The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
Piotr Felinski - One of the best experts on this subject based on the ideXlab platform.
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effect of pcm application inside an Evacuated Tube Collector on the thermal performance of a domestic hot water system
Energy and Buildings, 2017Co-Authors: Piotr Felinski, Robert SekretAbstract:Abstract The article presents an analysis of the effect of PCM application inside an Evacuated Tube Collector on the characteristic operating parameters of a solar water heating system. The temperature of hot water inside the tank and the solar fraction in a domestic hot water system were determined for a typical meteorological year in the Polish city of Czestochowa. A methodology for determining the thermal performance of the Evacuated Tube Collector/storage unit was proposed. The charging efficiency of the Evacuated Tube Collector/storage in a range from 33 to 66% was obtained depending on the solar radiation intensity and the temperature of PCM. An application of latent heat storage (technical grade paraffin) inside the Evacuated Tube Collector allowed the delayed release of heat in the evening, when the intensity of solar radiation was insufficient. As a result, an increase in the temperature of hot water inside the tank was observed during the hot water peak loads in every characteristic period of a typical meteorological year. Furthermore, an Evacuated Tube Collector/storage improved the annual solar fraction in a domestic hot water system by 20.5% compared with the reference Evacuated Tube Collector without storage.
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effect of a low cost parabolic reflector on the charging efficiency of an Evacuated Tube Collector storage system with a pcm
Solar Energy, 2017Co-Authors: Piotr Felinski, Robe SekreAbstract:Abstract This paper presents a novel concept of using a phase change material (PCM) to store thermal energy directly within a heat pipe Evacuated Tube Collector equipped with a compound parabolic concentrator (CPC). The excellent insulating properties of Evacuated Tubes and the use of latent heat are significant advantages of a PCM integrated Evacuated Tube Collector/storage (ETC/S) over traditional solar water heaters. However, during the charge cycle of the ETC/S, direct solar radiation only reaches the exposed area of the Evacuated Tubes, which results in uneven heating of the PCM due to a lower energy input in the shaded area. This can be prevented by using a CPC to concentrate the solar radiation on the shaded area of the Evacuated Tubes, thereby raising the temperature of the PCM and quantity of stored heat. Therefore, a polished, thin aluminum sheet was used as low cost CPC with a concentration ratio of 1.2x. Technical grade paraffin with an onset melting temperature of 51.24 °C was used as the PCM. The results from this study showed that the application of the CPC caused the temperature of paraffin on the shaded side of the Evacuated Tubes to increase more rapidly, especially during and after melting of the paraffin. Furthermore, the use of a CPC in a PCM integrated ETC/S improved the average gross charging efficiency from 31% to 36% and the maximum charging efficiency from 40% to 49%.
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experimental study of Evacuated Tube Collector storage system containing paraffin as a pcm
Energy, 2016Co-Authors: Piotr Felinski, Robe SekreAbstract:This article presents a newly developed concept for Evacuated Tube Collector/storage (ETC/S) system containing a phase-change material (PCM). To serve as the PCM, commercial-grade paraffin was placed inside Evacuated Tubes equipped with heat pipes. Experiments were performed to assess the impact of paraffin application on the thermal performance of the ETC/S system. The use of paraffin extended the operating time of the solar thermal system by enabling the recovery of stored heat during the discharge cycle. In addition, the lower mean temperature of the heating medium compared with that in a conventional Evacuated Tube Collector (ETC) resulted in less heat loss from both the test stand piping and the ETC/S unit itself. Notably, it was possible to bring the temperature of the heating medium to a useful level (approx. 45 °C). The results also showed that in comparison with an ETC, the total amount of useful heat obtained from the paraffin-integrated ETC/S system was increased by 45–79%, depending on the mass flow rate of the heating medium during the discharge cycle.
Robe Sekre - One of the best experts on this subject based on the ideXlab platform.
