Efficient cooling is crucial to avert the 30-50% postharvest losses of agricultural products in warm climates when temperature control fails, preserving food quality and the integrity of the supply chain. The need for energy to cool buildings is rising globally, especially in hot countries. Most of this increase is to meet medium- and large-scale refrigeration demands to keep agricultural produce fresh. A novel solar cooling system to meet such demand is highly desirable to help meet the increased demand for energy, reduce CO2 emissions, and cut electricity costs, especially in hot and arid areas. This research proposes a thermal solar cooling system to meet refrigeration demand. The proposed system was investigated for a hot and arid environment using trnsys 18 software. The main system variables, such as thermal solar collector area, collector slope angle, and storage capacity, were explored regarding solar fraction, coefficient of performance, and primary energy saving. The results demonstrate that a solar cooling system to cool a warehouse of 144-m(2) area used to store 112 tons of fruits and vegetables at 6-8 degrees C requires an evacuated tube solar collector of area 1173 m(2) supplied by TVP SOLAR with a claimed solar to thermal efficiency of 72%. Also, the solar panel gradient to achieve the highest values of solar fraction was 30 deg, with 60 m(3) storage capacity and collector pump flowrate of 20.8 kg/s with a backup system (boiler 100 kWh capacity), to achieve the highest values of solar fraction, coefficient of performance of the whole system, coefficient of performance (COP) of absorption chiller, and primary energy saving 0.53, 0.24, 0.68, and 0.24, respectively. However, financial analysis showed that the investment cost of the proposed system is 45% higher than that of the traditional system, the vapor compressor chiller system, in terms of pound/Wh. However, the solar thermal cooling system's ongoing (running) cost was 60% cheaper than a vapor compressor cooling system. Moreover, the investment payback period was nearly 10 years. Finally, CO2 emissions would be reduced by nearly 35% per annum by utilizing the proposed system compared to a vapor chiller compressor system.

The integration of Concentrated Solar Power (CSP) and Solid Oxide Electrolysis (SOE) holds great promise for efficient and sustainable green hydrogen production. However, there is a lack of comprehensive studies reviewing the combined potential of these two technologies, which could offer enhanced efficiencies and reduced costs for large-scale hydrogen production. This review addresses that gap by analyzing the technical and economic feasibility of integrating CSP with SOE systems. This review provides a comprehensive analysis of the integration between CSP and SOE systems for green hydrogen production. The study examines critical technical challenges, including high operating temperatures, material compatibility, and heat transfer efficiency, while evaluating the economic feasibility of these integrated systems. Different CSP configurations are analysed based on their ability to provide heat alone or both heat and electricity, with thermal energy storage identified as a key factor in enhancing system performance by mitigating intermittency issues. Methodologies used in integration studies, such as simulation models and experimental setups, are critically reviewed, highlighting gaps in practical designs and real-world applications of CSP-SOE systems. However, despite these promising advances, only one laboratory-scale prototype has been demonstrated to date, underscoring the urgent need for pilot-scale CSP–SOE field testing under real direct normal irradiation (DNI) and thermal energy storage (TES) conditions. By addressing these technical and economic obstacles, this review offers insights into optimising CSP-SOE systems for sustainable, large-scale hydrogen production and provides actionable recommendations for future development.

Electricity demand in Sub-Saharan Africa is rising, and in Nigeria, over 40% lack access to electricity. A photovoltaic-thermal (PV-T) system was simulated in TRNSYS, using shea butter for active cooling of photovoltaic (PV) modules. Its performance was compared with that of conventional paraffin wax, and the effects of system design parameters were examined. Efficiency gains from using shea butter and paraffin wax were 0.18% and 0.03%, respectively, during peak solar hours. Notably, shea butter reduced cell temperatures by 1.75 °C during peak sunlight compared with paraffin wax. Peak electrical power and efficiency reached 130.53 W and 11.35%, versus 109.78 W and 9.10% for conventional PV. The optimal flow rate was identified as 2.0 LPM, with a shea butter layer thickness of 0.04 m to optimise thermal capacity and heat transfer. Environmentally, shea butter is renewable and biodegradable, with a lower carbon footprint of 2.20 kg CO2/kg compared with 3.78 kg CO2/kg for paraffin wax, according to CarbonCloud data. As a bio-based energy storage medium, shea butter not only reduces global warming potential but also supports the SDGs, including affordable energy, climate action, and responsible consumption.

