Experimental characterisation of different hermetically sealed horizontal, cylindrical double vessel Integrated Collector Storage Solar Water Heating (ICSSWH) prototypes (original) (raw)
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Sustainable Energy Technologies and Assessments, 2019
This paper presents an experimental study involving the design, manufacturing and testing of a prototype integrated collector storage (ICS) solar water heater (SWH) in combination with a compound parabolic concentrator (CPC). The thermal efficiency of the developed system is evaluated in Kerman (latitude 30.2907°N, longitude 57.0679°E), Iran. The developed system is intended to supply hot water for a family in remote rural areas. A 6-month experimental study was undertaken to investigate the performance of the ICS SWH system. The mean daily efficiency and overnight thermal loss coefficient of each experiment were analyzed to examine the appropriateness of these collectors for regions in Kerman. The results showed that mirror has the highest mean daily efficiency (66.7%), followed by steel sheet (47.6%) and aluminum foil (43.7%). The analysis of hourly and monthly operation diagrams for variations of water temperature for the developed ICS system showed that by increasing the amount of radiation entering the water heater, the thermal efficiency of the system decreases, such that the highest efficiency was in April and the lowest in July. With the distribution of radiation intensity in the months of August and September, the thermal efficiency of the system increased. This regional study illustrates how selecting a proper concentrator can increase the thermal efficiency of this solar-based system. It also shows how the temperature gradient between the ambient air and internal water in the storage tank can influence the performance of such systems, and how a controlled amount of hot water withdrawal can affect the system's efficiency. Developing the ICSSWH system is an ideal sustainable solution in countries that benefit from a large amount of solar intensity.
The thermal behavior of an integrated collector storage solar water heater (ICSSWH) is numerically studied using the package Fluent 6.3. Based on the good agreement between the numerical results and the experimental data of Chaouachi and Gabsi (Renew Energy Revue 9(2):75-82, 2006), an attempt to improve this solar system operating was made by equipping the storage tank with radial fins of rectangular profile. A second 3D CFD model was developed and a series of numerical simulations were conducted for various SWH designs which differ in the depth of this extended surface for heat exchange. As the modified surface presents a higher characteristic length for convective heat transfer from the storage tank to the water, the fins equipped storage tank based SWH is determined to have a higher water temperature and a reduced thermal losses coefficient during the daytime period. Regarding the night operating of this water heater, the results suggest that the modified system presents higher thermal losses.
2019
Experiments are developed to investigate the performance of utilised materials for an environmental-friendly integrated collector storage (ICS) prototype as a solar water heater (SWH). The types of material of collectors have been investigated rigorously in order to obtain a real-dimensional curve of the deployed concentrator in the system. The parabola coordinates were found based on the observed variations of involute concentrator's angle (ψ) and Parabolic concentrator's angle (ω). The mean daily efficiency and the overnight thermal losses coefficient of mirror booster, steel sheet, and aluminum foil were calculated. The results are presented in the graphs.
Sustainable Energy Technologies and Assessments, 2019
Integrated Collector Storage Solar Water Heaters (ICSSWHs) can support growing hot water demands of off-grid populations and reduce harm to human health and the environment. Despite their simple design and fewer associated components, stored thermal energy dissipates easily in foul weather. While thermal-diodes are beneficial heat retention enhancement features in ICSSWHs, other simple additional strategies can enhance heat retention without significantly complicating the fabrication process. This article examines techniques of differing levels of complexity for the improvement of heat retention of a basic thermal-diode ICSSWH. A basic thermal diode ICSSWH is adapted into a scalable Asymmetric Formed Reflector with Integrated Collector and Storage (AFRICaS) system and tested for heat retention performance along with other thermal insulation measures. The AFRICaS system improves heat retention efficiency and reduces heat loss coefficient to at least 35% and 1.46 W/K respectively. These results contrast with a heat retention efficiency and heat loss coefficient of 20% and 2.29 W/K respectively for a basic thermal diode ICSSWH. The AFRICaS prototype is potential launchpad for sustainable solar energy cogeneration.
