Engineering reference for Indian students

Thermal & fluids

Refrigeration & HVAC

5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.

Topics

Vapour Compression Refrigeration
The VCR cycle's COP = refrigerating effect/compressor work = (h₁ − h₄)/(h₂ − h₁); the heat-pump COP is one greater. One tonne of refrigeration equals 3.517 kW, per P.K. Nag / RK Rajput.
Psychrometrics
Moist-air state uses specific humidity ω = 0.622·P_v/(P − P_v), relative humidity RH = P_v/P_vs, and enthalpy h = c_pa·T + ω(h_fg + c_pv·T). These are read from the psychrometric chart, per RK Rajput.
$Sensible heat factor SHF = \frac{Q_{s}}{(Q_{s} + Q_{l})}$
Air Conditioning Processes
AC processes move air on the psychrometric chart; the sensible heat factor SHF = Q_sensible/Q_total sets the slope of the process line. The apparatus dew point and bypass factor characterise the cooling coil, per RK Rajput.
Refrigerants and Ozone Impact
Refrigerants are rated by ozone-depletion potential (ODP) and global-warming potential (GWP); CFCs (high ODP) are banned under the Montreal Protocol. A good refrigerant has high latent heat and suitable saturation pressures, per RK Rajput.
Cooling Load Estimation
Cooling load sums conduction (Q = U·A·CLTD), solar, infiltration, and internal gains. Sensible and latent components are added to size the plant, per RK Rajput / ISHRAE practice.