[en] The article presents the results of the research and analysis of the impact of some major construction and operational parameters of thermal solar systems on the conversion efficiency of the solar radiation into heat. The criteria solar fraction and efficiency, as well as well specific annual energy, conversed by the system, were used for long-term evaluation. With the help of the financial analysis, concerning the maximal net present value, the optimal specific storage tank volume by replaced energy electricity and some specific profiles of daily consumption was determined. (author)

[en] It is shown that in solar constant measurements if the scattered solar radiation in to be taken into account the function of intermediate transformation of three wavelengths photometer may have a dual form of writing. The possibility of measuring of solar constant with three wavelength photometer taking into consideration the aerosol scattering of light is shown

[en] Graphical abstract: - Highlights: • We simulate a thermosiphon collector associated to a single zone using TRNSYS. • We examine the temperature of water in collector, in tank and in single zone. • We study the temporal evolution of the temperature and the energy for 11 h operation in January and 2880 h operation in winter. • The system gives good results in all operating states. • The use of solar energy in the residential building is interesting. - Abstract: The novelty of this paper is the coupling between a thermosiphon collector and a single zone with the following details; a thermosiphon system (TYPE 45) which uses the solar energy as an unlimited renewable energy to produce the heat by using an internal coupling of a flat plate collector and a storage tank in a closed loop realized in TRNSYS. Consequently, the user simply utilizes TYPE 45 as thermosiphon ready to be run, and a single zone (TYPE 19) is a complex type which is designed for residential buildings that can be specified by the user in order to obtain an acceptable heating within a house. The user specified the characteristics of the internal space, external weather conditions, walls, windows, and doors. To facilitate this description, the parameters and inputs for this component are organized in separate table according to a logical structure. According to us, the choice of this model of thermosiphon coupled with a single zone can have multiple interesting engineering applications, in particular ameliorating the mode of the heating in residential buildings. Two flat plate collectors of aperture area of 6 and 8 m² are modeled. The solar fraction of the entire system is used as the optimization parameter. The temperature of the water in the storage tank, the collector’s temperature, the temperature inside and outside the house, the solar fraction for different collector areas and the total energy were also measured in 11 h operation in January and 2880 h operation in winter. The average solar fraction obtained was 85% and the system could cover all the hot water needs of a house of six people. The maximum auxiliary energy was needed during 11 h operation in January and 4 months in winter. The results show that by utilizing solar energy, the designed system could provide 40–70% of the hot water demands in winter

[en] Highlights: • A forced-circulation solar water heater system for domestic use was investigated. • Six different climatic zones of Morocco were simulated. • Flat plate and evacuated tube installations were compared. • Solar fractions for the different scenarios were given. - Abstract: The aim of this study is to assess the technical feasibility of solar water heaters (SWH) under Moroccan conditions. Annual simulations in six different regions for two technologies: flat plate and evacuated tube collectors were carried out using TRANSOL program. It is found that high values of solar fraction can be reached in almost the studied regions with the preference of using evacuated tube collectors. Furthermore, the study emphasizes that the location and the climate are determinant parameters on the overall performance of solar water heating systems

[en] An accuracy of predicting energy performance of autonomous photovoltaic systems using various climatic databases (NASA POWER, SARAH-E, CLARA-A, ERA5, Meteonorm, etc.) has been analyzed for some geographic points in Russia by comparison with calculations based on data from the World Radiation Data Center. It has been showed that the databases considered provide a spread of predictions for required rated solar battery power at a level of 10–20% only when solar fraction is less than 70%. For a larger solar fraction prediction error of required rated solar battery power can reach several hundred percent.

[en] Full text: Concentrating solar power (CSP) technologies could be one of the major contributor to worlds future energy needs and which would be cheap and clean sources of energy. This would improve energy utilization, higher conversion efficiency with reliable and affordable supply of electricity to the public. The proposed approach is using different size and depth of solar dish concentrators to improve solar fraction using the aluminium foil as reflector. In this paper, different measurement of solar concentrators is investigated and aims to aims to introducing an improved methodology for solar fraction on incoming solar energy in wet climate. (author)

[en] Solar energy is the most promising source of clean, renewable energy and it has the greatest potential of any power source to solve the world's energy problems. However, the problem, is how best to harness this vast amount of solar energy. Nevertheless, even if highly efficient Concentrating Solar Power (CSP) could be made cheaply, there would be considerable change in solar power. This technology is expected to be more efficient and to achieve a manufacturing cost of less than $1/W near future. This paper reviews and elaborates the methodology utilized to design and fabricate the solar dish concentrator and outlines the parameters that can be used to increase the efficiency of solar fraction in parabolic dish concentrator under wet climate environment in Malaysia. The study finally provides ideas to the continually increasing ability of these technologies to concentrate and harness solar energy for electricity production and thus eliminate the growing concern over climate change and how it will hurt the region's environment, human health and economy. (author)

