Yazarlar
- Cuce, Erdem(25)
- Cuce, Pinar Mert(20)
- Tozlu, Alperen(17)
- Karaali, Rabi(11)
- Guclu, Tamer(10)
- Kahveci, Hakan(7)
- Özahi, Emrah(6)
- Keven, Arzu(5)
- Çorapsız, Muhammed Reşit(5)
- Bayram, Ozkan(4)
- Ceviz, Mehmet Akif(4)
- Igman, Erdal(4)
- Imamoglu, Ilyas Kays(4)
- Isik, Cem(4)
- Karaali, R.(4)
- Kosunalp, Selahattin(4)
- Köksal, Hüseyin(4)
- Ongan, Serdar(4)
- Ozel, Faruk(4)
- Ozel, Sultan Suleyman(4)
- Tozlu, A.(4)
- Abusoglu, Aysegul(3)
- Abuşoğlu, Ayşegül(3)
- Güngör, Okan(3)
- Korkmaz, Şadan(3)
- Kus, Mahmut(3)
- Kuziboev, Bekhzod(3)
- Pat, Suat(3)
- Sari, Fahriye(3)
- Simsek, Onder(3)
- Uyar, Mehmet(3)
- Çakir, Uǧur(3)
- Çomakli, Kemal(3)
- Özen, Soner(3)
- Şenay, Volkan(3)
- Abuşoǧlu, A.(2)
- Afshari, Faraz(2)
- Aloui, F(2)
- Arslantürk, Cihat(2)
- Atabani, A.E.(2)
Yayınlar
- BildiriYayıncıda açık erişim2016Scopus SJRQ4Exergy analysis of a combined power and cooling cycle
Karaali, R.
Ammonia-water power cycles are important for efficient utilization of low temperature heat sources such as geothermal, solar, waste heat sources, etc. For some special conditions ammonia-water power cycle is an important and economical option. This paper presents an exergetic analysis of a combined power and cooling cycle that uses ammonia-water mixture as working fluid. Such cycles, use solar or geothermal energy or waste heat energy from a conventional power cycle. Ammonia-water power cycle can be used as independent cycles to provide power output and cooling. For a range (25-55 Bar) of boiler pressure the performance of the combined power and cooling cycle is investigated. The exergy of the boiler is very low compared to its energy. There is a boiling process and a heat transfer process at low temperature, both of which destruct the energy given to the boiler, so that the energy efficiency is low; however the exergy efficiency is higher than the energy efficiency. Increasing the turbine inlet pressure decreases the energy and exergy efficiencies.
AtıfScopus13WoS12OpenAlex75
İncele - MakaleAçık Erişim2016Scopus SJRQ1A novel roof type heat recovery panel for low-carbon buildings: An experimental investigation
Cuce, Pinar Mert; Cuce, Erdem; Riffat, Saffa
Energy saving and its efficient utilization is of prime interest in today's world due to the limited energy resources and growing significance of environmental issues. Despite the intensive efforts to narrow the gap between conventional energy sources (wood, coal, gas, oil, etc.) and renewables, renewable energy resources currently supply only about 14% of total world energy demand. In this regard, energy management and optimization are considered compulsory as much as the clean energy generation. Recent works indicate that the buildings play a significant role on global energy consumption. They are responsible for about 40% of global energy demand. Among the different building types, domestic buildings have the largest share with 63% and most of energy is utilized for heating, ventilation and air conditioning (HVAC) systems in those buildings. Energy consumption levels of buildings can be notably reduced through waste heat recovery in HVAC systems. There are several attempts in literature addressing the possibility of decreasing energy consumption of buildings via waste heat recovery technologies. The heat recovery technologies are cost effective and user friendly applications. The use of heat recovery systems aims at mitigating the energy consumption for HVAC applications as well as the greenhouse gas emissions, and hence decreasing the adverse effects of global warming on the Earth. It is well-documented in literature that the heat recovery systems are very promising for domestic applications. In this paper, experimental results of a novel heat recovery system developed for low-carbon buildings are presented. The proposed heat recovery system consists of a plate-type heat exchanger, blower fans and ducts. The parallel-flow arrangement is used to run the system. The system is designed as under roof application. The aim of the system is to recover waste heat and to preheat fresh air using stale air. The experiments of the system are carried out in winter season in Kent, UK. The study aims to investigate the coefficient of performance (COP) of the system as well as the heat recovery efficiency. The results show that the heat recovery efficiency of the proposed system is around 89% while the COP is 4.5. The proposed system can be used in both winter and summer conditions without requiring additional work. Its labor cost is extremely low, so it is cost-effective and user friendly.
