Investigation of exergy ratios of a solar pond

In this paper, we present an experimental and theoretical investigation for exergetic assessment of a rectangular solar pond (with dimensions of 2 m × 2 m × 1.5 m) at various reference temperatures. The experimental solar pond was designed and built at Cukurova University in Adana, Turkey. The system was filled with salty water to form three zones (namely, Upper Convective Zone (UCZ), Non-Convective Zone (NCZ), and Low Convective Zone (LCZ)) accordingly. A data acquisition device was used to measure the temperatures hourly at various locations in the pond. An exergy model was developed to study the exergetic performance of the pond for its three zones in terms of exergy efficiencies. The lowest and highest reference environment temperatures for various days in the months were considered. The results show that the efficiency ratios of the LCZ are found to be higher than the corresponding the NCZ and also the UCZ. © Springer International Publishing Switzerland 2014

Investigation of hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resources

In present study, hydrogen production performance of chlor-alkali cell integrated into a power generation system based on geothermal resource is studied. The basic elements of the novel system are a separator, a steam power turbine, an organic Rankine cycle (ORC), an air cooled condenser, a saturated NaCl solution reservoir tank and a chlor-alkali cell. To enhance the performance of the cell, the saturated NaCl solution is heated by the waste heat from the ORC. So, this integrated system generates significant amount of electricity for the city grid and also yields three main products those are hydrogen, chlorine and sodium hydroxide. According to the parametric study, when the temperature of a geothermal resource varies from 140 to 155 °C, the electrical power generation increases from nearly 2.5 MW to 3.9 MW and hydrogen production increases from 10.5 to 21.1 kg-h. Thus, when the geothermal resource temperature of 155 °C, the energy efficiency of the system is 6.2% and the exergetic efficiency is 22.4%. As a result, the geothermal energy potential plays a key role on the integrated system performance and the hydrogen production rate. © 2018 Hydrogen Energy Publications LLCFEF2013YL42, FDK-2017-7005The authors acknowledge the support provided by University of Cukurova in Turkey (Grant Nos: FEF2013YL42 , FDK-2017-7005 )

Assessment of electricity and hydrogen production performance of evacuated tube solar collectors

In this work, a unified renewable energy system has designed to assess the electricity and hydrogen production. This system consists of the evacuated tube solar collectors (ETSCs) which have the total surface area of 300 m2, a salt gradient solar pond (SGSP) which has the surface area of 217 m2, an Organic Rankine Cycle (ORC) and an electrolysis system. The stored heat in the heat storage zone (HSZ) transferred to the input water of the ETSCs by means of an exchanger and thereby ETSCs increase the temperature of preheated water to higher level as much as possible that primarily affects the performance of the ORC. The balance equations of the designed system were written and analyzed by utilizing the Engineering Equations Solver (EES) software. Hence, the energy and exergy efficiencies of the overall system were calculated as to be 5.92% and 18.21%, respectively. It was also found that hydrogen generation of the system can reach up to ratio 3204 g/day. © 2018 Hydrogen Energy Publications LL

Investigation energy, exergy and electricity production performance of an integrated system based on a low-temperature geothermal resource and solar energy

In this work, energy, exergy and electricity generation performance of an integrated system was conceptually investigated by using Engineering Equation Solver (EES)under 200–1000 W/m2 solar irradiation interval. The system comprises evacuated tube solar collectors (EVTSCs)with the surface area of 100 m2, an organic Rankine cycle (ORC)and a low-grade geothermal resource. The EVTSCs were used to enhance the temperature of the low-grade water coming from the geothermal source. The calculations were carried out for three geothermal sources in Kula (63 °C), Saraycık (74 °C)and Turgutlu (86 °C), respectively. N-hexane, n-pentane and n-butane were selected as a working fluid in the ORC. It was determined that the selection of the working fluid affected the performance of the ORC. And also, the waste heat is extracted from the ORC were used efficiently for space heating. As a result, the overall energy and exergy efficiencies of the system and power generation of the ORC were seriously affected by enhancing the water temperature of the geothermal resources by EVTSCs. The maximum overall energy and exergy efficiencies of the system were calculated as to be 6.92% and 21.06% by using n-butane for the source in Turgutlu, respectively. The minimum overall energy and exergy efficiencies of the system were calculated as 0.32% and 2.19% by using n-hexane for the source in Kula, respectively. The maximum and minimum generated electricity were calculated as to be 19.46 kW and 0.6168 kW for the sources in Turgutlu and Kula, respectively. It was seen that the best performance of the system was found for n-butane compared to n-pentane and n-hexane. © 2019 Elsevier Lt

Performance analysis of a solar pond

In this contribution, we develop a theoretical solar pond in different geometries for the Adiyaman region in Turkey and analyze its performance assessment through energy efficiency. Some key parameters such as surface area, depth, densities of the layers, the thicknesses of the inner zones and the insulations of the walls to assess the solar pond are considered. In the parametric studies, the dimensions of the zones (e.g., upper convective zone, non-convective zone, and lowconvective zone) are varied to investigate their effects. Although the density and temperature gradient of the inner zones are considered similar to each other, the energy efficiencies of the storage zones become different due to varying dimensions of the pond. The shading area decreases by increasing the surface area of the inner zones. The amount of incoming solar energy to the upper surface is increased with the size of the solar pond. The energy efficiency of the solar pond is determined to be maximum (31.76 %) for case4a, and to be minimum (16.80 %) for case1b in August. As a result, through careful determination of the dimensions and insulation parameters, incoming solar radiation reaching the storage zone increases the energy efficiency of the solar pond. © Springer International Publishing Switzerland 2014

