scholarly journals A Standard-Based Method to Simulate the Behavior of Thermal Solar Systems with a Stratified Storage Tank

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 266 ◽  
Author(s):  
Edoardo Alessio Piana ◽  
Benedetta Grassi ◽  
Laurent Socal
Keyword(s):  
Solar System ◽  
Solar Energy ◽  
Storage Tank ◽  
Hot Water ◽  
Design Parameters ◽  
Fluid Temperature ◽  
Forced Circulation ◽  
Solar Systems ◽  
Solar Field ◽  
The Impact

Thermal solar systems are interesting solutions to reduce CO 2 emissions and gradually promote the use of renewable sources. However, sizing such systems and analysing their behavior are still challenging issues, especially for the trade-off between useful solar energy maximization and stagnation risk minimization. The new EPB (Energy Performance of Buildings) standard EN 15316-4-3:2017 offers several methods to evaluate the performance of a forced circulation solar system. One of them is a dynamic hourly method that must be used together with EN 15316-5:2017 for the simulation of the stratified storage tank connected with the solar loop. In this work, such dynamic hourly method is extended to provide more realistic predictions. In particular, modeling of the pump operation due to solar fluid temperature exceeding a set threshold, or due to low temperature differential between solar field and storage tank, is introduced as an on–off control. The implemented code is applied to a case study of solar system for the preparation of domestic hot water and the impact of different design parameters is evaluated. The model predicts a higher risk of overtemperature lock-out or stagnation when the solar field surface is increased, the storage volume is reduced and water consumption is set to zero to simulate summer vacation periods. Finally, a simple modulating control with a time step of a few seconds to a few minutes is introduced, quantitatively showing the resulting benefits in terms of useful solar energy increase, back-up operation savings and reduced auxiliary energy use.

Development of an Innovative Code for the Design of Different Parabolic Trough Solar Fields

2009 ◽  
Author(s):  
Ennio Macchi ◽  
Giampaolo Manzolini ◽  
Paolo Silva
Keyword(s):  
Solar Energy ◽  
Energy Demand ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
High Solar Radiation ◽  
Power Block ◽  
The Usa ◽  
Solar Field ◽  
Steam Cycle

The role of renewable energies and in particular solar energy could be fundamental in future scenarios of worldwide increase of energy demand: thermodynamic solar energy can play an important role in country with high solar radiation. This paper discusses the development and testing of an innovative code for the prediction of thermodynamic performances at nominal conditions and the estimation of costs of the whole plant, for different parabolic trough solar fields. The code allows a preliminary design of the solar field lay-out, the sizing of the main components of the plant and the optimization of the steam cycle. The code, named PATTO (PArabolic Trough Thermodynamic Optimization), allows to separately calculate the thermal efficiency of (i) parabolic trough systems in commerce as well as (ii) combination of components of various commercial systems, in order to exploit different technology solutions: combination of mirrors, receivers and supports. Using the selected parabolic troughs, the plant configuration is then completed by connecting pipes, heat exchangers, the steam cycle, and storage tanks. The code is also flexible in terms of working fluid, temperature and pressure range. Regarding the power block, a conventional steam cycle with super-heater and re-heater sections and up to seven regenerative bleedings is adopted. It is possible to use also simpler configuration as without re-heater or with less regenerative bleedings. Moreover, thanks to simple or sophisticated economic correlations depending on available data, the code calculates the overall investment cost for the considered solar field and the power block. The code performs steady state analysis at nominal conditions, while future developments are planned regarding part load analysis and transient simulations. The model is tested towards real applications and reference values found in literature; in particular, focusing on SEGS VI plant in the USA. Detailed results showing code potentiality, are presented in terms of solar field and power block energy balances, plant auxiliaries, piping and economic analysis.

scholarly journals Economic assessment and optimizing of the solar water heating system

2018 ◽  
Vol 210 ◽  
pp. 02023
Author(s):  
Jan Skovajsa ◽  
Martin Zálešák
Keyword(s):  
Solar System ◽  
Optimal Solution ◽  
Heating System ◽  
Hot Water ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System

The article deals with the economic evaluation of investment and optimization of the solar water heating system for family houses. From the point of view of solar systems, the optimal solution is based on the specific application of it. The design is dependent on the location of solar thermal collectors and ration between active aperture area and real daytime consumption. Common calculations according to actual standards often give overstated results, which also reflected in the value of the investments. The article presents the research of optimal parameters of the thermal solar system for preparing of domestic hot water. A combination of related standards and software TRNSYS are used to find optimal parameters. Thanks to created and verified simulation models, it is possible to design parameters so as to avoid under-dimensioning or over-dimensioning of the solar system. Energy price is another factor affects the payback period of investments. This is affected by the used energy sources and their combination. For example, buildings that use electricity to heat water or heating have different energy charges than a building that uses natural gas. So, the aim is to find technically and economically efficient solution.

