Inland Dredging v. Sanchez United States Court of Appeals for the 5th Circuit 468 F.3d 864 (Decided October 27, 2006)

Sıcaksu tanklarında hem depolama kapasitesini yükseltmen hem de tanktan eldeedilebilecek sıcak su miktarını arttırmak için kullanılabilecek en elverişliyöntemlerden biri tank içerisine faz değiştiren malzeme yerleştirmektir. Buçalışmada 450 litrelik bir düşey mantolu sıcak su tankının içerisine fazdeğiştiren malzeme olarak parafinin kapsüller içerisinde yerleştirilmesindekapsül hacminin etkisi deneysel olarak araştırılmıştır. Kapsüller, toplam hacmi65 litre ve kapsül içerisindeki parafin miktarı 32.5 kg olacak şekilde 5, 3 ve1 litrelik kapsüllerde tank içerisine yerleştirilmiştir. İçerisinde kapsülolmayan normal tank testi ile beraber toplam 4 farklı deney yapılmıştır. Herbir deney iki defa tekrarlanmıştır. Yapılan deneylerin sonucunda; içerisinesilindirik kapsüller içerisinde parafin yerleştirilen bir düşey mantolu sıcaksu tankında tanktan maksimum miktarda sıcak su elde etmek için parafinlerindüşük hacimli kapsüller içerisinde yerleştirilmesi gerektiği görülmüştür.Normal tanktan 490 litre sıcak su elde edilirken, 5 litrelik kapsülkullanılması durumunda 590 litre, 3 litrelik kapsül kullanılması durumunda 620litre ve 1 litrelik kapsül kullanılması durumunda ise 670 litre sıcak su eldeedilmiştir.In hot water tanks, one of the most convenient methodsfor increasing the storage capacity and increasing the amount of hot water thatcan be obtained from the tank is to place phase change material in the tank. Inthis study, the effect of capsule volume on the placement of paraffin as aphase changing material in a 450-liter vertical mantle hot water tank wasinvestigated experimentally. The capsules were placed in 5, 3 and 1-litercapsules with a total volume of 65 liters and the amount of paraffin in thecapsule was 32.5 kg. A total of 4 different experiments were performed withnormal tank test without capsules. Each experiment was repeated twice. As aresult of the experiments; it has been found that in a vertical mantle hotwater tank in which paraffin is placed in cylindrical capsules, the paraffinmust be placed in low volume capsules to obtain the maximum amount of hot waterfrom the tank. While 490 liters of hot water were obtained from the normal tank,590 liters were used in the case of 5-liter capsules, 620 liters in the case of3-liter capsules and 670 liters of hot water in the case of 1-liter capsules.</p

Effect of circular plates placed in the hot water storage tank on thermal stratification