The emergence of advanced absorption chillers designed for the effective utilisation of low-grade thermal energy indicates a notable advancement in the discipline of cooling technology. These chillers, which range from small air-cooled systems to larger solar-gas-fired units, are specifically designed to address the escalating requisites for environmentally sustainable cooling alternatives. This paper presents a comprehensive review of solar absorption chillers and their integration with thermal energy storage systems, with a focus on the application of phase change materials (PCMs). It analyses the performance and configurations of single, double, and triple-effect chillers, along with the role of various solar thermal collectors in delivering the required input temperatures for cooling applications. Sensible, thermochemical, and latent heat storage methods are explored, emphasising cascade PCM systems for improved thermal efficiency and load flexibility. While the review highlights the significant potential of solar-powered absorption chillers in advancing sustainable cooling, particularly in hot climates such as those found in Africa, it also identifies key research gaps. These include the limited analysis of medium-temperature cooling demand (2–12°C), the need for integrated thermal storage systems using PCMs for multi-level cooling demands, and the lack of region-specific feasibility studies in diverse African conditions. Overall, the paper offers valuable insights into optimising solar absorption cooling technologies through effective storage integration and system design, supporting their broader adoption in energy efficient, low carbon applications.

This research presents a Techno-Economic-Environmental (3E) evaluation of a cascade phase change material (PCM)-based thermal energy storage (TES) integrated into a solar-driven cooling system designed to meet different cooling loads, including freezing, refrigeration, and air-conditioning. The system employs paraffin and salt hydrate PCMs with modified melting points to enable multi-temperature operation through thermal stratification. The configuration combines ammonia-based charging and R134a/water discharging loops, supported by TRNSYS-MATLAB co-simulation, to analyse the dynamic thermal response, phase transition behaviour, and overall system efficiency. Results show that the cascade PCM arrangement provides stable cooling performance across diverse load ranges, with PCM2 (4 degrees C) and PCM3 (15 degrees C) contributing over 90 % of total stored energy. However, the high capital investment (2.2 pound million) leads to an extended payback period of approximately 115 years, despite significant electricity savings and a reduction in CO2 emissions compared to conventional systems. The findings underscore the technical feasibility and environmental merit of cascade PCM-based TES while identifying cost as the main barrier to large-scale adoption. The study contributes a general 3E framework combining thermal, economic, and environmental metrics to evaluate cascade PCM-TES integration for multi-load solar cooling. The results provide design guidance and highlight future research opportunities in cost optimisation, composite PCMs, and modular TES architectures to enhance both affordability and scalability.

Volumetric solar receivers integrated with reticulated porous ceramics (RPCs) are a key component in high-temperature concentrated solar power (CSP) systems, enabling efficient radiative absorption and convective heat transfer. While prior studies have largely focused on material properties and operating conditions, the influence of cavity geometry on thermal performance remains underexplored. This study presents a systematic computational investigation of four polygonal cavity configurations: hexagonal, heptagonal, octagonal, and nonagonal, using high-fidelity CFD simulations in ANSYS Fluent coupled with the Monte Carlo radiation model. All designs were evaluated under consistent geometric constraints and two solar heat flux inputs (4.1 kW and 4.9 kW), with varying air mass flow rates. The nonagonal receiver achieved the highest thermal efficiencies of 75 % and 73 % at the respective flux levels, outperforming conventional designs. This improvement is attributed to its compact internal structure and increased edge count, which enhance surface energy density and fluid–wall interaction. The findings demonstrate that geometric optimisation, particularly through polygonal cavity design, offers a viable pathway to enhance the thermal performance of volumetric receivers. This work provides new design insights for next-generation CSP applications requiring compact, high-efficiency thermal energy conversion.

This paper presents the design, and simulation of a novel concentrated solar power (CSP) system integration with solid oxide electrolysis (SOE) to generate superheated steam required for efficient hydrogen production. The system comprises of 10 parabolic dish collectors, SiSiC cavity receivers, and a heat exchanger with two components. An evaporator and a superheater collectively achieve a high thermal efficiency of 73%. Computational fluid dynamics (CFD) simulations demonstrated that the SiSiC receiver can maintain an air outlet temperature of 1555K, which is 8% more efficient than a similar design reported in the literature. This would facilitate the generation of superheated steam necessary for the SOE process. A water flow rate of 28.8kg/h directly influences the system's hydrogen production capacity, which reaches 2.56kg/h at optimal conditions. The heat exchanger components were designed using Aspen EDR, while the entire system simulation was conducted using Aspen Plus, demonstrating the system's potential to meet industrial standards for sustainable hydrogen production. This article serves as a good reference in investigating the feasibility of CSP-SOE systems as a promising pathway for large-scale renewable hydrogen production.

