Search

A study by dynamic simulation using the TRNSYS software was carried out to visualize the performance of a solar water heater with forced circulation for one year. Thermal needs in domestic hot water for an average family of six people living in the city of Oran in Algeria are covered by solar energy by up to 63%. Parameters such as the angle of inclination, the surface of the solar panel, the storage volume, the heat exchanger's surface, and the flow rate of the solar loop have been optimized. An analysis of the temperature stratification inside the balloon was presented, along with the calculation of charging and discharging efficiency. The influence of the position of the exchanger inside the tank has been shown on the temperature stratification and the charging and discharging efficiency [ABSTRACT FROM AUTHOR]

A study with the TRNSYS software of solar water heater installations was simulated for the domestic hot water needs of an average family in the Mediterranean climate of the city of Oran in Algeria. Comparisons of systems with one tank and two tanks have shown similarities in the quantities of energy consumed and captured by the solar panels, but differences have been observed in the coverage of auxiliary energies. On the other hand, the two-tank system makes it possible to produce very significant temperature stratification. [ABSTRACT FROM AUTHOR]

To improve the stability of solar heating and reduce the high cost of air source heat pump heating, the idea of air source heat pump assisted solar stable heating was proposed. A solar vacuum tube water heater-air source heat pump system was developed and bulit in Weiling Township, Qilihe District, Lanzhou, Gansu Province. The performance of the system was compared to analyze the heat collection efficiency, heat pump coefficient of performance (COP), solar energy guarantee rate, and energy efficiency ratio under sunny, overcast, and cloudy conditions. The results show that the effective heat obtained by solar energy under sunny, overcast, and cloudy conditions is 75.5 kW·h, 4.1 kW·h, and 49.2 kW·h respectively, the system heat collection efficiency is 61.3%, 26.6%, and 55.2%, the average coefficient of performance(COP) of the solar heat pump is 3.6, 3.4, and 3.6, the average COP of the air source heat pump is 0, 2.9, and 3.1, the actual heat supply of the system is 113.4 kW·h, 125.9 kW·h, and 124.8 kW·h, the system power consumption is 33.4 kW·h, 50.5 kW·h, and 42.7 kW·h, the system solar energy guarantee rate is 66.6%, 3.3%, and 39.4%, and the system energy efficiency ratio is 3.4, 2.5, and 2.9 respectively. The research results prove that the solar vacuum tube collector-air source heat pump system is feasible for heating and provide a new way for heating in cold areas.

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.

In this research, an advanced hybrid steam generation system using solar energy was designed, with higher performance and lower cost compared to other systems and researches. It's an ideal system where fossil fuels are still plentiful. The selected system units with the innovative automatic control allows the absorption of all levels of solar radiation and its exploitation in steam generation. The boiler is a classic fire tube one and the solar collector is a modified linear parabolic collector that tracks the sun in one of three tracking modes. A proper Matlab program has been prepared to determine and demonstrate the performance of the system and the optimal characteristic values of the collector that provide the maximum seasonal solar fraction of the plant. It was found that the average monthly daily solar fraction of the plant in Antalya, Mediterranean region, is 0.85 in June and 0.28 in January with the collector optimal characteristics and east-west tracking within 12 hours stable daily steam generation. It is demonstrated that the deviation in an optimum characteristic value of the collector causes a reduction in solar fraction. This study forms the basis for a similar plant construction project to test it in practice under real climatic conditions.

Fiji, a country that derives more than 35% of its GDP from tourism and relies on imported fuel for its energy need, demands renewable energy to make the country's tourism sustainable, affordable and more attractive to the tourist. In view of this, this study investigated the techno-economic performance of the SWH system in four selected locations representing each of the four regions in Fiji with the aim of promoting sustainable tourism. The result shows that the solar fraction ranges from 100-90%, 61.8-48.3% and 82.8-67.9% for unglazed, glazed and evacuated solar water collectors in all the selected locations, respectively. The energy saved ranges from 5149-4744 kWh, 3184-2544 kWh and 4265-3576 kWh for unglazed, glazed and evacuated tube SWH collectors for all four selected locations respectively. The emission reduction ranges from 1.7-1.6 ton-CO2, 1.1-0.86 ton-CO2 and 1.4-1.2 ton-CO2 for unglazed, glazed and evacuated tube SWH collectors for all the four selected locations, respectively. The equity payback periods range from 4.6-4.2 years, 13.8-10.7 years and 18.3-15.4 years for unglazed, glazed and evacuated tube SWH collectors for all the four selected locations. Generally, the unglazed collector is the most suitable for all the locations investigated in this study. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this study is to investigate the potential use of solar energy within an oil refinery to reduce its fossil fuel consumption and greenhouse gas emissions. A validated ASPEN HYSYS model was used to investigate the products produced from heavy crude oil in the refinery. Using TRNSYS software, the proposed Parabolic Trough Collector (PTC)-based solar heating system paired with the boiler is modelled. Sensible thermal energy storage (TES) system is integrated into the refinery's process heating to handle the intermittent nature of solar energy. It was discovered that 463 m2 of the PTC area coupled with a 15000-L TES tank can result in a maximum life cycle cost savings of 21.046 thousand USD for an annual heat supply of 116,944 MWh to generate steam at a temperature of 200–220 °C. In the proposed hybrid heating system, the yearly solar fraction is determined to be 26.99% and the payback period is 8.77 years with the average solar irradiance of 900 W/m2. In addition, the system can yearly reduce greenhouse gas (GHG) emissions by about 34.045 tonnes of CO2 equivalents.

