Proses elektrolisis air sedang dikembangkan untuk menghasilkan hidrogen. Namun, karena proses elektrolisis membutuhkan energi listrik sebagai pemicu reaksi, proses ini memberikan efisiensi yang relatif rendah. Proses elektrolisis berfungsi jika ketersediaan sumber energi listrik mudah diperoleh dengan harga murah. Pengujian dengan variasi jarak katoda dan anoda, campuran elektrolit dan jenis elektroda yang digunakan terus dikembangkan untuk mengurangi jumlah energi listrik yang digunakan dalam proses elektrolisis sehingga dapat diterapkan dalam kehidupan sosial, tetapi belum belum menuai hasil yang memuaskan. Penelitian ini menggunakan sumber arus baterai 12V, dan jarak yang telah ditetapkan pada katoda dan anoda ialah 80 mm,120 mm dan 200 mm. Jenis elektroda yang digunakan Stainless steel, Aluminium dan Tembaga, dengan jumlah campuran garam yang terlarut ialah 250 gram dalam lima liter air, atau 50 gram perliter air. Hasil dari pengujian, tekanan gas yang dihasilkan oleh elektroda yang berbahan stainless steel lebih tinggi dibandingkan oleh elektroda yang berbahan aluminium dan tembaga dan semakin dekat jarak elektroda maka tekanan gas yang dihasilkan semakin tinggi. Dengan menggunakan manometer tabung U tekanan gas hidrogen tertinggi diukur pada elektroda stainless steel pada sisi katoda jarak 80 mm sebesar 9733 Pa. Sedangkan tekanan hydrogen pada elektroda aluminium pada sisi katoda 9246.8 Pa, dan tekanan hidrogen terendah diukur pada elektroda tembaga 6034 Pa. Hasil pengujian menunjukkan perbedaan tekanan dari setiap jenis elektroda.

The technology of distilling seawater into fresh water has been carried out with various models and methods. The distillation process is one of the effective methods to get clean water by utilizing solar energy as the main energy source. The model is planned for a dual slope active system with a basin area of 1,932 m2 wide with 1 m2 glass surface with two pieces with 3 mm glass thickness and 15° glass slope angle. The water level from the bottom of 20 mm is kept constant and given a fog that circulates the water in the basin. The lowest solar intensity was 186.9 SR,W/mA2 with the amount of energy absorbed 20.9761 W/m2, and the highest solar intensity 700.6 SR,W/mA2 with the amount of absorbed energy 1813,667 W/m2 °C. The energy efficiency obtained from the results of the discussion of the highest test results data on the seventh day reached 77.92 %, and the lowest efficiency on the second day was 66.1853 %.

The surface of the evaporator glass in the seawater desalination process by utilizing solar energy as the main energy source is a phenomenon that has been widely studied and developed in order to get increased performance efficiency to produce fresh water. The heat energy from the sun will enter through the surface of the evaporator glass and absorbed by water inside the evaporator, while the evaporator wall is insulated using aluminium foil with a thickness of 20 mm in the hope that the heat energy received will not be wasted around the environment. The process of evaporation of seawater begins when the water has reached the point of evaporation without pressure and occurs naturally. When seawater starts to evaporate, it can be calculated the amount of heat energy absorbed by the water until it reaches the point of evaporation, in order to determine the increase in performance and efficiency of the desalination process. Efforts to improve continue to be done if it is still possible to increase the efficiency and performance of desalination devices with various energy utilization methods. After testing, the highest solar intensity obtained on the test day reached 420.85 W/m2, and the lowest solar intensity on the second day was 96.89 W/m2. The highest evaporation heat transfer coefficient reaches 10.54 W/m2 °C and the lowest is 4.42 W/m2 °C. The highest convection heat transfer coefficient reaches 51.15 W/m2 °C and the lowest heat conversion coefficient is 15.28 W/m2 °C. The total absorbed energy reaches 6.26 kW and the lowest absorbed energy reaches 1.37 kW. Energy efficiency reaching 85% and the lowest energy efficiency is 35%.

Solar desalination functions to filter water, both sea water and brackish water, to produce clean water that is fit for consumption with energy from the sun. Solar energy is a renewable energy source that has been widely studied for its use. One of its uses is in a double slope passive solar still where the sun is the main source. Energy and exergy obtained from solar energy are not all used to evaporate water in the desalination system, so it is necessary to calculate efficiency energy and exergy in the system. This study aims to obtain data on the amount of efficiency energy and exergy from the double slope passive solar still as well as the factors that affect efficiency energy and exergy. The results showed that energy efficiency was in the range of 30.20% to 55.15% and exergy efficiency was in the range of 0.93% to 5.36%. The factors that influence the amount of energy efficiency and exergy are solar intensity, basin area, basin cover area, amount of water produced and ambient temperature.

Fresh water from the desalination process is expected to be commercially produced in large quantities for world consumption needs. In this paper, experimental testing is carried out to obtain the overall characteristics of the desalination device to suit the placement of the test area. The single slope passive desalination tool model with a slope of 35o is still used as the object being tested because of its low cost and environmentally friendly use of solar energy. It is hoped that the performance improvement can be made after obtaining the characteristics of the desalination tool as a whole. It is obtained that the heat energy absorbed reaches 0.31 kWh with a solar intensity of 534.40 W/m2 at the same time. The production of fresh water during the test always follows the brightness and solar intensity. Experimentally obtained the allergy from the desalination device of 0.53 kW/m2 with an energy efficiency of 58.4% with the highest amount of hourly fresh water production of 2.6 kg.