Investigation of Integrated Collector Storage Solar Hot Water (ICSSHW
An integrated collector storage solar hot water (ICSSHW) is investigated theoretically and experimentally. The overall transient equations of the mathematical model are solved for a periodic thermosyphon flow conditions where the inputs are the ambient air temperature, solar radiation intensity and inlet cold water temperature. The effects of various parameters on the performance of the ICSSHW have been studied theoretically. Based on the results obtained from the experimental test with a mean global solar radiation of 545 (W/m 2), the average efficiency of the integrated collector storage solar hot water is 60%. Good agreement has been achieved between the experimental results and the mathematical prediction.
1999
Integral Collector / Storage (ICS) solar water heating systems suffer substantial heat loss during periods of low insolation or at night. Methods to reduce aperture heat loss include moveable insulated lids / shutters, transparent insulating glazing materials and selective glazing / absorber coatings. All of these approaches involve trade-offs with reduction in performance and / or an increase in cost. A novel ICS vessel design to mitigate heat loss is proposed. An ICS vessel utilising an inner sleeve arrangement is shown to reduce heat loss by up to 20%. This paper examines four inner sleeve design configurations, several of which demonstrate an increase in the heat retention capability over existing vessels, and an optimised design is presented.
Energy and Buildings, 2019
The need for substantial savings in building energy demand is necessitating global households" switch to solar water heating and nocturnal water cooling for possible incorporation with a hydronic system for controlling the temperature of buildings. Ambient energy technology application plays a prominent role in meeting the heating and cooling energy demands for buildings. These are not only environmental friendly but also require minimal maintenance and operation costs. A review of hybrid solar water heating/nocturnal radiation cooling system using a single collector/radiator for both functions is presented. The collectors that have been used for solar heating and cooling in meeting the building energy demand can be classified as photovoltaic-thermal collectors, water/air solar collectors and spectrally selective surface solar collectors. The performances of these collectors consistent with their usage at different regions of the world are concisely reported. The development of the primary component of the system, namely, the collector/radiator, vis-à-vis the combined heating and cooling function is examined. Current state of global system take ups are reported with factors limiting the widespread implementation. The prospects, technical advancements as well as technical, economic and societal constraints limiting the commercialization of the system are also reported, with suggestions for possible improvements.
Heat retaining integrated collector/storage solar water heaters
Solar Energy, 2003
An integrated collector / storage solar water heater (ICSSWH) that can significantly reduce heat loss to ambient during non-collection periods has been developed. Two thirds of the ICS vessel is mounted within a concentrating cusp, McIntire 'W' modified concentrator and incorporates an inner heat retaining vessel. The remaining upper 1 / 3 of the vessel is situated outside the reflector cavity and is heavily insulated. Over 60% of the thermal energy stored within the total vessel, and up to 67% of that in the upper immediate draw-off region can be retained over a 16-h non-collection period. Results of an experimental analysis of this design and a comparison with a standard ICS design are presented.
Experimental performance evaluation of a novel heat exchanger for a solar hot water storage system
Applied Energy, 2009
The performance of a novel heat exchanger unit ('Solasyphon') developed for a solar hot water storage system was experimentally investigated. The 'Solasyphon' is a simple 'bolt-on' heat exchange unit that can be integrated externally to a traditional single-coil hot water cylinder (HWC) avoiding the costly replacement of an existing HWC with a twin-coil HWC. The installation cost of a 'Solasyphon' is lower compared to a traditional HWC thus offers greater cost effectiveness. A data acquisition system was designed to compare the thermal performance of an integrated 'Solasyphon' HWC with a traditional twin-coil HWC under controlled simulated conditions. The analysis was based on experimental data collected under various operating conditions including different primary supply temperatures (solar simulated); primary supply patterns and draw off patterns. The results indicated that the 'Solasyphon' delivered solar heated water directly to the top of the HWC producing a stratified supply at a useable temperature. Under variable solar conditions the 'Solasyphon' would transfer the heat gained by a solar collector to a HWC more efficiently and quickly than a traditional HWC. The 'Solasyphon' system can reduce installation costs by 10-40% and has a lower embodied energy content due to less material replacement.