&lt;!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:14.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US;} p.MsoBodyText3, li.MsoBodyText3, div.MsoBodyText3 {margin:0cm; margin-bottom:.0001pt; text-align:center; mso-pagination:widow-orphan; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} p.zetmetni, li.zetmetni, div.zetmetni {mso-style-name:"&Ouml;zet metni"; margin-top:6.0pt; margin-right:0cm; margin-bottom:0cm; margin-left:0cm; margin-bottom:.0001pt; text-align:justify; mso-pagination:widow-orphan; font-size:11.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-fareast-language:EN-US; font-style:italic; mso-bidi-font-style:normal;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&gt; Silindirik sıcak su depolama tankı i&ccedil;erisine dairesel plakanın f/H ve g/D oranlarında yerleştirilmesinin ısıl tabakalaşma &uuml;zerine etkisi sayısal ve deneysel olarak araştırılmıştır. Silindirik sıcak su depolama tankı modelleri, ortasına g/D oranlarında delik a&ccedil;ılmış dairesel plakaların f/H oranlarında tank i&ccedil;erisine yerleştirilmesi ile oluşturulmuştur. Depolama tankının i&ccedil;erisine yerleştirilen dairesel plakalar ile tankın &uuml;st kısmındaki sıcak su ile alt kısmındaki soğuk suyun birbirleri ile karışması &ouml;nlenmiş ve tank i&ccedil;erisinde bulunan sıcak suyun ısıl tabakası korunmuştur. Burada H ve D sırası ile tankın y&uuml;ksekliği ve &ccedil;apı, f tankın taban y&uuml;zeyinden dairesel plakaya olan mesafe ve g ise dairesel plakaya a&ccedil;ılan deliğin &ccedil;apıdır. Isı depolamak i&ccedil;in kullanılan sıcak su depolama tankı g&uuml;neş enerjisi uygulamaları i&ccedil;in d&uuml;ş&uuml;n&uuml;lm&uuml;şt&uuml;r. Fakat bu &ccedil;alışmada suyun ısıtılması işlemi g&uuml;neş enerjisi ile değil de, ısıtma tankında bulunan elektrikli ısıtıcı ile yapılmıştır. Bu analiz s&uuml;reklilik, momentum ve enerji eşitliklerinin &uuml;&ccedil; boyutlu zamana bağlı durumu dikkate alınarak yapılmıştır. Sayısal &ccedil;alışmanın ge&ccedil;erliliği deneysel olarak da ispatlanmıştır. Sayısal sonu&ccedil;ların elde edilmesinde FLUENT paket programı kullanılmıştır. Tank i&ccedil;erisindeki sıcaklık değerlerinin g&ouml;r&uuml;n&uuml;m&uuml;, sıcaklık ve sıcaklık farkı dağılımları, &ccedil;eşitli f/H ve g/D oranlarında ve zamana bağlı olarak şekiller ve grafikler &uuml;zerinde g&ouml;sterilmiştir. Sonu&ccedil;lar; tank i&ccedil;erisine yerleştirilen dairesel plakanın ısıl tabakalaşmayı iyileştirdiğini ve bunun sonucunda da, engelsiz tank durumuna g&ouml;re, tanktan sağlanan kullanım suyu sıcaklığını arttırdığını g&ouml;stermektedir. En iyi ısıl tabakalaşma dairesel plakanın tank i&ccedil;erisine g/D=0.2 ve f/H=0.133 oranlarında yerleştirilmesi durumunda elde edilmiştir. &nbsp; Anahtar Kelimeler: Depolama tankı, ısıl tabakalaşma, dairesel plaka. &nbsp;In this study, effect of f/H and g/D ratios of circular plates placed in a cylindrical hot water storage tank on thermal stratification is investigated numerically and experimentally. The tank model is designed by placing a circular plate in the tank with a hole in the center at f/H and g/D ratios. Here H and D are the height and diameter of the tank respectively, while f is the distance from the bottom surface of the tank to the circular plates and g is also the diameter of the hole on the plates. This cylindrical hot water storage tank used to store heat for solar collector application is considered. The most commonly use of solar energy is the solar collector used for water heating. A hot water tank is used for storing part of the solar energy collected by the solar collector for later use. But in this study, the water remaining in the storage tank is heated by the heater tank with an electrical heater placed inside.  