ENERGY-SAVING USING MORNING AND EVENING CIVIL TWILIGHT IN THE STATE OF BAHRAIN

Comparison between the total solar irradiation including and excluding the civil twilight in Bahrain is studied. The solar intensity of the civil twilight (morning and evening twilight) in Bahrain is calculated . The calculations show that the maximum civil twilight is on summer s olistice (longest day) lasts for 52.3 min and the least on winter soli stice (shortest day) for 50.7 min, In spring and autumn equinox (day e qual to night), the duration of the civil twilight is 46.1 min. Montei th and Unsoworth equation [7] which estimates the daily global insolat ion for location having unprolonged dusk and dawn was evaluated for Ba hrain. Their equation was found to fit very well with the measured dat a in Bahrain (percentage difference of 6.5%). Discussion on the energy saving by introducing summer and winter time in Bahrain is presented