Investigation of drying behavior of Granny Smith apple in a novel solar drier

Tarımsal ürünlerin kurutularak dayanaklığının arttırılması ve kalitenin yükseltilmesi yöntemi, ilk çağlardan beri uygulanmakta olan en eski ve en yaygın gıda saklama yöntemidir. Kurutma işlemi, direk güneş altında açık sergi yöntemi ile yapılabileceği gibi teknik ekipmanlar ve metotlar kullanılarak da yapılabilir. Bu çalışmada, yeni tip bir kabin tasarımına sahip güneş enerji destekli kurutucuda kurutulan Granny Smith elmanın kuruma performansı deneysel olarak incelenmiştir. Çalışmada ayrıca deneylerden elde edilen verilerle belirlenen nem oranı (MR) için matematiksel ve Gauss Proses Regresyonu (GPR) kullanılarak tahminsel modeller oluşturulmuştur. İki gün kesintisiz devam eden kurutma işlemi sırasında sıcaklık, nem ışınım ve ağırlık gibi farklı parametreler ölçülmüştür. Deneyler sonucunda; ürünlerin kuruma davranışının iklim şartlarına bağlı olarak değiştiği görülmüştür. İlk ürün ağırlığı 1400 gr olan Granny Smith elmalardan iki günlük deney sonucunda yaklaşık 1100 gr nem çekilmiştir. Yapılan hesaplamalar sonucunda, kurutulan elma dilimlerinin ortalama kuruma hızı 0,0017 (grsu/grkm)/dk, en yüksek kuruma hızı ise 0,0094 (grsu/grkm)/dk olarak tespit edilmiştir. MR için matematiksel olarak oluşturulan ince tabaka kuruma modelleri arasında en iyi tahmin Sigmoid matematiksel modeli ile elde edilmiştir. MR’nin dört farklı GPR yöntemi ile tahmin edilmesinin sonucunda ise en iyi yakınsamanın Experimental GPR’de olduğu görülmüştür.The method of increasing the durability and increasing the quality by drying agricultural products is the oldest and most common food storage method that has been applied since ancient times. Drying can be done under direct sunlight by open exhibition method or by using technical equipment and methods. In this study, the drying performance of Granny Smith apple dried in a solar energy assisted dryer with a novel type of cabinet design was experimentally investigated. In the study, mathematical and predictive models were created using Gaussian Process Regression (GPR) for moisture ratio (MR) determined by the data obtained from experiments. During the uninterrupted drying process for two days, different parameters such as temperature, humidity, radiation and weight were measured. As a result of the experiments; It has been observed that the drying behavior of the products changes depending on the climatic conditions. Approximately 1100 g of moisture was removed from Granny Smith apples with a product weight of 1400 g after two days of experiment. As a result of the calculations, the average drying rate of apple slices was determined as 0,0017 (grw/grdm)/min, and the highest drying rate was determined as 0,0094 (grw/grdm)/min. Among the mathematically generated thin layer drying models for MR, the best estimate was obtained with the Sigmoid mathematical model. As a result of the estimation of MR by four different GPR methods, it was seen that the best convergence was in Experimental GPR

Thin layer drying of zucchini in solar dryer located in Osmaniye region

In this study, the dehydration behavior of zucchini using solar assisted drying system was examined according to 22 thin layer drying models available in literature. The correlation coefficient (R2), chi-square (χ2) and root mean square error (RMSE) values were calculated to check the suitability of models by non-linear regression analysis. It was found that Cubic and Modified Midilli-1 models were the most suitable equations and their R2 values were calculated as 0.99963. χ2 and RMSE values of related mathematical expressions were 1.89343×10‒5, 1.91692×10‒5 and 0.01685×10‒3, 0.01721×10‒3 respectively. In addition, heat transfer, mass transfer and diffusion coefficients, which were important parameters in design of drying systems were also determined as 5.18124 W/m2°C, 1.57129×10‒7 m/s and 2.335718×10‒9 m2/s respectively

Hygrothermal simulation-informed design of mesoporous desiccants for optimised energy efficiency of mixed mode air conditioning systems

This paper describes an optimization technique using hygrothermal numerical modelling to determine an ideal and unknown isotherm in order to inform the design of optimised mesoporous desiccants. Their suitability for passive humidity buffering as well as their impact on energy efficiency was assessed when assisting a mixed mode air-conditioning (AC) system. Three clear stages of water vapour adsorption were found that strongly correspond to the Dw gradient when assessing the kinetics of adsorption and exchange rates for periodic moisture loads. Consistent agreement was found between the latent heat of dehumidification used by the AC system and the desiccant decay time after successive sorption loop cycles. This confirmed the material's suitability for specific applications and was found to be highly sensitive to the portion of the isotherm between φi,L - φi,U (Dw gradient), compared with full adsorption capacity (total w) when assessing total energy consumption. The experimental results of sorption kinetics appeared to be slightly underestimated between the Dw gradient and the response time to reach equilibrium moisture content (EMC). The major underestimations were found to be consistent with the kinetics of adsorption/desorption when analysing their significance based on w differences. These were largely attributed to a combination of adsorption kinetics (time-response) and adsorption/desorption hysteresis. However, this was not evident when comparing long-term experimental data and numerical estimations for water vapour sorption isotherms, since numerical model accurately predicted them. This suggests that both adsorption kinetics and the scanning curve prediction, within a hysteresis loop, are not accurately represented by current hygrothermal models and are hence a priority for future research