This work aims to quantify the long-term performance improvement of solar water heater system by using both simple and hybrid nanofluids. For this purpose, transient system simulations of a flat plate solar collector have been carried out and discussed using titanium oxide, magnesium oxide, and copper oxide/multiwalled oxide–carbon nanotube nanofluid-based nanoparticles. Tunisian climatic conditions with a typical household need has been considered, and the investigations have been established in terms of energy amounts, solar fractions, and harmful CO2 emission avoidance. Results showed an increase in the collector performances using the considered nanofluids. In particular, using 0.2v% and 0.6v% TiO2 homogeneously dispersed in water reduced the auxiliary energy up to 47.6 and 60.9%, respectively, compared to the reference case using water. The flat plate solar collector has an annual production of 1294 kWh for a need of 1998 kWh, which equates to an annual coverage rate of roughly 65%. Additionally, it was shown that when MgO with MWCNT were used instead of MgO nanofluid-based nanoparticles, the solar fraction increased by 5.14%. The use of 0.6 volume percent TiO2 nanoparticles in water reduces hazardous CO2 emissions by up to 0.829 tons annually. [ABSTRACT FROM AUTHOR]

This paper focused on the performance monitoring and modeling of a 6.0 kW, 2000 L hybrid direct expansion solar assisted heat pump (DX-SAHP) water heater used for the production of hot water in a university students' accommodation with 123 females. The data of total electrical energy consumed, volume of hot water consumed, ambient temperature, relative humidity, and solar irradiance were obtained from the data acquisition systems and analyzed in conjunction with the energy factor (EF) of the system. A multiple linear regression model was developed to predict the EF. The EF of the hybrid DX-SAHP water heater was determined from the summation of the coefficient of performance (COP) of the heat pump unit and the solar fraction (SF) of the solar collectors. The operations of the hybrid energy system were analyzed based on three phases (first phase from 00:00–08:00, second phase from 08:30–18:30, and third phase from 19:00–23:30) over 24 h for the entire monitoring period. The average EF of the hybrid energy system per day during the second phase of operation was 4.38, while the SF and COP were 0.697 and 3.683, respectively. The developed multiple linear regression model for the hybrid DX-SAHP water heater accurately predicted the determined EF. [ABSTRACT FROM AUTHOR]

Currently, the development of energy production projects in the building sector using alternative energy sources such as solar energy is growing rapidly. This increasing technological progress to achieve the needs of comfort and safety can be considered a major priority, particularly with concerns about energy shortages and current environmental issues threatening not only human well-being but ecosystems as well. The present research aims to provide a comprehensive model for enhancing the energetic performance of rural Moroccan houses, by exploring solar radiant heating systems. The evaluation of the solar floor heating system is carried out by trnsys to evidence the effect of various design parameters on performance indexes of the system concerning six Moroccan cities, which representatively correspond to the Moroccan climatic zoning. The examined analyses cover the effect of the collector area, storage tank volume, and mass flowrate in the solar loop and the building heating loop. Moreover, how the variation of thickness and piping material affect the performances was discussed as well. The major finding of this work is optimizing the system performance gives the possibility to meet adequately the heating load. The energetic analysis shows the system's adaptability to the Moroccan climate, whose solar fraction is around 65% and 87%. For most of the examined sites, it was observed that the demand for auxiliary energy is limited from October to May. The economic investigations revealed that payback periods of the examined system ranged between 7 and 13 years. Besides, the energy and economic outcomes of such systems in Morocco, they are capable to mitigate the huge amount of CO2 emissions as compared to conventional heating systems. [ABSTRACT FROM AUTHOR]

Olympic swimming pools are places of enormous energy consumption. Controlling and predicting this behavior is an essential issue in order to minimize energy consumption by integrating renewable energy and proposing actions to reduce consumption. It is crucial to choose an efficient solar installation and optimize operating factors to specify the optimal combination of the best operation. This paper studies the case of an Olympic swimming pool with the standard size of 50 m in length and 25 m in width, with a depth of 3 m, the water temperature is maintained at around 25–28°C, suitable for prolonged and intense swimming. The aim is to integrate a solar thermal system to meet the energy needs of the pool under the climatic conditions of Rabat City in Morocco. In order to address the problem of the work, a comparative study was carried out first between the technology of solar thermal Flat-Plate Collectors (FPC) and Evacuated Tube Collectors (ETC). The purpose is to make the technological choice best suited to the case study, decision-based on analysis of critical indicators: temperatures, efficiency and solar fraction. After having optimized the installation technical characteristics, a parametric study was then started to present the best combination of the operating parameters of the pool. The study took into account the effect of thermal cover on the pool, the rate of cold-water intake, and the occupancy rate in the pool. The results showed the importance of a thermal cover for the energy of consumption reduction, with an occupancy rate of 0.15% and a water supply rate of 5% for optimal operation and a reduced energy bill. [ABSTRACT FROM AUTHOR]

