Page 82 - Hong Kong Green School Guide

3. Green School Guide - 3.3 Energy Saving
Hong Kong Green School Guide 80
3.3.4 Solar Tube & Heliostat Applies to NS & ES
Benefits
• Reduce energy demands created by artificial lighting;
• Direct daylight to areas with limited daylight access (e.g. area far away from
window);
• Studies show that humans performs better and are healthier under natural
daylight compared to artificial lighting; and
• Good demonstration project for students and other building occupants.
Issues to Consider
a. Opportunities
• Schools can install solar tube and/or heliostat to utilise daylight and reduce
the use of artificial lighting.
b. Constraints
• Roof area that is shaded by surrounding buildings; and
• For solar tube fitting at existing school, large modification of roof structure is
required.
c. Solutions
• Select roof area that can be exposed to sufficient daylight;
• There are two primary devices that can direct daylight to the indoor area for
lighting purposes: solar tube and heliostat;
• For adoption of solar tubes in new developments, building design and
structure which suit the solar tube (e.g. a hole on roof) shall be designed and
evaluated by Authorised Person (AP);
• For retrofits, heliostat is preferred as it transfers daylight through an optic
cable which can be bent at any angle, are small in diameter and do not
require structural modification (like solar tubes);
• Compliance with building regulations and maintenance access shall be
evaluated by Authorised Person (AP); and
• Install light shelves with highly reflective surfaces that reflect daylight deep
into space, which help reduce use of artificial lighting at daytime.
d. Professional Help
• Authorised Person (AP) – Appendix A (2)
• Solar Lighting Supplier – Useful References (1)