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CONTROLLING COMFORTNESS OF BIG PRODUCTION BUILDINGS IN TROPICAL REGION FACTORIES BY PROPER FAN ARRANGEMENT Rudi Irawan; Dena Hendriana
International Journal Science and Technology Vol. 1 No. 3 (2022): November: International Journal Science and Technology
Publisher : Asosiasi Dosen Muda Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56127/ijst.v1i3.332

Abstract

A production building is one of important buildings in a factory. A lot of factories in Indonesia are still considered labor intensive factories. People need a convenient place to work to produce quality products. A discomfort workspace condition for workers often causes not only poor productivity but also poor quality of product. Therefore, it is important to create healthy working environment for workers. Air comfort is determined at least by five factors that are temperature, relative humidity, oxygen content, air pressure and air flow. Common working space in a production building is a huge space, so it is almost impossible to apply air conditioner system to such a big space due to too high investment cost and operational cost and economically unfeasible. In tropical region, oxygen content, air pressure and air flow can be controlled by letting the fresh air from outside to enter the building. Air movement will also lower temperature sensation on human skin. Commonly in factories, the managements equip the factories with fans to improve air comfort in the production building. However, this current research found that improper fan system configuration and direction does not help to improve air comfort and even worsens the air condition because the air movement blown from improper fan configuration and direction can cancel each other and trap the heated air recirculated inside the building. This research found that arranging the fans in one direction will poster air movement from one end to the other end of building as well as keep the fresh air entering building from one side and the used air exiting the building through the other side. Because a fan is not a cooling device, the air temperature inside the building similar to that of fresh air, but the air movement pushed by the fans will reduce temperature sensation on human around 2 0C.
Self-Discharging and Corrosion Problems in Vanadium Redox Flow Battery Dena Hendriana; Mochamad Hamdan Aziz; Yohanes Acep Nanang Kardana; Muhamad Lutfi Rachmat; Gembong Baskoro; Henry Nasution
Reaktor Volume 22 No. 3 December 2022
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/reaktor.22.3.77-85

Abstract

Vanadium redox flow battery (VRFB) has a potential for large energy storage system due to its independence of energy capacity and power generation. VRFB is known to have challenges of high price, corrosion problem and lower energy efficiency. In this work, VRFB prototype with all components from existing parts sold in the market has been assembled and tested. Estimated electrochemical reactions are discussed for initial charging process with Vanadium Pentoxide powder as initial state to obtain fully charged battery state with V2+ ion in anolyte and VO2 + ion in catholyte. Material corrosion testes were done by immersing the material in a Vanadium electrolyte and by using the material as a bipolar plate in the VRFB system. Immersion test showed that copper, steel, lead and zinc were corroded badly. In bipolar plate material test, stainless steel 316, aluminum and silver plates were corroded after some hours of electric charging process. Simple carbon plastic composites and 3-mm thickness graphite plates were tested in the bipolar plate material test and failed due to corrosion problem as well. In the VRFB prototype, corrosion problems occurred on brass nipples, polyurethane plastic pipes and porous silicone seals. Stronger plastic components and better quality of silicone seals are needed for VRFB. Significant finding of this study is possible spontaneous chemical reaction within anolyte tank as a potential of self-discharging reaction which other researchers have not identified. Also, another finding from this study is that good bipolar plate for VRFB is not easily available in the market.