Design a PV system for the following application: A refrigerator/freezer unit for vaccine storage in a remote island of Roatan, Honduras \(\left(16^{\circ} \mathrm{N}\right.\) latitude, \(86^{\circ} \mathrm{W}\) longitude, temperature, range \(\left.15^{\circ} \mathrm{C}-30^{\circ} \mathrm{C}\right)\).

Two compressors-one each for refrigerator and freezer Each compressor draws 5 A at \(12 \mathrm{~V}\)

Design the PV system using the panels and the batteries described in Problem 6.15.

Problem 6.15

A flashing beacon is mounted on a navigation buoy in the shipping channel at a port at \(30^{\circ} \mathrm{N}\) latitude. The load consists of a single lamp operating \(1.0 \mathrm{~s}\) on and \(3.6 \mathrm{~s}\) off during the hours of darkness. Hours of darkness vary from \(9.8 \mathrm{~h}\) in July to \(13.0 \mathrm{~h}\) in December. The lamp draws \(2 \mathrm{~A}\) at \(12 \mathrm{~V}\) when lighted. A flasher controls the lamp and draws \(0.22 \mathrm{~A}\) when the lamp is on. There is a surge current of \(0.39 \mathrm{~A}\) each time the flasher turns on. This current flows approximately \(1 / 10\) th of the time the flasher is on. The design has 14 days of battery capacity. Provision has to be made to disconnect the load if the battery voltage drops below \(11 \mathrm{~V}\).

The available module has a rated voltage of \(17.2 \mathrm{~V}\) at \(25^{\circ} \mathrm{C}\left(15 \mathrm{~V}\right.\) at \(\left.55^{\circ} \mathrm{C}\right)\) and \(2.3 \mathrm{~A}\) at \(1 \mathrm{~kW} / \mathrm{m}^{2}\). The available battery has a rated capacity of \(105 \mathrm{Ah}\) at \(12 \mathrm{~V}\). Assume that maximum depth of discharge is \(0 \%\). Design the PV system.

Transcribed Image Text:

Compressors Remain on for Summer (h/Day) Winter (h/Day) Refrigerator Freezer 9 7 54 5 4