Heating, Ventilation, Air Conditioning & Refrigeration (HVACR) important questionsMost repeated in SPPU papers
These 35 questions appeared in more than one SPPU Heating, Ventilation, Air Conditioning & Refrigeration paper we have: 11 papers, from Oct 2022 to Nov 2025. The most-asked come first. Each one links to the papers it was asked in.
Repeated questions
Endsem questions (31)
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The atmospheric air at 30°C dry bulb temperature and 75% relative humidity enters a cooling coil at the rate of 200 m 3 /min. The coil dew point temperature is 14°C and the by-pass factor of the coil is 0.1. Determine: i) The temperature of air leaving the cooling coil ii) The capacity of the cooling coil in kW iii) The amount of water vapour removed per min, and iv) The sensible heat factor for the process 2
- 4×asked
A circular duct of 40 cm is selected to carry air at velocity 440 meter per minute if duct is replaced by rectangular duct of aspect ratio 1.5. Find the size of a rectangular duct for equal friction when; i) Velocity in two duct is same. ii) Discharge in two duct is same. If f = 0.015. Find the pressure loss per 100 m length of duct. Take density of air = 1.15 kg/m 3 .
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A conference room for sitting 100 persons is to be maintained at 22°C DBT and 60% relative humidity. The outdoor conditions are 40ºC DBT and 27 °C WBT. The various loads in the auditorium are as follows: i) Sensible and latent heat loads per person 80 W and 50 W respectively; ii) Lights and fans, 15000 W; iii) Sensible heat gain through glass ceiling etc. 15000 W. iv) The air infiltration is 20 m 3 /min and fresh air supply is 100 m 3 /min. v) Two-third of recirculated room air and one-third of fresh air are mixed before entering the cooling coil. vi) The bypass factor of the coil is 0.1. Determine 1) Apparatus dew point, 2) Grand total heat load and 3) Effective room sensible heat factor
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The air-handling unit of an air-conditioning plant supplies a total of 4500 cmm of dry air which comprises by weight 20% fresh air at 40 o C DBT, 27 o C WBT, and 80 % recirculated air at 25 o C DBT and 50% RH. The air leaves the cooling coil at l3 o C saturated state. Calculate the following. i) Total cooling load, and ii) Room heat gain
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Insem questions (4)
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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
Questions count as repeated when their wording matches closely across papers. Numericals that depend on a figure are left out, since the figure changes from paper to paper.