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effect of a low cost parabolic reflector on the charging efficiency of an Evacuated Tube Collector storage system with a pcm
Solar Energy, 2017Co-Authors: Piotr Felinski, Robe SekreAbstract:Abstract This paper presents a novel concept of using a phase change material (PCM) to store thermal energy directly within a heat pipe Evacuated Tube Collector equipped with a compound parabolic concentrator (CPC). The excellent insulating properties of Evacuated Tubes and the use of latent heat are significant advantages of a PCM integrated Evacuated Tube Collector/storage (ETC/S) over traditional solar water heaters. However, during the charge cycle of the ETC/S, direct solar radiation only reaches the exposed area of the Evacuated Tubes, which results in uneven heating of the PCM due to a lower energy input in the shaded area. This can be prevented by using a CPC to concentrate the solar radiation on the shaded area of the Evacuated Tubes, thereby raising the temperature of the PCM and quantity of stored heat. Therefore, a polished, thin aluminum sheet was used as low cost CPC with a concentration ratio of 1.2x. Technical grade paraffin with an onset melting temperature of 51.24 °C was used as the PCM. The results from this study showed that the application of the CPC caused the temperature of paraffin on the shaded side of the Evacuated Tubes to increase more rapidly, especially during and after melting of the paraffin. Furthermore, the use of a CPC in a PCM integrated ETC/S improved the average gross charging efficiency from 31% to 36% and the maximum charging efficiency from 40% to 49%.
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experimental study of Evacuated Tube Collector storage system containing paraffin as a pcm
Energy, 2016Co-Authors: Piotr Felinski, Robe SekreAbstract:This article presents a newly developed concept for Evacuated Tube Collector/storage (ETC/S) system containing a phase-change material (PCM). To serve as the PCM, commercial-grade paraffin was placed inside Evacuated Tubes equipped with heat pipes. Experiments were performed to assess the impact of paraffin application on the thermal performance of the ETC/S system. The use of paraffin extended the operating time of the solar thermal system by enabling the recovery of stored heat during the discharge cycle. In addition, the lower mean temperature of the heating medium compared with that in a conventional Evacuated Tube Collector (ETC) resulted in less heat loss from both the test stand piping and the ETC/S unit itself. Notably, it was possible to bring the temperature of the heating medium to a useful level (approx. 45 °C). The results also showed that in comparison with an ETC, the total amount of useful heat obtained from the paraffin-integrated ETC/S system was increased by 45–79%, depending on the mass flow rate of the heating medium during the discharge cycle.
J Garcia - One of the best experts on this subject based on the ideXlab platform.
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profitability of a solar water heating system with Evacuated Tube Collector in the meat industry
Renewable Energy, 2019Co-Authors: J Garcia, Carlos Javier Porrasprieto, Rosa Maria Enavente, Maria Teresa Gomezvillarino, Fernando R MazarroAbstract:Abstract The meat sector generates millions of jobs and billions of euros in value-added every year. The meat industries have a high demand for hot water, very variable in temperature, volume required and time interval. This demand, with large volumes at temperatures above 80 °C, translates into significant energy bills and CO2 emitted to the atmosphere, given the limited use of renewable energy. The present study, adapted to the unique demand of meat industries, shows that the use of Solar Water Heating Systems (SWHS) with Evacuated Tube Collector can be profitable in a large number of locations and scenarios in Europe. The type of energy supply in the industry, together with the large differences in the price of energy sources in each country, drastically affect the size of solar installations, the reduction in annual energy consumption and the savings generated. In a medium-sized industry with energy demand close to 85000 kWh/year, investing in a SWHS in locations of high irradiation can reach profitability values of € 1.1 per € invested, paybacks under 9 years, supply of more than 50% of the energy needed, reduction of the annual energy bill over 40% and reduction of CO2 emissions higher than 15000 kgCO2/year.