The main categories of solar water heating systems (SWHSs) are the thermosyphon and the forced circulation (FC). This paper presents an experiment carried out with the aim to compare the energy performance of the FC with a thermosyphon SHWS. Identical SWHSs were installed side by side at the University of West Attica in Athens, Greece. Domestic hot water load was applied to both systems via a microcontroller-based dispensing unit which mimics the demand profile. The trial period comprised the last two months of spring (April and May). For the first law assessment, two energy indicators were utilized: the solar fraction (SF) and the thermal efficiency of the system (ηth). On days with distinctive weather conditions, both systems obtained approximately equal SF and ηth values, without a specific preference between the ambient conditions and the type of SWHS. Regarding a four-day nonstop operation, the FC overperformed the thermosyphon system at both energy indicators. Namely, for the FC and the thermosyphon SWHS, the SF was calculated to be 0.62 and 0.48, and the ηth was 68.2% and 53.3%, respectively. [ABSTRACT FROM AUTHOR]

• The determination of solar electrical and thermal coverage of a PVT collector for domestic hot water and building heat pump through TRNSYS simulation. • The investigation of PVT size on the solar electrical and solar coverage. • The economic analysis for the system feasibility and cost effective. The application of Photovoltaic/Thermal and heat pumps in buildings is becoming more and more attractive to many scholars due to its advantage of providing building heating and cooling with clean energy that has less negative effects on the environment. In this research, we have investigated the energy coverage of different PVT sizes to satisfy the electricity demand of heat pump system to provide heating and cooling applications in a habitation building of three rooms in Chengdu city of China in the line of Zero Net Energy Homes. The Photovoltaic/Thermal system investigated here provides thermal energy for Domestic Hot Water while generating the electrical energy to the building equipment and operates air heat pump units responsible of cooling and heating the building. TRNSYS as thermal dynamic software is used to model and simulate the annual coverage of the Photovoltaic/Thermal module through solar fraction determination where the results show that there is a significant increase in solar electrical fraction with the increase of the Photovoltaic/Thermal area. The highest electrical solar factor of 0.85 and 0.56 were achieved with a Photovoltaic/Thermal module of total area of 78 m2 during the transition months of April and October, respectively. The economic analysis shows that the Photovoltaic/Thermal technology is not that much competitive in Chengdu city due to the weather with medium annual solar radiation intensity and high discount rate of Photovoltaic power in China. [ABSTRACT FROM AUTHOR]

In the present work, a system comprising cylindrical vertical type sensible-based thermal energy storage (TES) tanks integrated with external type compound parabolic concentrating (XCPC) solar collectors and heat loading device was designed, fabricated, constructed, experimented, and analyzed. The XCPC solar collector system transfers the solar energy to charge the insulated TES tanks through heat transfer fluid circulation and discharge the energy to the selected application. The primary objective of the present research is to study the performance and stratification effects during the charging and discharging cycles through various parameters to select the suitable phase change materials (PCMs) for the proposed cascaded latent heat storage (CLHS) system. Further, experiments were conducted under simultaneous and sequential modes of charging and discharging processes. The performance analysis of the overall system on a time-average basis (0.125 hr) was carried out. The results revealed that simultaneous mode would help to collect more energy from the solar collector, and it increases the cumulative energy stored in the tank and the average charging efficiency of the tank. The same was also ensured from the stratification performance parameters, such as stratification number, Richardson number, and mix number. The higher stratification achieved in both modes revealed that the CLHS system with three different PCMs of phase change temperatures of 70°C, 63°C, and 53°C, located at three different zones, will enhance the performance of the storage system. The results are highly beneficial for practicing engineers toward designing the CLHS system integrated with solar collector for any application. [ABSTRACT FROM AUTHOR]

Fossil fuels are being used to accommodate domestic heating needs all over the world, and the alarming rise in carbon footprint is demanding the world to shift towards renewable energy technologies. A key strategy to lessen household fossil fuel consumption is a solar hybrid district heating network integrated with seasonal thermal energy storage (TES). The objective of this study was to analyze and compare the thermo-economic performance of solar hybrid district heating systems integrated with borehole TES systems in ' 'Pakistan's five climate zones and identify the best suitable solar thermal collector technology. Based on the solar energy incident on different types of thermal collectors, a validated TRNSYS model was used to investigate the dynamic performance indices i.e., solar fraction, system efficiency, and thermal storage efficiency. The heat demand model and weather-related data were changed as input to the system. Based on mentioned performance indices, out of 5 different cities having different climates, climate Zone-C(Quetta), having a continental semi-arid climate, is selected as the most suitable, and Zone-E(Karachi) has tropical desert climate as the least favorable among five different zones with a seasonal storage efficiency of 61% and 19% respectively. The solar fraction is about 91%, also up to the mark as the proposed system utilizes both solar energy and auxiliary systems. Further, the implementation of different thermal collector technologies Parabolic Trough Collector, Evacuated Tube Collector & Flat Plate Collector, revealed that the thermal efficiency of ETC is best among all, with the highest value of 65%, followed by PTC at 44%, and FPC shows the least efficiency of 36%. The economic analysis shows that the model embedded with ETC has a minimum payback period of 6.90 years, followed by an FPC of 7.22 years and a maximum for PTC of 7.38 years. The analysis presented in the current study provides guidelines for researchers and policymakers to identify acceptable location-based best solar thermal collector technologies coupled with seasonal thermal storage for district space heating. • Borehole thermal energy storage efficiency is affected by district heating load. • A district heating system deployed in different climate zones gives varying results. • A higher solar fraction does not give better performance of district heating system. • Zone C(Quetta) is most suitable zone for proposed system providing maximum results. • Use of different solar thermal collectors affects payback period as well. [ABSTRACT FROM AUTHOR]