[en] Highlights: • A hybrid phase change CaO/CaCO₃-CaCl₂ thermochemical energy storage system is investigated. • A Mg-Cl hydrogen production process is developed using solar thermal energy. • Total exergy efficiencies of the energy storage system and Mg-Cl cycle are 62.2% and 84.3%. • Annual system efficiency, exergy efficiency and solar fraction are 63.74%, 54.76, and 83.59%, respectively. Hydrogen has been considered as a clean and sustainable fuel to meet heat requirements. The Mg-Cl hydrogen production cycle has been introduced as a promising thermochemical low-temperature cycle. In this paper, a solar system is integrated with a Mg-Cl cycle and a phase change CaO/CaCO₃-CaCl₂ thermochemical energy storage system (TCES). The heat generated by the solar tower is stored by the TCES in the charge mode. In the cases of low solar radiation, the TCES cycle stands in discharge mode and, if necessary, an auxiliary heat exchanger is utilized to provide the heat for the Mg-Cl cycle. The solar system is modeled by EES software and the other two cycles are simulated by Aspen Plus. Sensitivity and exergy analyses were performed for the system and reported along with the annual results of the whole system. The amount of 11.01 MW heat is stored in the charge mode and 9.536 MW is released in the discharge mode and 35.6 mol/s of hydrogen is acquired by the Mg-Cl cycle. The total exergy efficiencies of the TCES system and Mg-Cl cycle are 62.2% and 84.3%. The Mg-Cl cycle efficiency is enhanced due to the heat recovery of the internal streams and the TCES cycle efficiency is elevated due to the phase change process. The most exergy destroyer components of the TCES and Mg-Cl units belong to Carbonation and Electrolysis1 reactors with the value of 663.7 kW and 3747.4 kW, respectively. According to annual analysis, the most exergy destructions are related to the Electrolysis1 reactor, followed by solar system, which comprise 29.73% and 23.4% of total annual exergy destruction, respectively. Moreover, the annual system efficiency, exergy efficiency and solar fraction are 63.74%, 54.76, and 83.59%, respectively.

[en] Highlights: • Holistic optimization and control approach for solar-augmented industrial process. • Energy based optimization with investment constraints. • Transfer function based continuous heat transfer control. • Validated against a case study of a dyeing industrial process in textile industry. • Control enables 12.4% increase in solar gain and 5.6% reduction in payback period. -- Abstract: Process level integration of solar energy could give an economically feasible solution if the industrial process allows its practical integration. The solar-augmented industrial process behaves as a complex system influenced by uncertainty of solar radiation, variability of demand temperature and process time schedule as well as possibility of thermal stratification in the storage. Addressing these issues to reach the most economical solution has two dimensions to it. First, the solar thermal system needs to be optimally designed. This requires the development of a performance criterion that will deliver maximum solar energy to the industrial process, avoid large variations of energy in the storage, and meet investment constraints. Second, the identified optimal system should be dynamically controlled to enable uniform heat distribution and efficient auxiliary heat utilization. This paper presents a holistic design optimization and control approach for a solar-augmented industrial process to facilitate decision support. The proposed solution is designed and optimized for a dyeing industrial process case study that resulted in a 5.7 year payback period, 56.3% solar fraction, and 252.2 tons equivalent carbon emission reduction. Furthermore by implementing dynamic control, about 12.4% increase in solar gain that led to a 5.6% reduction in payback period is identified.

[en] This paper presents the thermal performance of a single stage solar adsorption system. The study includes a thermal performance comparison between two different locations in North Africa (Cairo and Casablanca) under different climate conditions. It was found that the solar fraction of the adsorption system is better under Cairo climate due to the relatively low daily solar radiation of Casablanca compared to Cairo. The solar fraction of the cooling plant was investigated theoretically for six months. The effect of the solar collector area and the mass flow rate of the solar loop on the solar fraction were investigated. The solar fraction was computed for 40 and 20 kW auxiliary heater capacity. The required solar collector area for optimum solar fraction was reduced from 140 to 88 m² with using 20 kW auxiliary heater and reduced to 46 m² with the 40 kW auxiliary heater using. The results proved that with the mass flow rate of the solar loop increasing from 0.18 to 1.5 kg/s the collector area required decreases from 110 to 60 m². This study was performed by the TRNSYS simulation using.