CLD Sustainable & Energy-Efficient Lighting Solutions

Question 1

Lighting Power Density (LPD) expresses:

Accepted Answer

Watts per square foot

Answer

Lighting Power Density (LPD) is a crucial metric in lighting design and energy codes. It quantifies the electrical power consumed by lighting systems per unit area, typically expressed as watts per square foot or square meter. This measurement helps assess and regulate the energy efficiency of lighting installations in buildings, ensuring compliance with energy standards.

Question 2

Daylight harvesting relies on:

Accepted Answer

Photosensors

Answer

Daylight harvesting systems are designed to optimize energy use by reducing artificial lighting when natural light is sufficient. Photosensors, also known as daylight sensors or photocells, detect the ambient light levels in a space. They then communicate with the lighting control system to dim or turn off electric lights, thereby saving energy and enhancing occupant comfort.

Question 3

Which rating system awards credits for efficient lighting?

Accepted Answer

LEED

Answer

LEED (Leadership in Energy and Environmental Design) is a globally recognized green building certification program. It awards points across various categories, including energy and atmosphere, where efficient lighting design and controls contribute significantly to achieving certification. This system encourages sustainable building practices by recognizing efforts to reduce energy consumption from lighting.

Question 4

L70 of 50 000 h means LED output will:

Accepted Answer

Be 70 % of initial

Answer

L70 is a standard metric for LED lumen maintenance, indicating the point in time when the light output of an LED source has degraded to 70% of its initial lumen output. Therefore, an L70 of 50,000 hours means that after 50,000 hours of operation, the LED is expected to still produce 70% of its original light output. This metric helps predict the useful lifespan of LED products before significant light depreciation occurs.

Question 5

Circadian‑centric tunable white systems:

Accepted Answer

Shift CCT through day

Answer

Circadian-centric tunable white lighting systems are designed to support human circadian rhythms, which are influenced by light exposure. These systems dynamically adjust the Correlated Color Temperature (CCT) and intensity of light throughout the day, mimicking natural daylight patterns. This shift from cooler, brighter light in the morning to warmer, dimmer light in the evening helps regulate sleep-wake cycles and overall well-being.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Sustainable & Energy-Efficient Lighting Solutions