Q19.The clearance volumetric efficiency is equal to a. to increase volumetric efficiency of of compressor, b. to allow the system to operate between higher pressures, c. to reduce risk of damage to refrigerant. Q1. View Answer. The Following Section consists Multiple Choice Questions on Basic Mechanical Engineering. The work done per kg of refrigerant is reduced in, with intercooler as compared to single stage, is a device which separates liquid from vapors. In vapor compression refrigeration system, refrigerant occurs as liquid between_____? d) all of the mentioned c) large installations use air-cooled condenser a) using a single stage with high pressure ratio decreases volumetric efficiency How it works : Energy equation for refrigerant, (h + KE +PE )of inlet + Q - W = (h +KE +PE)of outlet. In a vapour compression refrigeration system, a throttle valve is used in place of an expander because (A) It considerably reduces mass of the system (B) It improves the C.O.P., as the condenser is small (C) The positive work in isentropic expansion of liquid is very small (D) It leads to significant cost reduction Mechanical Engineering Refrigeration and Air Conditioning Important MCQ 1. (A) improve overall heat transfer coefficient Edit. However, calculated in cm³, the charge would be roughly the same liquid volume in the system. 3.Both the condenser and evaporator are heat exchangers with refrigerant as a common medium. Of the larger superheat horn of ammonia compression cycle. This is because, Latent heat of ammonia is higher than that of freon, Thermal conductivity of water is higher than that of air, Specific heat of water is higher than that of air. (A) circulating more quantity of cooling water through the condenser Hey Readers on the off chance that you are searching for the free download Thermal Engineering R S Khurmi And J K Gupta Book Pdf then you each the ideal spot.Today group ebooksfree4u.com share with you Thermal Engineering R S Khurmi And J K Gupta Book Pdf.This book will help you in Your scholarly examination or focused examinations. A short summary of this paper. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. Carbon, hydrogen and fluorine: B. Answer: b Q15. Evaporation. d) none of the mentioned The heat required to melt 1 tonne of ice in 12 hours is equivalent to. Discuss the use of flash tank for flash gas removal only (Section 12.5) 7. In a vapour compression system, the lowest temperature during the cycles occurs after, 5. Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air-conditioning of buildings and automobiles. 2. onsider the following statements in respect of absorption refrigeration and vapour compression refrigeration systems: 2. Match List-I (Refrigerant) with List-II (Designation) and select the correct answer using the codes given below the lists: Theoretical vapour compression refrigeration cycle is represented on a T-s diagram as. Improves volumetric efficiency for the given pressure ratio B. The first practical vapour-compression refrigeration system was built by James Harrison, a British journalist who had emigrated to Australia. In a mechanical refrigeration system the refrigerant occurs as liquid (or very wet vapour) between ; The condition of refrigerant before and after the expansion or throttle valve in a vapour compression system is ; Post navigation. Q22.The most widely used refrigerants are A Vapor Compression Refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev. Azeotrope is a mixture of refrigerants without phase separation. US2140415A US140534A US14053437A US2140415A US 2140415 A US2140415 A US 2140415A US 140534 A US140534 A US 140534A US 14053437 A US14053437 A US 14053437A US 2140415 A US2140415 A US 2140415A Authority US United States Prior art keywords oil compressors compressor conduit crankcase Prior art date 1937-05-03 Legal status (The legal status is an assumption and is not … Explanation: Because of these reasons we have to use multistage compression with intercooling. Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. So, COP R = Q C over W ref. Q16.For an expansion device, which of the following is true? View Answer. Reduces work done per kg of air C. Reduces cost of compressor D. Gives more uniform torque E. All of the above Then, COP of both A and B > COP of Reversed Carnot Cycle. Oil separator is NOT required in refrigeration system if: Refrigerant and oil are immiscible at all pressures and temperatures, Refrigerant and oil are immiscible at condensation pressure and temperature, Refrigerant and oil are miscible at all pressures and temperatures. Mechanical Engineering What is the main reason behind subcooling of liquid refrigerant at the condenser outlet in vapour compression refrigeration system? Non-condensable gases are present in the system, 3. Answer: a Need of throttling process- To reduce pressure and temperature without change in enthalpy. This flash chamber between the condenser and evaporator is known as flash intercooling. In the cascade system, two separate refrigerant system are interrelated. This test is Rated positive by 90% students preparing for Mechanical Engineering.This MCQ test is related to Mechanical Engineering syllabus, prepared by Mechanical Engineering teachers. 85. A standard ice point temperature corresponds to the temperature of (a) water at 0°C (b) ice … Next . Multiple Choice Questions (MCQ) and Answers on Chemical Engineering Thermodynamics Question 1 : The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. Condensation. 4.The amount of heat exchanged in condenser and evaporator are equal under steady conditions. Which of the following refrigerant is highly toxic and flammable? The purpose of installing a flash chamber in the refrigeration circuit is to Saturated liquid. Take the Quiz and improve your overall General Knowledge. In a vapour compression system, the condition of refrigerant before entering the compressor is, 3. In a vapour compression plant, if certain temperature differences are to be maintained in the evaporator and condenser in order to obtain the necessary heat transfer, then the evaporator saturation temperature must be: Higher than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts, Lower than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts, Lower than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts, Higher than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts. However, system chemistry and heat exchangers are complex, refrigerant compositions are sensitive, and compressor displace-ment is large. 3. Q9. which will improve your skill. What is the use of multistage compression in vapour compression refrigeration system? 2.The evaporator absorbs heat from the surroundings to be cooled. Vapour Compression Refrigeration System: Analysis of simple vapour compression Refrigeration cycle by p-h and T-S diagram. 50 Hz compressor with displacement 11.1 cm3/rev ; cascade and compound consisting of stoms:. Compression refrigerator employs the following is true solution, best for any competitive examination provide best coaching! Of throttling process- to reduce vapour bubbles which obstruct the flow of refrigerant before entering the compressor discharge increases. If YOU THINK that above POSTED MCQ is WRONG several methods are available for the preparation of Fpsc,,! 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