Various Types Of Solar Collectors Research Articles

Techno-economic feasibility of various types of solar collectors for solar water heating systems in hot and semi-arid climates: A case study

The pursuit for sustainability and a reduction in reliance on non-renewable energy sources has fueled the growing use of solar energy systems worldwide. This study assesses the feasibility of using domestic solar heating systems in Kirkuk, Iraq. The study utilized T*SOL software focused on three different solar collector systems: Thermital, Eraslan, and Apricus, chosen based on their type of collector loop (open loop or closed loop), type of collector (flat plate or evacuated tube), and collector size. The impact of varying the size of the hot water storage tank was also analyzed. The aim was to find a cost-effective solution that maximizes energy efficiency, reduces initial and maintenance costs, and cuts CO2 emissions. The results of the economic analysis showed that the energy demand for the case study was 1430 kWh. Both open loop and closed loop systems were found to achieve a solar fraction of 86% using evacuated tube collectors, but the open loop system required a smaller storage tank. The amount of CO2 emissions avoided was estimated to be between 689.5 and 1316 kg/year. The study concludes that domestic solar heating systems in Kirkuk, Iraq offer a sustainable and cost-effective energy solution, eliminating the need for an electrical water heater and resulting in substantial energy savings.

Characterization and performance investigation of metallic oxides based nanofluids in compound parabolic concentrating solar collector

Solar energy is the primary renewable and globally freely available resource of clean energy. Various types of solar collectors are used to extract thermal energy for low to medium temperature applications. Water and Ethylene Glycol, generally used as heat transfer fluids in such collectors, have low thermal conductivity which negatively impacts their performance. In this study, synthesis, stability analysis, characterization and thermal performance of metallic oxides-based nanofluids in a low concentration compound parabolic concentrating (CPC) solar collector is presented. Nanofluids with three volumetric concentrations (0.025, 0.05, 0.075 %) of MgO and Al2O3 nanoparticles are synthesized using water and Ethylene Glycol as base fluids. Two-step method is used to prepare colloidal suspensions with the help of magnetic stirring, shear homogenization, and ultrasonication process. For stability analysis, zeta potential measurements are carried out at 25 °C and 65 °C. Al2O3/EG and MgO/EG have shown zeta potential of −33.45 mV and +32 mV respectively at 25 °C. Maximum thermal conductivity enhancement of 33.80 % is noted for Al2O3/H2O while dynamic viscosity enhancement of 11.83 % is recorded for MgO/EG nanofluids with 0.075 %. volumetric concentration. Thermal performance of a stationary CPC collector is also evaluated using prepared nanofluids at flow rates of 0.02 kg/s and 0.015 kg/s. The experimental results show that a maximum temperature difference of 8.93 °C is achieved using Al2O3/H2O nanofluid with a volumetric concentration of 0.075 % at a flow rate of 0.015 kg/s. Maximum thermal efficiency enhancement of 25.03 % and 24.02 % is recorded for MgO/EG nanofluid with 0.075 % volumetric concentration at flowrate of 0.02 kg/s and 0.015 kg/s, respectively.

Augmented Kalina Cycle Using Renewable Energy as Input for Power Generation

Kalina cycle is an idealized thermodynamic cycle that generates power using a binary mixture as a working substance. Depending on the application, the Kalina Cycle increase power plant efficiency by 10% to 50% over the Organic Rankine Cycle. The relative advantage of the Kalina cycle rises when operating temperatures are reduced and Kalina cycle is generating by mixture. Kalina cycle is identified as a bottoming cycle that demonstrates improved efficiency. Ammonia-water mixture is high-energy than a single component. Producing electricity of the inlet turbine and the temperature of the separator increase the performance of the cycle. It may be more effective to use the Kalina cycle for concentrating renewable energy sources such as solar power plants that use direct steam production to enhance heat exchange efficiency, and therefore, increase total system performance. This research attempts to build a Kalina cycle system, which will help to transform the natural source from sunlight to energy. Python open-source software has been used to design and implement the Kalina cycle. The suggested cycles include various types of solar collectors and extra heat recovery technologies. Systems uses a medium temperature heat source to analyze the Kalina cycle for different system characteristics and to conduct parametric research to determine which input temperature, ammonia concentrations, separator temperatures yield the optimal energy production. The Kalina cycle of binary plants generates 30% to 50 % more power for a provided heat source. With the Kalina cycle as a bottoming cycle for a cogeneration plant, the exhaust gas temperature has been reduced from 427 K to 350 K, which reduces the environmental impact.

Potential Use of Nanofluids in Solar Collectors: A Review

Solar energy is clean and easily available everywhere. It is trapped by a device called a solar collector. Solar collectors are used to utilize solar energy. Generally, the performances of the solar collector are low. Nanofluid is used in solar collectors to boost up the performance of the solar collector. This paper presents a review of the literature on the role of nanofluids in various types of solar collectors. It is found that the performance of the solar collector improves by using nanofluids as a heat transfer medium.

