Solar Collector Area Research Articles

Long term accumulation of heat energy from the sun

The source of hot water production for the investigated storage tanks are solar collectors. Solar collectors provide recharging of underground storage tanks all year round. Due to the large active area of solar collectors - 225 m2, there are also large tanks for long-term accumulation. Accumulation tanks are in 3 sizes with a total volume of 160 m3. With regard to the size of the tanks, the mode is switched between the tanks according to the season. The tanks are made of a reinforced concrete packaging structure and are stored under the terrain of the Center of Research anf Innovation in Construction (CVIS laboratory).

Transient simulation and design parameters optimization of a cold store utilizes solar assisted adsorption refrigeration system

Storing of products at their recommended storage temperature plays a vital role in products cost estimation especially in hot and humid climate. In this paper, a simulation of a solar assisted adsorption refrigeration system utilized in cold stores applications is carried out for hot-humid and hot-dry climatic conditions. Then an optimization based on the system design parameters have been performed to get the optimal system performance and maximum solar fraction. Finally, the optimized system performance characteristics have been evaluated monthly at different product storage temperatures for different climatic conditions. Reported results revealed that, an optimum solar collector area of 40 m2, storage tank volume of 1.5 m3 and collector flow rate 1000 kg/h are required to achieve an annual solar fraction of 0.79. Based on the annual system performance, SF and COP increase as cold store temperature increase for both climatic conditions. In fact, hot-dry climate has higher SF and COP at 13 °C than hot-humid by 6% and 11%, respectively. Furthermore, the economic assessment of the proposed system showed that the minimum LCOC of 0.203 USD/kWh is found at hot-dry climate at cold store temperature of 18 °C while the highest LCOC of 0.485 USD/kWh occurred at hot-humid environment at 13 °C.

Solar assisted air source heat pump systems for campus water heating in China: Economic optimization of solar fraction design

• TRNSYS software is to simulate the solar assisted air source heat pump system . • The solar fraction design values of solar water heating systems are not economically optimal in China. • Long-term economic optimization of solar fraction design values for solar assisted air source heat pump systems is performed. • An ANN-generated proxy model is to predict the most economical solar fraction design values of solar assisted air source heat pump systems. The solar assisted air source heat pump (SAASHP) system is widely used for campus water heating owing to its cost-effectiveness and cleanliness. In the current design process of the SAASHP system, the solar collector area is determined by the solar fraction ( f ). However, it is difficult to design a cost-optimal f that can comprehensively take the atmospheric factors, device model, electricity price and initial investment into consideration. To address this issue, a SAASHP system that meets the bathing hot water demand of 480 students was established by TRNSYS software, and the cost-optimal solar collector areas and f values for 12 cities across 4 different solar resource regions in China were obtained by the TRNOPT tool of TRNSYS. Moreover, the effects of SC price, electricity price, bathing hot water demand and rated COP of ASHP on cost-optimal f values were investigated by sensitivity analysis. Finally, a proxy model was generated by the artificial neural network toolbox of MATLAB to predict the cost-optimal f values for different scenarios. The results showed that compared to the economically optimized SAASHP system, the designed SAASHP system according to the national design standards for solar heating systems in China has a larger SC area value, leading to an increase in the annual life cycle cost of the system. The difference between the optimized and designed values of solar collector area and f for the SAASHP system was minor in rich resource and sub-rich resource regions but was larger in general resource and poor resource regions. The solar collector price, electricity price, bathing hot water demand and the rated COP of the SAHP were significant factors affecting the annual life cycle cost, the cost-optimal f and solar collector area of the SAASHP system. The proxy model generated by the artificial neural network toolbox of MATLAB can accurately predict the economically optimal solar collector area and f values for SAASHP systems in different cities and system factors, providing a method for the economic design of SAASHP systems in China.