As soon as hot water is drawn from the tank, cold tap water flows into the tank mixing with the remaining hot water, and therefore lowering the water temperature in the tank. This is an undesirable result. In this study, a solar hot water storage tank with a circular plate placed inside is considered and optimum plate dimensions are searched to minimize the mixing of hot and cold water so that water may be supplied at higher temperatures. This analysis is based on unsteady, three- dimensional continuity, momentum and energy equations. The governing equations are used to determine the temperature and velocity distributions in the flow field by using boundary and initial conditions. The thermodynamic properties of the water are considered in this study. The velocity is assumed to be zero at the beginning. The operation pressure in the tank is taken 1 atmosphere and the hot water temperature is assumed to be 335 K when the water usage started. The temperature and velocity of water supplied by the heater tank are taken 335 K and 0.8 m/s and these of cold tap water entering the tank are taken 290 K and 0.6 m/s, respectively. The time between the water is started to be used and the water usage was finished is assumed as calculation region. This time is taken as 30 minute and the problem was solved unsteady. The velocity and temperature distributions inside the tank were obtained by using FLUENT computer code. Three dimensional unsteady solutions are taken by using implicit method in segregated solver. The discretization is achieved by using Standard method for pressure and by using first upwind method for momentum, energy and continuity equations. The SIMPLE (semi-implicit method for pressure-linked equations) algorithm was used for flow calculations. A numerical investigation of optimizing dimensions of a plate placed in a hot water tank for thermal stratification is performed. A first observation of temperature distributions in the tank indicates that placing plate in the tank improves thermal stratification compared with no plate case. It appears that increasing f/H ratio increases temperature of stratified region whereas decreasing the volume of this region. In another words, increasing f/H decreases the amount hot water that can be taken from the tank. Increasing g/D ratio decreases the temperature of stratified region, and therefore, smaller values of g/D are desirable Temperature distributions in the tank, water temperature supplied by the tank, water temperature going to collector, various water temperature differences between tank outlet and inlet and appearance of the temperature values in the tank are shown on the graphs and figures for various f/H and g/D ratios and according to time. For higher thermal stratification, the temperatures T3 and T2 should be high and T1 should be low. In another words, the differences T3-T1 and T2-T1 should be as high as possible. An investigation of effects of g/D and f/H ratios of plate dimensions on these temperature differences shows that the best thermal stratification can be obtained for a g/D ratio of 0.2 and an f/H ratio of 0.133 among considered cases. Using circular plates in hot water storage tanks improves thermal stratification in the tank and consequently increases the temperature of hot water supplied by the tank. It also decreases the temperature of water supplied to the collector, and thus improving collector efficiency.   Keywords: Storage tank, thermal stratification, circular plate