Using alternative and clean energy resources is considered the most effective method to deal with the environment and energy crises nowadays. In this study a comparative analysis of FPC data for DHW are theoretically and experimentally evaluated to optimise the design parameters. A forced circulation solar heating system using flat-plate collector, is modelled using T*SOL as a new approach, for hot water requirements of a laboratory unit at Szent Istvan University, in Gödöllő, Hungary. The modelling shows 69% solar fraction and 510 kWh annual solar gain. Furthermore, the comparison study was based on these two factors, and the two results matched with 93.12% accuracy. After the modelling, practically, the exergy analysis was conducted to determine and highlight the losses of the system. Since Hungary is considered a cold climate country, it was found that the thermal and optical losses from the collector and the piping system were tremendous. Then all the necessary design parameters were studied to achieve the optimal working points using non-linear correlation response surface method (RSM, which has never been used as an analysis tool in the solar field) at two perspectives (solar fraction and annual yield) for seven factors using R script. The factors were collector surface area, inclination angle, glycol-water ratio, tank capacity, boiler capacity, desired hot water temperature, and volume flow-rate. We identified the most influential single factors using ParetoPlot and each two-factorsꞌ interaction using contour plots. The most influential factors on the solar yield are solar collector surface area, tank capacity, desired hot water temperature and volume flow rate by magnitude effects of +129.7, +125.3, +50.9 and +17.2 kWh per annum, respectively.

A solar cooling and heating plant with a 1000 l hot water storage tank has been operated since 2018. Two main problems were observed: (1) a fluctuating operation of the absorption chiller due to a high number of stat-up and shut-down procedures; (2) high electricity consumption caused by a low solar fraction SFn of 50.9% during the cooling period. In 2021, the solar plant was retrofitted by employing a shell and tube heat exchanger based on a PCM melting at 64 °C and by adjusting the control strategy. The system performance was evaluated and compared before and after retrofitting based on the operational data in 2021 and 2022. The total number of switch-on times of the chiller shrank by 33.5% and the operation time was increased by 65% in 2022 due to the stable hot water inlet temperature. Contributing to the high heat storage capacity of the PCM storage, more solar thermal energy was utilized and the average SF n reached 75.6% during the cooling period in 2022, leading to a 24.4% reduction in the total electricity consumption compared to 2021. • A fluctuating operation of the absorption chiller was observed before retrofitting due to a higher number of stat-up and shut-down procedures. • A high electricity consumption was caused by a low solar fraction SF n of 50.9% during the cooling period before retrofitting. • After retrofitting, the total number of switch-on times of the chiller shrank by 33.5% and the operation time was increased by 65% due to the stable hot water inlet temperature. • Contributing to the high heat storage capacity of the PCM storage, the average SF n reached 75.6% during the cooling period in 2022, leading to a 24.4% reduction in the total electricity consumption compared to 2021. [ABSTRACT FROM AUTHOR]

There is a limited number of empirical studies on the actual energy output of solar water heating systems (SWHSs). In the Sahel, where solar potential is abundant, the transition to sustainable energy solutions requires comprehensive evaluations of SWHSs, including their economic viability. Such assessments are crucial for informed decision-making by stakeholders and for facilitating the widespread adoption of SWHSs, including their integration into industrial processes. This paper presents a year-round experimental study assessing the real-world performance and economic viability of a SWHS integrated into a hospital laundry in Ouagadougou, Burkina Faso. The primary aim of the study is to analyse the practical performance of the integrated collector storage (ICS) SWHS and evaluate its economic viability. The performance of the ICS SWHS is monitored over the course of a year. Data collection included measurements of solar irradiation, ambient temperature, inlet and outlet water temperatures, and energy output of the SWHS. Economic assessments considered factors such as installation costs, energy savings, and payback periods. Environmental implications were evaluated through the estimation of avoided CO 2 emissions. The ICS SWHS achieved an efficiency of 38 % and a solar fraction of 17 %, resulting in approximately 1.3 t of avoided CO 2 emissions annually. Economic assessments revealed extended payback periods, leading to exploration of alternatives. Subsequently, a water-in-glass evacuated tube collector (ETC) system, deemed more cost-effective, was selected and it indicated superior energy production. Preliminary results suggest compelling payback periods for the ETC system, ranging from 3.1 to 4.5 years under realistic scenarios. The study underscores the significance of practical experimentation, appropriate technology selection, and improved market regulations for informed decision-making. SWHSs present a promising avenue for sustainable energy solutions in the Sahelian region and beyond, offering both economic benefits and environmental impact. • Examined SWHS in Sahelian climate through a year-round field trial in Burkina Faso. • Evaluated ICS SWHS with 17 % solar fraction, 38 % efficiency, serving a hospital laundry. • Identified economic viability concerns with a long payback period for ICS system. • Proposed cost-effective Water in Glass ETC SWHS, demonstrating superior performance. • Stressed the need for suitable SWHS technology in healthcare settings. [ABSTRACT FROM AUTHOR]

