The document discusses vapor compression refrigeration systems (VCRS) and vapor absorption refrigeration systems (VARS) for vehicle air conditioning. VCRS is commonly used but uses environmentally unfriendly refrigerants, while VARS can utilize wasted engine heat and has lower operating costs. VARS works by absorbing refrigerant with a heat source like exhaust gases, while VCRS relies on mechanical compression. VARS offers benefits like reduced noise, lower maintenance needs, and ability to recover otherwise wasted engine heat. The document proposes a VARS design for vehicle air conditioning that recovers exhaust heat as the heat source.

2. TABLE OF CONTENT
1. INTRODUCTION
2. PERCENTAGE OF ENERGY IN A SYSTEM
3. VCRS
4. VARS
5. VCRS VS VARS
6. ADAVANTAGES
7. SCOPE OF WORK
8. CONCLISION

3. INTODUCTION
Air conditioning of a vehicle can be done by two methods
Vapor Compression Refrigeration System (VCRS).
 Vapor Absorption Refrigeration System (VARS)
The commonly utilized method of cooling currently used in vehicles is Vapor Compression Cycle, but the
refrigerants in vapor compression refrigeration systems are mainly hydrocarbons like HCFCs and HFCs, which are
not environmental friendly, resulting in undesirable changes in the atmosphere and environment like global
warming, ozone layer depletion, etc.
The implementation of VARS system in automobile vehicle reduces the additional running cost for air
conditioning.
There is a great impact on the running cost of a vehicle due to increasing cost of fuel. The A/C system adds nearly
35 % extra cost in fuel expenses.
An automobile engine utilizes only about 35% of available energy and rests are lost to cooling and exhaust system.

4. The basic objective of developing a vapor absorption refrigerant system for automobiles is to lower the
temperature of a small space inside the vehicle by utilizing waste heat and exhaust gases from engine
It is a well known factor that an IC engine has an efficiency of about 35%-40%, which means that
only one-third of the energy produced by the combustion of the fuel is converted into useful work
done.
About 60-65% of the energy in the form of heat is lost to environment. In which about 28%-30% is
lost by coolant and lubrication losses, around 30%-32% is lost thorough exhaust gases from the
exhaust pipes and remainder of the energy is lost by radiation and convection.
In a Vapor Absorption Refrigerant System, the heat required for running the system can be obtained
from that which is wasted into the atmosphere from IC engine. Hence to utilize the exhaust gases and
waste heat from an engine the vapor absorption refrigerant system can be put into practice which
increases the overall efficiency of car.
Keeping these point in mind ,a car air conditioning system is designed from recovery of Exhaust waste heat using as
source/generator for VARS.

5. PERCENTAGE OF ENERGY IN SYSTEM

6. VAPOUR COMPRESSION REFRIGERATION
SYSTEM

7. VAPOUR ABSORPTION REFRIGERATION
SYSTEM

8. VARS VS VCRS
Particulars Vapour compression Vapour Absorption
Working method Refrigerant vapor
is compressed
Refrigerant is absorbed and heated
Type of the energy Supplied Mechanical work supply to the compressor Heat energy supply to the generator
Input work required More compression work is required. Less mechanical energy is required to run pump.
COP High (Approx. 3) Low (Approx. 0.6)
Capacity Limited up to 1000 tons for single compressor It may be above 1000 tons
Noise More Quiet operation
Leakage More leakage due to
high pressure
Almost there is no
Leakage
Operating cost High because of
compressor consumes
more work
Less because of less heat energy is required

9. ADVANTAGES OF VARS OVER VCRS
 1.No moving parts so ,quite in operation ,subjected to little wear, low maintenance cost. The pump
required quite small power in comparison with compressor.
 2. Large capacity.
 3.Exellent part load efficiency and almost constant c.o.p. of the system over a wide range of load.
 4.Automatic capacity control is easy.
 5.Smaller space per unit capacity.
 6.No harm on OZONE layer.
 7.Leakage can be easily detected in case of aqua-ammonia system.

10. SCOPE OF THE WORK
The engine waste heat can be recovered by using generator in VARS. The arrangement of
various components of air conditioning system is also a challenge because of the fixed size
of vehicles.
In the proposed model condenser and evaporator will be arranged same as the
conventional unit.
VARS system is to be used to cool the confined spaces with limited temperature for heavy vehicle.

11. CONCLUSION
Thus we have seen that the VARS is efficient in every respect, and can be successfully
implemented with better designs and sophistication. Now it is the task of the up-coming engineers
to overcome the hurdles in the way if any and make our country’s people enjoy the comfort and
luxury of A/C and fuel will also be saved to a greater extent which would have been consumed in
excess by the (VCRS) air conditioner. And also, the environment is kept healthy and pollution free.