AtıfScopus28WoS23OpenAlex31İncele - MakaleAçık Erişim2016Scopus SJRQ1Novel glazing technologies to mitigate energy consumption in low-carbon buildings: A comparative experimental investigation
Cuce, Erdem; Cuce, Pinar Mert; Riffat, Saffa
Buildings play a key role in total world energy consumption as a consequence of poor thermal insulation characteristics of facade materials. Among the elements of a typical building envelope, windows are responsible for the greatest energy loss because of their notably high overall heat transfer coefficients. About 60% of heat loss through the building fabric can be attributed to the glazed areas. In this respect, novel cost-effective glazing technologies are needed to mitigate energy consumption, and thus to achieve the latest targets toward low/zero carbon buildings. Therefore in this study, three unique glazing products called vacuum tube window, heat insulation solar glass and solar pond window which have recently been developed at the University of Nottingham are introduced, and thermal performance analysis of each glazing technology is done through a comparative experimental investigation for the first time in literature. Standardized co-heating test methodology is performed, and overall heat transfer coefficient (U-value) is determined for each glazing product following the tests carried out in a calibrated environmental chamber. The research essentially aims at developing cost-effective solutions to mitigate energy consumption because of windows. The results indicate that each glazing technology provides very promising U-values which are incomparable with conventional commercial glazing products. Among the samples tested, the lowest U-value is obtained from the vacuum tube window by 0.40W/m2K, which corresponds to five times better thermal insulation ability compared to standard air filled double glazed windows.
AtıfScopus35WoS33OpenAlex37İncele - MakaleAçık Erişim2016Scopus SJRQ1Exergetic interrelation between an heat pump and components
Çakır, Uğur; Çomaklı, Kemal
In this study, the relation between the exergetic performance of the heat pump and its components are investigated experimentally by using an air to water heat pump. Moreover, the effects of the working conditions of the components on the exergetic performance of the system are exposed and discussed. An experimental air to water heat pump system was designed and built. The results were evaluated by comparing the components and heat pump according to their performances. 33–45% of the all destructed exergy of the heat pump system comes into existence in the compressor. The contribution of the condenser to the total exergy destruction rate of the heat pump is between 23% and 34%. Contribution of the compressor to the exergy destruction rate of heat pump decreases with an increase in the air temperature and it increases with a decrease in the air mass flow rate. Contribution of the compressor to the exergy destruction rate of heat pump decreases with an increase in the air temperature and it increases with a decrease in the air mass flow rate. In terms of exergetic performance of the heat pump, the importance and priority of the components vary with the heat source thermal conditions.