Solar cooling systems, specifically solar absorption cooling systems, are becoming an attractive subject since they are great alternatives to the conventional cooling systems which lead to high electrical consumption. In addition, this system can provide cooling without greenhouse gas emissions. Hence, many combinations of different components might be adopted to apply the solar absorption cooling system. This paper will discuss the absorption chiller working cycle, the absorption chiller working fluids, the solar collectors to be combined with solar cooling systems and the single-effect absorption chiller. Furthermore, the variation of the coefficient of performance, the solar fraction and the economic study will be discussed. The goal of this review is to present previous studies and analyze their results; highlight the environmental, energetic, and economic viability of such systems and tackle future challenges regarding solar absorption cooling system and discuss the application of this system on new climates and more specifically on Lebanon.

Using solar systems is increasing due to oil shortage, environmental effects, and renewability. Solar thermal combisystems use the energy taken to provide for both domestic hot water (DHW) and space heating (SH), which is under investigation by energy researchers. This study uses a dynamic energy analysis of the solar system to evaluate the solar parameters. Also, the environmental and economic effects of using solar systems are discussed. The study is done on four different consumption usages in four different climates of Iran. Energy simulation shows that hot & humid climates, office, and mall usages have the largest solar fraction (minimum of 95.2, 38.5, and 35%, respectively). The lowest optimal collector surface area belongs to a hot and humid climate with 4–21.5 m2 and office usage with 4–159 m2. Also, collector efficiency decreases with higher collector area amounts. 20-year economic analysis shows that the net present value of hospital usage with a maximum of $2216.8, cold climate with a maximum of $768.4, and hot & humid climate with a maximum of $2765.9 are the most affordable. The environmental analysis illustrates that CO2 emission avoidance is highest in hospital usage with a maximum of 1924.5 kg, residential usage with a maximum of 1707.8 kg, and hot & dry climate with a maximum of 1349.2 kg. Lastly, the preference selection index (PSI) method is used to rank all application possibilities, which shows that using systems is highly recommended in cold, hot & humid climates with the best ranks of 1 and 3 and hospital usage with the best rank of 1. • Solar fraction of solar thermal combisystems can reach up to 95% in hot and humid climate. •Collector efficiency is higher in low collector areas. •Economic analysis shows that cold and hot and humid climates are mostly affordable. •Environmental analysis indicates that residential and hospital usages avoids more CO2 emissions. •PSI method of mathematical prioritizing is used to rank choices. [ABSTRACT FROM AUTHOR]

Increasing surface temperature has a significant effect on the electrical performance of photovoltaic (PV) panels. A closed-loop forced circulation serpentine tube design of cooling water system was used in this study for effectively management of the surface temperature of PV panels. A real-time experiment was first carried out with a PV panel with a cooling system at heat transfer fluid (HTF) flow rates of 60 kg h−1, 120 kg h−1, and 180 kg h−1. Based on the experimentation, a correlation for a nominal operating cell temperature (NOCT) and thermal efficiency for collector was developed for experimental validation of useful energy gained, cell temperature, and electric power generation. The developed correlations were validated with the use of electric power electrical power and useful energy gained in photovoltaic serpentine thermal solar collector (PV/STSC) and fitting into the experimental results with a deviation of 1% and 2.5% respectively. Further, with the help of developed correlations, a system was developed in the TRNSYS tool through which an optimization study was performed based on electric and hot water demand. The findings indicated an optimal system with an 8-m2 PV/STSC area, a HTF flow rate of 60 kg h−1, and thermal energy storage (TES) system having a volume and height of 280 l and 0.8 m could meet 91% and 33% of the hot water demand for Ac loads and 78% or DC loads, respectively. [ABSTRACT FROM AUTHOR]

While milk is the most consumed human drink, industrial food processes exist everywhere. It consumes a massive amount of hot water at moderate temperature levels, essential to generating the final product. The integration of small and medium enterprises (SMEs) with solar thermal systems creates noticeable savings in fuel and electricity. Identifying the integration system employed can be solved using innovative engineering simulation tools like T*sol. And the maximum points and configuration can be adjusted to achieve the maximum solar yield. This paper compares the middle east and central Europe for a medium-size pasteurising plant with an average daily consumption of 20 kWh and an annual energy requirement of 7.3 MWh. The processed heating system is supported parallelly with a 25 kW boiler for two main cities, Damascus and Budapest, with different standard collector types, FPC, ETC, and CPC. It shows that for a small-medium-sized pasteurising plant with 20 kWh daily consumption, a solar system consists of 30 m2 and 20 m2 for Budapest and Damascus. With the performance of annual solar fraction 64% and 82%, and total system efficiency 14.9% and 17.2%, respectively. It shows the importance of having solar thermal technologies in the abovementioned regions. [ABSTRACT FROM AUTHOR]

