Previous year question paper for HEAC (B-TECH automobile engineering 5th)

Heat Exchanger

Function, Classification, types and applications of heat Exchangers, heat rejection ratio, elements of heat

exchanger, Working fluid: Liquid and Gas, Dalton’s law of partial pressures; Effect of leakage of air. Methods to

check and prevent air infiltration, selection of heat exchangers, heat exchanger design methodology.

Single Phase Heat Exchangers: LMTD and NTU methods for evaporator and condenser tubes, and parallel and

counter flow heat exchangers, calculation of number and length of tubes in a heat exchanger. Rating and sizing

methods, design criteria, geometry, process parameters, pressure drops and applications

Condensation Mechanism, types of condensers and design procedures, Evaporators, Design procedures,

augmented surface heat exchangers, Heat transfer coefficients, pressure drops, compact heat exchangers and

air coolers, plate heat exchangers and plate fine heat exchangers

Heat Pipe Heat Exchangers: Types and design procedure and applications

Installation, Operation and Maintenance: Fouling factors, type of fouling, and cleaning methods

Air Conditioning

Basic Concept

Natural and Mechanical refrigeration; Application of Refrigeration; Units of refrigeration and Coefficient of

performance; Refrigeration effect, cooling capacity and COP of a refrigerator; Reversed Carnot cycle and its

limitations, Meaning of air conditioning,

Refrigerants

Classification, properties, selection criteria, commonly used refrigerants, alternative refrigerants, eco-friendly

refrigerants, and applications of refrigerants. Refrigerants used in automobile air conditioning, Basic vapour

compression system.

Air Conditioning Concept and Applications;

Psychometric properties of air; Dry bulb, wet bulb and dew point temperatures; Relative and specific humidity;

degree of saturation adiabatic saturation temperature, enthalpy of air and water vapours; psychometric chart.

Human requirement of comforts; effective temperature and comfort charts; Industrial and comfort air

conditioning.

Psychometric Processes

Sensible heating and cooling, cooling with dehumidification; Heating with

dehumidification; by-pass factor; chemical dehumidification; adiabatic mixing, air washer.

Calculations for Air –conditioning Load and for Rate and state of Supply Air

Sources of heat load; sensible and latent heat load; sensible heat factor; apparatus dew point temperature; Rate

and state of air supply for air- conditioning of vehicles.

Air Conditioning Equipment

Brief description of compressors, condensers, evaporators and expansion devices; Cooling towers; Ducts;

dampers; grills; air filters; fans; room air conditioners; split units; automotive air conditioning systems-HVAC

model