AtıfScopus15WoS14OpenAlex16İncele - Derleme MakaleYalnız künye2016Scopus SJRQ1Vacuum glazing for highly insulating windows: Recent developments and future prospects
Cuce, Erdem; Cuce, Pinar Mert
A comprehensive review of vacuum glazing technology from state-of-the-art developments to future prospects has been presented. The review has been conducted in a thematic way in order to allow an easier comparison, discussion and evaluation of the findings. First, a thorough overview of historical development of vacuum glazing has been given. Then, numerous experimental, theoretical, numerical and simulation works on the scope have been evaluated and the characteristic results from the said works have been analyzed. Commercial vacuum glazing products in market have been assessed in terms of several performance parameters such as overall heat transfer coefficient, visible light transmittance, solar heat gain coefficient and cost. Techno-economic and environmental aspects of vacuum glazing technology have also been discussed. It can be concluded from the results that overall heat transfer coefficient of a vacuum glazing can be reduced up to 0.20 W/m2K through optimized integrations with low-e coatings. The incomparable U-value range of vacuum glazing enables significant mitigation in energy consumption levels and greenhouse gas emissions. Retrofitting 25.6 million homes in the UK with vacuum glazing can provide a carbon abatement of about 40 million tonnes a year, which is very promising.
AtıfScopus138WoS117OpenAlex148İncele - MakaleYalnız künye2016Scopus SJRQ1Optical, morphological properties and surface energy of the transparent Li4Ti5O12 (LTO) thin film as anode material for secondary type batteries
Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
LTO thin film was deposited for the first time on a glass microscope slide (MS) by RF magnetron sputtering technology. This method has been suitable for preparation of high-quality thin films. The surface properties of the produced film were determined by atomic force microscope (AFM). The surface of the produced film appeared smooth and homogeneous. LTO coated on MS had compact structure and low roughness. A UV-vis spectrophotometer was used to determine intensity of light passing through the samples. Thus, according to the results obtained the produced film was highly transparent. The refractive index of the LTO thin film was presented in a low MSE value by spectroscopic ellipsometry (SE) and it was about 1.5. The optical band gap (Eg) was determined by the Tauc method. The produced LTO thin film exhibited a wide band gap semiconductor property with a band gap energy of about 2.95 eV. Finally, the surface free energy of the LTO thin film was calculated from the contact angle measurements using the Lewis acid-base, OWRK/Fowkes, Wu and Zisman methods.
AtıfScopus24WoS23OpenAlex27İncele - Derleme MakaleYalnız künye2016Scopus SJRQ1Toward multi-functional PV glazing technologies in low/zero carbon buildings: Heat insulation solar glass - Latest developments and future prospects
Cuce, Erdem
Heat insulation solar glass (HISG) is a recently developed multi-functional photovoltaic (PV) glazing technology to mitigate energy consumption of buildings and to provide optimum thermal comfort conditions to occupants. In essence, HISG represents an improved transparent amorphous silicon (a-Si) PV module prepared with several optimized coatings and structures. HISG differs from conventional PV glazing products by having some characteristic features such as thermal insulation, sound absorption, self-cleaning and notable energy saving. In addition, HISG has a 100% UV blocking rate and remarkably low shading coefficient, which provides desired lighting related thermal comfort conditions for indoor environments. HISG is also competitive with conventional double glazed products in market in terms of fabrication cost. In this respect, it is highly expected that HISG has a strong potential to dominate the fenestration market in the near future. In this research, a comprehensive review of HISG technology is presented. Power generation, thermal insulation, energy saving, self-cleaning, acoustic and aesthetic features of HISG are evaluated in detail through the state-of-The-art literature survey. Existing research projects on the scope and future prospects are also addressed within the scope of this study.
AtıfScopus75WoS62OpenAlex84İncele - MakaleYalnız künye2016Scopus SJRQ1Energy saving potential of heat insulation solar glass: Key results from laboratory and in-situ testing
Cuce, Erdem; Cuce, Pinar Mert; Young, Chin-Huai
HISG (heat insulation solar glass) is a recently developed multi-functional glazing technology to mitigate energy consumption of buildings. HISG can generate electricity similar to conventional PV (photovoltaic) glazing products when exposed to sunlight, however it differs from them by having some extraordinary characteristic features such as thermal insulation, which is competitive with Argon filled triple glazed windows, acoustic comfort, remarkable energy saving potential and self-cleaning ability owing to TiO2 nano coating. Within the scope of this research, latest results from laboratory and in-situ testing of HISG are presented in terms of its key role in mitigating heating and cooling demand of buildings as well as clean energy generation. Lighting and thermal comfort related parameters such as shading coefficient, UV, IR and visible light intensity are also investigated through the tests conducted in real operating conditions. It is achieved from the results that instant electricity generation of HISG is 16% higher than that of standard PV glazing owing to its nano layer reflective film. Shading coefficient of HISG is only 0.136, which provides almost 80% reduction in solar heat gain compared to ordinary glazing. Indoor air temperature measured from HISG test house in summer time is very close to the ambient temperature, whereas it is found to be 14.7 °C higher in ordinary glass test house due to greenhouse effect. Annual heating and cooling demand tests indicate that HISG provides 38 and 48% energy saving in heating and cooling season, respectively.