Experimental investigation of phase change material utilization inside the horizontal mantled hot water tank

Sensible thermal energy storage and hot water tanks are an important issue for solar thermal application in hot water usage. Hot water tanks are commonly used in solar domestic hot water systems. There are many types and classicifation for hot water tanks. However, the main classification is related to position of the tank which are horizontal and vertical. There is a limited number of studies which are related to horizontal mantled hot water tank. There is no clear study using phase change material in horizontal mantled hot water tank. This study deals with process of storing latent heat in horizontal mantled hot water tanks. Effect of paraffin amount on thermal energy storage in horizontal mantled hot water tanks was determined experimentally. A commercial horizontal mantled hot water tank model was used. At the end of study, it was found that using paraffin inside the hot water tank increases the thermal energy storage capacity. However, the amount of obtained hot water did not increase proportionally with the increase of the amount of paraffin because, the volume of tank is constant, and the water volume was reduced with increasing the paraffin volume. Stored energy in the paraffin was not transferred to water. Temperature of the water did not increase to desired level. The optimum paraffin amount was found as 4 liters.</p

Düzlemsel Güneş Kolektörlerinin Panel Yapılarının Sıcak Su Üretimine Etkisinin İncelenmesi

Bu &ccedil;alışmada, d&uuml;zlemsel g&uuml;neş kolekt&ouml;rlerinde ısıtılan suyun dolaştığı panellerin, geometrik yapılarına ve borularda dolaşan akışkan hızına bağlı olarak, akışkanı ısıtma kabiliyeti incelenmiştir. Kolekt&ouml;r panellerinde suyun dolaşım şekline g&ouml;re, yaygın kullanılan iki farklı panel tipinin &uuml;lkemiz ışınım şartlarına uygunluğu incelenmiştir. İncelenen panel tiplerinin ilki, &uuml;lkemizde yaygın kullanılan alt ve &uuml;st kısımda b&uuml;y&uuml;k &ccedil;aplı borulardan oluşan ve manifold denilen borular ile bunları birbirine bağlayan k&uuml;&ccedil;&uuml;k &ccedil;aplı borulardan oluşan tek borulu panel tipidir. İkincisi, d&uuml;ş&uuml;k &ccedil;aplı bir borudan oluşan ve bu borunun panel &uuml;zerinde &ccedil;ok sayıda S&rsquo;ler oluşturarak yerleştirildiği tiptir. Bu &ccedil;alışmanın kapsamında her iki panel yapısı i&ccedil;in farklı ışınım ve akışkan hızı değerleri i&ccedil;in suyun kolekt&ouml;rden &ccedil;ıkış sıcaklıkları hesaplanmıştır. Hesaplamalar sonucunda tek borulu panel yapısındaki kolekt&ouml;rlerin, T&uuml;rkiye gibi y&uuml;ksek ışınım değerlerine sahip &uuml;lkelerde kullanılması uygun olmadığı g&ouml;r&uuml;lm&uuml;şt&uuml;r. Panelde dolaşan su kısa s&uuml;rede buhar haline gelmektedir. Bu durum, d&uuml;ş&uuml;k kolekt&ouml;r verimine ve sağlık a&ccedil;ısından olumsuzluklara sebep olabilmektedir.&nbsp;In this study, ability of heating water depends on panel types which are water circulating in them and velocity of the fluid. According to type of the water cycling, flat-plate solar collectors which are two different panel types were determined whether suiting to use for our country climate and radiation conditions. The first type of collectors which are taken into account is the panel type which is widely used in our country, formed by many small-diameter pipes which connect the large diameter pipes called manifold at the lower and upper parts. The second type is made of a low diameter pipe and this pipe is placed on the panel, creating S shape. In this study, water temperatures were calculated for each two panel structure. As the result of calculations, it was determined that collectors with single tube-low diameter structure&nbsp; can cause adverse health consequences and low collector efficiency in the region or countries such as Turkey which has high radiation and water temperature, due to the conversion of circulating water into steam in a short time.</p

NUMERICAL INVESTIGATION ON EFFECT OF INLET AND OUTLET POSITIONS ONTHERMAL STRATIFICATION IN VERTICAL HOT WATER TANK

Mantled hot water tanks are used commonly in solardomestic hot water systems (SDHWS). There are three maininlet and outlet port models for mantled tanks. These areordinary, single-piped and double-piped. These types generallyhave been selected according to their cost and easy productionby manufacturer. However these inlet and outlet port hasimportant effect on thermal stratification. In present study effectof the inlet and outlet ports of mantled hot water tanks onthermal stratification has been investigated numerically. As aresult, double-piped system has supplied better thermalstratification, better energy and better exergy amount inside thetank.</p

Developments of Solar Energy Industry and Utilization in Turkey

Solar Energy has become an industry sector since end of the 1970s in Turkey. Although there are many applications of solar energy, recently thermal applications and PV electricity have taken over in among solar energy applications. In Turkey, although thermal applications have taken over, manufacturing and utilization of solar thermal systems have been decrease from 2004 to 2010. In 2010 and 2011 years, it has been increased. It is thought that because of natural gases prices and some encouragement, this increasing and decreasing occur. In this study, it is given the knowledge that development about thermal applications of solar energy in Turkey and around the world

Improved thermal stratification with obstacles placed inside the vertical mantled hot water tanks

Thermal stratification is a significant performance parameter for thermal energy storage tanks. In present study, the thermal stratification of vertical mantled hot water tank was investigated by placing different obstacle inside the tank. Four different obstacles were placed inside the tank in four different distances from the tank bottom. Thus effects of the obstacle types and positions were investigated. At the end of study, it was found that obstacle placed inside the tank enhanced the thermal stratification. Results were presented in the terms of temperature distribution, energy storing capacity, Richardson Number, consumption outlet and mantle outlet temperature. All these values were improved by placing the obstacle inside the tank, according to ordinary tank. The best thermal stratification was obtained between Y= 200 and Y=300 mm the distance from the tank bottom. A type obstacle supplied the best thermal stratification. (C) 2016 Elsevier Ltd. All rights reserved