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influence of required tank water temperature on the energy performance and water withdrawal potential of a solar water heating system equipped with a heat pipe Evacuated Tube Collector
Solar Energy, 2014Co-Authors: Carlos Javie Porrasprieto, Fernando R Mazarro, Victoria De Los Mozos, J GarciaAbstract:Abstract Hot water is a key demand of many industrial and domestic heating systems. This demand is, however, variable, both in terms of when hot water is needed, and the water temperature required. The present work examines the use of solar energy as an alternative means of producing hot water. A solar water heating system (SWH) with a heat pipe Evacuated Tube Collector (ETC) was designed, and the effect of the required tank water temperature (rTWT) on the energy performance of the system examined. The maximum quantity of withdrawable hot water was also determined. The results show that, as rTWT increases, the net energy that can be stored by the system falls, with differences of over 1000 W h m−2 d−1 between rTWTs of 40 °C and 80 °C at a solar radiation input of 8000 W h m−2 d−1 (system efficiency range 56–73%). This reduction is a consequence of the decreasing Collector efficiency and increasing energy losses in the circuit’s tubing with increasing rTWT. The higher the rTWT, the more solar radiation is required for the first discharge of hot water to take place (6500 W h m−2 d−1 for 80 °C). In addition, the time between discharges increases, and therefore the number of discharges possible over the day decreases. As rTWT increases, the amount of hot water discharged falls, the consequence of falling Collector efficiency and the greater energy content of the water, etc. This reduction fits a power curve for which R2 = 0.99: over 300 L m−2 d−1 are produced for an rTWT of 40 °C, but just 20 L m−2 d−1 for one of 80 °C (global efficiency 62% and 21% respectively). For an rTWT of 80 °C, an important percentage of the incoming energy would accumulate in the water tank as hot water, but without the required temperature being reached. Auxiliary systems would be required to profit from this energy, which should be used as soon as possible; certainly, nocturnal heat losses from the tank would considerably reduce the amount available if this water were not used until the next day. The viability of this type of installation as a sole provider of hot water is therefore reduced drastically as the rTWT increases.
Ahme Sari - One of the best experts on this subject based on the ideXlab platform.
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thermal performance of phase change material integrated heat pipe Evacuated Tube solar Collector system an experimental assessment
Energy Conversion and Management, 2020Co-Authors: K Chopra, V V Tyagi, A K Pandey, Ahme Sari, Ati K Pathak, S AnandAbstract:Abstract This manuscript presents an experimental investigation of heat pipe Evacuated Tube solar Collector with and without phase change material for water heating application under the same weather conditions. In this study, a comparative analysis of two systems has been done in the same weather condition. Where Evacuated Tubes of the first system (Evacuated Tube Collector-A) were left without phase change material and second system (Evacuated Tube Collector-B) was integrated with SA-67 as phase change material. In order to ensure the thermal and chemical stability of the selected phase change material, thermal cycling treatment was carried out. The results showed that SA-67 has excellent chemical and thermal stability even after 1500 thermal cycling treatment. In order to analyze the thermal performance of the designed systems, the experiment was conducted with five different water flow rates (8, 12, 16, 20 and 24 L per hour). The daily thermal efficiency of Evacuated Tube solar Collector with and without phase change material was varied in the range of 42–55% and 79–87% respectively. Although, the daily energy efficiency of Evacuated Tube Collector integrated with phase change material was 37.56%, 35.31%, 36.69%, 32.34%, and 32.73% higher than Evacuated Tube Collector without phase change material for water flow rates of 8, 12, 16, 20 and 24 L per hour respectively. The daily thermal efficiency for both systems was maximum at the flow rate of 20 L per hour. The heat transfer parameters for the designed systems have also been evaluated and compared.
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global advancement on experimental and thermal analysis of Evacuated Tube Collector with and without heat pipe systems and possible applications
Applied Energy, 2018Co-Authors: K Chopra, V V Tyagi, A K Pandey, Ahme SariAbstract:Abstract Sun is the prime source of energy. There are two types of technologies available for the harnessing of solar energy i.e. Solar Thermal and Solar photovoltaic. Solar thermal energy having a potential to provide the domestic and industrial energy demand for hot water, air heating, solar cooling, solar drying etc. Among multiple applications of solar energy, water heating, space heating, and cooling are consuming more energy. The energy consumption in production of hot water represents a large contribution of total building energy consumption. The Collector is the important aspect for efficient energy needs for these applications. Among all thermal Collectors specifically for low/medium temperature applications, Evacuated Tube Collector is found to have the best efficiency. This paper addresses the advancement, different types of Evacuated Tube Collectors and its low/medium temperature applications. The use of heat pipe in Evacuated Tube has been studied by many researchers around the globe to overcome the lower performance issue in direct flow Evacuated Tube Collector. This turns out to be one of the most important advancement in this area. Another, important advancements in this research have been found to be integration of phase change materials with Evacuated Tube Collector which has the great impact on its performance. This makes the Evacuated Tube technology more efficient, reliable and user-friendly. This review covers the recent research areas of the direct flow and heat pipe Evacuated Tube Collector with different applications and comprehensive knowledge of the theoretical analysis. This paper also provides financial advantages, classification with and without thermal energy storage, advantages and drawbacks of Evacuated technology and future recommendation for future improvement and recent research trend have also incorporated in this manuscript for researchers and practice engineers.