AtıfScopus52WoS46OpenAlex56İncele - BildiriAçık Erişim2016Scopus SJRQ4Thermodynamic analysis of a cascade refrigeration system
Karaali, R.
There is a need for cooling by using the waste heat energy in food industry. Absorption cycles can be driven by waste thermal, geothermal, solar or industrial processes energies. In this study, cascade refrigeration system is thermodynamically modeled, and analyzed by using first law of thermodynamics, and exergy method. Thermodynamic properties such as pressure, temperature, entropy, enthalpy, exergy, mass flow rate in each stream are calculated for 50, 75, 100?C and for 0.8, 1.0, and 1.5 MPa pump pressure. A computer program is used that was prepared in FORTRAN by the author for the analyses. It is found that the compression-absorption cascade cooling cycle is appropriate for most of the kind of waste heat applications. Increase of the generator inlet heat temperature increases the generator inlet heat, the absorber outlet heat and the condenser 2 outlet heat energies and decreases the coefficient of performance of the absorption and the overall cycles. The generator heat decreases with increase of the pump pressure. Also increase of the pump pressure decreases the coefficient of performance of the absorption and the overall cycles. Increase of the pump pressure and the generator temperature decreases the exergetic coefficient of performance. Increase of the generator temperature and pump pressure increases the generator inlet exergy. It is concluded that increase of the generator temperature and the pump pressure increases the total destructed exergy of the cycle.
AtıfScopus10WoS5OpenAlex13İncele - Kitap BölümüYalnız künye2016Investigation of the effect of canola methyl ester on cyclic variation using wavelet analysis method
Efe, Şükran; Ceviz, M.A.
Diesel engines are the most commonly used internal combustion engine in transportation, power generation, and other industries. Combustion in the diesel engines takes place at high temperatures due to the high compression ratio, and therefore high energy is obtained when diesel fuel is used. But the most commonly used alternative fuel diesel engines is biodiesel today. The market share of biodiesel is on the rise because of the increasing damage of diesel and decreasing oil reserves to the environment. In this study, cyclic variation that occurred when canola biodiesel (canola methyl ester) that is produced by transesterification method was used as diesel fuel was investigated. Three different biodiesel ratios, B20, B50, and B100 were used in the study. In interpretation cyclic variations wavelet analysis method is used and all results are compared with diesel fuel. It is concluded that the use of biodiesel in diesel engines has positive effect on cyclic variation and this effect increases with the increasing ratio of biodiesel in the mixture.
- Derleme MakaleYalnız künye2016Scopus SJRQ1Renewable and sustainable energy saving strategies for greenhouse systems: A comprehensive review
Cuce, Erdem; Harjunowibowo, Dewanto; Cuce, Pinar Mert
In this study, a comprehensive review focusing on key strategies of energy saving and climate control technologies for greenhouses is presented. Following the brief and concise assessment of existing greenhouse systems in terms of their role in total energy consumption; cost-effective, energy-efficient and environmentally friendly technologies are analyzed in detail for potential utilization in greenhouses for notable reductions in energy consumption and emission levels. The technologies considered within the scope of this research are mainly renewable and sustainable based solutions such as photovoltaic (PV) modules, solar thermal (T) collectors, hybrid PV/T collectors and systems, phase change material (PCM) and underground based heat storage techniques, energy-efficient heat pumps, alternative facade materials for better thermal insulation and power generation (heat insulation solar glass, PV glazing, aerogel and vacuum insulation panel, polycarbonate sandwich panels), innovative ventilation technologies using pre-heating and cooling (high performance windcatchers) and efficient lighting systems. The findings from the research clearly reveal that up to 80% energy saving can be achieved through appropriate retrofit of conventional greenhouses with a payback period of 4-8 years depending on climatic conditions and crop type.