A preface to the special issue section on “The Second International Hydrogen Technologies Congress (IHTEC 2017), 15–18 March 2017, Adana, Turkey”

[No abstract available

Exergetic performance analysis of a solar pond

In this paper we present an experimental and theoretical investigation of the exergetic performance of a solar pond (with a surface area of 4 m2 and a depth of 1.5 m) which was built at Cukurova University in Adana, Turkey. The system was filled with salty water to form three zones (e.g., upper convective, non-convective and heat storage) accordingly. A data acquisition device was used to measure and record the temperatures hourly at various locations in the pond (distributed vertically within and at the bottom of the pond, and horizontally and vertically within the insulated side-walls). An exergy model is developed to study the exergetic performance of the pond and its three zones in terms of exergy efficiencies which are then compared with the corresponding energy efficiencies. The reference environment temperature is specified for exergy analysis as the average representative temperature of each month of the year (for example, it is taken as an average temperature of 28 °C for August). Thus, the highest energy and exergy efficiencies are found for August to be: 4.22% and 3.02% for the upper convective zone, 13.80% and 12.64% for the non-convective zone, and 28.11% and 27.45% for the heat storage zone, respectively. © 2007 Elsevier Masson SAS. All rights reserved.Natural Sciences and Engineering Research Council of CanadaThe authors acknowledge the support provided by Cukurova University in Turkey, and the Natural Sciences and Engineering Research Council of Canada in Canada

Exergy analysis of a solar pond integrated with solar collector

In this paper we present the energetic and exergetic performance of a solar pond integrated with four flat plate solar collectors. The integrated solar pond system was built and tested at Cukurova University in Adana, Turkey. The solar pond consists of salty water zones to prevent convection heat losses from the heat storage zone (HSZ) of the solar pond. The temperature distributions of the solar pond and the inlet-outlet of the heat exchanger were measured by using thermocouples and a data acquisition device. An energy and exergy models were developed to study the energetic and exergetic performance of the integrated solar pond. The energy and exergy performances were compared for the each zone of the solar pond. The reference environment temperature in the exergy analysis was specified as the average representative temperature of each month of the year. The energetic and exergetic performances of the integrated solar pond for the heat storage zone were found to be maximum 32.55% and 28.69% in August, and to be minimum 9.48% and 5.51% in January, respectively. © 2014 Elsevier Ltd.FEF2010BAP5The authors are thankful to University of Cukurova in Turkey for financial support of the present work (Grant No: FEF2010BAP5 )

The effect of sunny area ratios on the thermal performance of solar ponds

In this study, we investigated the effect of the sunny area ratios on thermal efficiency of model solar pond for different cases in Adiyaman, Turkey. For this purpose, we modeled the solar ponds to compute theoretical sunny area ratios of the zones and temperature distributions in order to find the performance of the model solar ponds. Incorporating the finite difference approach, one and two dimensional heat balances were written for inner zones and insulation side walls. Through, careful determination of the dimensions, insulation parameter and incoming solar radiation reaching the storage zone increased the efficiency of the solar pond. The efficiencies of the model solar pond were determined for case1a-2a-3a-4a to be maximum 14.93%, 20.42%, 23.51% and 27.84%, and for case1b-2b-3b-4b to be maximum 12.65%, 16.76%, 21.37% and 23.30% in August, respectively. With the increase of the sunny area ratio, the performance of the solar pond significantly increased. However, with the increasing rate of the surface area, performance increase rate decreased gradually. The results provide a strong perspective to determine the dimensions of the solar pond before starting the project of a solar pond. © 2014 Elsevier Ltd. All rights reserved

The daily performance of a solar pond integrated with solar collectors

The present study deals with heat storage performance investigation of integrated solar pond and collector system. In the experimental work, a cylindrical solar pond system (CSPS) with a radius of 0.80. m and a depth of 2.0. m and four flat plate collectors dimensions of 1.90 m × 0.90. m was built in Cukurova University in Adana, Turkey. The CSPS was filled with salty water of various densities to form three salty water zones (Upper Convective Zone, Non-Convective Zone and Heat Storage Zone). Heat energy collected by collectors was transferred to the solar pond storage zone by using a heat exchanger system which is connected to the solar collectors. Several temperature sensors connected to a data acquisition system were placed vertically inside the CSPS and at the inlet and outlet of the heat exchanger. Experimental studies were performed using 1, 2, 3 and 4 collectors integrated with the CSPS under approximately the same condition. The integrated solar pond efficiencies were calculated experimentally and theoretically according to the number of collectors. As a result, the experimental efficiencies are found to be 21.30%, 23.60%, 24.28% and 26.52%; the theoretical efficiencies to be 23.42%, 25.48%, 26.55% and 27.70% for 1, 2, 3 and 4 collectors, respectively. Theoretical efficiencies were compared with the experimental results and hence a good agreement is found between experimental and theoretical efficiency profiles. © 2012 Elsevier Ltd.The authors are thankful to University of Cukurova for financial support of the present work (Grant No. FEF2004BAP4, FEF2009D2, and FEF2010BAP5)