This study presents an optimisation simulation-based approach for the ideal solar absorption cooling system design, including a thermal storage tank and a solar thermal collector. The strategy aims to reduce the costs of solar chilling systems by determining the optimal collector area and storage capacity while minimising electricity consumption to operate system. A hybrid approach is used to achieve the optimal configuration by combining dynamic simulation with TRNSYS and an optimisation algorithm using Gen-Opt. The system's life cycle cost, over 20 years, serves as the optimisation goal. The study examines the effects of three economic factors: solar collector area, storage capacity, and electricity prices, on the design. The outcomes are analysed from technical and economic perspectives across various African locations. Additionally, techno-economic optimisation was conducted to identify the best set of system design parameters. The findings illustrate how electricity prices and climatic conditions influence the techno-economic feasibility of the system. Alkufra demonstrates and achieves the best techno-economic performance due to its high solar radiation and lower reliance on auxiliary power, which reduces electricity costs throughout the system's lifetime. Cairo achieves a fairly reasonable performance, providing satisfactory economic viability compared to Lagos or Accra, due to sun availability and electricity costs.

This work introduces a new indoor method for the artificial soiling of solar reflectors, employing a closed-loop wind tunnel chamber to replicate controlled deposition methods in a laboratory setting. The experimental setup includes dispersing a constant dust amount and allows manipulation of deposition to examine the impact of airflow speeds (1, 3, and 4.5 m/s), dust concentration and various humidity levels. The results show significant improvements of artificial soiling deposition, leading to more uniform deposition on the mirror surfaces and allowing a repeatable test.

The optical design and the mechanical structure of a new heliostat is described for application in the Solar Water plc large-scale desalination plant, to be constructed in the Middle East. The heliostat field is required to reflect direct solar radiation onto a section of the desalination dome, requiring the design of a new type of heliostat. A novel dual-tilted dual-axis tracking heliostat is the design selected to meet the optical requirements specification. The supporting structure also requires a unique approach, which we describe in this paper. The optical and mechanical analysis of the heliostat and its operation are also presented.

The research work explores the impact of temperature on Silicon photovoltaic (PV) panels considering Nigeria as case study. It is found that high solar radiation in Nigeria increases surface temperature of PV panel above 25oC of optimal operating temperature of PV panels. Redundant energy gain from incident solar energy is dissipated at the rear of PV panels as heat, which reduces the efficiency of PV panel. Cooling mechanism is needed to cool the PV panels to increase the efficiency. In this study we demonstrated a unique design of a bifunctional photovoltaic-thermal (PVT) system by employing heat exchanger at the rear of PV panel and water is used as a working fluid that is circulated through the heat exchanger to remove the excess heat. It is observed from the simulation results that Maiduguri peak annual electrical power output gives 1907kWh/kWp which is the highest, because of high solar radiation average of 727W/m2 in a year. And for Makurdi the peak annual electrical power output of 1542kWh/kWp while for Port Harcourt the peak power output of 1355kWh/kWp respectively. Interestingly, Polycrystalline Si-PV surface temperature decrease from 49.25oC to 38.38oC. Electrical power increased from 1526.83W to 1566.82W in a day and efficiency increase from 13.99% to 15.01%.

The research work explores the impact of temperature on Silicon photovoltaic (PV) panels, considering Nigeria as a case study. It is found that high solar radiation in Nigeria increases the surface temperature of PV panels above 25 °C of the optimal operating temperature. The redundant energy gain from solar irradiance creates heat at the rear of solar panels and reduces their efficiency. Cooling mechanisms are therefore needed to increase efficiency. In this study, we demonstrated a unique hybrid system design employing a heat exchanger at the back of the panel, with water circulated through the back of the PV panel to cool the system. The system was simulated using TRNSYS at three locations in Nigeria—Maiduguri, Makurdi, and Port Harcourt. The results of the peak annual electrical power output in Maiduguri give a power yield of 1907 kWh/kWp, which is the highest, due to a high solar radiation average of 727 W/m2 across the year. For Makurdi, the peak annual electrical power output is 1542 kWh/kWp, while for Port Harcourt the peak power output is 1355 kWh/kWp. It was observed that the surface temperature of Polycrystalline Si-PV was decreased from 49.25 °C to 38.38 °C. The electrical power was increased from 1526.83 W to 1566.82 W in a day, and efficiency increased from 13.99% to 15.01%.

