Sürdürülebilir Kalkınma Amaçları
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- MakaleAçık Erişim2021Osmotic Dehydration Applications in Meat
Kantar, Naciye Kutlu; Kamiloğlu, Aybike; Elbir, Tugba
Osmotic dehydration is a non-thermal, partial drying process applied for the removal of water in food products, as well as for the absorption of various solutes (salt, sugar, etc.). In the osmotic dehydration process, the food material is immersed in a high concentration solution to obtain a final product with lower water activity. However, since the final products with very low water activity cannot be obtained with osmotic dehydration, this method is applied as a pretreatment. The water loss in the product takes place in a shorter time with the osmotic dehydration process applied before drying. The most effective factors on osmotic dehydration are the type of osmotic agent, concentration, process temperature, process time and sample/solution ratio. The low process temperature in osmotic dehydration prevents the loss of color and aroma in food products and contributes the functional, nutritional and sensory properties of products. In addition, the fact that it is a very economical process and does not pose any negative effects in terms of human health makes the method advantageous. In this review, when the osmotic dehydration process is used as a pretreatment in meat processing, the effects on the quality characteristics of the product were mentioned. It has been determined that osmotic dehydration used in various meats (chicken, pork, beef, lamb, ostrich meat and a wide variety of seafood) improves many quality parameters such as color and sensory properties and shelf life of the products. Dried meat with better texture were obtained with the use of specific osmotic agents. It is also recommended to use osmotic dehydration in combination with some applications such as ultrasound or high pressure for effective drying of meat. It was determined that osmotic dehydration process used before convective drying significantly reduced the drying time of meat.
AtıfTR Dizin1
İncele - MakaleYalnız künye2017Exergy Analyses of Half-Effect, Single-Effect and Double-Effect Absorption Cooling Cycles
Karaali, Rabi
This work presents exergy and energy analysis of a half effect parallel flow, single effect and double effect absorption systems for comparison. For the thermodynamic properties of lithium bromide-water solutions a computer program is developed by the author in FORTRAN codes for th e energy and exergy analysis. It is found that the coefficient performance (COP) and the exergetic coefficient performance (ECOP) of the double effect parallel flow absorption systems are higher than the single effect and the half effect cycles. For the do uble effect cycle COP and ECOP are found as 1.196 and 0.284, and for the single effect cycle COP and ECOP are found as 0.68 and 0.254, respectively. For the half effect cycle COP and ECOP are found as 0.455 and 0.24, respectively. The exergy loss is calculated for each component. Most of the irreversibilities are found in the evaporator and in the absorber. It is concluded that the performance of the absorber and the evaporator is crucial for the three cycles. Improving and better design of the evaporator and the absorber will directly affect positively and improve the performance and the working conditions of the three cycles
- MakaleYalnız künye2017Scopus SJRQ3Gaz türbinli kojenerasyon tesislerinin performans analizleri
Karaali, Rabi; Öztürk, İlhan Tekin
In this study, some improving methods of gas turbine cogeneration cycles are applied on a simple cogeneration cycle. These methods are preheating air, preheating air and fuel, inlet air cooling by using evaporative cooling and absorption cooling. These cogeneration systems are evaluated with respect to energy efficiency (energy utilization factor), exergetic efficiency, electric and heat power, electric-heat energy rate, artificial thermal efficiency and fuel energy saving ratio and are compared with each other. In these analyses, the thermodynamic parameters such as compressing ratio, air and fuel mass ratio and compressor inlet temperatures of the cycles are used. It is concluded that these parameters can be listed from most effective to least effective as air fuel ratio, pressure ratio and compressor inlet temperature. It is also concluded that the most efficient cycle is found to be the air-fuel preheated cycle for obtaining more electric power and less heat power, and the simple cycle is the most suitable one for obtaining more heat power and less electric power
AtıfTR Dizin1İncele - MakaleYalnız künye2017Hava sızdırmazlığının konvansiyonel pencerelerin ortalama ısıl yalıtım performansındaki rolü
Cuce, Erdem
Binalarda yapı elemanlarının ısıl direnç yeteneklerinin iyileştirilmesi ve yapı elemanlarından gerçekleşen enerji kayıplarında ciddi bir role sahip olan hava sızdırmazlığının maliyet etkin yöntemlerle minimize edilmesi güncel düşük/sıfır karbon bina standartlarının yakalanabilmesi açısından büyük önem arz etmektedir. Bina yapı elemanları arasında pencereler infiltrasyon esaslı ısı kayıplarına hatırı sayılır ölçüde etki ederler. Cam yüzeylerden gerçekleşen infiltrasyon kaynaklı ısı kayıpları özellikle eski pencerelerde ve özensizce gerçekleştirilen montajlarda azımsanmayacak değerlere ulaşabilmektedir. Literatürde hava sızdırmazlığının konvansiyonel pencerelerden olan enerji kayıplarına etkisini belirlemeye yönelik bazı teşebbüsler olmasına rağmen, elde edilen sonuçlar arasında pek çok çelişkiler mevcuttur. Bu yüzden bu araştırmada, hava sızdırmazlığının konvansiyonel hava dolgulu çift camlı pencerelerin ortalama ısı transfer katsayısına (U-değeri) olan etkisi kapsamlı bir deneysel çalışma ile incelenmektedir. Testler Nottingham'da bulunan ve konvansiyonel hava dolgulu çift camlı pencerelerle restore edilmiş karakteristik Birleşik Krallık mimarisine sahip bir konutta gerçekleştirilmektedir. Konuttaki pencerelerden bir tanesi ısıl yalıtım testlerine tabi tutulmaktadır. Test penceresinin bir kanadı mükemmel hava sızdırmazlığı temin eden özel saydam bir örtü ile ön yüzeyden kaplanırken, diğer pencere kanadı sıradan durumu temsil edecek şekilde olduğu gibi bırakılmaktadır. Ölçümler Nisan 2016'da yapılmakta ve dinamik co-heating test metodu ile hava sızdırmaz pencere kanadının U-değerindeki iyileşme miktarı değerlendirilmektedir. Elde edilen sonuçlara göre, hava sızdırmazlığı ve saydam örtü ile hava sızdırmaz pencere kanadının iç cam yüzeyi arasında oluşan sera etkisine bağlı olarak özellikle gündüz saatlerinde etkisi belirginleşen ters ısı akıları neticesinde, hava sızdırmaz pencere kanadının ortalama U-değeri sıradan pencere kanadına göre kayda değer ölçüde düşük çıkmaktadır. Sıradan pencere kanadının ortalama U-değeri 2.67 W/m2K iken, hava sızdırmaz pencere kanadının ortalama U-değeri 1.79 W/m2K olarak belirlenmektedir. Buradan hareketle, hava sızdırmazlığı temin edilen konvansiyonel pencerelerde enerji kayıplarının %33 mertebesinde azaltılabileceği sonucuna varılmaktadır.