AtıfScopus354WoS302OpenAlex382İncele - MakaleAçık Erişim2016Scopus SJRQ1A New Energy Prediction Algorithm for Energy-Harvesting Wireless Sensor Networks With Q-Learning
Kosunalp, Selahattin
Traditional wireless sensor networks (WSNs) face the problem of a limited-energy source, typically batteries, resulting in the need for careful and effective utilization of the energy source. However, inevitable energy depletion will eventually disturb the operation of a WSN. Energy harvesting (EH) technology is acquiring particular interest, because it has the potential to provide a continuous energy supply in battery-powered WSNs. Solar energy is the most effective environmental energy for EH-WSNs because of its high energy intensity, which comes from a non-controllable source. Therefore, the prediction of future energy availability is a critical issue, as the amount of the harvestable energy may vary over time. In this paper, a novel solar energy prediction algorithm with Q-learning, called Q-learning-based solar energy prediction (QL-SEP), is proposed. Q-learning is an effective way of predicting future actions based on past observations. The distinctive feature of QL-SEP is that not only past days' observations but also the current weather conditions are considered for prediction. The performance of QL-SEP is simulated in this paper using real-world measurements obtained from a solar panel in comparison with the state-of-art approaches.
AtıfScopus128WoS96OpenAlex135İncele - MakaleYalnız künye2015Scopus SJRQ1Thermoeconomic optimization of gas turbine cogeneration plants
Karaali, Rabi; Öztürk, Ilhan Tekin
In this study, a novel thermoeconomic optimization method that is simple and efficient, for real complex cycles is introduced. First, a thermoeconomic analysis method that is called non-linear simplex direct search method is improved for the purposes of this study. The objective of this paper is to apply this method to four cogeneration cycles that are simple cycle, inlet air cooling cycle, air preheated and air-fuel preheated cycles for analyzing and optimizing. The four cycles are thermoeconomically optimized for constant power and steam mass (30 MW and 14 kg/s saturated steam flow rate at 2000 kPa), for constant power (30 MW) and for variable steam mass, and for variable power and steam mass by using the cost equation method and the effect of size on equipment method. The results obtained by the effect of size on equipment and by the cost equations methods are very different from each other. For the case of global optimization, the optimum electricity costs which also correspond to minimum are obtained as 0,0432 $/kWh for simple cycle, 0,0514 $/kWh for inlet air cooling cycle 0,0577 $/kWh for air preheated cycle and 0,058 $/kWh for air-fuel preheated cycle by using cost equations method. (C) 2014 Elsevier Ltd. All rights reserved.
AtıfWoS32OpenAlex39İncele - MakaleAçık Erişim2015Scopus SJRQ3Experimental and numerical investigation of a novel energy-efficient vacuum glazing technology for low-carbon buildings
Cuce, Erdem
In this study, a recently developed innovative window technology called vacuum tube window is introduced, and its performance assessment is presented through an experimental and numerical research. The novel design of vacuum tube window consists of evacuated tubes surrounded by Argon as inert gas to eliminate conductive and convective effects inside the window and thus to produce a building element with remarkably low overall heat transfer coefficient (U-value). Heat transfer inside the window was modelled via a reliable commercial computational fluid dynamics software ANSYS FLUENT. The accuracy of simulations was verified by environmental chamber tests. For the vacuum tube diameter of 28 mm, an excellent agreement between experimental and numerical data was achieved. For different values of design parameters such as pane thickness, tube thickness, tube diameter and Argon gap, total heat loss and U-value of the vacuum tube window and optimum data were evaluated. Optimum tube diameter was found to be 60 mm in terms of thermal performance characteristics, cost, lightness and aesthetic issues. It is concluded that the vacuum tube window is able to provide a U-value lower than 0.40 W/m2K, which is very promising for both retrofitting of existing buildings and new-build applications.
