## Articles Posted in the " Gas Refrigeration " Category

• ### * Analysis of Simple aircraft cooling system-2

Analysis of Simple aircraft cooling system-2 (iii) Calculation of T4 after the HEAT EXCHANGER T4 temperature after the cooler (heat exchanger) on the basis effectiveness of the heat exchanger which can be assumed as 80 % if not given. ЄHEX =( T3—T4)/( T3 — T2) = Actual temp drop/Theoretical temp drop possible (iv) Calculation of temperatures T5 […]

• ### Interview Short Question Answers on Aircraft Cooling

Interview Short Interview Question Answers on Aircraft Cooling  Why Is The Necessity of Aircraft cooling? In an aircraft, cooling systems are required to keep the cabin temperatures at a comfortable level. Even though the outside temperatures are very low at high altitudes, still cooling of cabin is required due to: (i)  Large internal heat generation […]

• ### Refrigeration-Air-Interview Short Question Answers

Refrigeration-Air-Interview Short Question Answers Air refrigeration is used in all the air crafts. Its COP is less than 1 because of sensible cooling. Air is a safe refrigerant and requires less equipment. Q. Compare open cycle and closed cycle air Refrigeration systems. Why closed cycle is called a dense system?  OPEN CYCLE: The conditioned air […]

• ### AIRCRAFT COOLING SYSTEMS

AIRCRAFT COOLING SYSTEMS Boot Strap Aircraft cooling : Two types Without evaporative cooling, With evaporative cooling   FIG.  Boot Strap  without evaporator   This Bootstrap system has two compressors, two heat exchangers and one turbine. Normally second compressor is run by the expansion turbine. System with evaporative cooling, there is  another water cooled heat exchanger  […]

• ### *Analysis of aircraft cooling systems-1

Analysis of aircraft cooling systems-1 Refrigerant is air in all the systems of the aircraft cooling. FIG. SIMPLE AIRCRAFT COOLING SYSTEM ON TEMP -ENTROPY CHART  Mathematical analysis of Simple Aircraft Cooling System—-1 Properties of air are cP =1.005 k J/kg 0c cv =0.714 k J/kg 0c γ =  1.4 =Cp/Cv Rair=287 k J/kg K 1kWh […]

• ### Refrigeration- vapor vs air

Refrigeration- vapor vs air Air refrigeration is based on bell Coleman Cycle and is used in all the air crafts. It causes cooling by sensible effect.Though it has a low COP but certain amount of power is saved in carrying only (1/10)th of refrigeration equipment load as compared to that in vapor compression refrigeration. Air […]

• ### Refrigeration-Air and Vapor-Short Interview Question Answers

Refrigeration-Air and Vapor-Short Interview Question Answers Q. What is Bell Coleman Cycle or Reversed Brayton Cycle or Reversed Joule Cycle or Gas Refrigeration Cycle?  It is a cycle which consists of two isen-tropic processes and two isobaric processes. Since in this cycle the working substance is air (OR gas) work of expansion is recovered in […]

• ### Refrigeration-Aircraft-Interview Short Question Answers

Refrigeration-Aircraft-Interview Short Question Answers  Q.  WHY IS AIR USED AS REFRIGERANT IN AIRCRAFT’S?  (i) Air is cheap, safe, non-toxic, non corrosive, inert and non-flammable. Leakage of air is not a problem (ii). Cold air from the turbine can directly be sent to cabin for cooling. Thus it eliminates the low temperature heat exchanger (cooler ) in […]

• ### Refrigeration-Air-Interview Short Question Answers

Refrigeration-Air-Interview Short Question Answers DEFINE REFRIGERATING EFFECT OR COOLING EFFECT, N It is heat removed by 1 kg of refrigerant from the products to be cooled. It is represented by ‘N ‘. It is expressed as k J/kg.  GIVE DEFINITION OF WORK INPUT TO A REFRIGERATING UNIT, W Work input is work required to compress […]

• ### Refrigeration-Air Cycles-Open and Closed

Refrigeration-Air Cycles-Open and Closed  TWO WAYS OF OPERATING OF BELL COLEMAN CYCLE (i) Open air refrigeration cycle: When cooled air from the turbine enters the cabin and comes in physical contact with the occupants. It is not much in use because of moisture added to air in the cabin. (ii) Closed air refrigeration cycle OR dense cycle: When cooled […]