AbstrakSalah satu pemanfaatan energi surya adalah mengkonversi energi termalnya menjadi energi listrik. Konvertor yang digunakan adalah generator termoelektrik. Panas matahari diterima sisi panas termoelektrik melalui penyerap panas, sedangkan sisi dinginnya dilekatkan sistem pendingin aktif dengan fluida air. Penelitian ini memiliki tujuan untuk mendapatkan daya luaran semaksimal mungkin dari sistem generator termoelektrik yang mengkonversi energi termal surya menjadi energi listrik pada model bangunan. Metode penelitian yang digunakan adalah eksperimental, yang didahului dengan perancangan dan pembuatan alat penelitian. Alat penelitian berbentuk sistem generator yang diletakkan di atap model bangunan. Sistem generator terdiri dari penyerap panas aluminium, termoelektrik yang terdiri dari 15 set, dan sistem pendingin yang menggunakan fluida air bersirkulasi. Pengujian terhadap sistem dengan cara mengoperasikannya sambil melakukan pengamatan dan pengambilan data. Variabel dalam penelitian ini adalah susunan sambungan generator termoelektrik (seri dan paralel). Sementara data masukan adalah kelembaban udara, kecepatan angin, temperatur, dan aliran alir; sedangkan data luaran adalah tegangan listrik dan arus listrik. Hasil penelitian mendapatkan bahwa dengan perbedaan temperatur 12,8oC menghasilkan daya maksimum sebesar 2,214 watt dari susunan seri sambungan termolektrik. Sementara dengan perbedaan temperatur 15,4oC mendapatkan daya maksimum sebesar 0.101 watt dari susunan paralel sambungan termoelektrik.  Kata kunci: energi, surya, termoelektrik, atap, daya AbstractOne of the uses of solar energy is converting its thermal energy into electrical energy. The converter used is a thermoelectric generator. The sun's heat is received by the thermoelectric hot side through the heat sink, while the cold side is attached by an active cooling system with water fluid. This study aims to obtain the maximum possible output power from a thermoelectric generator system that converts solar thermal energy into electrical energy in the building model. The research method used is experimental, which is preceded by the design and manufacture of research tools. The research tool is in the form of a generator system that is placed on the roof of the building model. The generator system consists of an aluminum heat sink, a thermoelectric consisting of 15 sets, and a cooling system that uses circulating water fluid. Testing the system by operating it while observing and collecting data. The variable in this research is the connection arrangement of the thermoelectric generator (series and parallel). While the input data are humidity, wind speed, temperature, and flow flow; while the output data is electric voltage and electric current. The results showed that with a temperature difference of 12.8°C the maximum power was 2,214 watts from the series arrangement of the thermoelectric junction. Meanwhile, with a temperature difference of 15.4°C, the maximum power is 0.101 watts from the parallel arrangement of the thermoelectric connection. Keywords: energy, solar, thermoelectric, roof, power

This research was conducted to utilize waste heat energy zinc roof for a revamped into a source of electrical energy. Waste heat utilization of zinc using thermoelectric generator type of TEC-12706 to convert thermal energy into electrical energy and the fan with speed 5 m/s to hold a low temperature in a cold area of heatsink. This research was conducted using a test simulation tool made by zinc, aluminum and acrilic. Waste heat utilization of testing zinc roof done starting at 09.00 WIB until 15.00 WIB for 3 days, with some measured parameters required as the intensity of  solar radiation (Es), airspeed (v), current (I), power (W) and temperature (T) some of which are found in the system tools of simulation testing. From the results of testing performed, the value of the highest efficiency i.e. of 0,00888% and the largest electrical power generated in the amount of 0,0042 W. A high intensity of the solar radiation it will affect the temperature of the environment which will also have an effect on the temperature in the cold area of heatsink, then the value of the temperature difference will also be affected. Heat resistance value on the system also affects the value of the waste heat energy can be changed into electrical energy.

