Abstract:
Automobile air-conditioning is a necessity of present life. Designing energy efficient
and cost effective products are the main challenge in modern world. From that
perspective when we look at a vehicle air conditioning system, it doesn’t fit that
criteria in most of the cases. Vapor compression refrigeration cycle used in modern
automobile uses refrigerant 134-a and the compressor of automobile air-conditioning
is run by engine crankshaft, which reduces the mileage of the automobile. An internal
combustion engine gives about 35% efficiency and when we put the load of air
conditioning, it consumes upto 15-20% energy of the crankshaft. Also 65% heat
energy is wasted through exhaust and cooling system. In many industries waste heat is
used to reutilize in refrigeration system using Vapor Absorption System. The main
theme of this project is to utilize the waste heat of the exhaust gases generated in
internal combustion engines. Before leaving these gases to the atmosphere through the
exhaust necessary mass of exhaust gases is by passed and is made to deliver it
generator so as to run the vapour absorption refrigeration system there by conserving
the energy. We have made the same system in smaller scale so that it can be used in
vehicles and cabin temperature can be kept at a comfortable level. By controlling the
heat provided in generator and pump flow rate we have ensured that the cabin
temperature stays at the thermal comfort zone of 20-25 degree Celcius. In this project
we have used Temperature sensors, Water flow sensor, Pressure gauge, Valves,
Electromagnetic relay and Arduino to monitor the system conditions with time. This
also enables us to control the system completely which wasn’t done in a smaller scale
before. This project takes the idea of using VARS for air cooling one step closer to
industrialization and with continual research this can be developed to use in vehicles
in near future. Owing to the threat of global warming due to high thermal disposal and
to compensate the energy crisis, VARS is likely to gain immense prominence in the
coming years. The aim of the project is to perform analysis on absorption refrigeration
system using lithium-bromide as absorbent and water as refrigerant to find out the
optimal operating temperatures on the thermal loads of components and their coefficient of performance. Finally coming up with the operating conditions where it
can run by effectively utilizing the waste heat of the exhaust gases.
