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EFEKTIVITAS PENGGUNAAN THERMOSTATIC EXPANTION VALVE PADA REFRIGERASI AC SPLIT -, Harianto; Yawara, Eka
T R A K SI Vol 13, No 2 (2013): TRAKSI
Publisher : Universitas Muhammadiyah Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (216.263 KB) | DOI: 10.26714/traksi.13.2.2013.%p

Abstract

Vapor compression refrigeration is one of refrigeration systems that is mostwidely used for the cooling process in a variety of human needs. In this type of machine there is a component that can be varied kind, namely the expansion valve, such as a capillary tube and thermostatic expansion valve (TXV).Experimental tests have been conducted in a one HP split air conditioningrefrigeration machine capacity to compare the performances between the useof a capillary tube and TXV expansion valve.  The experimental results showthat the use of a capillary tube responds to the greater cooling load of thesmaller COP, COP highest achieved in the condition of the refrigerant out ofthe evaporator in the form of vapor saturated with COP = 5.3. While the useof TXV, COP value increases with the addition of the cooling load. Thehighest COP achieved is 5.87.
Effect of Tapper Ratio on a Car Rear Spoiler Performance Harianto, Harianto; Irawan, Yosua Heru; Yawara, Eka; Bakhtiar, Husni
JEMMME (Journal of Energy, Mechanical, Material, and Manufacturing Engineering) Vol 4, No 1 (2019)
Publisher : University of Muhammadiyah Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (553.081 KB) | DOI: 10.22219/jemmme.v4i1.7982

Abstract

The increasing development of car modification and the lack of understanding on the function of using spoilers or rear wings on vehicles, underlies the research on the aerodynamic forces acting on cars. The influence of this aerodynamic device will produce a compressive force to the bottom of the vehicle or called downforce, where this force is greatly influenced by the CL (lift coefficient) value. The purpose of this study was to determine the effect of variations in the tapper ratio on the value of downforce and drag force on on single-element type spoilers made using a NACA 6412 airfoil. The research was conducted using the Computational Fluid Dynamic method using ANSYS Fluent software with steady state pressure based solver. In this study five variations of the tapper ratio were used, namely: 1:1; 1:0.5; 1:0.7; 0.5:1; and 0.7:1. The fluid properties used are adjusted to the climate and weather in general air conditions and at air flow speeds of 100 km/h. Based on the research conducted, it can be concluded that the highest lift coefficient value was achieved in the 1:1 tapper ratio variation which was equal to CL = -0.2275 and CD = 0.0195. The highest downforce value is achieved in the 1:1 tapper ratio variation that is equal to L = -107,529 N and the largest drag force value is also achieved in the 1: 1 tapper ratio variation that is equal to D = 9.2269 N. The best CL/CD results are obtained at the 1:05 tapper ratio variation with a value of 12.82.
Pengaruh Profil Sudu Terhadap Koefisien Daya Turbin Gorlov Yawara, Eka; Jayatun, Yohannes Agus; Sugati, Daru
KURVATEK Vol 1 No 2 (2016): November 2016
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v1i2.235

Abstract

Masalah keterbatasan penyediaan sumber energi dari energi fosil diatasi dengan optimalisasi sumber energi terbarukan, misalnya sumber daya dari air. Salah satu kendala yang dihadapi dari penyediaan pembangkit daya air berskala besar adalah problem lingkungan. Oleh karena itu pembangkit daya air skala kecil atau mikro terus diupayakan pengembangannya, misalnya penggunaan Turbin Gorlov yang memanfaatkan potensi air dengan head rendah atau sangat rendah. Pada penelitian ini dilakukan studi pengaruh profil sudu terhadap koefisien daya pada Turbin Gorlov. Penelitian dilakukan dengan cara simulasi menggunakan perangkat lunak SolidWorks. Profil yang dipilih adalah NACA0012, NACA0017 dan NACA0022, selanjutnya sudu dipuntir dengan sudut puntir 30o, 60o dan 90o. Pada rasio tip-speed yang ditetapkan sebesar 2, hasil terbaik diberikan oleh Turbin Gorlov dengan profil NACA0017 dan sudut puntir 30o, yaitu rata-rata 17,3%.