CFD modeling of a thermal energy storage based heat pipe evacuated tube solar collector

Abstract The increase in greenhouse gases makes it necessary to utilize renewable energy sources such as solar energy. The most important component of any solar system is solar collector. Among various types of solar collectors, evacuated tube solar collector (ETC) has attracted many attentions especially for the application in solar water heating systems (SWHs). However, due to the intermittency in solar intensity, the ETCs may not work at their maximum functionality. In this study, the computational fluid dynamics (CFD) modeling of a heat pipe ETC (HPETC) with and without the integration of phase change materials (PCMs) is performed. In order to cross-validate the obtained results from CFD and recent experimental analysis, the boundary conditions are set as the field-testing data. In phase-I, the 3D model of commercially available HPETC is simulated, while in phase-II, the HPETC integrated with the PCM is developed. The selected type of PCM is Tritriacontane paraffin (C33H68) with melting point of 72∘C. The simulation results show an acceptable agreement with the experimental data with an average deviation of 4.80% and 2.04% for phase-I and phase-II, respectively. The result from this study can be a benchmark for further optimization of HPETCs in thermal energy storage systems.

State-of-the-Art Solar Collectors: Typical Parameters and Trends

The paper presents a comparative analysis of design and thermal parameters of various types of solar collectors, including Russian-manufactured ones. It is shown that over the last 15 years, the massdimensional characteristics and thermotechnical excellence of flat-plate solar collectors have remained virtually unchanged, the manufacturing technologies of such collectors have not sufficiently improved, the collectors have reached parameters close to limiting ones. In terms of thermal excellence, Russian-manufactured collectors are highly competitive with foreign models. Evacuated tubular solar collectors currently on the market can be divided into several types, of which the most efficient are U-shaped heat removal pipe Sydneytube collectors. Popular heat pipe Sydney-tube collectors, which are considered promising, are significantly less efficient.

Thermodynamic modeling and exergy analysis of a solar adsorption cooling system with cooling tower in Mediterranean conditions

Thermally driven chillers offer a reliable and environmentally friendly alternative to conventional electrically powered chillers. Solar energy can be utilized in order to provide the necessary heat to these heat driven cooling cycles. This work examines the application of an adsorption chiller cooling system powered by solar energy under climatic conditions of eastern Mediterranean area. Athens and Nicosia the capitals of Greece and Cyprus respectively and Alexandria of Egypt are the three examined cities. A single-stage, two bed adsorption chiller is selected for investigation. A lumped parameter model is used to simulate the performance of the cooling system. The maximum cooling capacity of the system is about 14.7 kW and is observed for Nicosia climatic conditions in July. Subsequently, the performance of the system is examined for various types of solar collectors under Athens climatic data. The utilization of hybrid photovoltaic-thermal (PV/T) collectors is studied and the production of electric power is calculated. The overall energy and exergy efficiencies are also calculated for the combined systems. Following the analysis of the adsorption chiller performance (cooling capacity, COP), the selective solar thermal collector is the optimum collector for the cooling system with maximum cooling capacity and COP around 16 kW and 0.51 respectively. The overall energy efficiency of the system is also maximized when the selective solar collector is utilized (21.7%). However the overall exergy efficiency is maximized when the unglazed PV/T solar collector is used (11.35%). Finally, the effect of the cooling tower's cooling water outlet temperature on the adsorption chillers performance is investigated.

A review of solar collectors and thermal energy storage in solar thermal applications

Thermal applications are drawing increasing attention in the solar energy research field, due to their high performance in energy storage density and energy conversion efficiency. In these applications, solar collectors and thermal energy storage systems are the two core components. This paper focuses on the latest developments and advances in solar thermal applications, providing a review of solar collectors and thermal energy storage systems. Various types of solar collectors are reviewed and discussed, including both non-concentrating collectors (low temperature applications) and concentrating collectors (high temperature applications). These are studied in terms of optical optimisation, heat loss reduction, heat recuperation enhancement and different sun-tracking mechanisms. Various types of thermal energy storage systems are also reviewed and discussed, including sensible heat storage, latent heat storage, chemical storage and cascaded storage. They are studied in terms of design criteria, material selection and different heat transfer enhancement technologies. Last but not least, existing and future solar power stations are overviewed.

