This research aims at investigating the corrosion behavior and hardness of AISI Stainless Steel 304 (AISI SS 304) in corrosive hydrochloric acid solution and temperature variation treatment. In this study, the samples of AISI SS 304 are immersed for six (6) days in the corrosive acid solution at the temperature of 30°C and 50°C. The solution used as the corrosive media are HCl, FeCl3, and NaCl in the concentration of 5%, 10% and 15%. The results show that the higher the concentration of the solution, the higher the corrosion rate of AISI SS 304 will be, and the higher the temperature, the higher corrosion rate will also occur in all corrosion media. The corrosion that occurs in AISI SS 304 is mostly in the form of uniform corrosion and some pitting corrosion, and the value of hardness decreases after corrosion.

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The heat exchanger is an important component in the gas and steam power plant (PLTGU) industry. One of the most important heat exchangers in gas turbine cooling systems is the gas turbine radiator. The gas turbine radiator functions to cool the cooling water, which circulated to various components of the gas turbine by using environmental air as the cooling medium. The purpose of this study was to determine the effect of environmental temperature on the performance of gas turbine radiators and to compare operational data in 2017 with operational data when the study conducted in 2019. Data collected for 3 days with 2-3 hour intervals. Data processing and analysis shows that the higher the ambient temperature, the higher the radiator effectiveness value. Data in 2017 shows the highest average value of effectiveness obtained at an ambient air temperature of 35 ˚C of 71,274%. Meanwhile, data in 2019 shows the highest average value of effectiveness at an ambient air temperature of 35 ˚C of 58,859%. Thus, the average effectiveness value of gas turbine radiators has decreased by 12,415% from 2017 to 2019

Using inhibitors becomes an alternative way to reduce the level of corrosion. One type of the inhibitors proven effective is inorganic or chemical inhibitors. Regarding this, the purpose of this study is to determine the effectiveness of chemical inhibitors in reducing the level of corrosion. This study showed that the addition of natrium acetate and natrium was proven effective in reducing the corrosion, with the level of inhibitor efficiency of 75%. The result also showed that the inhibitors gave good performance to inhibit corrosion attack in natrium chloride acid medium, the form of corrosion that occurs in API 5L material is uniform corrosion.

The use of energy storage materials in a solar distillation system is intended to increase condensate production by making changes in the temperature of the system change slowly, not following fluctuations in the intensity of solar radiation that can change quickly and drastically. One of the effective energy storage systems is the use of Phase Change Materials (PCMs), materials that involve a phase change process in storing and releasing heat, because the latent heat involved in the phase change process has a large enough value under constant temperature conditions so that temperature stability in the system is achieved. The choice of PCM type used in solar distillation is determined by the average temperature that can be reached by the water in the basin, which is strongly influenced by local environmental conditions. This study compares the productivity of the distillate produced by the double slope solar distillation system that uses Lauric Acid as PCM and that does not use PCM. Both studies were conducted at the same time. The optimal amount of LA that must be added to the solar distillation system to get the highest increase in condensate production value is 7.54 kg of Lauric Acid for 64.8 kg of raw water..