Design, installation and performance
Peak sun hours (PSH)
Also known as: PSH, peak sunlight hours, sun hours.
Definition
Peak sun hours express a location's daily radiation as the number of equivalent hours of sun at maximum intensity. They are a key figure for sizing a system: the more PSH, the more energy each installed kWp generates.
Sources: Solar Radiation Atlas of Colombia (opens in a new tab)
The concept simplifies an irregular reality. Radiation on a real day rises from dawn, reaches its maximum around midday and falls until dusk, with ups and downs according to cloud cover. PSH condense that whole curve into a single number: the hours a constant sun of 1,000 W/m² would have lasted to deliver the same total energy. A place with 4.5 PSH receives the same daily energy as if it had had four and a half hours of sun at full intensity.
Its use is direct: a system's estimated daily output is, approximately, its kWp multiplied by the site's PSH and by the system's performance ratio. A 5 kWp system in an area with 4.5 PSH and a 78% performance ratio produces on the order of 17.5 kWh a day. That sum is the basis of any serious savings estimate.
In Colombia PSH vary noticeably between regions: La Guajira and much of the Caribbean sit in the country's high band, while cloudy Andean areas and the Pacific fall below. The official reference for looking them up is IDEAM's Solar Radiation Atlas; a serious installer starts from that figure and not from a generic average.
The essentials of Peak sun hours
- 1 PSH is equivalent to one hour of sun at 1,000 W/m².
- Daily output ≈ kWp × PSH × system performance ratio.
- They vary by region, altitude and cloud cover, not by temperature.
- Official source in Colombia: IDEAM's Solar Radiation Atlas.
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Frequently asked questions about Peak sun hours
How many peak sun hours are there in Colombia?
It depends greatly on the region: the Caribbean coast and La Guajira are among the highest-radiation areas of the country, while some cloudy Andean areas and the Pacific record considerably lower values. IDEAM's Solar Radiation Atlas publishes values by location and is the reference to use in any sizing.
Are PSH the hours of daylight?
No. A day can have twelve hours of light and only four or five peak sun hours, because for much of those twelve hours the radiation is well below the maximum. PSH measure accumulated energy, not the length of the day.
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