18-10-2014, 04:02 PM
VECHILE AIR CONDITIONING BY
EXAUST GASES”
1408152945-pptofproject2.ppt (Size: 1.21 MB / Downloads: 15)
INTRODUCTION
The aim of our project is to develop a system which increases the efficiency of cars. For this use the waste energy of the cars i.e. exaust gases released by the cars which can waste in the environment. We use these gases for the air conditioning purpose in cars by using vapour absorption system.
Energy distribution in vehicle
In order to save fuel consumption in vehicles,
what can be done?
(1)Can we reuse some energy
from the engine coolant?
(2)Can we recover some
energy from the exhaust gas?
(3)Can we recover some
mechanical energy?
CONVENTIONAL A/C SYSTEM USED IN VEHICLES
The air conditioning system used usually in a vehicle is a vapor compression refrigeration system. It consists of a compressor, condenser, expansion valve, an evaporator blower set and a refrigerant which is circulated through the system.
WHY PARTICULAR TOPIC IS CHOSEN
Vapour compression system has some disadvantages.
A vapour compression system has more, tear and noise due to moving parts of the compressor.
The amount of work required to compress the gas in the compressor is very high.
Vapour compression system take the mechanical power directly from the engine i.e. why the engine are less efficient.
4. The capacity of vapour compression system drops rapidly with lowered evaporator pressure.
5. The performance of a vapour compression system at partial loads is poor.
OBJECTIVES AND SCOPES
It is well known that an IC engine has an efficiency of about 35-50%, which means that only one-third of the energy in the fuel is converted into useful work.
About 50-55% is wasted to environment. In which about 28-30% is lost by cooling water and lubrication losses,
Around 30-32% is lost in the form of exhaust gases and remainder by radiation, etc.
In a Vapour Absorption Refrigeration System replaces the mechanical process of the Vapour Compression Refrigeration System by using energy in the form of heat rather than mechanical work.
The heat required for running of a Vapour Absorption Refrigeration System can be obtained from the exhaust.
TECHNOLOGIES USED
There are different types of vapour absorption systems which are given below :
Aqua-Ammonia Vapour Absorption System
LiBr-H2O Vapour Absorption System
Domestic Electrolux (Ammonia Hydrogen) Refrigerator
HOW ABSORPTION CYCLE WORKS
Absorption refrigeration systems replace the compressor with a generator and an absorber. Refrigerant enters the evaporator in the form of a cool, low-pressure mixture of liquid and vapor (4). Heat is transferred from the relatively warm water to the refrigerant, causing the liquid refrigerant to boil. Using an analogy of the vapor compression cycle, the absorber acts like the suction side of the compressor—it draws in the refrigerant vapor (1) to mix with the absorbent. The pump acts like the compression process itself—it pushes the mixture of refrigerant and absorbent up to the high-pressure side of the system. The generator acts like the discharge of the compressor—it delivers the refrigerant vapor (2) to the rest of the system.
The refrigerant vapor (2) leaving the generator enters the condenser, where heat is transferred to water at a lower temperature, causing the refrigerant vapor to condense into a liquid. This liquid refrigerant (3) then flows to the expansion device, which creates a pressure drop that reduces the pressure of the refrigerant to that of the evaporator. The resulting mixture of liquid and vapor refrigerant (4) travels to the evaporator to repeat the cycle.
ADVANTAGES
No dedicated IC engine is required for the working of the refrigerating unit.
No refrigerant compressor is required.
No extra work is required for the working of the refrigerating unit.
Reduction in weight of unit.
Reduction in capital cost.
Reduction in fuel cost.
Reduced atmospheric pollution.
Reduced maintenance.
Reduced noise pollution.
CONCLUSION
It is possible to install a vapour absorption refrigeration system in an automobile working using the waste heat of the vehicle engine to produce refrigerating effect inside the automobile cabin.
It contains various advantages.