Page 93 - Hong Kong Green School Guide

3. Green School Guide - 3.3 Energy Saving
Hong Kong Green Building Council 91
Benefits
• Reduce energy consumption through the use
of energy efficient lift system; and
• Liftswith regenerativemotorscanput electricity
back to the building grid when the lift is going
downward. The electricity generated over one
year by a typical lift fitted with a regenerative
motor is sufficient for 100 25-Watt light bulbs
to operate for a year.
Issues to Consider
a. Opportunities
• Schools can retrofit and/or select lift system with energy efficient motor,
regenerative motor, automatic control of services inside the lift car and light-
weight decorations to reduce load and traction, etc.
b. Constraints
• Potential structural modification is required for retrofitting lift systems in
existing schools.
c. Solutions
• When retrofitting existing lift system that requires structural modification,
Authorised Person (AP) and Registered Structural Engineer (RSE) shall be
consulted;
• Adopt variable voltage variable frequency (VVVF) motor drive as it uses
considerably less energy during lift acceleration and deceleration compared
to conventional lift motor. Useful Reference (1) provides more information;
• Adopt electronically controlled motor drive. They are highly efficient because
of the brushless and permanent magnet motor (less friction) design. There are
also additional benefits such as low noise generation and low contamination
(from brush dust);
• Consider regenerative lift / motor when retrofitting or replacing the lift system,
as regenerative lifts can produce electricity when the lift goes downward.
Useful Reference (2) provides more information;
• Adopt automatic control to switch off all fans and lights in the lift which is idle
for a long period of time; and
• Lift system, motor type, control method of lift, installation issues, lighting and
mechanical ventilation inside lift car shall be evaluated by Registered Lift
Contractor.
3.3.8 Energy Efficient Lift Applies to NS & ES