Performance study of savonius style wind turbines in a solar chimney power plant under guided flow environment

With the uprise in global population and rapid industrialisation in developing nations, increasing energy demand to compensate for societal and industrial needs is inevitable. However, popular energy resources such as gas, petroleum, and coal, on which the global energy mix is heavily reliant, induce environmental pollution and global warming. Thus, clean energy sources, such as wind and solar, are increasingly sought to mitigate these adverse environmental effects and identify alternative sustainable and renewable energy technologies. The existing literature suggests minimal research has been conducted on the turbine component of the solar chimney power plant (SCPP). The present research proposes the study of a vertical axis wind turbine (VAWT), namely the Savonius-style wind turbine (SSWT), for power augmentation in the SCPP under the influence of guide vanes and shields that are installed in the solar collector area. A two-dimensional numerical analysis is performed using the ANSYS Fluent software. The SSWT and SCPP models used in the simulations were validated using numerical and experimental results from previous literature data. The angle of the guide vanes was varied while the dimensions of the SCPP model and the energy extractor considered were kept constant. The optimum turbine performance was identified based on the flow analysis and the power output of the rotary component from different guide vane configurations. The present study shows an overall improvement in the turbine’s performance coefficient and power output under the influence of the guide vane and shield in the SCPP. The turbine with the guide vane and shield at an angle of 45° enhanced the performance by 22.22% and power output by 22.25% compared to the turbine without the guide vane and shield.

Study on the Energy Efficiency Improvement and Operation Optimization of a Solar Water Heating System

The solar-assisted electric boiler water heating systems adopted in student apartments at universities have some shortcomings, such as unsuitable system designs, unstable water supply temperature, and excessive power consumption. As discussed in this paper, the hot water supply system was reformed, and two apartments with the same building area, same solar collector area, and similar water consumption were selected to be used in comparative experiments. The auxiliary heat source for one of the apartments was changed from an electric boiler to three air source heat pumps, and a constant temperature water tank was added to form a double-tank water supply system. In addition, the operation strategy was adjusted. The other apartment was not modified. The energy consumption, solar fraction, water supply quality and economy of the two systems were analyzed and compared. The results showed that the transformation plan is reasonable and feasible. The solar fraction of the reformed system was significantly improved. The water supply temperature of the original system ranged from 35 °C to 60 °C, but it was shown to stabilize between 40 °C and 50 °C after the transformation. The average power saving rate of the reformed system reached 72.70%, and this economic benefit is highly significant. Additionally, the TRNSYS simulation software was used to model and optimize the control of the system.

Enhancing the efficiency of a steam jet ejector chiller for chilled ceiling

• Steam jet ejector chillers (SJECs) can be suitable for buildings with high solar gains. • SJEC was combined with radiant chilled ceiling instead of convective cooling terminal. • Increasing evaporation temperature by using chilled ceiling improved COP. • This allows lower generation temperature resulting in smaller solar collector areas. Steam jet ejector chillers (SJECs) can be a suitable cooling technology in buildings where solar heat gains constitute a significant part of the cooling load. In this study, an SJEC was combined with a radiant chilled ceiling (CC) instead of traditionally used convective cooling terminals in an effort to increase the coefficient of performance (COP) by increasing the supply water temperature to the terminal ( T water,sup ) and thus the evaporation temperature. Experiments were used to verify a mathematical model of SJEC. The model was combined with T water,sup obtained from heat transfer calculations in three types of CC performed by a verified software. The COP of the ejector cooling system was 0.25 and 0.38 for R718 (water) and R1233zd, respectively, at a generation temperature of 130 °C and T water,sup of 7 °C, assuming a fancoil. Increasing T water,sup to 9 °C, which was considered to be the lowest T water,sup theoretically possible for CC involving pipes underneath the surface, improved COP by up to 14% while providing a maximum cooling capacity of about 80 W per m 2 of room area. Further increasing T water,sup to 15 °C improved the COP by 50% compared to the fancoil, while covering cooling loads of at least 40 W per m 2 . The estimated reduction in generation temperatures due to increased COP was up to 12% ( T water,sup = 9 °C) and 37% ( T water,sup = 15 °C). This means a lower energy input needed for the cooling machine, which allows a smaller solar collector area.

