B.TECH - Semester 7 regrigeration and air conditioning Question Paper 2019 (jul)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- 704 : REFRIGERATION AND AIR CONDITIONING (M) Time : 3 Hours Max. Marks : 100 PART - A Answer all questions. Each question carries 2 marks. Steam tables permitted.
- Describe ice refrigeration.
- Define COP, what is the unit of refrigeration effect?
- State the merits and demerits of an air refrigeration system.
- What is the difference between 'wet compression' and 'dry compression'?
- What are the methods of improving COP of a simple vapour compression cycle?
- Discuss the function of evaporator in a refrigeration system.
- How leaks is deducted in R12 refrigeration system?
- Define (a) Saturated air
- Define (b) Specific humidity.
- What are the factors that govern optimum effective temperature.
- What is the function of 'duct'? Which material is most commonly used for duct design? ( $\mathbf{1 0} \boldsymbol{\times} \mathbf{2} \boldsymbol{=} \mathbf{2 0}$ Marks) P.T.O. PART - B
- (a) Describe with a neat sketch the reduced ambient air refrigeration system.
- (b) The cold storage plant is required to store 20 tonnes of fish when supplied $25^{\circ} \mathrm{C}$ temporation. The required storage temperature of fish is $-8^{\circ} \mathrm{C}$, specific heat of fish above freezing point is $2.93 \mathrm{~kJ}...
- (i) Capacity of refrigeration plant. (ii) Carnot cycle COP between the temperature range. (iii) If the actual COP is $1 / 3^{\text {rd }}$ of Carnot COP, find the power required to run the plant. OR
- (a) Describe the arrangement used for creating low temperature by adiabatic demagnetisation of paramagnetic salt.
- (b) A B Coleman- refrigerator operates between pressure limits of 1 bar and 8 bar. Air is drawn from cold chamber at $9^{\circ} \mathrm{C}$ compressed and then it is cooled to $29^{\circ} \mathrm{C}$ before entering the expansion cylinder. Expansion ...
- (a) Explain the cascade refrigeration system.
- (b) A two stage vapour compression refrigeration system using R12 working between pressure limits of 9.6 bar and 1.8bar for saturation temperature $38^{\circ} \mathrm{C}$ and $-10^{\circ} \mathrm{C}$ for a mass flow of 0.2 kg per second . obtain the ...
- (a) Explain the two stage compression with inter cooling and sub cooling by external cooling source.
- (b) A food source locker requires a refrigeration capacity of 50 kW . It works between a condenser temperature of $35^{\circ} \mathrm{C}$ and an evaporator temperature of $-10^{\circ} \mathrm{C}$. the refrigerant is $\mathrm{NH}_{3}$. It is sub cooli...
- (i) Power required. (ii) Cylinder dimension.
- (a) Explain with neat sketch the working of steam jet refrigeration system.
- (b) What are the different types of food preservation, Explain them briefly.
- (a) What are the function of condenser in refrigeration system ? Explain with diagram working of evaporative condenser.
- (b) Discuss about the charging of refrigerant. How would you ensure correct charge in system.
- (a) Define the following in detail
- (i) Psychometric process. (ii) Dehumidification process. (iii) Dew point temperature. (iv) Wet bulb temperature.
- (v) Bye pass factor.
- (b) Explain with neat sketch the working of window type air conditioner.
- (a) (i) Distinguish between summer and winter air-conditioning (ii) Explain with diagram a year round air conditioning.
- (b) Air at $12^{\circ} \mathrm{C}$, DBT and $70 \%$ Relative humidity is to be heated and humidified to $36.5^{\circ} \mathrm{C}$ DBT and $21^{\circ} \mathrm{C}$ WBT. The air is preheated sensibly before passing the air washer in which water is recir...
- (i) Temperature to which should be preheated. (ii) Total heating required. (iii) Make up water required in the air washer (iv) Humidification efficiency of air washer.