Solar Collector

Continuous escalation of the cost of generating energy is preceded by the fact of scary depletion of the energy reserve of the fossil fuels and pollution of the environment as developed and developing countries burn these fuels. To meet the challenge of the impending energy crisis, renewable energy has been growing rapidly in the last decade. Among the renewable energy sources, solar energy is the most extensively available energy, has the least effect on the environment, and is very efficient in terms of energy conversion. Thus, solar energy has become one of the preferred sources of renewable energy. Flat-plate solar collectors are one of the extensively-used and well-known types of solar collectors. However, the effectiveness of the collector’s absorber plate to absorb solar energy limits the efficiency of this type of collector, as does the inefficient transfer of the solar energy via heat transfer to the fluid in the collector’s flow channels. To improve its efficiency and perf...

The Solar Energy Research Group in the Universiti Kebangsaan Malaysia has been set-up more than two decades ago. One of the activities is in the field of solar thermal process, particularly in development of solar assisted drying systems. Solar drying systems technical development can proceed in two directions. Firstly simple, low power, short life, and comparatively low efficiency-drying system. Secondly, the development of high efficiency, high power, long life expensive solar drying system. The group has developed four solar assisted drying systems namely (a) the V-groove solar collector, (b) the double-pass solar collector with integrated storage system, (c) the solar assisted dehumidification system for medicinal herbs and (d) the photovoltaic thermal (PVT) collector system. The common problems associated with the intermittent nature of solar radiation and the low intensities of solar radiation in solar thermal systems can be remedied using these types of solar drying systems. These drying systems have the advantages of heat storage, auxiliary energy source, integrated structure control system and can be use for a wide range of agricultural produce.

The paper is focused on the dynamic simulation of a Photovoltaic/Thermal collector (PVT) integrated in a high-temperature Solar Heating and Cooling (SHC) system. The system is based on the following main components: concentrating parabolic PVT (photovoltaic thermal) collectors, a double-stage LiBr-H2O absorption chiller, storage tanks, auxiliary heaters, balance of plant devices. The PVT is made-up by a parabolic dish concentrator and a triple-junction receiver. The polygeneration system provides electricity, space heating and cooling and domestic hot water for a given building, whose simulation is also included in the model. In particular, PVT produces electric energy, which is in part consumed by the building loads (lights and equipments), in part by the system parasitic loads, whereas the eventual excess is sold to the public grid. Simultaneously, the PVT provides the heat required to drive the absorption chiller. The system was simulated by means of a zero-dimensional transient model, that allows the evaluation of temperature profiles and also heat/electrical energy flows for whatever period of the year. It is also possible to evaluate the overall energetic and economic performance on whatever time basis (day, week, month, year, etc.). The economic results show that the system under investigation can be profitable, if a proper funding policy is available. The paper also includes an extensive parametric analysis aiming at evaluating the set of design and operating parameters (solar field area, tank volumes, set point temperatures, etc.) that maximize the energetic and/or economic performance of the system.

A solar assisted absorption refrigeration system (SAARS) was designed for acclimatizing of villas in Mardin which is located in Turkey and the performance of the system under different temperatures was analyzed by using MATLAB. Hourly cooling load calculation of the villas was done between 15th of May and 15th of September by considering the season for the cooling. Cooling capacity

