HVAC & Air Conditioning

Heating, Ventilation, and Air Conditioning (HVAC) systems provide thermal comfort, indoor air quality, and humidity control in buildings. Indian standards: IS 11338 (industrial ventilation), NBC 2016 Part 8 (HVAC), ECBC 2017 (Energy Conservation Building Code). Major Indian HVAC manufacturers and integrators: Voltas, Daikin India, Carrier India, Hitachi India, Blue Star, LG India, Trane.

Main HVAC system types: (1) Window AC — small residential (1-2 ton capacity per room); cheapest but inefficient. (2) Split AC (most common in modern Indian residential and commercial) — wall-mounted indoor unit + outdoor compressor; 1.0-2.5 ton typical. (3) Central / VRF (Variable Refrigerant Flow) — multiple indoor units served by single outdoor system; commercial offices and apartments; better efficiency. (4) Chilled water — central chiller plant + air handling units (AHU); large commercial and industrial; highest efficiency. (5) Cooling tower — for chilled-water and process cooling. Capacity: small office 1-2 ton/30 m²; large office 1 ton/15 m²; industrial higher.

Design per ECBC 2017: (a) Cooling load calculation per ASHRAE / Indian methodology; (b) Equipment selection — split, VRF, or central based on building size; (c) Energy efficiency — minimum SEER (Seasonal Energy Efficiency Ratio) per BEE 5-star rating; (d) Ductwork sizing — air velocity 2-4 m/s for residential, 5-10 m/s for industrial; (e) Indoor air quality — fresh air 10-15 cfm/person typical. The most-overlooked aspect: building-level HVAC sizing. Many Indian commercial projects oversize HVAC by 20-30% — adding capital cost and energy waste. Proper cooling load calculation prevents this.