Penelitian ini bertujuan untuk mengukur kinerja kincir air tipe Detridge wheel yang menggunakan head sangat rendah sebagai tenaga penggerak. Detridge wheel pertama digunakan untuk mengukur kecepatan aliran pada irigasi sawah, seorang peneliti pernah menguji kincir air ini dengan simulasi Computational Fluid Dynamics (CFD) efisiensi maksimal yang dihasilkan adalah 60 %. Penelitian ini menggunakan material plat baja tebal 1,8 mm dan multiplek sebagai runner kincir air. Air disirkulasikan dengan variasi debit yang berbeda menggunakan pompa menuju bangunan air dan kembali lagi ke tangki penampung. Parameter yang diukur adalah putaran (rpm), gaya (N), kecepatan aliran air ( ) dan ketinggian air (m). Pada keenam variasi debit, efisiensi tertinggi dengan debit pertama yaitu 43,314 %. Daya air sebesar 1,862 watt dan daya kincir air yang dihasilkan 0,806 watt. Semakin tinggi kenaikan debit menyebabkan rugi-rugi yang terjadi juga semakin besar.

AbstrakShot peening merupakan metode pengerjaan dingin dengan menumbukkan permukaan logam menggunakan partikel-partikel bulat yang berukuran kecil dan berkecepatan tinggi. Dengan proses shot peening dapat dikurangi inisiasi dan propagasi retak yang menyebabkan terjadinya kegagalan terhadap logam. Tujuan penelitian ini adalah untuk mengetahui pengaruh intensitas dan coverage shot peening terhadap tegangan sisa dan kekerasan pada permukaan Al 7075 T7351. Penelitian dilaksanakan dengan menembakkan permukaan logam dengan intensitas 0,0062 A dan 0,0091 A, serta coverage masing-masing 100% dan 200%, kemudian dilakukan pengujian kekerasan permukaan dan tegangan sisa. Hasil penelitian menunjukkan bahwa shot peening menyebabkan terjadinya perubahan tegangan sisa, yaitu 92,5021 MPa pada keadaan tanpa shot peening menjadi -111,8726 sampai -170,5675 MPa setelah dilakukan dishot peening. Selain itu kekerasan pada permukaan meningkat antara 23,4% sampai dengan 44,7%. Meningkatnya kekerasan menunjukkan bahwa terjadi pengerjaan dingin yang besar pada permukaan logam. Pengaruh pelapisan (coverage) 200% ternyata meningkatkan besarnya tegangan sisa dan kekerasan permukaan walaupun belum melampaui intensitas yang lebih besar. Kata kunci : shot peening, intensitas, coverage, kekerasan permukaan, tegangan sisa AbstractShot peening is a cold working method by striking metal surfaces using small, high-speed and round particles. Shot peening can reduce the initiation and propagation of cracks that cause metal failure. The purpose of this analysis is to determine the effect of shot peening intensity and coverage on residual stress and hardness on the surface of Al 7075 T7351. The research was carried out by firing metal surfaces with intensities of 0.0062 A and 0.0091 A, and coverage of 100% and 200%, respectively, then testing surface hardness and residual stress. The results showed that shot peening caused a residual stress change, which was 92.5021 MPa in the state without shot peening to -111.8726 to -170.5675 MPa after it was shot peening. In addition, surface hardness increased from 23.4% to 44.7%. Increased hardness indicates that there is large cold working on the metal surface. The effect of 200% coverage apparently increases the amount of residual stress and surface hardness even though it has not exceeded the greater intensity. Keywords: shot peening, intensity, coverage, surface hardness, residual stress

Solar energy can be used by buildings. Parts of the building can convert solar thermal energy into electrical energy.The roof and walls are the parts of the building that receive the most sunlight. Therefore, the roof and walls of the building can supply electricity with the thermoelectric generator. The aim of this research is to get the maximum possible output power from the thermoelectric generator system. From the output power produced, it will be possible to find the feasibility of a thermoelectric generator to be used as an energy source for the roof and walls of the building model. The building model is designed simply where the roof and walls can be located a thermoelectric generator system, which consists of a heat sink, a thermoelectric circuit and a cooling system. The heat sink used is aluminum. The thermoelectric circuit consists of 15 sets which are assembled in a series connection arrangement. The cooling system used is active cooling, where water as the cooling fluid circulates continuously during the operation of the system. The thermoelectric hot side temperature is obtained from solar thermal radiation through a heat sink. Meanwhile, the temperature on the cold side of the thermoelectric is the result of the effect of the cooling system that is attached. The temperature difference between the hot and cold sides of the thermoelectric produces a system output in the form of electric voltage and electric current. This study obtain that the generator system on the roof with a temperature difference of 8.90 oC on the hot-cold side produces a power of 1.953 watts. While the generator system on the wall with a temperature difference between the hot-cold side of 1.80 oC produces a power of 0.030 watts.