Light sources selection for solar simulators: A review

Solar energy has certain limitations such as seasonal variations, cloudy weather etc. Because of these limitations, it is very difficult to perform the experiments in Rainy and winters seasons. To tackle this problem, we have to use solar simulators. It is source of artificial lights, very much similar to concentrated sunlight. It can be analyzed that increased demand in manufacturing and development of solar simulators for testing and simulation of solar photovoltaic and solar thermal energy utilization. This paper reviews the solar simulator light sources for testing photovoltaic panels as well as for thermal applications. Light intensity, cost, durability and stability were included as a criterion for comparing solar spectrum with lamp wavelength spectrum. The classification of solar simulator depend on the light source application and their technological innovations were considered according to the literature. Also, carbon arc lamp, argon lamp, high pressure sodium lamps, quartz tungsten halogen lamp, mercury xenon lamps, xenon arc lamps, metal halide lamps, LEDs and super continuum laser are discussed in details. Also, multi light source solar simulator discussed as a separate topic.

Influence of Light Spectra on the Production of Cannabinoids

In recent years, more attention has been paid to cannabis from both medical and political points of view. This study investigates the influence of 5 different light spectra on the active substance content in THC-poor hemp of the Alessia chemotype II variety. The focus is on comparing conventional growing under metal halide lamps with growing under high-pressure sodium (HPS) vapor lamps with regard to different spectra of LED lighting modules. Growing was carried out in 10 growing boxes under controlled and mostly identical conditions for all boxes. The photoperiod during the vegetative phase was 18 h light and photosynthetic photon flux density ∼520 μmol⋅m⁻² s⁻¹. The flowering phase was 12 h light and ∼540 μmol⋅m⁻² s⁻¹. During the experiment, CO₂, temperature, and humidity were measured and logged. Additionally, weekly measurements of chlorophyll, electric conductivity of the fertilizer, activity measurement (salt content) of the soil, and pH value of the soil were checked. The content of cannabinoids was measured by high-performance liquid chromatography (HPLC). Plant height and growth were monitored during the whole experiment by cameras taking pictures every 30 min and loading them onto a cloud storage platform. Cannabinoid content was measured using HPLC. Plant wet weight was determined at the end of the experiment and showed that plants under the high pressure lamp treatment had less flower weight than those under the LED treatment. In conclusion, it could be shown that certain LED spectra can considerably increase the amount of cannabinoids with respect to conventional illumination (HPS).

Energy Efficiency in Lighting for Historical Buildings: Case Study of the El Aman Caravanserai in Province of Bitlis, Turkey

Historical buildings are bridges between the past and the present. Moreover, it is a mirror of the life of societies, which lived in other ages. Historic buildings need to be illuminated to provide better visual conditions. The demand for electricity is increasing day by day. Energy must be used efficiently to reduce the amount of energy being dissipated. Therefore, energy efficiency in the lighting for historical buildings is a topic of great importance. Various luminaires are used for interior and exterior lighting of historic buildings. However, new lighting technologies, such as light emitting diode (LED) luminaires, are many times more efficient than traditional technologies, such as incandescent luminaires. The use of new technologies can lead to significant reductions in net energy consumption and associated reductions in greenhouse gas emissions. Historic buildings can serve as powerful and highly visible demonstrations of energy-efficient lighting technologies. In this study, the cost and energy efficiency have been analyzed considering the investment costs and the energy consumption of LED luminaires instead of luminaires with incandescent, halogen and metal halide lamps using almost the same luminous flux in the example of the El Aman Caravanserai in Bitlis, Turkey. As a result, of the calculations, the annual energy consumption (9-066.6 kW·h) was reduced by 78.21 % compared to the conventional system (41-610 kW·h) installed with incandescent, halogen and metal halide lamps. Thus, the cost of using LED lighting system have been amortised in about 135 days. Later, lighting has been made with less energy consumption, and the energy has been used efficiently.

A Loss-Free Resistor-Based Versatile Ballast for Discharge Lamps

This paper presents a versatile ballast for discharge lamps, whose operation is based on the notion of a loss-free resistor (LFR). The ballast consists of two stages: (1) a boost converter operating in continuous conduction mode (CCM) and exhibiting an LFR behavior imposed by sliding-mode control; and (2) a resonant inverter supplying the discharge lamp at high frequencies. Thanks to this mode of operation, the power transferred to the lamp is regulated by the LFR input resistance, allowing successful ignition, warm-up, nominal, and dimming operation of a range of discharge lamps, with no need for complex regulation schemes based on lamp models. The versatility of the ballast has been experimentally proven for both conventional and electrodeless discharge lamps. Tests include induction electrodeless fluorescent (IEFL), high-pressure sodium (HPS) vapor, and metal-halide lamps.

Effectiveness of Light Source on Detecting Thin Film Transistor

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the third and fourth layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.

Effectiveness of Light Source on Detecting Thin Film Transistor

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the 3rd and 4th layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.