Energetic and Exergetic Analysis of a Solar-Driven Single-Effect Absorption Refrigeration System Using LiBr + LiCl/H2O Solution Mixture

Abstract Comprising an eco-friendly blueprint, absorption refrigeration systems have attracted a lot of interest as they can use biomass, solar and geothermal energy sources which can mitigate climate change. The current study presents a methodology based on energy and analysis for solar-driven single-effect absorption refrigeration systems, which offer a 50-kW cooling capacity. This study proposes a new mixture ratio of LiBr + LiCl (mass ratio of 2:1)/H2O solution and compared it to LiBr/H2O thermodynamically. Based on the climate data of Kocaeli province in Turkey, an evacuated tube collector is employed to benefit from solar energy to meet the generator heat load of the system. Although at an evaporator temperature of 5 °C, enhanced thermodynamic performance is evident with the use of the LiBr + LiCl/H2O system, and a diminished solar collector area is required compared to the system utilizing LiBr/H2O; there is a level of attrition relating to the impact of the former with a single degree rise in evaporator temperature. However, this remained at a greater value than for the latter system. The final results pointed out that LiBr + LiCl/H2O has a 48.93% lower circulation ratio, 8.81% higher coefficient of performance (COP) of chiller, 8.88% higher solar COP, 8.96% higher exergy efficiency of chiller, 8.90% higher exergy efficiency of solar-driven system, 8.92% lower solar collector area, and 8.91% lower storage tank volume than LiBr/H2O system in the investigated operating temperature ranges. The final results of the present study can be safely tested in the experimental design of single-effect absorption chillers.

Performance of a collector-storage solar air heating system for building mechanical ventilation preheating in the cold area

The application of solar thermal energy to preheat cold fresh air for mechanical ventilation could save a lot of energy and ensure the stable operation of the ventilation system. In this paper, a kind of collector-storage solar air heating system (CSSAHS), in which the thermal storage unit (TSU) is characterized by a dual S-channel for heat transfer, is proposed and the mathematical model for the integrated system was established. The model including the TSU, solar air collector, heat recovery device, and the fan was verified by an experimental study set up in a typical cold city in China. The model has been verified by experiments. The simulation results demonstrate that fresh air is the most important factor affecting storage/release efficiency. The increasing rate of heat release efficiency in the range of fresh air temperature -6–18°C is about 1.58%/°C. The solar heat collector area and the size of the TSU suitable for representative cities in cold regions are optimized based on multi-condition simulation analysis. The CSSAHS can preheat fresh air for 5 h after heat storage and the release efficiency is between 52 and 74%. Compared with other systems, the energy-saving rate of the CSSAHS is 26.5–33.3% in cold winter, and the heat supply ratio of the TSU is 24.4–35.1%.

Price inflation effects on a solar-geothermal system for combined production of hydrogen, power, freshwater and heat

This study explores the effects of price inflation on the optimal performance of a solar-geothermal system capable of combined production of hydrogen, power, freshwater and heat. Multi-objective optimization is applied, with the ground water mass flow rate and the solar collector area as the decision variables, alongside the payback period and the annual production of hydrogen, power, freshwater and heat as the objective functions. The results show that when inflation rises four-fold from 0.05 to 0.20, the ground water mass flow rate drops by 20.1%, while the solar collector area rises by 14.4%. Accompanying this are 15.0%, 12.2% and 12.0% decreases in annual freshwater, power and heat production, respectively, alongside a 9.9% increase in annual hydrogen production. The payback period, meanwhile, increases only modestly, from 6.11 to 7.39 years, demonstrating the economic viability of such a combined solar-geothermal system, even in inflationary times.