Rosa Maria Benavente - One of the best experts on this subject based on the ideXlab platform.
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profitability variations of a solar system with an Evacuated Tube Collector according to schedules and frequency of hot water demand
Energies, 2016Co-Authors: Carlos Javier Porrasprieto, Susana Benedictoschonemann, Fernando R Mazarron, Rosa Maria BenaventeAbstract:The use of solar water heating systems with Evacuated Tube Collectors has been experiencing a rapid growth in recent years. Times when there is demand for hot water, the days of use and the volumes demanded may determine the profitability of these systems, even within the same city. Therefore, this paper characterizes the behavior of a solar system with active circulation with the objective of determining the profitability variations according to the timing and schedule of demand. Through a simplified methodology based on regression equations, calculated for each hour of the day based on data from an experimental facility, the useful energy is estimated from the time and frequency of the demand for hot water at 60 °C. The analysis of the potential profitability of the system in more than 1000 scenarios analyzed shows huge differences depending on the number of days when the water is demanded, the time when demand occurs, the irradiation and the average price of energy. In cities with high irradiation and high energy prices, the system could be profitable even in homes where it is used only on weekends. The study of profitability in a building of 10 homes shows that by applying an average European household’s profile for hot water demand, levels close to full potential would be reached; for this, it is necessary to optimize the collection surface.
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feasibility of active solar water heating systems with Evacuated Tube Collector at different operational water temperatures
Energy Conversion and Management, 2016Co-Authors: Fernando R Mazarron, Carlos Javier Porrasprieto, J L Garcia, Rosa Maria BenaventeAbstract:Abstract With rapid advancements in society, higher water temperatures are needed in a number of applications. The demand for hot water presents a great variability with water required at different temperatures. In this study, the design, installation, and evaluation of a solar water heating system with Evacuated Tube Collector and active circulation has been carried out. The main objective is to analyze how the required tank water temperature affects the useful energy that the system is capable of delivering, and consequently its profitability. The results show how the energy that is collected and delivered to the tank decreases with increasing the required temperature due to a lower performance of the Collector and losses in the pipes. The annual system efficiency reaches average values of 66%, 64%, 61%, 56%, and 55% for required temperatures of 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C. As a result, profitability decreases as temperature increases. The useful energy, and therefore the profitability, will decrease if the demand is not distributed throughout the day or focused on the end of the day. The system’s profitability was determined in two cases: considering maximum profitability of the system, assuming 100% utilization of useful energy (scenario 1); assuming a particular demand, considering that on many days all the useful energy the system can supply is not used (scenario 2). The analysis shows that through proper sizing of the system, optimizing the number of solar Collectors, the investment in the solar system can be profitable with similar profitability values in the two contemplated scenarios. In scenario 2, a combined-delivery system (solar and diesel boiler) generates savings of between 23% and 15% compared to a single-delivery system of diesel, with a reduction in consumption of diesel close to 70%. The number of Collectors that maximizes the profitability depends on the required temperature; therefore, in designing this kind of installation water temperature requirements must always be taken into account. From an environmental point of view, CO 2 emissions can be reduced between 392 and 325 kg CO 2 per m 2 of Collector, depending on the required temperature. The results of this study can be very useful in determining the feasibility of using such systems to supply a part of demand for hot water.