DESIGN AND PERFORMANCE ANALYSIS OF AN AUTOMOBILE-REMOVABLE SOLAR SYSTEM FOR WATER AND CABIN HEATING

2014 ◽  
Vol 38 (4) ◽  
pp. 505-515
Author(s):  
Mohamed Bentrcia
Keyword(s):  
Saudi Arabia ◽  
Performance Analysis ◽  
Solar System ◽  
Solar Energy ◽  
Solar Collector ◽  
Storage Tank ◽  
Solar Heating ◽  
Passenger Compartment ◽  
Camping Trip ◽  
And Performance

A detachable, automotive solar system for water and passenger compartment heating is developed. The study shows that an adjustable 1 m2 solar collector is sufficient to satisfy the needs of a small group during a short camping trip in Saudi Arabia desert. Also it is found that an adequate water temperature in the storage tank, due to ambient solar heating, is maintained in all cold months, except December when it is insufficient. Among the advantages of the system is its entire operation on renewable solar energy and its ability to heat the car compartment whenever the heated water reaches the required temperature and solar energy is still available.

scholarly journals Numerical Simulation Study for the Performance of a Large Solar Hot Water System With Horizontal Storage Tank

2015 ◽  
Author(s):  
Ru Yang ◽  
Geng-Yi Lin
Keyword(s):  
Numerical Simulation ◽  
System Performance ◽  
Storage Tank ◽  
Large Scale ◽  
Cooling System ◽  
Water System ◽  
Thermal Storage ◽  
Hot Water ◽  
Design Parameters ◽  
Total Load

A large solar hot water system can be utilized to provide driving energy for heating system, heat-driven cooling system, as well as to provide hot water. This research addresses the effects of the storage tank design parameters on the performance of a large-scale solar hot water system with a horizontal storage tank. Most literatures only considered the stratification performance of the thermal storage tank itself instead of considering the overall system performance. Also, there is lack of experimental research data available for the design purpose. Therefore, this study employs a numerical simulation technique to study the design parameters effect of a horizontal thermal storage tank on the performance of a large-scale solar hot water system. In this study, the ANSYS-CFX program is employed to calculate the flow and temperature distributions inside horizontal thermal storage tank. Then the inlets and outlets of the tank are combined with the TRNSYS program to simulate the entire system performance under the weather of three representative cities of Taiwan, (Taipei, Taichung and, Kaohsiung). The results of the present study indicate that the vertical stratification baffles in the tank have important effects on system performance improvement. Quantitative increase of solar fraction of the total load is obtained. The comparison with the system with vertical storage tank is provided. The results of the present study can provide important reference for the large solar hot water system design in improving system efficiency.

A Software Optimization of the Solar Energy System Performance

2014 ◽  
Vol 899 ◽  
pp. 199-204
Author(s):  
Lukáš Skalík ◽  
Otília Lulkovičová
Keyword(s):  
Solar System ◽  
Solar Energy ◽  
System Performance ◽  
Solar Collector ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Thermal Protection ◽  
Energy Systems ◽  
Energy System ◽  
Hot Water

The energy demand of buildings represents in the balance of heat use and heat consumption of energy complex in the Slovak national economy second largest savings potential. Their complex energy demands is the sum of total investment input to ensure thermal protection and annual operational demands of particular energy systems during their lifetime in building. The application of energy systems based on thermal solar systems reduces energy consumption and operating costs of building for support heating and domestic hot water as well as savings of non-renewable fossil fuels. Correctly designed solar energy system depends on many characteristics, i. e. appropriate solar collector area and tank volume, collector tilt and orientation as well as quality of used components. The evaluation of thermal solar system components by calculation software shows how can be the original thermal solar system improved by means of performance. The system performance can be improved of more than 31 % than in given system by changing four thermal solar system parameters such as heat loss coefficient and aperture area of used solar collector, storage tank volume and its height and diameter ratio.

scholarly journals Application of Solar Thermal Energy for Medium Temperature Heating in Automobile Industry

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 19
Author(s):  
Anagha Pathak ◽  
Kiran Deshpande ◽  
Sandesh Jadkar
Keyword(s):  
Solar Energy ◽  
Thermal Energy ◽  
Automobile Industry ◽  
Storage Tank ◽  
Fossil Fuel ◽  
Heating System ◽  
Hot Water ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Medium Temperature

