This research was conducted as an experiment to purify seawater as raw water in coastal and remote areas. Membranes are essential in desalination and are designed to utilize coffee skin waste. Coffee skin is converted into activated carbon. The study aimed to increase evaporation from the seawater desalination process as pure water. The research method is an experiment that processes coffee skin into carbon. The carbonization process was carried out at a temperature of 500˚C with the impregnation method with H3PO4 activated for 3 hours. The results of the TGA analysis obtained the highest fixed carbon of 66.27% and ash content of 3.01%; FTIR analysis obtained with the composition of the temperature obtained has functional groups OH, CH, and C = C. Polyvinylidene fluoride (PVDF) membranes are mixed with coffee skin nanocarbon. From the results of SEM observations, the membrane's pores are large enough so that the evaporation that occurs has an efficiency above 60%. These results show that the coffee skin mixture membrane effectively manages energy and desalination.

The need for clean water for people in Indonesia is increasing, especially in coastal areas, while the availability of clean water is minimal. One of the efforts to anticipate this is by utilizing seawater with a solar distillation system. In this study, the absorber used is rice husk briquettes. Various distillation technologies have been developed, but distillation technology with solar energy sources still experiences various obstacles, so further technology and research are needed. In order to develop this technology, research was conducted with the aim of (1) producing a design for the thickness and density of rice husk briquettes in a seawater distillation system. (2) to produce clean water for each pair of thickness and density of rice husk briquettes through a seawater distillation system. (3) To find out how much heat absorption efficiency is using a rice husk briquette absorber. The research method used is comparative, namely a study that is comparative, where in this study, the thickness and density of rice husk briquettes are compared. The data analysis method used is descriptive. The parameters to be analyzed are plate temperature (Tp), glass temperature (Tg), water temperature (tw), basin room temperature (Tsv), ambient temperature (Ta) and distilled water (AT), absorber plate area (Ac), collector and distillation efficiency. This study produces a design for distilling seawater into clean water using a rice husk briquette absorber plate that can increase clean water production.