Wind loads on residential and large-scale solar collector models

Previous studies on solar water heaters have mainly focused on the thermal efficiency of various types of solar collectors, and there has been limited work done on the aerodynamic characteristics of solar collectors or their supporting structure. However, typhoons are among the natural hazards that have a costly impact on residential construction and solar water heaters are usually installed on the flat roofs of buildings for hot water production. Thus, the safety of solar water heaters under severe wind load during typhoon season is a critical issue in the promotion of solar water heaters. In this study, an experimental program was conducted to examine the aerodynamic characteristics of solar collector models (residential and large-scale solar water heaters). The unit sectional uplift coefficient with or without a guide plate is also addressed. Measurements of mean longitudinal and spanwise surface pressure were performed. The data show that the presence of a water storage tank (or a horizontal cylinder) tends to reduce the suction force on the upper surface within the first half of the tilt flat panel (solar collector). Stronger negative longitudinal differential mean pressure is observed for the test case of a tilt flat panel only, which corresponds to strong wind load. The inverted U-shape of mean spanwise pressure distributions is also noted. With a guide plate, less wind load and more uniformity of spanwise differential mean pressure distributions are associated with a larger projected area of a guide plate on the lower surface of a tilt flat panel. This is essentially attributed to the attenuation of corner vortices and a decrease in uplift force.

Thesis Summary: Theoretical and Experimental Investigation of a Solar-Biomass Hybrid Air Heating System for Drying Applications

The overall objective of this research was to design, develop, and investigate the performance of a renewable energy-based (solar-biomass) hybrid air heating system. The system consists of an unglazed transpired solar collector (UTC), a rock bed thermal storage, and a biomass gasifier stove with heat exchanger, to supply hot air at a required temperature and flow rate for a daily load fraction exceeding 90%. From a review of literature, an air heating system aimed at reducing the weather dependency and improving the temperature and flow rate stability without a conventional back-up heater was designed. Among the various types of solar collectors, thermal storage, biomass stoves, and heat exchangers that are generally used, specific designs were chosen and analyzed. Based on the analyses, individual components of the air heating system were designed and developed. The components were coupled, and detailed experimentation was carried out on the integrated system.

An analytical study on the thermal characteristics of flat-plate and evacuated solar collectors

In this study, we highlighted differences in the standards used in performance tests of solar collectors. We analyzed testing results for different types of solar collectors to determine the effects of the collector area and mass flow rate, which were not necessarily consistent across all tests. Our analysis showed that the factor,F′ (τα), including collector efficiency factor (F′), could be correlated with the flow rate or area regardless of the collector type. Moreover, the collector loss coefficient (F′U L ) per flow rate or area for an evacuated collector was less that of a flat-plate collector; this was also correlated with the flow rate or area, regardless of the type of evacuated collector. As a result of this analysis, we propose a modified heat loss coefficient that includes the effects of all parameters that can be considered in a performance test and show that this coefficient could better describe the thermal characteristics of various types of solar collectors.

Second-law analysis of solar-thermal processes

The second law of thermodynamics provides an analytic framework for the assessment of the potential displacement of fossil fuels by solar energy. the most promising areas are those which have entropy levels corresponding to the entropy level of the solar resource as converted to heat in various types of solar collectors. Since the entropy of solar heat can be partitioned by the means of collection—d.g., by the collector concentration ratio—solar can be matched much more precisely to many tasks at temperatures up to 300°C than can fossil fuels which are low entropy sources now widely misused for high entropy tasks.

Annual available radiation for fixed and tracking collectors

Values for the long-term average annual radiation incident on horizontal surfaces in six US locations are tabulated, and the significance of these values for predicting the performance of various types of solar collectors is discussed. (WHK)

The NASA-Langley building solar project and the supporting Lewis solar technology program

The National Aeronautics and Space Administration will use solar energy to heat and cool a new office building that is now under construction at its Langley Research Center in Hampton, Virginia. Planned for completion in December 1975, the 53,000 ft 2, single story building will utilize 15,000 ft 2 of various types of solar collectors in a test bed to provide nearly all of the heating demand and over half of the air conditioning demand. This is a cooperative project involving joint participation between Langley and NASA's Lewis Research Center in Cleveland, Ohio. Drawing on its space-program-developed skills and resources in heat transfer, materials and systems studies, NASA-Lewis will provide technology support for the Langley building project. A solar energy technology program underway at Lewis includes solar collector testing in an indoor solar simulator facility and in an outdoor test facility, property measurements of solar panel coatings, and operation of a laboratory-scale solar model system test facility. Based on results obtained in this program, NASA-Lewis will select and procure the solar collectors for the Langley test bed. The selection will be made in late 1974 or early 1975. Early results from simulator tests indicate that non-selective coatings behave more nearly in accord with predicted performance than do selective coatings. Initial experiments on the decay rate of thermally stratified hot water in a storage tank have been run. Results suggest that where high temperature water is required to drive a chiller, excess solar energy collected by a building solar system should be stored overnight in the form of chilled water rather than hot water.