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Currently, crude oil still remains an irreplaceable energy source for chemical industrial processes, transportation systems, electricity, and other human activities. However, crude oil contains sulfur elements as the major impurities in the form of aliphatic and aromatic organosulfur compounds. During the combustion of fuel, these organosulfur compounds are converted to harmful SOx gases; thus, many countries strictly limit the maximum sulfur content in the fuels. To fulfill the government regulation, refineries are trying to decrease the maximum sulfur content in crude oil through several desulfurization technologies, such as hydrodesulfurization, adsorption, oxidative‐desulfurization, alkylation, and biodesulfurization. Each desulfurization technology has its own advantages and disadvantages. In this review article, we aimed to briefly summarize the progress in the developing science and technology of each desulfurization process of crude oil. Several fields in the desulfurization process are still facing challenges to create better designs and development for a safer future of the world.

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Abstract. In this research, cooling system optimization using thermal energy storage (TES) in shopping center buildings was investigated. Cooling systems in commercial buildings account for up to 50% of their total energy consumption. This incurs high electricity costs related to the tariffs determined by the Indonesian government with the price during peak hours up to twice higher than during off-peak hours. Considering the problem, shifting the use of electrical load away from peak hours is desirable. This may be achieved by using a cooling system with TES. In a TES system, a chiller produces cold water to provide the required cooling load and saves it to a storage tank. Heat loss in the storage tank has to be considered because greater heat loss requires additional chiller capacity and investment costs. Optimization of the cooling system was done by minimizing the combination of chiller capacity, cooling load and heat loss using simplex linear programming. The results showed that up to 20% electricity cost savings can be achieved for a standalone shopping center building.

Indonesia terletak pada iklim khatulistiwa, sehingga Indonesia mempunyai sumber energi surya yang berlimpah dengan intensitas radiasi matahari rata-rata sekitar 4,8 kWh/m2 perhari diseluruh wilayah. Sel surya semakin populer bagi masyarakat karena sumber energi yang tidak terbatas dan ramah lingkungan. Melihat jumlah fosil saat ini digunakan sebagai pembangkit energi listrik terus berkurang, jika dibiarkan terus terjadi, maka sumber energi ini akan habis. oleh karena itu para ilmuwan berlomba-lomba mencari cara untuk meningkatkan efisiensi energi terbarukan sebagai sumber pembangkit energi listrik salah satunya adalah panel surya.

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