Investigation of a solar heating system assisted by coupling with electromagnetic heating unit and phase change energy storage tank: Towards sustainable rural buildings in northern China

• New coupled solar heating system proposed for clean heating of rural buildings. • Hooke–Jeeves algorithm is adopted to optimise four key parameters in a SHS. • LCC reduced by 4.17%–23.62%; CO 2 emission reduced by 13.07–26.73 T. • Based on applicability evaluation, the cost of investment grant is more operative than operating expense grants. Detached buildings in rural areas have considerable potential to promoting the application of solar heating systems (SHSs) from the perspective of low-carbon development. However, SHSs are designed to operate at the maximum building load, leading to energy wastage. To optimally design the key parameters of a SHS assisted by coupling with an electromagnetic heating unit and a phase change energy storage tank (SAEPT), a simulation model was established through the dynamic cosimulation of Designer's Simulation Toolkit and Transient System Simulation Program between the hourly heating supply and the hourly load of the building. The area of solar collectors, collector inclination, tank volume, and electromagnetic energy heating unit power were selected as the optimisation parameters, with life cycle cost (LCC) as the objective function. Generic Optimization Program was used to adopt the Hooke–Jeeves algorithm to iteratively optimise the configuration. Compared with the designed values, LCC was reduced by 4.17%–23.62%, and the CO 2 emission reduction was 13073–39801 kg. To evaluate the applicability of SAEPT in 16 regions, a multiattribute evaluation of energy-economic-environment was conducted based on 11 specific indicators. SAEPT was particularly suitable for regions with abundant solar energy resources and relatively low load of buildings. The payback period was approximately 3.78–7.98 years. The initial investment subsidy by the government can be between 0% and 25%. The findings of this study provide crucial insights for policymakers and SHSs promotion, which can facilitate sustainable low-carbon rural buildings in northern China.

Total site integration considering wind /solar energy with supply/demand variation

Energy integration using pinch technology in a Total Site (TS) has been widely used for optimization and energy saving. In this paper, wind and solar energy are integrated into a TS system using pinch concepts to reduce environmental pollution. A new procedure of Total Site Heat Storage Cascade (TS-HSC) construction is proposed, which is shorter than the current method. A strategy for estimating wind power economy in different wind turbine capacities is also presented, which includes parameters of Feed-in tariff (FiT) rate and Levelized Cost of Electricity (LCOE). A TS case study with energy supply/demand variations is considered to illustrate the proposed procedures. In the case study, a central solar heating plant with daily/seasonal storage and different solar thermal collector areas is used to compare the external hot utility requirements. The results showed that by increasing the area from 100 to 700 m2, the heating requirement reduction with daily/seasonal storage changes from 37.89% to 94.27%. Also, by increasing the wind turbine capacity from 1.5 to 2 MW, the reduction percentage of power grid usage changes from 54.23% to 79.97% and using a 2 MW wind turbine is more cost-effective than other wind turbine capacities with a 32.21% reduction in costs.

Amelioration of thermodynamic performance and environmental analysis of an integrated solar power generation system with storage capacities using optimized ternary hybrid nanofluids

The optimization of heat transfer fluids as cooling agents in solar technologies have gained significant attention, especially with the groundbreaking achievements in nanofluid synthesis and practical utilizations. The synthesis of hybrid nanofluids has shown improved thermal performance in their application as heat transfer fluids in parabolic trough systems. However, the lack of clear understanding regarding the behavior of ternary hybrid nanofluids, (especially with their unique particle type behaviors) hinders further improvement in these systems. In this study, the performance of an integrated solar parabolic trough system is investigated using eight water based-ternary nanofluids with different operational conditions. This study is also carried out to estimate the potential of designing a smaller solar collector that can produce optimal performance by using ternary nanofluids as an alternative to water. From this study, it was estimated that the maximum exergy efficiency of the ternary nanofluid 1 (ZnO-Al2O3-SiO2), 2 (Fe-Cu-Ag), 3 (Fe-Cu-ZnO), 4 (Fe-Cu-MWCNT), 5 (Ag-Al2O3-TiO2), 7 (Fe-MWCNT-TiO2), and 8 (Fe-Graphene-TiO2) gave values of 69.07%, 66.23%, 66.74%, 66.35%, 68.04%, 69.08%, 67.74% and 68.32% respectively. The MWCNT - Al2O3 – TiO2 (ternary fluid 6), ZnO – Al2O3 – SiO2 (ternary fluid 1), Fe - Graphene – TiO2 (ternary fluid 8), and Ag – Al2O3 – TiO2 (ternary fluid 5) gave the highest useful heat measured as 15,859 kW, 15,858 kW, 15,679 kW, and 15,614 kW respectively. As compared to water, the solar collector's area can be reduced up to 30.45%, 27.66%, 28.17%, 27.76%, 29.46%, 30.48%, 29.18%, and 29.74% for the ternary fluid 1, ternary fluid 2, ternary fluid 3, ternary fluid 4, ternary fluid 5, ternary fluid 6, ternary fluid 7, and ternary fluid 8 respectively. The maximum CO2 emission of 3826 kg avoided was recorded for the ternary fluid 6. The ternary fluid 6 (MWCNT-Al2O3-TiO2) also showed the optimum energy efficiency, exergy efficiency and heat storage capacity.

