Browsing by Author "Kilkis, Siir"

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Educating Future Energy Engineers for Sustainability: Case Study in Energy Economy
(2015) Kilkis, Siir
This paper analyzes the case study of an interdisciplinary course in Energy Economy that was developed at the Energy Engineering Graduate Program at Baskent University. The course integrated several unique pedagogical features to satisfy the aim of developing a working knowledge in energy economy with an energy systems perspective. The novel aspects of the course thematically led to a capstone research project where 5 teams of 17 course participants analyzed their prioritized solutions towards improving the energy self-sufficiency of the campus based on the practice of energy economy. The results of the teams' solutions towards a net-zero energy/exergy campus included electric buses for city-campus transport, poly-generation for the new Arts Center, LED/OLED lighting for campus lighting, dynamo driven/piezoelectric sports center, biofuels from the university-owned dairy products farm, and an energy efficient technology incubation center. This unique course with participatory learning is compared with others before concluding that the case study is a useful international example for energy economy.
Hydrogen Economy Model for Nearly Net-Zero Cities with Exergy Rationale and Energy-Water Nexus
(2018) Kilkis, Birol; Kilkis, Siir; AAJ-2321-2020
The energy base of urban settlements requires greater integration of renewable energy sources. This study presents a "hydrogen city" model with two cycles at the district and building levels. The main cycle comprises of hydrogen gas production, hydrogen storage, and a hydrogen distribution network. The electrolysis of water is based on surplus power from wind turbines and third-generation solar photovoltaic thermal panels. Hydrogen is then used in central fuel cells to meet the power demand of urban infrastructure. Hydrogen-enriched biogas that is generated from city wastes supplements this approach. The second cycle is the hydrogen flow in each low-exergy building that is connected to the hydrogen distribution network to supply domestic fuel cells. Make-up water for fuel cells includes treated wastewater to complete an energy-water nexus. The analyses are supported by exergy-based evaluation metrics. The Rational Exergy Management Efficiency of the hydrogen city model can reach 0.80, which is above the value of conventional district energy systems, and represents related advantages for CO2 emission reductions. The option of incorporating low-enthalpy geothermal energy resources at about 80 degrees C to support the model is evaluated. The hydrogen city model is applied to a new settlement area with an expected 200,000 inhabitants to find that the proposed model can enable a nearly net-zero exergy district status. The results have implications for settlements using hydrogen energy towards meeting net-zero targets.
Integrated Circular Economy and Education Model to Address Aspects of An Energy-Water-Food Nexus in A Dairy Facility and Local Contexts
(2017) Kilkis, Siir; Kilkis, Birol; 0000-0003-3466-3593; 0000-0003-2580-3910; E-5934-2015; AAJ-2321-2020
Universities have responsibilities for accelerating pedagogical innovation to enable a more sustainable future. This research work develops a three-phased approach for integrating principles of a circular economy system within a course in energy policy. The phases involve scanning available resources, identifying possible matches based on the quality of energy, namely exergy, and determining solution areas. The case study is a university-founded dairy facility in the province of Ankara, Turkey with a biogas production potential of 982 m(3) per day. Four scenarios are analyzed based on options for combined heat and power, organic Rankine cycle, waste heat recovery, absorption chillers, ground source heat pumps, photovoltaic thermal arrays, and/or low-speed wind turbines. In total, 184.1 kW(e) of high exergy power and 285.3 kW(t) of low exergy thermal power may be produced. Further evaluation of the scenarios indicates that the level of exergy match may reach 0.87 while primary energy and primary exergy savings over separate energy production from renewables may be 38% and 61%, respectively. The solution areas can address aspects of an energy, water, and food nexus based on energy from waste, energy for irrigation and agriculture, and other linkages. The results are used to engage students in advancing the Sustainable Energy Action Plans of local municipalities. The approach has applicability to other cases in a time when pedagogical innovation is urgently needed to stimulate environmental sustainability. (C) 2017 Elsevier Ltd. All rights reserved.
New Exergy Metrics for Energy, Environment, and Economy Nexus and Optimum Design Model for Nearly-Zero Exergy Airport (Nzexap) Systems
(2017) Kilkis, Birol; Kilkis, Siir; 0000-0003-2580-3910; 0000-0003-3466-3593; AAJ-2321-2020; E-5934-2015
This paper introduces the Nearly-Zero Exergy Airport (nZEXAP) concept that brings an energy, environment, and economy nexus to a common basis using the Second-Law of Thermodynamics. An nZEXAP airport has a district energy plant of its own, which receives at least 70% of the total exergy input at winter design conditions and 60% at summer design conditions, from onsite renewable energy resources and sustainable systems. These numerical criteria are consistent with the fact that especially ground heat, and solar heat have low exergy, compared to fossil fuels, and solar and wind energy applications in airports are limited. This definition is the basis of the new optimum plant design model for satisfying these new conditions with the least cost that is attributed to the cogeneration (aka CHP) system using an optimum mix of fossil and alternative fuels, such as on site-produced biogas. The main renewable exergy inputs are biogas, ground heat, building integrated or attached PV, and waste heat. Extensive use of on site wind and roof-top or on-land type of solar applications are limited in compliance to Federal Aviation Administration (FAA) regulations against glint and glare to pilots and air traffic controllers besides potential electromagnetic hazards on avionics. The exergetic performance of the airport district plant is defined and analyzed with the use of the Rational Exergy Management Model (REMM). New exergy metrics for the performance analysis and rating of nZEXAP airports, based energy, economy, and environment nexus were also developed. The optimization problem has three primary design variables, namely the ratio of the optimum cogeneration engine capacity to the peak power load, the split of the generated power supply between the airport and the groundsource heat pumps, and the natural gas to biogas mixing ratio. The objective function solves the primary design variables by a simple search method. The new tool was applied to a conceptual study for the Amsterdam Schiphol Airport in order to compare the impact of an nZEXAP design with the ongoing deep retrofit work. Amsterdam Schiphol Airport aims to make its own activities climate neutral and to generate 10% of its own energy sustainably by 2020. In this comparison, the relative impact of the biogas share, solar input, size and performance of the ground-source heat pumps, and the power-to-heat ratio of cogeneration and absorption cooling were investigated. The results indicate that with the new optimization model, nZEXAP objectives may be satisfied, if techno-economic constraints are also satisfied. Further refinements in the definition may be needed. (C) 2017 Elsevier Ltd. All rights reserved.