Refrigeration & Air Conditioning (RAC)

• Principles and methods of refrigeration, freezing
• Mixture cooling by gas reversible expansion, throttling, evaporation, Joule‑Thomson effect and reverse Carnot cycle
• Unit of refrigeration, coefficient of performance, vortex tube & thermoelectric refrigeration, adiabatic demagnetization
• Air refrigeration cycles – Joule’s cycle, bootstrap cycle, reduced ambient cycle and regenerative cooling cycles

• Vapour compression cycle, p‑h and t‑s diagrams
• Deviations from theoretical cycle, sub‑cooling and super‑heating
• Effect of condenser and evaporator pressure on COP
• Multi‑pressure system: removal of flash gas, multiple expansion & compression with flash intercooling
• Low temperature refrigeration: production of low temperatures, cascade system, dry ice, air liquefaction system

• Theoretical and practical vapour absorption systems such as aqua‑ammonia, Electrolux and other systems
• Steam‑jet refrigeration: principles, simple cycle operation, description and working of simple system
• Refrigerants – nomenclature & classification, desirable properties, common refrigerants, comparative study, leak detection methods
• Environment‑friendly refrigerants and refrigerant mixtures, brine and its properties

• Calculation of psychrometric properties of air by tables and charts
• Psychrometric processes: sensible heating and cooling, evaporative cooling, cooling and dehumidification, heating and humidification, mixing of air streams, sensible heat factor
• Principles of air conditioning, comfort requirements, ventilation standards, infiltrated air load, fresh air load, human comfort, effective temperature chart
• Heat production and regulation of the human body

• Calculation of summer & winter air‑conditioning load
• Bypass factor of coil, calculation of supply air rate and its condition
• Room sensible heat factor, gross sensible heat factor, effective sensible heat factor, dehumidified air quantity
• Problems on cooling load calculation
• Air distribution and ventilation systems

• 7. General Study of Water cooler 8. General Study of Psychrometers (Absorption type) 9. General Study of Leak Detectors (Halide Torch). 10. General Study and working of Gas charging Rig. 11. General Study of window Air Conditioner. 12. General Study and working of Vapor compression Air conditioning Test rig. 13. Experimentation on Cold Storage of Calculate COP & Heat Loss. 14. Experimentation on Vapor compression Air Conditioning test rig. 15. Changing of Refrigerant by using Gas Charging Kit.

The syllabus lists no separate topics for this unit.