THERMODYNAMIC ANALYSIS OF AUTOMOTIVE HVAC SYSTEM.
PRESENTED BY
Prof D.V.THAKUR 1,
1AISSMS’S POLYTECHNIC PUNE-01,
Department Of Mechanical Engineering, Pune - 01
_________________________________________________________________________ ABSTRACT

A experimental set up has been developed for refrigeration circuits of automobile air conditioning systems. The experimental set up includes a variable capacity compressor and a thermostatic expansion valve in addition to the evaporator and micro channel parallel flow condenser. An experimental bench made up of original components from the air conditioning system of a compact passenger vehicle has been developed in order to check results from the model. The refrigeration circuit was …show more content…
The charge quantity in grams of Refrigent and condenser outlet pressure in bar were plotted and result shown in figure.
From figure it is observed that the pressure in the condenser remains stable in 480 to 620 grams of Refrigerant at 18 bars. From that we can decide the quantity of Refrigent for effective performance of HVAC system.

Fig3.Graphical representation charge quantity and different parameters.

6.1 Assumptions:

• Compression process is isentropic. • No pressure losses in piping. • Condenser temperature = 46°C. • Evaporator Temperature = 4° C. • Refrigerant is not sub cooled.

6.2. Design Parameters & Considerations • Heat Load on the HVAC = 7.287 kW • Cabin Relative Humidity = 40% • Evaporator Temperature = 4°C • Refrigerant Used = R134a • Refrigeration Cycle : Vapour Compression • Cabin design – cooling and heating requirements • Temperature and Humidity range • Placement of Vents and Ducts • Space considerations • Effect on car performance • Efficiency • Environmental Impact
6.3 Results • Evaporator Pressure = 3.38 bar • Condenser Pressure = 11.9 bar • Heat Load = 5.287 KW • Condenser Cooling Load = 6.308 KW • Compressor Work = 1.02 KW • Mass Flow