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InsemAug 20252019 patternBE Mech

Heating, Ventilation, Air Conditioning & Refrigeration (HVACR) SPPU Insem Question Paper Aug 2025

All 4 questions from this SPPU insem paper, as printed. Read them here or open the PDF.

Open the PDFMost repeated HVACR questions
Subject code
402041
Pattern
2019 pattern
Exam
Insem
Session
Aug 2025
Max. marks
30
Time
1 Hour
Semester
VII
Paper code
[6580]-558

Printed for: B.E. (Mechanical) (Insem.)

Instructions to the candidates

  1. Answer Q1 or Q2, Q3 or Q4.
  2. Neat diagrams must be drawn wherever necessaly.
  3. Figures to the right side indicate full marks.
  4. Use of electronic pocket calculator is allowed.
  5. Use of steam table and psychrometric chart is allowed.

Questions

  1. Q1

    1. a)

      Explain the concept of DART in air refrigeration cycles and compare various air refrigeration cycles using DART.

      Also asked:Oct 2022

      [6]
    2. b)

      The following data refers to a bootstrap air cycle evaporative refrigeration cycle used for an evaporator to take 20 tonnes of refrigeration load : Ambient air temperature = 15°C Ambient air pressure = 0.8 bar Mach number of flight = 1.2 Ram efficiency = 90% Pressure of air after main compressor = 4 bar Pressure of air after secondary compressor = 5 bar Isentropic efficiency of main compressor = 90% Isentropic efficiency of secondary compressor = 80% Isentropic efficiency of cooling turbine = 80% Temperature of air leaving the first heat exchanger = 170 °C Temperature of air leaving the second heat exchanger = 155 °C Cabin pressure = 1 bar : Cabin temperature = 25 °C Find : i) Draw neat temperature entropy plot of given system ii) Mass of air required to take cabin load iii) Power required for the refrigeration system iv) C.O.P. of the system

      Also asked:Oct 2022

      [9]

  2. Q2

    1. a)

      Explain the following properties of refrigerants i) Latent heat of vaporization ii) Boiling point iii) Miscibility iv) Specific heat of vapour refrigerant

      Also asked:Oct 2022

      [8]
    2. b)

      Explain Boot -Strap air refrigeration system with T-S diagram

      [7]

  3. Q3

    1. a)

      Explain two stage compression with Intercooling and sub cooling by external cooling source.

      [6]
    2. b)

      A Single Compressor using R-12 as Refrigerant as three evaporators of capacity 10 TR, 20 TR, 30 TR. All evaporators operate at -10°C and the vapors within the compressor are dry and saturated. The condenser temperature is 40°C, the liquid refrigerant leaving the condenser is sub cooled to 30°C. Assuming the Isentropie Compression, Find i) Mass flow rate of refrigerant flowing through each evaporator. ii) The power required to drive the compressor iii) COP of the system

      [9]

  4. Q4

    1. a)

      Explain with schematic and P-h diagram a complete two stage compression system with flash chamber acts as intercooler and gas removal.

      Also asked:Sep 2023

      [6]
    2. b)

      With the neat diagram Explain working of Cascade refrigeration system. 

      [9]