis persists all across the globe. We think of
recovering the energy which is already spent but not being utilized
further, to overcome this crisis with no huge investment. The
climatic change and global warming demand accessible and
affordable cooling systems in the form of refrigerators and air
conditioners. Annually billions of dollars are spent in serving this
purpose.
Hence forth, we suggest NO COST Cooling Systems. Petroleum
gas is stored in liquefied state before its utilization as fuel. The
energy spent for pressurizing and liquefying is not recovered
afterwards. If it is expanded in an evaporator, it will get vaporized
and absorb heat to produce cooling.

5. PROBLEM IDENTIFICATION
Slide 4
Chlorofluorocarbons, commonly referred to as CFCs, are non-
combustible liquids that were, at one time, frequently used as
refrigerants and aerosol propellants, as well as for cleaning
products. Since scientists linked CFCs to the depletion of the
ozone layer, they have been largely phased out, but old
refrigerators and other devices that use CFCs might still be in
service.
Through inhalation, digestion or other physical contact, as well
as from exposure to harmful levels of ultraviolet rays, CFCs
can have a negative impact on human health.

6. PROPOSED SOLUTION
Slide 5
The basic idea behind LPG refrigeration is to use the evaporation of
a LPG to absorb heat. LPG is stored in the LPG cylinder under high
pressure when the gas tank of regulators is opened then high
pressure LPG passes in gas pipe. This LPG is going by high
pressure gas pipe in capillary tube. It works on the principle that
during the extraction of heat the LPG expanded there is a pressure
drop and increase in volume of LPG that results in the drop of
temperature and a cooling effect.
Thus the refrigeration effect can be obtained while burning a stove
using the LPG gas. The LPG gas from the gas tank passes over the
capillary tube as said above and enters a refrigeration cycle and
reaches the burner. Hence as long as the burner is burnt, the cooling
effect can be 12 obtained.

7. METHODOLOGY
Slide 6

8. METHODOLOGY
Slide 7

9. CALCULATION
Slide 8
Heat absorbed by LPG (QLPG) = Latent heat absorbed
(QL)LPG +Sensible heat gain(QSen)LPG
We have the volume flow rate of LPG is 0.1 liter per
min. and the specific volume of LPG at 1.22 bar pressure is
1.763×10-3 m3/Kg.
Therefore mass flow rate of LPG is = 0.0001/1.763×10-3
= 0.0567 Kg/min
m = 9.448×10-4 Kg/sec
= mLPG .xLPG .hfg + mLPG .cpLPG . (Tsup-Tsat)
=9.448×10-4×0.5×375×103×5400+
9.448×10-4×1.67×(48)
= 0.956812 MJ/Hr.
h2 = hf+X.hfg
= 107.3 + 0.5 x 375
= 294.8 KJ/Kg
hg = hf+ hfg
= 107.3 + 375
= 482.3 KJ/Kg.

10. h3 = hg + Cp. ΔT
= 482.3 + 1.67 x 48
= 562.46 KJ/Kg
So the refrigerating
effect is,
RE = h3 – h2
= 562.46 – 294.8
= 267.66 KJ/Kg
CALCULATION
COP of the LPG Refrigeration System
COP = (h3-h2)/W
= 267.66/42.39
= 6.3
After finding out the COP of the LPG refrigerator we found
out the heat liberated by LPG after burning in the burner
with the burner efficiency of 92 %.
Heat liberated by LPG to atm. QL= m×Cv
The volume flow rate of LPG is 0.1 liter per min. and the
specific volume of LPG at 1.525 bar pressure is 1.763×10-3
m3/Kg.
Therefore mass flow rate of LPG is
= 0.0001/1.763×10-3
= 0.0567 Kg/min
m = 9.448×10-4 Kg/sec
Cv = 46.1 MJ/Kg
QL= 9.448×10-4× 46.1×103
= 43.56 W
Hence, from this we have got the refrigerating effect from
the system as well as heat from the LPG.

11. DESIGN
Slide 9

12. DESIGN
Slide 10

13. BILL OF MATERIALS
Slide 11

14. EXPERIMENTAL WORK
Slide 12

15. TESTING
The following test are to be done on the machine
1. Maximum load carrying capacity of refrigerator.
2. Cooling rate
3. Velocity of gas flow.
4. Expansion of gas
5. Pressure regulation
6. Testing for leaks and deformities
Slide 13

16. ADVANTAGES
Slide 14
• It is efficient to save fuel.
• Low Weight.
• The fridge works when the electricity is off.
• It is efficient to save fuel.
• No Pollution.
• Running cost is zero.
• Eliminates the compressor and condenser.
• Noiseless in operation.
• No need of separate power for running the
refrigeration system.
• The cost of the system is low.

17. RESULTS AND DISCUSSION
Slide 15
The refrigeration capacity with ambient temperature for LPG
and the current alternative refrigerant (R134a) in vapour
compression refrigeration system. It was observed that for the
two investigated refrigerants, refrigeration capacity decreases
with increase in ambient temperature. At the same ambient
temperature, the refrigeration capacity obtained from LPG is
higher than that obtained from R134a by 4.2%. Average
refrigeration capacities of 23.236 kW and 22.295 kW were
obtained during the tests using LPG and R134a

18. RESULTS AND DISCUSSION
Slide 16
The variation of the coefficient of performance
(COP) with ambient temperature for LPG and
R134a is shown. It was observed that the
coefficient of performance decreases with increase
in ambient temperature. At the same ambient
temperature, The COP of LPG is higher than that
obtained for R134a by 11.16%. Average COP of
3.725 and 3.351 were obtained during the tests
using LPG and R134a, 49 respectively.

19. RESULTS AND DISCUSSION
Slide 17

20. FUTURE SCOPE
Slide 18
LPG (Liquefied Petroleum Gas) is supplied in pressurised
cylinders to keep it liquefied. The LPG cylinders, from past many
years, are being manufactured in our country from the very
conventional metallic material such as steel. The weight of the
cylinder becomes more as density of steel is higher compared to
other light weight materials. In household applications, thrust
should be given towards use of low density materials so that the
weight will come down. With the advancement of low density
materials like GFRP (Glass Fibre Reinforced Polymer)
composites, we can think of producing LPG cylinders with GFRP
to reduce its weight in future, to increase safety, for measuring
the amount of liquid consumption etc.

21. CONCLUSION
Slide 19
The aim of the LPG refrigerator was to use LPG as a
refrigerant and utilizing the energy of the high pressure LPG
cylinder for producing the refrigerating effect. We also
conclude that, we are trying to burn the exhaust LPG, the
pressure of exhaust gas is less than 10 PSI, so that the flame
produce by the burner is spreading outside. This system is most
suitable for hotel, industries, refinery, chemical industries
where consumption of LPG is very high.

22. Thank You
Slide 20