This paper evaluates the potential effect that operation lifetime could have on the accuracy and reproducibility of the Condor reflectometer. For this purpose, three Condors with different operation lifetimes have been used and compared in this study. In addition to the device’s operation lifetimes, reproducibility and the repeatability of the measurements have also been evaluated. Silvered glass mirrors at different states have been used, e.g., clean, soiled and eroded in order to evaluate the effect of the surface properties on the difference reported using different devices. The obtained results have shown that the difference in specular reflectance reported by the three different Condors is more noticeable in case of soiled and eroded glass mirrors compared to clean sample. This could be linked to the surface roughness more than to the years of operation of the device itself.

The durability of thick solar glass mirrors has been evaluated in this study by exposing samples at two potential exposure sites. Samples have been exposed for a period of 18 months at different orientations (North, South, East, and West) to evaluate the impact of orientation on the durability. The samples performance has been evaluated by measuring the specular reflectance of the glass samples before and after an appropriate cleaning process. In addition, the contact angle and the surface energy have been analysed. Obtained results show that mirror durability is very specific to the environmental conditions of the exposure site.

The research introduces an innovative approach to enhancing the efficiency of Multi-tower Concentrated Solar Power (CSP) through a configuration termed Auxiliary Tower with Subfield (ATS). ATS introduces an auxiliary tower and creates a subfield by adding heliostats near its position, aiming to optimize the solar field's optical efficiency and offer modular decentralized power output. ATS configuration employs existing field configurations to pinpoint inefficiencies where an additional tower can be installed, and heliostats are systematically added to the subfields through numerical optimization using various design variables. Although the inclusion of a subfield in the ATS configuration enhances energy output, it does not always offset the additional costs of the auxiliary tower, receiver, and extra heliostats, in small fields. However, when applied to larger fields, starting from 200MWth, ATS begins to provide a lower Levelized Cost of Heat (LCOH) compared to optimized conventional thermal fields, demonstrating its potential applicability and efficiency in larger-scale CSP setups. Applying ATS to a 120 MWth Gemasolar-like plant further confirms its advantages, with 160 MWth emerging as the optimal enhancement point that boosted efficiency while lowering LCOH. ATS shows promise as an efficient, modular approach to scaling up power tower system.

Parabolic trough collectors (PTC) are an already established technology set to prove its competitiveness. Recently, a lot of research is ongoing to further enhance the thermal performance of PTC systems. Computational Fluid Dynamics (CFD) can help in the design and development of PTCs with optimized thermal efficiency. In the current work, a combined enhancement in the performance of a PTC is evaluated, involving modifications to the geometry of the absorber tube and the use of a heat transfer fluid (HTF) (Syltherm800). Absorber tube geometries involving dimpled protrusions (D-PTC) and circumferential inclined ribs (IR-PTC) are used. The performance of PTC with and without turbulators is compared with that of a smooth absorber tube by calculating the Nusselt number (Nu), friction factor (f) and performance evaluation criterion (PEC). PEC values of 1.46 and 1.18 are observed by using inclined ribs and dimpled protrusions, respectively at an absorber tube inlet temperature (Tin) of 500 K and mass flow rate (m) of 0.5 kg s-1. Thus, a significant enhancement in thermo-hydraulic performance of PTC is observed with inclined rib turbulators.

Spain is one of the front runners of the development of Concentrated Solar Power (CSP) projects. In recent years, however, the CSP industry in Spain has faced significant financial challenges due to a dramatic withdrawal of the Feed-in-Tariff (FIT) in 2013. The primary aim of this paper is to assess when, and under what conditions, CSP projects, in particular, Parabolic Trough Collectors can potentially reach grid parity in the absence of any subsidies. This paper also goes further to investigate whether and how Parabolic Trough Collector (PTC) projects can be financially viable in the post-subsidy period, using the System Advisor Model as a simulation tool to conduct techno-economic analyses. The simulation results indicated that a 50MWe PTC project with TES of 4 hrs and a PPA price of ?0.20 per kWh is the most viable model for developing CSP projects in Spain under post-subsidy condition. This paper concludes that, under current retail electricity prices and post-subsidy conditions, PTC projects can reach grid parity and become viable without direct incentives. Even though direct incentives will not be required, the CSP industry in Spain is still far from becoming fully self-sustained.