Energy Systems Engineering / Enerji Sistemleri Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4752
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Article Citation - WoS: 33Citation - Scopus: 41Development of a Personalized Thermal Comfort Driven Controller for Hvac Systems(Elsevier Ltd., 2021) Turhan, Cihan; Simani, Silvio; Gökçen Akkurt, GüldenIncreasing thermal comfort and reducing energy consumption are two main objectives of advanced HVAC control systems. In this study, a thermal comfort driven control (PTC-DC) algorithm was developed to improve HVAC control systems with no need of retrofitting HVAC system components. A case building located in Izmir Institute of Technology Campus-Izmir-Turkey was selected to test the developed system. First, wireless sensors were installed to the building and a mobile application was developed to monitor/collect temperature, relative humidity and thermal comfort data of an occupant. Then, the PTC-DC algorithm was developed to meet the highest occupant thermal comfort as well as saving energy. The prototypes of the controller were tested on the case building from July 3rd, 2017 to November 1st, 2018 and compared with a conventional PID controller. The results showed that the developed control algorithm and conventional controller satisfy neutral thermal comfort for 92 % and 6 % of total measurement days, respectively. From energy consumption point of view, the PTC-DC decreased energy consumption by 13.2 % compared to the conventional controller. Consequently, the PTC-DC differs from other works in the literature that the prototype of PTC-DC can be easily deployed in real environments. Moreover, the PTC-DC is low-cost and user-friendly.Article Citation - WoS: 44Citation - Scopus: 45Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Elsevier Ltd., 2021) Uzundurukan, Arife; Akça, Elif Seda; Budak, Yağmur; Devrim, YılserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm2 active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm2, 125 mW/cm2 and 113 mW/cm2 were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 °C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. © 2020 Elsevier LtdArticle Citation - WoS: 29Citation - Scopus: 39Investigation of Indoor Microclimate of Historic Libraries for Preventive Conservation of Manuscripts. Case Study: Tire Necip Paşa Library, Izmir-Turkey(Elsevier Ltd., 2017) Şahin, Cem Doğan; Çoşkun, Turgay; Durmuş Arsan, Zeynep; Gökçen Akkurt, GüldenConservation of library collections requires an interdisciplinary approach. Dealing with the agents of deterioration via curative and preventive conservation methods has become a significant goal with new standards and norms in recent years. Preventive conservation aims indirect physical interventions such as climate control, good housekeeping and pest management. The aim of this study is to assess the degradation potential of indoor climate on valuable manuscripts that date back to 12th century, in a historic library in Tire-İzmir, Turkey. Through the study, first the library, namely Necip Paşa Library was continuously monitored by measurements of thermo-hygrometric parameters for one year. Then, the measured data were evaluated for the risk assessment based on the control classes of ASHRAE Chapter 21 to evaluate the mechanical, chemical and biological degradation risks. Finally, the conservation-oriented measures were proposed in order to keep the manuscripts under the better conditions. Results suggest that introducing a heating, ventilation and air-conditioning system to the building should be considered as the last option since natural hygrothermal behavior of the library gives reasonably sufficient evidences to prevent the manuscripts from degradations to some extent. Therefore, passive solutions should be given higher priorities not to disturb environmental past of the historic library.Article Citation - WoS: 74Citation - Scopus: 85A Transdisciplinary Approach on the Energy Efficient Retrofitting of a Historic Building in the Aegean Region of Turkey(Elsevier Ltd., 2015) Şahin, Cem Doğan; Durmuş Arsan, Zeynep; Tunçoku, Selim Sarp; Broström, Tor; Gökçen Akkurt, GüldenAbstract Buildings account for 40% of total energy consumption in the European Union, yet at the same time they have considerable energy saving potentials. Historic buildings should be treated different from contemporary ones when it comes to energy improvements. The specifications which underline historical, sociocultural and architectural values require certain care during realization of energy saving implementations to sustain these values. The purpose of this study is to demonstrate how the energy efficient retrofitting in historic buildings should be managed in a transdisciplinary approach with a case study conducted on the historic building in ̄zmir - Turkey. A detailed building energy simulation tool was used to determine the impacts of energy efficient retrofits. The actual energy consumption of case building was based on the utility bills regarding electricity and heating fuel consumption. Building energy simulation tool was calibrated by comparing the measured and simulated indoor air temperatures and total energy consumptions. The inappropriate retrofits, which contradict to the cultural heritage values, were eliminated with a transdisciplinary approach. Later appropriate retrofits were gathered into three packages to evaluate their effects on the energy consumption. The results show that energy saving of more than 34% can be obtained without damaging the heritage values.