5.3.6 Rainwater harvesting
Rainwater harvesting is the accumulation and storage of rainwater for reuse. The
water can then be used, without expensive treatment, for washing cars, watering
plants, washing floors and windows, etc. Rainwater collected from the roofs of
buildings and the podium of the shopping mall can make an important contribution to
the availability of water, reduce the wastage of treated water and lower financial cost
of metered water charges.
The Building Services Branch of the Architectural Services Department of the Hong
Kong SAR Government issued a B.S.B circular in 2008 as a Design Guideline for
the Rainwater and
Recycling Installation. For shopping malls, it is worth
adopting such a system since there will be plants inside and outside the shopping
malls for greening and refreshing purposes. Recycled rainwater can be used for
irrigating these plants and reducing water and sewerage charges.
5.3.7 Professional help
It is important to engage professionals for detailed consultation on the implementation of plumbing and drainage systems
for shopping malls and shops. The following is a list of references for obtaining professional help:
• Registered professional engineers (RPE) in the building services discipline – Appendix A (4)
• Registered air conditioning contractors – Appendix B (1)
5.4
Electricity and lighting
Apart from air conditioning, power for lighting constitutes the second major source of energy consumption contributing
to the electricity bill. Copper loss from the electrical distribution system and motor efficiency can also be optimised to
contribute to the energy efficiency of the electrical system.
5.4.1 Use of energy efficient lighting
For the lighting design, energy efficient light fittings should be chosen. The efficiency of lighting sources is described by
luminous efficacy, which is the ratio of the light emitted and the power consumed by a lamp. Typical efficacies of different
lamp types are summarised in the table below.
Lamp type
Efficacy range (lumen/watt)
GLS
12 – 18
T8 tubular fluorescent (Electromagnetic ballast)
69 – 79
T8 tubular fluorescent (Electronic ballast)
85 – 95
T5 tubular fluorescent (Electronic ballast)
95 – 105
Compact fluorescent
55 – 80
Low pressure sodium
70 – 115
High pressure sodium
65 – 110
High pressure mercury
30 – 55
Metal halide
65 – 75
Induction
37 – 75
LED
90 – 100
Figure 111 Efficacy of different lamp types
Figure 110 Simple rainwater
harvesting system
5
Energy efficient building systems for shopping malls and shop spaces
5.3
Plumbing and drainage
5.4
Electricity and lighting
134 Hong Kong Green Shop Guide
