New model air con should end big freeze on KMB buses

PUBLISHED : Tuesday, 29 August, 2006, 12:00am
UPDATED : Tuesday, 29 August, 2006, 12:00am

Kowloon Motor Bus is hoping a new model of air conditioner will put an end to environmentalists' protests against 'freezing' buses.

The 'fourth-generation' product, previously fitted only in luxurious sedans, will be used on public transport for the first time when new buses go into service next year.

KMB's principal engineer for bus engineering, Kane Shum Yuet-hung, said the equipment would reduce temperature fluctuation inside the bus and reduce fuel consumption and the emission of pollutants. 'Older types of air con cut off the emission of cold air when the bus gets too cold, and vice versa, so it's either all or none and the fluctuation tends to be bigger,' he said. 'But the new air con adjusts temperature every 30 seconds and it is never completely switched off.'

Maintaining a minimal circulation of cold air helps save up to 23 per cent of energy that is wasted in restarting the machine, and less fuel consumption means less pollution.

'In winter, energy consumption could be greater than normal, but after levelling off with the amount we save [in summer] there are still benefits,' Mr Shum said.

KMB is also upgrading the air-conditioning in older buses.

At present, 2,930 of its 3,500 air-conditioned vehicles are equipped with so-called third-generation equipment and the rest will be upgraded by the end of next year. Adjustable vents will also be installed in all buses.

Earlier this month, environmental group Green Sense found that 90 per cent of 70 air-conditioned buses it tested had a temperature below 25.5 degrees, with one Citybus vehicle found to be at 15.1 degrees.

But Mr Shum said it was impossible to keep bus temperatures at 25.5 degrees due to the changes in ambient temperature and humidity, passenger loads and the influx of hot air when the doors opened.

An ongoing survey conducted by the KMB since last November found that the number of complaints rose four-fold after the bus temperature was set at 25.5 degrees instead of its standard 23 degrees.

KMB received 50 complaints over the past 10 months relating to the 52 buses set with a temperature of 25.5 degrees, an average of 1.04 complaints per bus, compared to 22 complaints on the 87 buses with a temperature of 23 degrees, an average of 0.25 complaints per bus.