Design, modeling and optimization of a renewable-based system for power generation and hydrogen production

Due to the environmental concerns caused by fossil fuels, renewable energy systems came into consideration. In this study, a renewable hybrid system based on ocean thermal, solar and wind energy sources were designed for power generation and hydrogen production. To analyze the system, a techno-economic model was exerted in order to calculate the exergy efficiency as well as the cost rate and the hydrogen production. The main parameters that affect the system performance were identified, and the impact of each parameter on the main outputs of the system was analyzed as well. The thermo-economic analysis showed that the most effective parameters on the exergy efficiency and total cost rate are the wind speed and solar collector area, respectively. To reach the optimum performance of the system, multi-objective optimization, by using genetic algorithm, was applied. The optimization was divided into two separate case studies; in case A, the cost rate and the exergy efficiency were considered as two objective functions; and in case B, the cost rate and the hydrogen production were assigned as two other objective functions. The optimization results of the case A showed that for the total cost rate of 30.5 $/h, the exergy efficiency could achieve 35.57%. While, the optimization of the case B showed that for the total cost rate of 28.06 $/h, the hydrogen production rate could reach 5.104 kg/h. Furthermore, after optimizing, an improvement in exergy efficiency was obtained, approximately 19%. • Proposing a novel integrated system based on ocean thermal, solar and wind energy. • Applying a comprehensive thermo-economic model to analyze the system. • Hydrogen production, exergy efficiency, and cost rate are the objective functions. • Enhancing the exergy efficiency 19% and the hydrogen production 1.14 kg/h.

Optimization of the solar space heating system with thermal energy storage using data-driven approach

The employment of solar space heating is a significant measure to achieve carbon neutrality. However, the design of the solar space heating system usually leads to the dilemma of a trade-off between the economic benefit and environmental protection, which cannot be solved by single-objective optimization. In this work, in order to design a solar space heating system of a bungalow equipped with radiant floor heating, multi-objective optimization of the solar collector area and the volume of the water thermal energy storage (TES) tank is performed by coupling TRNSYS simulation, machine learning and genetic algorithm (GA). Simulation for the entire winter operation of the solar space heating system is conducted in TRNSYS, and a database with various combinations of the design variables are generated, based on which an artificial neural network (ANN) is constructed to capture the mapping of the design variables and the system performance indicators. After proper training and validation, the ANN model with satisfactory forecasting precision is utilized as the objective function for optimizing the system. GA is employed for searching the solutions of the multi-objective optimizations. This data-driven approach combining ANN and GA is helpful to achieve the optimal solutions. For the solar space heating system, the CO2 emission reduction can benefit most from the enlargement of the solar collector area and the TES tank volume, while the payback period reaches its minimum when both the solar collector area and the TES tank volume are small. By comparing single-objective with multi-objective optimizations, it is found that the single-objective optimization cannot reveal the interactions among the CO2 emission reduction, annualized life cycle cost (ALCC) and payback period (PBP) and that the optimization focusing on a single objective probably leads to apparent defects and inapplicability in reality. Better balance among the CO2 emission reduction, ALCC and PBP can be achieved from the Pareto optimums of the multi-objective optimization rather than the single-objective optimization. According to the TOPSIS evaluation, the most appropriate design scheme is obtained from the multi-objective optimization and has the potential to reduce the carbon emission by 5480.6 kgCO2eq/year while the ALCC and payback period are only 33.40 ¥/(m2·year) and 3.70 years, respectively.