This paper focused on the performance monitoring and modeling of a 6.0 kW, 2000 L hybrid direct expansion solar assisted heat pump (DX-SAHP) water heater used for the production of hot water in a university students’ accommodation with 123 females. The data of total electrical energy consumed, volume of hot water consumed, ambient temperature, relative humidity, and solar irradiance were obtained from the data acquisition systems and analyzed in conjunction with the energy factor (EF) of the system. A multiple linear regression model was developed to predict the EF. The EF of the hybrid DX-SAHP water heater was determined from the summation of the coefficient of performance (COP) of the heat pump unit and the solar fraction (SF) of the solar collectors. The operations of the hybrid energy system were analyzed based on three phases (first phase from 00:00–08:00, second phase from 08:30–18:30, and third phase from 19:00–23:30) over 24 h for the entire monitoring period. The average EF of the hybrid energy system per day during the second phase of operation was 4.38, while the SF and COP were 0.697 and 3.683, respectively. The developed multiple linear regression model for the hybrid DX-SAHP water heater accurately predicted the determined EF.

A decrease in the utilization of fossil energies, mainly by replacing them with renewable energy sources (RESs), is regarded as a potential energy source in today's applications. RESs are broadly utilized for heating purposes and particularly with applications in solar water heater (SWH). Despite the accessibility of SWH technologies and their affordable prices in Iran, there is no comprehensive study to explain the potential of Iranian regions to supply hot water for household applications. This one-year work, hence, attempts the first dynamical simulation of a solar heating system to provide sanitary hot water (SHW) as well as hot water demanded to heat 47 stations in Iran. Weather data were extracted from METEONORM and environmental-technical analyses performed by thermal solar (TSOL) software. Stations were ranked based on CCR and BCC models in data envelopment analysis (DEA) method using GAMS V 24.1. As with results, a total of 223.1 MWh solar heat is generated annually from all stations that prevent the emission of 64.5 t CO2 every year. According to CCR and BCC models, Bandar Abbas, Chabahar, Fasa, Iranshahr, Kermanshah, Khoramabad, Sarab, Shahr-e-kord, Yasuj, Zanjan, and Zahedan are the best in this regard. Also according to the economic analysis, the average price of home solar heating in Iran is 0.160 $/kWh. [ABSTRACT FROM AUTHOR]

A decrease in the utilization of fossil energies, mainly by replacing them with renewable energy sources (RESs), is regarded as a potential energy source in today’s applications. RESs are broadly utilized for heating purposes and particularly with applications in solar water heater (SWH). Despite the accessibility of SWH technologies and their affordable prices in Iran, there is no comprehensive study to explain the potential of Iranian regions to supply hot water for household applications. This one-year work, hence, attempts the first dynamical simulation of a solar heating system to provide sanitary hot water (SHW) as well as hot water demanded to heat 47 stations in Iran. Weather data were extracted from METEONORM and environmental-technical analyses performed by thermal solar (TSOL) software. Stations were ranked based on CCR and BCC models in data envelopment analysis (DEA) method using GAMS V 24.1. As with results, a total of 223.1 MWh solar heat is generated annually from all stations that prevent the emission of 64.5 t CO2 every year. According to CCR and BCC models, Bandar Abbas, Chabahar, Fasa, Iranshahr, Kermanshah, Khoramabad, Sarab, Shahr-e-kord, Yasuj, Zanjan, and Zahedan are the best in this regard. Also according to the economic analysis, the average price of home solar heating in Iran is 0.160 $/kWh.

• A novel triangular solar air collector was proposed. • The dynamic model of triangular solar air collector was established and validated. • The performance of triangular collector and flat plate collector was compared. • The heat collection capacity of triangular collector increased by 24.3%. The application of solar air collector (SAC) in rural residence is beneficial to the realization of clean heating in rural areas and improvement of the thermal comfort in the rural residence, but the available covered area for the SAC on the south wall of rural residence is limited. In this research, a novel triangular solar air collector (TSAC) with a tilted transparent cover plate is proposed. With the same south wall covered area, the TSAC can receive more solar irradiance, which improves the heat collecting power. A mathematical model of the TSAC is established. Experiments are conducted to validate the model. The performances of the TSAC and the flat plate solar air collector (FSAC) with the same perforated corrugated absorber (PCA) are compared and analyzed under different operation conditions. Results indicate that: (1) The collecting power per unit south wall covered area (CPUWA) of the TSAC with the 60° transparent cover plate (TSAC 60°) is 100 ∼ 130 W/m2 higher than that of the FSAC. (2) The thermal efficiency of the TSAC increases faster with the increase of solar irradiance, due to the large area of transparent cover plate. (3) During the heating period, the heat collection capacity and solar fraction of the TSAC 60° are 24.3% and 11.7% higher than those of the FSAC, respectively. [ABSTRACT FROM AUTHOR]

The negative impacts of the increasing number of air conditioning systems in Australia include excessive strain on grids and associated blackouts, higher electricity costs and associated carbon emission issues. The installation of sustainable cooling technologies such as solar absorption cooling systems provides a promising alternative. However, the feasibility of the system for the Australian subtropical climate has not systematically studied. The paper aims to investigate the feasibility of implementing solar absorption cooling technology in student residential building in Australia's subtropical climate region. The feasibility study allows the user to determine if the solar cooling system is technically, economically and environmentally sustainable in the long term. Through the simulation, the key performance parameters such as power consumption data and component performance details were determined. The simulation results showed that the solar absorption chiller can provide comfort in the building by maintaining room temperature within 20–24 °C. The system's performance optimisation studies were conducted, and it was found that the collector area 20 m2 paired with a storage ratio of 0.02 m3/m2 had provided a high solar fraction (SF) of 0.91. The economic analysis is also carried out to determine the annual savings in energy cost, carbon emission reduction, and the payback period.

