Pengaruh Kondisi Operasi Terhadap Efektivitas Oil Cooler di PLTA Sutami - Pangihutan Panggabean, Polin; Suprapta Winaya, I Nyoman; Astawa, Ketut (Teknik Desain Mekanika, 2019)
Abstrak Kehandalan unit Pembangkit Listrik Tenaga Air (PLTA) Sutami dipengaruhi oleh efektivitas oil cooler tipe shell and tube yang berfungsi sebagai pelumasan bearing. Pola operasi yang dinamis disesuaikan dengan kondisi debit waduk dan permintaan dispatcher (APB). Untuk menjaga pengoperasian tetap handal maka perlu analisis efektivitas.Data dari laporan harian (logsheet) digunakan sebagai data primer untuk pengolahan. Data operasi seperti temperatur (Th,in, Th,out, Tc,in, Tc,out) dan laju alir fluida (?h , dan ?c) digunakan untuk menghitung nilai kalor spesifik (cp,h, cp,c), laju kapasitas kalor (Ch ,Cp ) dan perbandingan laju kapasitas kalor (Cr). Setelah itu, dilakukan perhitungan untuk mengetahui pengaruh kondisi operasi 20 MW dan 30 MW terhadap nilai log mean temperature difference (?TLMTD), number of transfer unit (NTU), dan nilai efektivitas (?) oil cooler tipe shell and tube.Kenaikan kondisi operasi 20 MW ke 30 MW menghasilkan nilai ?TLMTD yang semakin besar, yaitu masing-masing 5,22 °C dan 5,57 °C. Sedangkan, nilai NTU mengalami penurunan seiring dengan kenaikan kondisi operasi, yaitu masing-masing 1,551 dan 1,452. Nilai efektivitas oil cooler pada kondisi operasi 20 MW dan 30 MW masing-masing sebesar 74,21 % dan 72,25 %. Kata kunci: oil cooler, log mean temperature difference, number of transfer unit, efektivitas Abstract The reliability of the Sutami Hydroelectric Power Plant (PLTA) is influenced by the effectiveness of the shell and tube type oil cooler which functions as a bearing lubricant. The dynamic operating pattern is adapted to reservoir discharge conditions and dispatcher requests (APB). To maintain reliable operation, effectiveness analysis is needed.Data from daily reports (logsheets) are used as primary data for processing. Operating data such as temperature (Th, in, Th, out, Tc, in, Tc, out) and fluid flow rate (?h , and ?c) are used to calculate specific heating values (cp, h, cp, c), heat capacity rate (Ch , Cp ) and the ratio of heat capacity (Cr). After that, a calculation is performed to determine the effect of the operating load of 20 MW and 30 MW on the log mean temperature difference (?TLMTD) value, number of transfer units (NTU), and the effectiveness value (?) of the shell and tube type oil cooler.The increase in operating load of 20 MW to 30 MW results in a greater value of ?TLMTD namely 5.22 ° C and 5.57 ° C, respectively. Meanwhile, the value of NTU has decreased in line with the increase in operating load, which are respectively 1.551 and 1.452. The effectiveness value of the oil cooler at 20 MW and 30 MW operation load is 74.21 % and 72.25 %, respectively. Keywords: oil cooler, log mean temperature difference, number of transfer unit, effectiveness