Solar energy is so far the most promising and sustainable alternative energy source to fossil fuels. The new solar technology proposed in this research, building-integrated
photovoltaic-thermal (BIPV/T) systems, can be attached to the façade or replace conventional cladding, enabling on-site generation of solar electricity and heat, which can fulfill a significant portion of the building energy requirements. The overall objective of this research is to develop (a) prototype BIPV/T systems coupled with open-loop corrugated Unglazed Transpired Solar Collectors (UTC); (b) new modeling
representations for design, analysis, and control of BIPV/T integrated in the operation of building Heating, Ventilation and Air Conditioning (HVAC) systems; (c) an innovative
energy management framework, over a future planning horizon, based on model-predictive control algorithms that can anticipate the variability of solar irradiance and building load, thus enabling the optimal operation of high performance buildings with distributed solar energy resources and active thermal energy storage.
To this end, high-resolution, three-dimensional Computational Fluid Dynamics (CFD) models are developed to investigate the complex airflow and heat transfer mechanisms in BIPV/T systems and provide a solid foundation that supports the
formulation of thermal analysis models. The CFD models are validated using data from an experimental set-up in a state-of-the-art solar simulator facility, in terms of the cavity
exit air temperature (the error less than 1°C), the stream-wise development of plate surface temperature (the error less than 1°C), and vertical profiles of stream-wise velocity (average error within 10 %) and turbulent kinetic energy (average error within 20 %).
Energy prediction models for both corrugated UTCs and UTCs integrated with BIPV/T systems are established to evaluate their performance (electrical and thermal energy output, outlet air temperature, etc.) for different weather (incident solar radiation
and wind speed) and system design parameters (corrugation geometry, PV module coverage ratio, suction velocity, etc.). Comprehensive Nusselt number and effectiveness correlations, representing both the exterior and interior convective heat transfer processes in BIPV/T systems, are obtained from the CFD simulations and subsequently used in the energy models. Experimental data for prototype BIPV/T collectors installed at Purdue’s Architectural Engineering Lab are used to validate the energy models. Comparison between the model predictions and the experimental data verifies the dynamic response
of the collectors to weather and operating conditions, with the root mean square error within 1 °C in terms of cavity exit air temperature for the UTC configuration and within 2 °C (PV surface temperature) for the model of UTC with PV modules. The methodology for the analysis of the thermal boundary layer development and convective heat transfer process can be generalized to uniform approaching flow over corrugated plates with discrete suction, while the Nusselt number and effectiveness correlations and the physical modeling approach can be adopted to other BIPV/T systems.
Then the energy models are implemented in building simulation platforms to enable integration of BIPV/T with building HVAC systems (air handling unit and radiant floor heating) and active thermal storage systems. Finally, a deterministic model-predictive control algorithm is formulated for the integrated solar system. This includes building up a detailed dynamic system model in TRNSYS, presenting a system
identification approach to obtain simplified gray and black-box models that capture the relevant system dynamics and are computationally efficient for implementation in real controllers, formulating the cost function and setting up the constraints and the optimization environment, and examining the potential impacts associated with the prediction accuracy of the solar irradiance, which is the most significant disturbance acting on the system. The energy saving potential of the integrated system and the predictive controller is investigated in comparison with baseline operation strategies used in commercial buildings, using the Hydronic Laboratory at Purdue’s Living Laboratories as a simulation test-bed. The investigation shows that efficient integration concepts and
optimal control strategies are necessary to predict and plan the energy cost for the integrated solar system, resulting in total energy savings for the integrated solar system that can be up to 45 %. The modeling representations and approaches developed in this study can be generalized and extended to other commercial buildings with different integrated solar systems, HVAC systems and energy storage.
In summary, the solar technology (prototype BIPV/T collectors), systems representation, validated models, and the numerical prototypes of predictive-control algorithms developed in this dissertation found to be an efficient approach for buildingscale
renewable energy generation and utilization in high performance commercial buildings. The research presented herein is a necessary precursor for future investigation and expansion of smart buildings or net-zero energy buildings and the adoption of innovative energy management concepts in engineering practice. With large-scale deployment, this could be an effective pathway to reduce greenhouse gas emissions and
the need to build new fossil fuel power plants.

In this paper, a numerical investigation of the two modes of heat transfer, natural convection and surface thermal radiation, in a tilted slender cavity such a collector is presented. The 2-D conservation of mass, momentum and energy are coupled with a radiative model through the boundaries and solved by the finite volume method. The studied parameters are: aspect ratios (8≤A≤16), inclination angles (15°≤≤35°) and Rayleigh numbers (104≤Ra≤106). The results indicated that the radiative surface radiation coupled with the natural convection modifies the flow patterns and the average heat transfer in the slender cavity between the absorber plate and the glass in the collector. The convective heat transfer coefficient and the radiative heat transfer coefficient as a function of the aspect ratio and the inclination angles are shown. It was found that the radiative heat transfer contributes more than 40% of the total heat transfer. A comparison between the present Nusselt numbers against the ones used for the design of solar collectors reported in the literature is presented.

