B.TECH - Semester 7 refrigeration and air conditioning Question Paper 2020 (sep)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Describe vapour refrigeration system.
- Draw T-S diagram for simple boot strap refrigeration system.
- What is meant by one tonne of refrigeration?
- What is meant by flash gas removal in refrigeration system.
- What is superheating process? Draw the PV diagram for the same.
- Write the functions of condenser in refrigeration system.
- How the vapour compression refrigeration system works? Draw the T-S diagram to represent vapour compression process.
- Define by-pass factor.
- Give the short note on working of year round air-conditioning system.
- Write some industrial applications of air-conditioner? ( $\mathbf{1 0} \boldsymbol{\times} \mathbf{2} \boldsymbol{=} \mathbf{2 0}$ Marks) P.T.O. Answer any one from each Module.
- (a) Explain with neat sketch working of regenerative air-conditioning system with its T -s diagram.
- (b) A simple air cooled system is used for a aeroplane having the load of 9 TR. The atmospheric pressure and temperature are 0.9 bar and $10^{\circ} \mathrm{C}$ respectively. During ramming pressure increases to 1.013 bar. In the heat exchanger the t...
- (i) Power required to take the load of cooling in the cabin (ii) COP of the system.
- (a) A bootstrap cooling system of 9 TR capacity is employed in an aeroplane . The ambient air temperature and pressure is $20^{\circ} \mathrm{C}$ and 0.86 bar respectively. The pressure of air increases from 0.86 bar to I bar due to ramming action of...
- (i) The power required to operate the system T-s (ii) COP of the system. Take $\mathrm{C}_{\mathrm{P}}$ of air $=1 \mathrm{~kJ} / \mathrm{kgK}, \gamma=1.4$ (iii) Draw the schematic and temperature specific entropy diagrams.
- (b) A Bell-Coleman cycle works between 1 bar and 5 bar. The adiabatic efficiency of the compressor is $85 \%$ and expansion is $90 \%$. Find the COP of the system and its tonnage when the air flow rate is $1 \mathrm{~kg} / \mathrm{sec}$. The ambient ...
- (a) Briefly explain in detail about the methods of improving COP for a multi evaporator system.
- (b) Explain the cascade refrigeration system with neat sketch and state its advantages.
- (a) The vapour compression system is used to maintain a temperature of $-23^{\circ} \mathrm{C}$ in a refrigerated space. The ambient temperature is $37^{\circ} \mathrm{C}$. The compressor takes dry saturated vapour of $\mathrm{F}_{-12}$. A minimum $1...
- (i) Tonnage of refrigeration. (ii) Power requirement (iii) Ratio of COP of this cycle to COP of Carnot cycle
- (b) An ammonia refrigerator works between $-20^{\circ} \mathrm{C}$ and $30^{\circ} \mathrm{C}$. The vapour is being dry at the end of isentropic compression. Assuming there is no subcooling, Find
- (i) Theoretical COP (ii) Power of the motor to run the compressor to absorb $100 \mathrm{MJ} / \mathrm{hr}$. Use the following properties for $\mathrm{NH}_{3}$. | Temp ${ }^{\circ} \mathrm{C}$ | $h_{f}(\mathrm{~kJ} / \mathrm{kg})$ | $h_{g}(\mathrm{~...
- (a) Draw and explain the neat diagram of Electrolux refrigerator with its working principle? What is the important role of Hydrogen in this refrigeration system.
- (b) Discuss briefly about the various methods used for capacity control of a reciprocating air compressor.
- (a) Explain briefly about the factors which affect the heat transfer capacity of an evaporator.
- (b) Derive a expression for find out the mass of motive steam requires per kg of water vapour produced.
- (a) Explain with neat sketch and describe
- (i) Psychometric process (ii) Humidification process.
- (b) Explain with neat sketch the working of window air-conditioner.
- It required to design an air-conditioning system for a restaurant with the following data | Inside design conditions | $24^{\circ} \mathrm{C}$ DBT,55\%RH | | :--- | :--- | | Outdoor conditions | $39^{\circ} \mathrm{C}$ DBT,28\%WBT | | Infiltrated ai...