[EL] 問﹕燈有啲乜種類及特點？有啲乜節能方式？

答﹕

首先搞清楚以下幾點基本概念

LED:
如果問你Lighting方面有啲乜節能方式，可以答

Luminous Flux: (光通量)

單位(Lumen)  ，描述一個光源既發光能力

 [1 lux=1lm/m2, 概念同 Density=mass/volume 一樣]

Efficacy: (發光效率)

發光效率, 單位 (lm/W)

燈膽 8-18lm/W; 光管 37-100lm/W, 明顯地光管發光效率較高

Colour Temperature: (色溫)

顏色描述，低過3300K屬暖色，3300-5300K屬中間色，5300K屬冷色

Colour Rendering: (顯色性)

用Ra, 0-100, 數值越高，越能令物件體現出其真實顏色, 鎢絲燈及卥鎢燈可去到95

Design 上，Lighting Power Density 跟EMSD BEEO; 用幾多Lux就跟CIBSE Code
for Interior Lighting

Incandescent Lamp:

即係普通鎢絲燈膽，由25W-200W。

特徵﹕Low installation and replacement cost, Excellent colour rendering, Instantanouos
on/off, Short life, Low efficacy, high heat output

Tubular Fluorescent Lamp:

原理係加熱燈絲，電子撞擊Hg蒸氣，Hg蒸氣令其發紫外線，紫外線射到管內壁螢
光物質，從而發可見光。

分T12/T10/T8/T5

Good efficacy, Broad range of colour rendering & temperature, With control gear

Compact Fluorescent Lamp:

原理同 fluorescent lamp 一樣，只不過個型狀係燈膽型燈膽頭

特徵﹕Direct replacement for incandescent lamp, Control gear integral in the lamp,
relative high initial cost, less efficiency than tubular

Sodium Lamp:
External lighting, Highest efficacy, Long Lift, Poor colour rendering

High Pressure Mercury Lamp:
Replaced by high pressure sodium and metal halide lamp, 冇乜點用，得個知字

Metal Halide Lamp:
Good efficacy, Good colour rendering, Long life, floodlight, long start up and
restrike time, 由於colour rendering好，所以响啲精緻裝飾地方會用

LED:

High efficacy, instant light, fitted into existing lighting fittings, various colour temperature,
low voltage supply, long life, realiable, colour rendering都好
隨住LED起嚟越平，用電少散熱少效率高應用又廣泛，將會對比其他種類既燈有
絕對優勢，會取代幾乎所有燈﹕

Lighting Energy Saving Strategies有下列幾種
- Digital & Addressable Lighting Interface (DALI): 簡單嚟講即係CCMS;
- Occupancy Sensor: 冇人郁就算動熄燈；
- Photocell Sensor: 放近窗邊，夠光就自動關啲燈；

- Task Lighting, 即係大環境放少啲燈，但跟據辦公室佈置每位比啲localized啲既燈；

- T5管或Electronic Ballast, 相對Low既答法，因為都已面臨全面淘汰；
- Astronomical Time Switch - 自動決定某啲燈如Landscape Lighting幾時開，配合埋
Photocell Sensor用

-------------------------------------------------------------------------------------------------------------------

Emergency Lighting
當冇咗燈嗰陣，照住成條exit route.
紅皮書要求Escape Route 1 Lux, Staircase 1 lux;
一冧Normal電就要五秒之內起動到，發電機冇可能咁快起到，所以要自己揹舊
Central Battery, 呢舊電起碼要頂到30mins直到發電機著

Exit Sign
min. 2 hours

---------------------------------------------------------------------------------------------------------------

Lumen Method

N = number of lamps required.

E = illuminance level required (lux)

A = area at working plane height (m2)

F = average luminous flux from each lamp (lm)

UF = utilisation factor, an allowance for the light distribution of the luminaire

          and the room surfaces.

MF = maintenance factor, an allowance for reduced light output because of

deterioration and dirt.

---------------------------------------------------------------------------------------------------------------

Also reference: Football Field / Stadium Lighting Design

鳴謝﹕Ir.理查德