Page 103 - Hong Kong Green School Guide

3. Green School Guide - 3.3 Energy Saving
Hong Kong Green Building Council 101
Benefits
• Utilise a ‘free’ resource in the form of solar energy for electricity generation
on site;
• Valuable demonstration project to showcase the school’s green initiatives;
• Practical feature for students to observe energy produced by the system
(e.g. via energy meter, connection to lighting system) and to learn about
renewable energy; and
• PV panel can generate electricity around 170 kWh/m2 of panel area per
year (equivalent to powering 25-Watt light bulbs for 6,800 hours) in ideal
conditions (e.g. no shading from surroundings).
Issues to Consider
a. Opportunities
• PV panels can be installed to generate electricity from the sun for providing
building services (such as lighting).
b. Constraints
• Shading from surrounding buildings;
• Structural loading to the roof due to additional weight and wind effect;
• In compliance with The Provision of Means of Escape in Case of Fire, roof
designated as refuge floor should not be obstructed by the installation;
• Water proofing & potential water seepage issues during installation; and
• Electrical issues, e.g. electrical supply for controls.
c. Solutions
• Select roof area with sufficient daylight;
• System types: Flat-plate System and Building Integrated Photovoltaic (BIPV)
System. Generally, flat-plate is more efficient and cheaper than BIPV per
installed area for the same output, but BIPV can be integrated into the
building façade for daylight to pass through as well as acting as architectural
features;
3.3.12 Photovoltaic (PV) Panel Applies to NS & ES