Prinsloo, G.J. (2014). Automatic positioner and control system for a motorized parabolic solar reflector. MSc Thesis, Stellenbosch University. p 1-142. DOI: 10.13140/RG.2.1.1130.3522
This project deals with the CAD design and construction of an automatic Solar Tracking system for Sun Tracking and Sun Following based upon the sun vector and the sun's position at any given time and the position of the sun for any GPS location on the earth. It drives hybrid solar Stirling technology for thermal and electricity generation and finds application in smart microgrid development for power and energy distribution an dispatch in off-grid and grid-tied applications. Automatic sun tracker positioner and control system for a motorized parabolic dish solar reflector and mechatronic solar tracking control system project describes the development and CAD design in a dual-axis sun tracker application for a stand-alone off-grid 3 kW solar electrical self-tracking concentrating solar power system. This autonomous power stand-alone solar tracking application and parabolic collector harness sunlight in a dish Stirling system or concentrated photovoltaic system by implementing a dynamic mechatronic platform and digital electronic control system for an autonomous concentrating solar power for CSP and CPV. The same sun tracker can also be used in solar PV photovoltaic where the solar panels follow the sun throughout the day. Design specifications required a high-precision automatic positioning and solar tracking control system for a self-tracking motorized parabolic solar collector with an optical solar harnessing capacity of 12 kW solar thermal. The solar receiver is a point-focussing parabolic dish that pinpoints towards the sun to collect sun energy, but may also be a line-focussing solar trough. Stand alone off-grid concentrated solar and solar tracking system require intelligent digital control approaches to ensure optimal energy efficiency and management of the power budget. In co-generation systems, this is especially true for digitally controlled solar micro combined heat and power (mCHP or CHP), solar micro combined cooling heating and power (mCCHP or CCHP) trigeneration and polygeneration type systems that feed into microgrid and smartgrid systems in district power systems, remote areas, island power, rural villages, eco-estate housing schemes and industrial process heating systems.

Seeking innovative methods is critical for efficient solar energy utilization. In this study, a promising alternative to the conventional systems is introduced by integrating heat pipes to widely used flat plate collectors as a means of heat extraction devices. It is expected that such configuration can avoid some of the drawbacks that inherently exist in the traditional flat plate collectors. Transient performance analysis was performed for a complete forced circulation solar water heating system operating with a heat pipe flat plate collector (HPFPC). In addition, thermal behaviour of the whole system and its daily energetic and exergetic performances were discussed considering hourly weather data from the coldest month of the year with the mean daily temperature of 9.56 C in Fez, Morocco. Moreover, a simulation environment was introduced and dynamic simulations were performed to assess the overall performance under worst-case scenario. Performance factors including solar fraction, collector thermal and exergetic effi-ciencies were evaluated on hourly and daily basis. The simulation results were compared to the experimental results found in the literature and they showed a good agreement. These results proved that the solar water heating system was capable of maintaining reasonable thermal efficiencies of up to 33% and exergetic efficiencies of up to 4% with a daily solar fraction above 58% during the coldest month of the year in the studied location.

... Ahmet Koca a , Hakan F. Oztop b , Tansel Koyun c and Yasin Varol a , Corresponding Author Contact Information , E-mail The Corresponding Author. ... from 1.22 to 2.63 kW, whereas the rate of heat stored in the LHS unit were 111.2 and 79.9 W. Sari and Kaygusuz [11] conducted ...

In this paper a survey of the various types of solar thermal collectors and applications is presented. Initially, an analysis of the environmental problems related to the use of conventional sources of energy is presented and the benefits offered by renewable energy systems are outlined. A historical introduction into the uses of solar energy is attempted followed by a description of the various types of collectors including flat-plate, compound parabolic, evacuated tube, parabolic trough, Fresnel lens, parabolic dish and heliostat field collectors. This is followed by an optical, thermal and thermodynamic analysis of the collectors and a description of the methods used to evaluate their performance. Typical applications of the various types of collectors are presented in order to show to the reader the extent of their applicability. These include solar water heating, which comprise thermosyphon, integrated collector storage, direct and indirect systems and air systems, space heating and cooling, which comprise, space heating and service hot water, air and water systems and heat pumps, refrigeration, industrial process heat, which comprise air and water systems and steam generation systems, desalination, thermal power systems, which comprise the parabolic trough, power tower and dish systems, solar furnaces, and chemistry applications. As can be seen solar energy systems can be used for a wide range of applications and provide significant benefits, therefore, they should be used whenever possible.

