Heat Build-Up in a Stalled Elevator Cabin During a Power Outage: A Cabin Thermal Model and a Passive Design Priced per Cabin

A single-node thermal model of a 6.48 m3 elevator cabin (occupant sensible heat 100 W per person, wall conduction to the shaft, 0.6 air changes per hour leakage, effective heat capacity 122.8 kJ/K) gives times to cross 30 C discomfort and 35 C danger thresholds for 1, 4 and 8 occupants against shaft temperatures of 25, 32 and 40 C. Unmodified, a full cabin crosses danger in 39.7 minutes (cool shaft), 17.4 minutes (warm shaft) and 8.5 minutes (hot shaft); 4 occupants in a warm shaft cross at 34.9 minutes. A passive design - a manually operated 0.20 m2 vent pair to the shaft, 24 kg of phase-change lining melting at 28-30 C, and an insulated reflective lining - priced at $1,586 per cabin meets a 120-minute rescue target for a cool shaft at any occupancy and for 4 occupants in a warm shaft (danger delayed to 207.4 minutes, 28.0 C at 120 minutes). It fails the target for a full cabin in a warm shaft (danger at 105.9 minutes) and at every occupancy in a hot 40 C shaft (danger at 58.3, 26.1 and 15.1 minutes). SIMULATED, NOT MEASURED.