Middle East and North Africa region's abundant solar and wind resources provide a valuable opportunity to diversify energy production and offer a high potential for renewable energies. Thus, the solar water heating systems offer a key element in the deployment of renewable energy throughout the region. To this end, a model was developed and validated to evaluate the performance of these systems with different collectors. Then, an exhaustive energetic, exergetic, environmental and economic analysis of all the region's countries was carried out on the basis of the required meteorological data. Regarding the results for the entire region, the maximum solar fraction values attain 60 % and 83 % for the flat plate and evacuated tube systems, respectively. Under current economic assumptions, propane water heating is cheaper on a life cycle cost basis than electric and diesel heating throughout North Africa. Also, the use of auxiliary electric generators is suitable for all countries in the Middle East region except for Manama-Jordan, Abu Dhabi-UAE and Ankara-Turkey.

The main categories of solar water heating systems (SWHSs) are the thermosyphon and the forced circulation (FC). This paper presents an experiment carried out with the aim to compare the energy performance of the FC with a thermosyphon SHWS. Identical SWHSs were installed side by side at the University of West Attica in Athens, Greece. Domestic hot water load was applied to both systems via a microcontroller-based dispensing unit which mimics the demand profile. The trial period comprised the last two months of spring (April and May). For the first law assessment, two energy indicators were utilized: the solar fraction (SF) and the thermal efficiency of the system (ηth). On days with distinctive weather conditions, both systems obtained approximately equal SF and ηth values, without a specific preference between the ambient conditions and the type of SWHS. Regarding a four-day nonstop operation, the FC overperformed the thermosyphon system at both energy indicators. Namely, for the FC and the thermosyphon SWHS, the SF was calculated to be 0.62 and 0.48, and the ηth was 68.2% and 53.3%, respectively.

• An ejector refrigeration machine (ERM) powered by hybrid energy is realized. • Performances of the ERM are determined under different generator temperatures. • New formulation of the 1D model of the ejector and ERM performances are predicted. The present study aims to evaluate the performance of a solar-driven ejector refrigerating machine (ERM). In the first part of this work, an experimental study is carried out on a 500 W cooling capacity ejector machine using an evacuated tube heat pipe solar collector. The working fluid is R141b and the tests are carried under different operating conditions. The tests indicate that the entrainment ratio increases with the generator temperature and it is maximum for T g = 90 °C for which the critical conditions of the ejector operation are reached. The thermodynamic COP of the ERM is around 0.18. It is also demonstrated that the solar fraction is higher than 60% and it increases when operating with low generator temperature. In the second part of this work, a mathematical model is developed based on the mass, momentum, and energy balance equations. The model results are compared to the experimental tests from the literature as well as those obtained from the present study, and a good agreement is obtained. The discrepancies between the results issued from the present model and those obtained experimentally in the literature range between −13.5% and +5.9% for a wide series of ejectors, and the discrepancies between the model results and the experimental tests issued from the present study range between −0.3% and −0.2%. [ABSTRACT FROM AUTHOR]

The standard flat-plate solar collector utilises a single copper tube to remove the absorber plate’s heat. This type of collector’s primary purpose is to provide hot water for a single application. Hot water can be required for different applications at different temperatures. Besides, using the standard collector’s configuration may increase thermal demand and increase the collector’s size. Therefore, this study proposes a novel solar water heating configuration that uses three in-line fluid passages. The goal is to design a single collector that provides hot water for various uses: Sterilisation, washing, and postnatal care. Thus, the proposed system was modelled, and a numerical simulation conducted. This analysis compares the proposed system’s output and the standard collector’s output. The results showed that the thermal load demand was reduced by 27% when the hot water demand for these services was generated using three separate tanks. The serpentine collector’s efficiency with three fluid passages is increased by 20% compared to the traditional serpentine collector. The thermal energy delivered to meet load was 30% higher than that of the traditional serpentine system. The experimental and simulated system performance is in near agreement with an average percentage error Cv(RMSE) of 8.75% and confidence level NSE of about 87%. Since the proposed serpentine collector has a higher overall thermal production, it is recommended for use with hot water, which has to be heated to different temperatures. [ABSTRACT FROM AUTHOR]

In this paper, the typical system of solar energy system: natural circulation system and forced circulation system are analyzed. The two systems are simulated on the TRNSYS platform, and the configuration of the system itself has been discussed. The purpose is to provide reference for the scientific implementation of solar energy architecture integration. On the basis of summarizing the solar energy construction technology, the natural circulation system and the forced circulation system of solar hot water system have been discussed emphatically. The simulation experiment is designed on the TRNSYS platform. The influence of different heat collection area and water tank volume on solar energy guarantee rate and system efficiency has been discussed by simulation data. Finally, the optimal allocation scheme of natural constraints of natural circulation and forced circulation has been obtained. [ABSTRACT FROM AUTHOR]