Prinsloo, G.J. "Hardware Sun Tracking Systems and Digital Sun Position Hardware Solar Tracker Controllers". In Solar Tracking. GJ Prinsloo. 1st ed. Stellenbosch: SolarBooks, 2016. ISBN 978-0-620-61576-1. doi: 10.13140/2.1.2748.3201
Chapter in free eBook on Solar Tracking Systems, Sun Tracking Systems, Sun Tracker, Solar Tracker, Follow Sun, Sun Position. A number of commercial and proprietary solar tracking controller solutions for a variety of automation platforms are available in the market. These sun tracker solutions include algorithms for computing the sun vector, mostly for PLC (Programmable Logic Controller) and PAC (Programmable Automation Controller) processors as well as FPGA (Field Programmable Gate Arrays). Most of these solar tracking controllers are universal controllers suitable for a variety of solar systems and mode switchable to control point focus, linear (parabolic trough) or central receiver Heliostat solar receiver systems. This chapter aims at giving the reader a wide angle view of available sun tracker solutions and presents some of the solar tracking automation solutions presently available.
Free to download eBook on Practical Solar Tracking Design, following the sun solar tracking system, sun tracking system, sun tracker system, solar tracker system, sun positioning system, and sun path tracking with follow the sun position calculation (azimuth, elevation, zenith), sun trajectory, sun following system, sunrise tracking, sunset tracking, sunlight-phases, dawn, dusk, moon-phase, twilight, moonrise, moonset calculator. Solar Tracking is a key Technology to unlock the full potential of RE in RES.
https://www.researchgate.net/profile/Gerro_Prinsloo
Solar Tracking, Sun Tracking, Sun Tracker, Solar Tracker, Follow Sun, Sun Position
https://www.researchgate.net/publication/263128579_Solar_Tracking_Sun_Tracking_Sun_Tracker_Solar_Tracker_Follow_Sun_Sun_Position

Drying for agricultural and marine products are one of the most attractive and cost-effective application of solar energy. Numerous types of solar dryers have been designed and developed in various parts of the world, yielding varying degrees of technical performance. Basically, there are four types of solar dryers; (1) direct solar dryers, (2) indirect solar dryers, (3) mixed-mode dryers and (4) hybrid solar dryers. This paper is a review of these types of solar dryers with aspect to the product being dried, technical and economical aspects. The technical directions in the development of solar-assisted drying systems for agricultural produce are compact collector design, high efficiency, integrated storage, and long-life drying system. Air-based solar collectors are not the only available systems. Water-based collectors can also be used whereby water to air heat exchanger can be used. The hot air for drying of agricultural produce can be forced to flow in the water to air heat exchanger. The hot water tank acts as heat storage of the solar drying system.

Energy resources and their utilization intimately relate to sustainable development. In attaining sustainable development, increasing the energy efficiencies of processes utilizing sustainable energy resources plays an important role. The utilization of renewable energy offers a wide range of exceptional benefits. There is also a link between exergy and sustainable development. A sustainable energy system may be regarded as a cost-efficient, reliable, and environmentally friendly energy system that effectively utilizes local resources and networks. Exergy analysis has been widely used in the design, simulation and performance evaluation of energy systems.The present study comprehensively reviews exergetic analysis and performance evaluation of a wide range of renewable energy resources (RERs) for the first time to the best of the author's knowledge. In this regard, general relations (i.e., energy, exergy, entropy and exergy balance equations along with exergy efficiency, exergetic improvement potential rate and some thermodynamic parameters, such as fuel depletion ratio, relative irreversibility, productivity lack and exergetic factor) used in the analysis are presented first. Next, exergetically analyzed and evaluated RERs include (a) solar energy systems; (a1) solar collector applications such as solar water heating systems, solar space heating and cooling, solar refrigeration, solar cookers, industrial process heat, solar desalination systems and solar thermal power plants), (a2) photovoltaics (PVs) and (a3) hybrid (PV/thermal) solar collectors, (b) wind energy systems, (c) geothermal energy systems, (c1) direct utilization (district heating, geothermal or ground-source heat pumps, greenhouses and drying) and (c2) indirect utilization (geothermal power plants), (d) biomass, (e) other renewable energy systems, and (f) country based RERs. Studies conducted on these RERs are then compared with the previously ones in tabulated forms, while the Grassmann (or exergy flow) diagrams, which are a very useful representation of exergy flows and losses, for some RERs are given. Finally, the conclusions are presented. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the exergetic design, simulation, analysis and performance assessment of RERs.