AtıfScopus16WoS11OpenAlex18İncele - BildiriAçık Erişim2015Scopus SJRQ3Investigation of an alternative fuel for diesel engines
Keven, A.; Karaali, R.
Internal combustion engines use generally fossil fuel products. World resources of it is limited. Renewable alternative energy sources are getting important solution for energy demand. Hazelnut oil ethyl ester is obtained from raw hazelnut and mixed with diesel oil in certain proportions to use in a four-stroke direct injected single cylinder diesel engine. In this study the effects of the mixture of diesel oil with hazelnut oil ethyl ester on the engine performance and exhaust gas emissions are investigated for the first time in literature. The fuel injection system is regulated to use the mixture in the engine for the investigation. The results show that, the mixture with 25% ethyl ester extracted from hazelnut oil can be used as an alternative fuel without any change or regulation of the diesel engine.
AtıfScopus7WoS3OpenAlex7İncele - BildiriAçık Erişim2015Scopus SJRQ3Thermoeconomic analyses of steam injected gas turbine cogeneration cycles
Karaali, R.; Öztürk, I.T.
In this study, three different gas turbine cogeneration systems that are preheating air, preheating air-fuel and simple cycles where steam injected in to combustion chamber are analyzed. The effects of steam injection on thermoeconomic performance are calculated and obtained. By using the first law of thermodynamics, the exergy analysis and economic methods, simulation programs written by the authors in FORTRAN code are obtained to use for the analyses. Thermoeconomic performance of these three different cycles for different stage and variable mass of injected steam are obtained and compared with literature. The effects of injection steam in to combustion chambers of those three cycles for variable compressing ratios, on power, efficiencies, product price and performances are obtained. Consequently, the advantages and the disadvantages of injection steam are evaluated. The results obtained in this study are compared with the results available in the literature. Injection steam into combustion chamber increases the electricity efficiency and electricity power but decreases the heat power of the cycles. Also the produced electricity price for per kWh is increasing.
AtıfScopus15WoS12OpenAlex18İncele - MakaleAçık Erişim2015Scopus SJRQ1Using solar greenhouses in cold climates and evaluating optimum type according to sizing, position and location: A case study
Çakir, Uğur; Şahin, Erol
This study deals with a comparison among five common greenhouse types with regard to total solar radiation gaining rates in greenhouse using season under some assumptions. Additionally, possibility of using greenhouses in cold climate regions is investigated. We analyzed five greenhouse types and developed a script in MATLAB platform for the solar radiation availability. This model is applicable and suitable for other buildings and places on the world. Even-span, uneven-span, vinery, semicircular and elliptic types of greenhouses have been analyzed. A "k" value (ratio of length to width of greenhouse) and greenhouse azimuth angle (GAA) are described. Seven different floor area are assigned for each greenhouse type such as 50m2, 100m2, 150m2, 200m2, 250m2, 300m2 and 400m2, respectively. For each floor area, k value is assigned from 1 to 10. Each greenhouse is oriented in 90 different angles according to south facade. Seasonal total solar energy gaining rates is computed individually for all possible greenhouse types, area, k number and orientation. Then a comprehensive comparison is made to determine the optimal greenhouse. The results show that greenhouses are usable and suitable for using in cold climate regions to increase the productivity. In addition, the elliptic type is the optimum one in all analyzed types of greenhouses for Bayburt conditions for all floor areas. It is followed by uneven-span, even-span, semi-circular and vinery type of greenhouses respectively. Shape and type of the roof are main effective parameters on solar energy gaining rates of greenhouses. Elliptic greenhouse should be preferred on the band of the latitude of Bayburt, unless there is restrictive factor like sizing and terrain.