Evaluation and Design of Large-Scale Solar Adsorption Cooling Systems Based on Energetic, Economic and Environmental Performance

In hot and dry regions such as the Gulf Cooperation Council (GCC) countries, the cooling demand is often responsible for more than 70% of electricity consumption, which places a massive strain on the electricity grid and leads to significant emissions. Solar thermal driven Silica-Gel/Water adsorption chillers, used for space cooling, could provide low carbon emission cooling and reduce the reliance on grid electricity. However, a meticulous design is required to make this both economically and environmentally beneficial. This paper aims to evaluate the solar thermal adsorption chiller performance based on large-scale cooling demand through a TRNSYS simulation for 1 year of operation. The proposed system consists of two main parts: first, the solar loop with evacuated tube solar collectors; and second, the adsorption cooling system with a silica-gel/water adsorption chiller. A neighbourhood of 80 typical 197 m2 villas in Riyadh, the capital city of the Kingdom of Saudi Arabia (KSA), was taken as a case study. The solar adsorption cycle’s performance has been compared to the conventional vapour compression cycle in terms of energy, economic and environmental performance. In addition, a parametric study has been performed for the main design parameters. Results reveal that the system can reach a solar fraction of 96% with solar collector area of 5500 m2 and a storage tank volume between 350 and 400 m3. Furthermore, the annual energy cost can be reduced by 74% for the solar adsorption system compared to the conventional vapour compression cycle. Meanwhile, the CO2 saving percentage for the solar adsorption cycle was approximately 75% compared to the conventional vapour compression cycle. Carefully designed solar thermal cooling systems can reduce greenhouse gas emissions while covering a large scale of cooling demands. This can reduce the strain on the electricity grid as well as greenhouse gas emissions.

Design of solar tray tomato drier

Drying is one of the oldest, cheapest and most common methods of preservation and storing agricultural products. Open air sun drying of agricultural products is the traditional method employed in most of the developing countries. Sun drying is used to denote the exposure of a commodity to direct solar radiation and the convective power of the natural wind. Many of our food crops have 80 to 90 per cent moisture content and most of these need to be removed for long term storage. In practice, most of the dryers used have an operating efficiency of 50-60 per cent and this indicates that significant amounts of energy are used in the post-harvest activity. A small scale village level solar dryer for tomato was designed in Mainefhi subzone using locally available materials. The theoretical design of the solar dryer was composed of the solar collector, blower, drying chamber and chimney. Designing a solar collector parts which include solar collector area, absorber surface area, selection of suitable blower with the recommended capacity, designing solar drying chamber area and sizing of drying chamber and chimney were the specific aim of the study. The results on the basis of calculations and assumptions with the recommended value were obtained. The solar dryer with collector area of 2.26 m2 and drying capacity of 5kg was designed to dry tomato from 90 per cent to 8 per cent moisture content wet bulb during the sunshine hours, 8.21 hrs per batch. After drying, 5kg of tomato was reduced to 0.544kg of tomato.

Techno-environ-economic-energy-exergy-matrices performance analysis of evacuated annulus tube with modified parabolic concentrator assisted single slope solar desalination system

In the present study, a sophisticated novel design of solar desalination system with evacuated annulus tube collector augmented unique combination of modified compound parabolic concentrators has been analyzed and simulated with the help of the computational tool (MATLABR2015a) for Techno-Environ-Economic-Energy-Matrices observations under the specific meteorological conditions of New Delhi, India. The current approach emphasizes the utility of modified parabolic concentrator integrated evacuated tube that effectively improves the solar absorbing performance of the irradiated solar energy uniformly through its periphery, as well as enhancing the thermo siphons working loom appreciably than the conventional applications of vacuum tubes. The proposed system is being optimized to get the maximum possible basin water temperature as 99.5 °C for the larger water depth (0.16m) at the same orientation of still top cover and evacuated tubes (30°). The maximum circulation rate (thermo siphon) is achieved as 54.96 kg/h. The daily overall energy-exergy efficiencies are 50.8% and 3.8%, respectively. The daily yield (16.2 kg/day or 5.4 kg/m2 with respect to the solar energy collection area and its production cost (0.005 $/l) at a nominal selling price (0.07 $/l) found good. The energy-exergy based CO2 mitigates and environmental earned revenue are 131.97 tons, 67.44 tons, $1318.36, and $673.77, respectively. The establishment cost of the system is quite low at $214.92, and the system's productivity is found as 940.8%, which is more than 100% that depicts the system as appreciably feasible. The noticeable yield output at low production cost, environmental revenue credits, high mitigation, and low pay-off time makes the system compatibly sustainable and feasible with smaller and effective collector areas for the respective solar irradiations.