Solar pond powered liquid desiccant evaporative cooling

Liquid desiccant cooling systems (LDCS) are energy efficient means of providing cooling, especially when powered by low-grade thermal sources. In this paper, the underlying principles of operation of desiccant cooling systems are examined, and the main components (dehumidifier, evaporative cooler and regenerator) of the LDCS are reviewed. The evaporative cooler can take the form of direct, indirect or semi-indirect. Relative to the direct type, the indirect type is generally less effective. Nonetheless, a certain variant of the indirect type - namely dew-point evaporative cooler - is found to be the most effective amongst all. The dehumidifier and the regenerator can be of the same type of equipment: packed tower and falling film are popular choices, especially when fitted with an internal heat exchanger. The energy requirement of the regenerator can be supplied from solar thermal collectors, of which a solar pond is an interesting option especially when a large scale or storage capability is desired

Application of evaporative cooling to comfort air-conditioning

TEZ4585Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 2003.Kaynakça (s. 68-69) var.x, 69 s. ; res. ; 30 cm.

Desisif soğutma ile iklimlendirme.

TEZ9104Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2010.Kaynakça (s. 129-134) var.xvii, 156 s. : res. (bzs. rnk.), tablo ; 29 cm.Bu çalışmada, nem almalı bir iklimlendirme sistemi tasarlanıp kurulmuş ve test edilmiştir. Sistemde, iklimlendirilen mahale gönderilen taze hava, önce bir nem alıcı üzerinden geçirilerek nemi düşürülmekte ve daha sonra buhar sıkıştırmalı bir soğutma çevrimiyle soğutulan suyun kullanıldığı “kuru serpantin” üzerinden geçirilerek sıcaklığı düşürülmektedir. Sistemin performansını artırmak için, dış havayla ön soğutma, atık soğu geri kazanımı ve atık havanın buharlaştırmalı soğutma ile soğutulması gibi teknolojiler kullanılmaktadır. Yapılan deneylerden elde edilen sonuçlar kullanılarak sistemin enerji analizleri yapılmıştır. Ayrıca bu tür sistemlerin hastaneler gibi hijyenin önemli olduğu uygulamalar için yapılabilirliği, uygunluğu ve tasarım parametreleri araştırılmıştır.In this study, a desiccant based air-conditioning system was designed, constructed and tested. In the system, the moisture of the fresh air was reduced passing it through a solid desiccant wheel and then its temperature was decreased by the “dry coil” of a vapor-compression cycle. To enhance the performance of the system, some technologies such as “pre-cooling with outdoor air”, “waste cool recovery” and “pre-cooling of waste air with evaporative cooling” were utilized. Energy analyses of the system were performed by using the results obtained from the experiments. Design parameters and suitability of the system suggested were investigated for the health care facilities in which hygiene is crucially important

Bir tedarik zinciri için stokastik talep altında tedarikçi kontrolü ile envanter yönetimi.

Vendor Managed Inventory (VMI) is a business practice in which vendors monitor their customers’ inventories, and decide when and how much inventory should be replenished. VMI has attracted a lot of attention due to its benefits. In this study, we analyze the benefits of VMI in a supply chain consisting of a single retailer and a single capacitated supplier under stochastic demand. We propose a VMI setting and compare the vendor managed system with the traditional system to quantify the benefits of VMI. In our proposed VMI system, the retailer shares the inventory level information with the supplier, which is not available in traditional system; and the supplier is responsible to keep the retailer’s inventory level between the specified minimum and maximum values, called (z,Z) levels, set by a contract. We examine the benefits of such a VMI system for each member and for the overall chain; and analyze the effects of system parameters on these benefits. The performance of VMI in coordinating the overall chain is examined under different system parameters.M.S. - Master of Scienc

Energy Resources And Turkey S Geoenergetic Position

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2005Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2005Bu çalışmada, geleneksel (kömür, petrol ve doğalgaz), yenilenebilir (hidroelektrik, rüzgar, güneş, jeotermal, okyanus), alternatif (nükleer, füzyon) enerji kaynakları; ara enerji sistemi (hidrojen) ve güç üretim sistemleri (buhar türbini, gaz türbini, mikro türbin, içten yanmalı motorlar, yakıt pili) incelenmiştir. Bu enerji kaynaklarından elektrik ve ısı elde etme metotları detaylı bir şekilde açıklanırken, her bir enerji kaynağının potansiyeli, geleceği, ekonomisi, olumlu ve olumsuz çevresel etkileri üzerinde de durulmuştur. Dünya enerji platformu Amerika, Birleşik Krallık, Avrupa Birliği, Japonya ve gelişmekte olan ülkeler başlıkları altında incelenirken; ülkemizin enerji yönetimi açıklanmış, enerji kaynaklarımız hakkında detaylı bilgiler verilmiş, enerji alanında yapılması gerekli yatırımlar ve alınması gerekli önlemler sunulmuş ve güncel örneklerle bu düşünceler desteklenmiştir.In this study, conventional (coal, oil, natural gas), renewable (hydraulic, wind, solar, geothermal, ocean), alternative energy resources (nuclear, fusion); intermediate energy systems (hydrogen energy system), prime movers (steam turbine, gas turbine, micro turbine, reciprocating engines, fuel cells) were detailed. As electricity and heat production from these sources has been explained; potential, future, economy and positive and negative environmental affects of each resource illustrated. As world energy platform was searched under USA, UK, Japan, EU and developing countries, our country’s energy management has been clarified, our natural resources has been detailed, things to be done and steps to be made about energy sector was presented and recent examples has been given in order to support these ideas.Yüksek LisansM.Sc