AtıfScopus93WoS77OpenAlex95İncele - MakaleAçık Erişim2015Scopus SJRQ2MAC protocols for energy harvesting wireless sensor networks: Survey
Kosunalp, Selahattin
Energy harvesting (EH) technology in the field of wireless sensor networks (WSNs) is gaining increasing popularity through removing the burden of having to replace/recharge depleted energy sources by energy harvester devices. EH provides an alternative source of energy from the surrounding environment; therefore, by exploiting the EH process, WSNs can achieve a perpetual lifetime. In view of this, emphasis is being placed on the design of new medium access control (MAC) protocols that aim to maximize the lifetime of WSNs by using the maximum possible amount of harvested energy instead of saving any residual energy, given that the rate of energy harvested is greater than that which is consumed. Various MAC protocols with the objective of exploiting ambient energy have been proposed for energy-harvesting WSNs (EH-WSNs). In this paper, first, the fundamental properties of EH-WSN architecture are outlined. Then, several MAC protocols proposed for EH-WSNs are presented, describing their operating principles and underlying features. To give an insight into future research directions, open research issues (key ideas) with respect to design trade-offs are discussed at the end of this paper.
AtıfScopus56WoS45OpenAlex57İncele - Derleme MakaleYalnız künye2013Scopus SJRQ1Toward a sustainable energy future in Turkey: An environmental perspective
Serencam, Huseyin; Serencam, Ugur
As long as the energy future of Turkey is concerned there is a consensus among all parties involved in the subject that a strong sustainability based on diverse range of renewable and variety of sources with efficient and fair use of energy is a must. The main criterion in this approach is to use energy with the least possible greenhouse gases and other harmful emissions. A shift in focus to meeting the needs of energy service sector will be immediately felt in the sustainable energy future in Turkey. Another important aspect of the sustainable energy future of Turkey is that all energy users, as more knowledgeable and active participants will be more involved in various stages of the process. However, Turkey has a long way to reach this vision, because of growing greenhouse emissions related to energy production and utilization of alternative energy is slow. Besides, the intensity of energy of the Turkish economy is decreasing slower than many other OECD countries. In addition, energy consumption per person in Turkey is far above the service needs, even for modern lifestyles. There are substantial obstacles on the way to a sustainable energy future of Turkey, such as various aspects of economic structure, a misdirected energy market process, and a lack of vision among the decision makers.
AtıfScopus12WoS10OpenAlex12İncele - MakaleAçık Erişim2013Scopus SJRQ2Energetic and exergetic comparison of air to air and air to water heat pumps according to evaporator conditions
Çomakli, Kemal; Çakir, Uǧur; Şahin, Erol; Kuş, Ayşegül Çokgez
This paper presents an experimental energetic and exergetic comparison for a heat pump system that can be run in different modes as air to air and air to water. Components of the heat pump do not change when the running mode changes, except for the condenser. This means that some external and internal effects (like compressor type, pipe lines) that can affect the system performance will be the same for each running mode. The comparison which was made in this study demonstrates which system leads to an efficient conversion and supply of energy and exergy. In the analysis, four balance (mass, energy, entropy and exergy) equations are applied to the system for the two modes. Exergy and energy efficiency values for both systems are given, while exergy destructions in each of the systems are determined and presented. It is seen that the heat pump unit which has the highest COP value is the air to air type (3.45-3.8); second is the air to water type (3.35-3.41). The exergy efficiency of the air to air heat pump (29-32%) is higher than the exergy efficiency of the air to water type heat pump (24.1-25). Ranking of the exergy destruction rates of the two heat pump types from high to low is as follows: air to air and air to water.
AtıfScopus5OpenAlex5İncele
