Solar Simulation FAQ

EYE Lighting / Iwasaki Electric designs and manufactures the lighting source (lamp) along with the solar simulation equipment. This integrated approach is unique in the marketplace. Any solar simulation system is only as good as the lighting source. Our systems are designed from inception around the proper lighting source for the particular application. This ensures outstanding yet efficient system performance.

What is insolation?

Insolation is a measure of solar radiation energy received on a given surface area in a given time. It is commonly expressed as average irradiance in watts per square meter (W/m²) or kilowatt-hours per square meter per day (kW·h/(m²·day)), or in the case of photovoltaics it is commonly measured as kWh/kWp•y (kilowatt hours per year per kilowatt peak rating). Sometimes a long-term average intensity of incoming solar radiation will be given in units such as watts per square meter (W/m² or W·m-2) and called insolation, with the duration (such as daily, annual, or historical) stated or only implied.

The given surface may be a planet, or a terrestrial object inside the atmosphere of a planet, or any object exposed to solar rays outside of an atmosphere, including spacecraft. Some of the solar radiation will be absorbed, causing radiant heating of the object, and the remainder will be reflected. The proportion of radiation reflected or absorbed depends on the object's reflectivity or albedo, respectively.

Direct insolation is the solar radiation that is transmitted directly through the atmosphere to the earth's surface without interacting with atmospheric components. Diffuse insolation is the solar radiation that is scattered or reflected by atmospheric components.

What is CRI?

CRI stands for Color Rendering Index. Color Rendering Index is a rating system (from 1 to 100) that measures the accuracy of how well a light source reproduces the (total) color of an illuminated object. A palate consisting of eight (8) colors (R1 through R8) is used as the "standard" to calculate CRI. This rating system is designed specifically for visual display lighting and really has little correlation to true sunlight spectrum (as defined by ASTM/IEC/JIS. In fact, some lamps may have a CRI of 100 but still not even qualify for Class C solar spectrum matching. One major problem is that even colors such as R9 (red), one of the most common processed colors, is not one of the 8 colors used in calculating CRI as this color is difficult to achieve with standard metal halide technology.  EYE Lighting / Iwasaki Solarlux™ solar simulation lamps are designed with application specific chemistry to closely match the solar spectrum. Although CRI is a good reference for lighting when designing commercial displays, this should not be a consideration when designing a solar simulation system. International standards for solar simulation lighting are well defined.

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What is Color Temperature?

Color Temperature, or more correctly Correlated Color Temperature (CCT) of a light source is determined by comparing its chromaticity with that of an ideal black-body radiator. The unit of measure is degrees Kelvin. CCT represents the color temperature at which an object (such as steel) is heated until it gives off light. As steel is heated, its color changes from black to dull red, orange, yellow, white and finally blue. When referring to the sun, daylight has a spectrum similar to a black body. For photography or display lighting applications, international standards have been established to represent "standard" daylight illumination from the sun, such as D50 (equal to a CCT of 5000K) or D65 (CCT 6500K) which is considered the daylight standard illuminant by CIE (International Commission on Illumination), basically corresponding to mid-day sun in Western Europe. See section on Full Spectrum Lighting.

While this is a representation of the spectral power density of the sun, it should not be used for qualifying light sources for solar simulation applications. International standards have been agreed upon that specify the reference global solar spectral distribution at AM1.5. This table, as described in IEC 60904-3, is the bases with which to classify all lighting used for solar simulation applications.

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How much heat does the solar array create?

Our sun is a very efficient heat source. It is obvious that a large solar simulation array will also generate a significant amount of heat. Regardless of whether the simulation array is in an enclosed chamber, or whether it is an open array in a large room, this heat must be managed. A chamber often requires an external chiller and sufficient airflow to maintain the desired operating, or device-under-test, temperature. If you are operating an open array in a large room, the HVAC system for the area must be sized to ensure an acceptable room ambient temperature is maintained. Below is a quick calculator to assist in sizing your air handling system. After you know the lamp wattage and number of lamps that will be used in your solar simulation array, simply type in the total amount of lamp wattage and click on "calculate". The resultant answer will be the amount of heat in BTU/hr that the simulation array will generate.

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What is AM 1.5?

Air Mass is the measure of how far light travels through the Earth's atmosphere. One air mass, or AM1, is the thickness of the Earth's atmosphere. Air mass zero (AM0) describes solar irradiance in space, where it is unaffected by the atmosphere. The power density of AM1.5 light is about 1,000W/m²; the power density of AM0 light is about 1,360W/m², which is considered to be the solar constant.

See section on Solar Energy for more information.

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How do I dispose of my lamps?

1.  Standard infrared (IR) lamps are filament lamps and can be disposed of like any incandescent lamp, usually in general waste.

2.  ALL high intensity discharge (HID) lamps contain mercury, a naturally occurring element. This includes our full spectrum and Xenon based lamps. It is important that lamps and other products containing mercury be properly managed to protect public health and the environment.

Solarlux HID lamps should be recycled based on your local requirements, these lamps should not be discarded in general waste. Please check with your state laws, as each state has different “hazardous waste” requirements which may be more strict than Federal law .

For information on how to recycle your lamp, including a list of companies that recycle lamps, visit www.lamprecycle.org.

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How do I purchase EYE Lighting Solarlux products?

Due to the varied industrial application requirements and applicable standards, all EYE Lighting Applied Optics products, including Solarlux lamps, electronic ballasts, and systems, are handled directly by our sales and technical support specialists at our factory in Mentor, Ohio. Our experienced staff will assist you in solving your application needs. In most cases we are able to offer options to provide you a selection of cost/performance solutions.

Please click on the following link to contact us in whichever method is most convenient to you. We look forward to working with you.

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