The utilization of a hybrid energy system (combined solar water heater (SWH) and an air source heat pump (ASHP) water heater) can result in over 80% reduction in the electrical energy consumed as the system is capable to operate with an energy factor of above 4.0. A major challenge is to develop credible methodology or mathematical model to predict energy savings. The research focused on the design and installation of a hybrid energy system and a data acquisition system to monitor its performance. The average weekday volume of hot water consumed, thermal energy gained by water in the tank of the air source heat pump (ASHP) water heater, electrical energy consumed, and the COP were 225.03 L, 5.25 kWh, 1.52 kWh, and 3.50. The average weekday global solar radiation, ambient temperature, solar fraction of the solar water heater (SWH) and the energy factor of the hybrid energy system were 579.67 W/m2, 23.58°C, 0.52, and 4.02, respectively. A multiple linear regression model was developed to predict the energy factor of the hybrid energy system. Both the modelled and validated results showed very good determination coefficients of 0.952 and 0.935, with the trained and validated dataset. Hence, by employing both multiple linear regression model and a multiple 2D contour plot simulation, the energy factor and the variation of the input parameters can be accurately determined. The developed model can help homeowners, energy service companies, and policy makers to appreciate and confidently support the rollout of the technology for sanitary water heating.

• A thermal solar system for space heating was designed and built. • A TRNSYS model is developed and validated through experimental measurement. • A sensitivity approach is proposed to quantify the influence of the design parameters on solar fraction. • Pump control impacts considerably the solar fraction in large solar systems. • The proposed approach can be used for the optimization of solar space heating systems design. In this paper, a solar water heating system (SWHS) based on 4 m2 flat plate collectors is integrated to an office building to ensure the heat demand. The SWHS is equipped with Labview software and a multichannel digital card that makes the system control and data acquisition automatic. A TRNSYS model is developed and validated against experimental data and then used for optimization purposes. A sensitivity approach based on the Design of Experiments method and dynamic simulations is proposed to optimize the solar fraction. For this purpose, 134 simulations have been carried out. Metamodels of the solar fraction have been then established for three ranges of the collector area; namely, [2–10] m2; [10–20] m2 and [20–30] m2. The results have shown that the solar fraction is highly dependent on the collectors' area and the storage volume. Furthermore, the impact of the pump control strategy on the solar fraction has increased with larger systems. Finally, optimum design parameters have been obtained using the fitted models to achieve the targeted solar fraction of 60%. The proposed approach could be used for the optimization of solar heating systems design. [ABSTRACT FROM AUTHOR]

• A modulating heat pump is integrated in a solar seasonal storage heating system. • The solar fraction and the efficiencies of the system components are analyzed. • The heat pump integration becomes more beneficial for the unfavorable analyzed cases. • A heat pump can be a feasible solution to increase the solar fraction of the system. Solar systems can supply space heating and domestic hot water to houses covering a large part of the demand by using solar energy. The use of long-term (seasonal) storage systems is fundamental to reach high levels of solar fraction for the application of these systems in cold climates. Building-scale systems are an attractive solution despite a higher specific installation cost of the tank, because they require less space and have smaller distribution networks which helps reduce thermal losses and costs. However, small-scale systems have restraints on reaching high levels of solar fraction. The integration of a heat pump unit in the system can be strategic to increase the performance level of the system and to enhance the use of solar energy. This study examines the integration of a modulating water-to-water heat pump in a solar system equipped with a seasonal storage. The heat pump uses the water of the seasonal tank as the heat source, exploiting the residual heat stored in the tank at the end of the heating season. The system performance is assessed through a number of energy simulations using TRNSYS. A similar solar system without the heat pump is used as a reference system to compare the results and assess the impact of the heat pump integration. The results show that the solar fraction can be increased by approximately five percentage points by including a heat pump. [ABSTRACT FROM AUTHOR]

The utilization of a hybrid energy system (combined solar water heater (SWH) and an air source heat pump (ASHP) water heater) can result in over 80% reduction in the electrical energy consumed as the system is capable to operate with an energy factor of above 4.0. A major challenge is to develop credible methodology or mathematical model to predict energy savings. The research focused on the design and installation of a hybrid energy system and a data acquisition system to monitor its performance. The average weekday volume of hot water consumed, thermal energy gained by water in the tank of the air source heat pump (ASHP) water heater, electrical energy consumed, and the COP were 225.03 L, 5.25 kWh, 1.52 kWh, and 3.50. The average weekday global solar radiation, ambient temperature, solar fraction of the solar water heater (SWH) and the energy factor of the hybrid energy system were 579.67 W/m2, 23.58°C, 0.52, and 4.02, respectively. A multiple linear regression model was developed to predict the energy factor of the hybrid energy system. Both the modelled and validated results showed very good determination coefficients of 0.952 and 0.935, with the trained and validated dataset. Hence, by employing both multiple linear regression model and a multiple 2D contour plot simulation, the energy factor and the variation of the input parameters can be accurately determined. The developed model can help homeowners, energy service companies, and policy makers to appreciate and confidently support the rollout of the technology for sanitary water heating. [ABSTRACT FROM AUTHOR]