This article provides a study of the thermal efficiency benefits associated with surface-mounted LEDs compared to recessed LEDs in residential applications. This study focuses on energy loss from air leakage as a result of recessed downlight ceiling cutouts; energy loss through insulation gaps required for recessed downlights, and the energy required to run the […]
An explanation of the traceability chain at the NMISA photometry and radiometry laboratory to support the South African lighting industry. The South African lighting industry requires a calibration service for light measuring instrumentation and lamps used as source standards. Examples include illuminance meters, luminance meters, photometers, colorimeters, luminous intensity lamps and luminous flux lamps. […]
An alternative method for measuring the spectral irradiance of high-powered focused light sources at distances typically between 50 and 100 m from the target plane. Concerns about the effect on the eye of high-powered, focused light sources lead to an investigation into the measurement of the spectral irradiance produced by these light sources. The […]
Designing luminaires around a solder temperature of 105 °C, considering the effect on the mechanical components and highlighting the consequence of expected LED light depreciation. One of the benefits of LED light sources is their very long usable lifetime. Unlike other lighting technologies, LEDs typically do not fail catastrophically during use. However, the light […]
Optical measurement of white LEDs represents a major challenge due to factors such as operating temperature, burn-in phase and ageing, which affect lamps’ emission performance. These spectral and intensity changes also cause a change in colour appearance. The latter must be analysed and specified properly to ensure good reproducibility of the measurements. Colour appearance […]
Heat rise inside bulkhead-type fluorescent emergency light fittings will age the batteries prematurely and, in serious cases, damage the emergency gear itself. The worst offenders here are switch-start CFLs due to the electromagnetic ballast dissipation. These are thankfully experiencing an ever-decreasing share of the market. The problem boils down to lumen efficacy. The idea […]
Capturing mercury from broken CFLs: sample selection, photometric data analysis and the test methods of the chosen treatment techniques. The replacement of incandescent lamps with compact fluorescent lamps (CFLs) was identified as an effective approach of promoting energy savings as they provide the same or more light and reduced power consumption. While the benefits of […]
The advantages of LED technology are numerous, yet patchy knowledge of the underlying technology often leads to indecisiveness and even incorrect decisions. An LED is a semiconductor component that only lets current pass in one direction. If forward current is applied, the LED will emit light, depending on the semiconductor material and doping i.e. […]
Digital LED lighting systems provide new and practical solutions that can double the energy saved at marginal increase to upfront cost. The rise in popularity of solid-state LED lighting has led to a demand for more intelligent controllers and drivers for this technology. These will ensure more effective LED lighting solutions which, in return, […]
How the lighting engineer or designer can determine and apply the correct maintenance factor for LED lighting solutions to help prevent over-lighting. In conventional technology (luminaires and lamps), the lamp manufacturer is responsible for the lamp lumen depreciation (LLD) and the lamp survival factor (LSF) whereas the manufacturer of the luminaire is responsible for the […]