AtıfTR Dizin1İncele - MakaleAçık Erişim2017Exergetic Comparison of Single and Double Effect Absorption Cooling Cycles
Karaali, Rabi
Absorption cooling cycles are environmental and can use solar or waste heat for cooling with very small electric power. This workpresents exergy analysis of a double effect parallel flow and single effect absorption cooling systems for comparison. A computerprogram is developed for the thermodynamic properties of lithium bromide-water solutions by the author in FORTRAN codes forthe exergy analysis. The double effect parallel flow absorption systems have better advantages than the single effect absorption system.The coefficient performance (COP) and the exergetic coefficient performance (ECOP) of the double effect parallel flow absorptionsystems are higher than the single cycles. For the double effect cycle COP and ECOP are found as 1.195 and 0.28, and for the singleeffect cycle COP and ECOP are found as 0.68 and 0.23, respectively. For each component the exergy loss and exergy destruction iscalculated. Most of the irreversibilities are found in the evaporator and in the absorber which about 74 % for the double effect, and 72% for the single effect of the total irreversibility. It is concluded that the performance of the evaporator and the absorber is crucial forthe two cycles. Improving and better design of these two components will directly improve and affect positively the working conditionsand the performance of the cycles.
- Proje2016Biyobozunur Katı Atık Tesislerinin Termodinamik, Termoekonomik Analiz Ve Optimizasyonları Çerçevesinde Yenilenebilir Enerji Potansiyellerinin Araştırılması Ve Sıfır Atık Yaklaşımıyla Sürdürülebilir Modellerin Geliştirilmesi
Abuşoğlu, Ayşegül; Özahi, Emrah; Tozlu, Alperen
In this study, thermodynamic and thermoeconomic analysis are performed using actual operating data of the Gaziantep Solid Waste Power Plant in Gaziantep. ASPEN Plus Engineering and Engineering Equation Solver (EES) software programs are used in order to analyze the current system thermodynamically. Energetic and exergetic efficiencies of the system are evaluated as 39.57 % and 56.29 %, respectively. Thermoeconomic analyses are performed by using "specific exergy costing" (SPECO) method and the payback period is found to be 5.82 year according to the analyses. In additition, five different scenarios are carried out for the purpose of energy recovery from the exhaust gas of the system and thermodynamic and thermoeconomic analyses of scenarios are also carried out. Scenario 2 (Electricity production using gas turbine cycle) is found to be the optimal scenario which can be integrated into the system in terms of the thermodynamic and thermoeconomic analyses. As a result of the thermodynamic analyses of scenario 2, energetic and exergetic efficiencies are found to be 47.16 % and 61.83 %, respectively. Also, 1287 kW extra power can be produced using second scenario which has a short payback period of 3.7 year. By means of these proposed scenarios and conducted analyses, the first study for solid waste power plant in Turkey is carried out in detail. This detailed study is conducted for the first time that related to solid waste power plants in Turkey with proposed scenarios and performed analyses. In addition to this, the other novelty of this study is to assess the proposed scenarios in the project for other solid waste power plants in Turkey in the frame of zero waste.
- MakaleYalnız künye2015Thoermodynamic Analyses of Steam Injected Gas Turnine Cogeneration Cycles
Karaali, Rabi; Öztürk, İlhan Tekin
In this study, air preheating, air-fuel preheating and simple cycles where steam injected in to combustion chamber are analyzed. The effects of steam injection on thermodynamic performance are calculated and obtained for the three different gas turbine cogeneration systems. Simulation programs written by the authors in FORTRAN code are obtained for the analyses by applying the first law of thermodynamics and the exergy analysis method. Thermodynamic performance of these three different cycles for variable mass of injected steam and different stages are obtained and compared with the results of the literature. The effects of injection steam into combustion chambers of those three cycles for variable compressing ratios, on power, efficiencies and performance are obtained. Consequently, the advantages and the disadvantages of injection steam are evaluated and all results of this study are compared with the literature. Injection steam into combustion chamber increases the electricity power and the electricity efficiency but decreases the heat power of the cycles.