CR Avenue: Chandni Chowk Metro station, where the joke is that a train usually comes along before you can find an overhead air vent that works, has had its air-conditioning equipment replaced 14 years after a project started to overhaul cooling systems across all platforms.
Since the estimated lifespan of a cooling unit is around 10 years, the system installed at Esplanade station at the start of the project in 2004 is already overdue for replacement.
For commuters at Chandni Chowk station, the good news is that the next 10 years will possibly be more comfortable than the previous decade was. "The air-conditioning at Chandni Chowk never seemed to work until a few days ago. Hope it stays this way," said Sudipto Das, whose office is near Bentinck Street.
One of the air-conditioning units at Chandni Chowk, among the busier stations on the Noapara-Kavi Subhash route, was replaced in 2017 and two this year. "The three new imported units have a capacity of 200 tonnes each. Each unit cost around Rs 50 lakh and the total expenditure on Chandni Chowk alone was around Rs 3.5 crore," Indrani Banerjee, the spokesperson for Metro Railway, said.
After Esplanade, Park Street was the station that had its cooling system overhauled. The other stations were covered in phases. By 2017, Chandni Chowk was the only one left with units installed at the time of building the station.
The 15 underground Metro stations have centralised air-conditioning systems comprising water-cooled chillers, towers, coils and ducts through which cool air is released into the platform, concourse and mezzanine levels.
Surface stations like Dum Dum, Noapara and those between Mahanayak Uttam Kumar (Tollygunge) and Kavi Subhash (New Garia) don't have cooling units.
The Metro air-conditioning system consumes around 1.10 lakh units of electricity daily during summer. To put it in perspective, a two-tonne split AC usually consumes less than 15 units a day.
The temperature is maintained at around 28-30 degrees Celsius. "The average summer temperature is 35-38. If the reading inside is below that, there will be health hazards for people coming from outdoors," an official said.
Metro Railway now plans to install more bracket fans across its stations. Work will start in July, an official said.
