Development of an Ac System Using Waste Heat of an Ic Engine

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  • Topic: Heat transfer, Heat, Log mean temperature difference
  • Pages : 35 (7927 words )
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  • Published : April 25, 2012
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DEVELOPMENT OF AN A/C SYSTEM USING WASTE

HEAT OF AN IC ENGINE

PROJECT REPORT Submitted by

ALEX ROY
JIJIN JOSEPH
RAKESH R
SAJI ABRAHAM
K S SHAN

ABSTRACT

The refrigerating units currently used in road transport vehicle are of Vapour Compression Refrigeration system (VCRS). This system utilizes power from the engine shaft as the input power to drive the compressor of the refrigeration system, hence the engine has to produce extra work to run the compressor of the refrigerating unit utilizing extra amount of fuel. This loss of power of the vehicle for refrigeration can be neglected by utilizing another refrigeration system i,e. a Vapour Absorption Refrigeration System (VARS).

It is well known that an IC engine has an efficiency of about 35-40%, which means that only one-third of the energy in the fuel is converted into useful work and about 60-65% 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, a physicochemical process 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 the Vapour Absorption Refrigeration System can be obtained from that which is wasted into the atmosphere from an IC engine. LIST OF TABLES

TablePage

2.1 Refrigerant - Absorber Pairs8
7.1 Properties of refrigerant at each point of the system23

u

LIST OF FIGURES

Figure

1. 1Conventional refrigeration system used in automobiles
2Pressure enthalpy diagram
1Block diagram of a vapour absorption refrigeration system 2. 2A simple absorber 2. 3A generator
1Block diagram of the system
1Vapour absorption system with a pre-heater
1Isometric view of pre-heater 8. 2Isometric view of generator 8. 3Isometric view of absorber NOMENCLATURE

SymbolDefinition

|A |area of flow- | |Cpe |specific heat at constant volume of exhaust gas | |Cpvv |specific heat of water | |Di |inside diameter of tube | |D0 |outside diameter of tube | |Df |outer diameter of the fin | |Evol |volumetric efficiency of the engine | |Gr |Grashoff Number | |h |thermal heat transfer co-efficient | |hfg |latent heat of refrigerant | |K |thermal conductivity | |L |length of tube | |Lc |equivalent diameter | |LMTD |log mean temperature difference | |niair |mass flow rate of air in to the cylinder | |ma |mass flow rate of the solution back to the absorber...
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