Laundry HVAC — Balancing Energy Use vs Productivity India

Laundry HVAC — Balancing Energy Use vs Productivity

Hotel laundries are among the most energy-intensive spaces per square metre in any building. Tumble dryers, steam presses, flatwork ironers, and washer-extractors collectively generate enormous heat and moisture loads. Yet laundry HVAC is often an afterthought in Indian hotel MEP design — specified as a generic exhaust and supply system without understanding the process loads. The result is an uncomfortable, humid laundry that reduces staff productivity and pushes workers to open doors, compromising the entire building’s pressurisation strategy.

1. Heat and Moisture Sources in Hotel Laundry

2. Why Laundry HVAC Fails in Indian Hotels

• Dryer exhaust not fully ducted outside — moisture recirculates into the space
• Make-up air insufficient — negative pressure develops, doors stay open, back-of-house conditioned air sucked in
• No dehumidification in supply air — humid Indian outdoor air makes condition worse in monsoon
• Supply air temperature too cold — workers feel cold while working near hot presses, opening doors
• Exhaust fans too small — cannot handle dryer + press + infiltration load simultaneously

3. Correct Laundry HVAC Design Approach

Step 1 — Fully Duct All Dryer and Ironer Exhaust

1. Each dryer requires dedicated 200–250mm diameter exhaust duct to outside
2. Each flatwork ironer requires 300–400mm exhaust duct — high moisture and heat
3. Do not combine dryer exhausts into a manifold — back pressure reduces dryer efficiency and increases fire risk
4. Install lint trap at each dryer exhaust — clean weekly

Step 2 — Calculate Make-Up Air

1. Make-up air = total exhaust volume (dryers + presses + general exhaust)
2. Typical laundry: 40–60 air changes per hour total exhaust — this is a high-exhaust space
3. Supply make-up air at 18–22°C — not conditioned to comfort standards
4. Temper make-up air in summer — supply at >18°C to avoid cold draft on workers

Step 3 — General Space HVAC

1. Design for 24–26°C space temperature — workers at heavy work (high metabolic rate) prefer cooler
2. Relative humidity: 50–60% maximum — above this, linens do not dry efficiently
3. Supply from perimeter at high level — general dilution ventilation

4. Heat Recovery Opportunity

Laundry dryer exhaust is at 50–70°C with high humidity — valuable waste heat. Options:

• Heat recovery unit on dryer exhaust: pre-heats make-up air — reduces heating load
• Heat exchanger on dryer exhaust to preheat washer water — significant saving in gas/steam cost
• Note: must use indirect (run-around coil) heat recovery — direct rotary wheel will transfer lint and moisture

5. Energy Benchmarks for Hotel Laundry