Performance improvement of solar-assisted ground-source heat pumps with parallelly connected heat sources in heating-dominated areas

Solar-assisted ground-source heat pumps (SGSHPs) with a serial configuration have been introduced to reduce the performance degradation of ground-source heat pumps (GSHPs) for their long-term operation. However, SGSHPs with parallel configurations have rarely been investigated in heating-dominated areas. In this study, the heating performances of a GSHP and SGSHPs with serial and parallel configurations in a heating-dominated building are analyzed using TRNSYS and compared for 20 years by varying the borehole length and solar collector area. With a borehole length of 120 m and solar collector area of 10 m2, an SGSHP with a serial configuration showed a 12.6 and 11.5% higher ground temperature and solar collector efficiency, respectively, than the parallel configuration owing to the solar heat injection into the ground. However, an SGSHP with a parallel configuration decreased the energy consumption by 19.6 and 13.8% compared to those for the GSHP and SGSHP with a serial configuration, respectively, owing to an improved heating capacity. Furthermore, an SGSHP with a parallel configuration can considerably decrease initial costs by reducing the borehole length.

Analysis of Energy and Exergy of a Two-Circuit Solar Installation with Thermosiphon Circulation

In this paper, a new system is proposed to improve the thermodynamic and economic indicators of solar room heating. The heat pump is integrated with a conventional solar heating system, in which the temperature of the collected heat is reduced by 20 °C to 30 °C to increase the efficiency of solar energy collection. The low-temperature heat collected by the solar collector is increased using a heat pump to generate high-temperature heat for indoor heating in winter and low-pressure process steam for industrial use in other seasons. The results show that the efficiency of the solar collector has increased by 30.50%, its annual effective operating time has reached 2000 hours, which is about four times more than that of a conventional solar heating system. In addition, the parameters of the solar collector area, the volume of the storage tank and the power of the heat pump have been optimized. This work provides a new way to use solar energy more efficiently and economically. Energy analysis shows that with the new flat solar collectors, the average annual values were 2.5 kW, and also high, the COP system in November was 4%.

Performance analysis of an integrated pumped-hydro and compressed-air energy storage system and solar organic Rankine cycle

This research presents the performance study of a new energy storage system, i.e. Pumped-Hydro and Compressed-Air storage system, coupled with organic Rankine cycle (ORC) and Linear Fresnel solar reflector (LFR). The proposed cycle is capable of generating electricity and heat as well as storing storage. The LFR receives solar energy and turns it to the thermal power. The heat obtained from this way is used to supply heat to the evaporator of the ORC, and this system generates power. This power is then fed to the storage system pump. In the result section, the performances of storage system, solar and ORC systems, as well as coupled process are examined. The effect of key parameters such as operating pressures of the storage system, inlet temperature and pressure of organic fluid of the turbine of ORC, solar system inlet temperature and solar irradiance on process operation is examined. Furthermore, it is assumed that the solar collector works in the weather conditions of Esfahan (in Iran). The findings showed that the energy required by the pump and the energy level in the vessel for the isothermal process are 3.24 and 2.43 MJ/m3, respectively. These values were 2.79 and 2.09 MJ/m3, respectively, for the isentropic process. In addition, the system storage efficiency is equal to 60%. Furthermore, the isentropic process compared to isothermal process requires less solar collector area.