There is a huge potential to deploy solar thermal energy in process heat applications in industrial sectors. Around 50 % of industrial heat demand is less than 250 °C which can be addressed through solar energy. The heat energy requirement of industries like automobile, auto ancillary, metal processing, food and beverages, textile, chemical, pharmaceuticals, paper and pulp, hospitality, and educational institutes etc. can be partially met with solar hybridization based solutions. The automobile industry is one of the large consumers of fossil fuel energy in the world. The automobile industry is major economic growth driver of India and has its 60 % fuel dependence on electricity and remaining on oil based products. With abundant area available on roof top, and need for medium temperature operation makes this sector most suitable for substitution of fossil fuel with renewable solar energy. Auto sector has requirement of heat in the temperature range of 80-140 oC or steam up to 2 bar pressure for various processes like component washing, degreasing, drying, boiler feed water preheating, LPG vaporization and cooling. This paper discusses use of solar energy through seamless integration with existing heat source for a few processes involved in automobile industries. Integration of the concentrated solar thermal technology (CST) with the existing heating system is discussed with a case study for commonly used processes in auto industry such as component washing, degreasing and phosphating. The present study is undertaken in a leading automobile plant in India. Component cleaning, degreasing and phosphating are important processes which are carried out in multiple water tanks of varying temperatures. Temperatures of tanks are maintained by electrical heaters which consumes substantial amount of electricity. Non-imaging solar collectors, also known as compound parabolic concentrators (CPC) are used for generation of hot water at required process temperature. The CPC are non-tracking collectors which concentrate diffuse and beam radiation to generate hot water at required temperature. The solar heat generation plant consists of CPC collectors, circulation pump and water storage tank with controls. The heat gained by solar collectors is transferred through the storage tank to the process. An electric heater is switched on automatically when the desired temperature cannot be reached during lower radiation level or during non-sunny hours/days. This solar heating system is designed with CPC collectors that generate process heating water as high as 90OC. It also seamlessly integrates with the existing system without compromising on its reliability, while reducing electricity consumption drastically. The system is commissioned in April, 2013 and since then it has saved ~ 1,75,000 units of electricity/year and in turn 164 MT of emission of CO2 annually.

scholarly journals Experimental and Modeling Dynamic Study of the Indirect Solar Water Heater: Application to Rabat Morocco

2018 ◽  
Vol 7 (1) ◽  
pp. 86
Author(s):  
Ouhammou Badr ◽  
Azeddine Frimane ◽  
Aggour Mohammed ◽  
Brahim Daouchi ◽  
Abdellah Bah ◽  
...  
Keyword(s):  
Storage Tank ◽  
Weather Conditions ◽  
Hot Water ◽  
Experimental Setup ◽  
Solar Water Heater ◽  
Water Heater ◽  
Forced Circulation ◽  
Solar Water ◽  
Experimental Values ◽  
Temperature Output

The Indirect Solar Water Heater System (SWHS) with Forced Circulation is modeled by proposing a theoretical dynamic multi-node model. The SWHS, which works with a 1,91 m<sup>2</sup> PFC and 300 L storage tank, and it is equipped with available forced circulation scale system fitted with an automated sub-system that controlled hot water, is what the experimental setup consisted of. The system, which 100% heated water by only using solar energy. The experimental weather conditions are measured every one minute. The experiments validation steps were performed for two periods, the first one concern the cloudy days in December, the second for the sunny days in May; the average deviations between the predicted and the experimental values is 2 %, 5 % for the water temperature output and for the useful energy  are 4 %, 9 % respectively for the both typical days, which is very satisfied. The thermal efficiency was determined experimentally and theoretically and shown to agree well with the EN12975 standard for the flow rate between 0,02 kg/s and 0,2kg/s.

An Investigation of a Residential Solar System Coupled to a Radiant Panel Ceiling

1988 ◽  
Vol 110 (3) ◽  
pp. 172-179 ◽  
Author(s):  
Z. Zhang ◽  
M. Pate ◽  
R. Nelson
Keyword(s):  
Heat Exchanger ◽  
Solar System ◽  
Flat Plate ◽  
Storage Tank ◽  
Heating System ◽  
Hot Water ◽  
Radiant Heating ◽  
Solar Collectors ◽  
Water Storage Tank ◽  
Radiant Panel

An experimental study of a solar-radiant heating system was performed at Iowa State University’s Energy Research House (ERH). The ERH was constructed with copper tubes embedded in the plaster ceilings, thus providing a unqiue radiant heating system. In addition, 24 water-glycol, flat-plate solar collectors were mounted on the south side of the residence. The present study uses the solar collectors to heat a storage tank via a submerged copper tube coil. Hot water from the storage tank is then circulated through a heat exchanger, which heats the water flowing through the radiant ceiling. This paper contains a description of the solar-radiant system and an interpretation of the data that were measured during a series of transient experiments. In addition, the performance of the flat-plate solar collectors and the water storage tank were evaluated. The characteristics of a solar-to-radiant heat exchanger were also investigated. The thermal behavior of the radiant ceiling and the room enclosures were observed, and the heat transfer from the ceiling by radiation and convection was estimated. The overall heating system was also evaluated using the thermal performances of the individual components. The results of this study verify that it is feasible to use a solar system coupled to a low-temperature radiant-panel heating system for space heating. A sample performance evaluation is also presented.

Air temperature prediction model to control solar energy heating in a germination greenhouse at night

1998 ◽  
Vol 38 (4) ◽  
pp. 409 ◽  
Author(s):  
Ibrahim E. A. Elbatawi
Keyword(s):  
Solar System ◽  
Solar Energy ◽  
Air Temperature ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Weather Forecast ◽  
Hot Water ◽  
Outdoor Air ◽  
Maximum Temperatures ◽  
Air Temperature Prediction

Summary. The outdoor air temperature is not constant especially in spring in Okayama city. The average night temperature ranges from –2 to 20°C which is too low for the germination of most seeds. A good knowledge of the future outdoor air temperature is necessary to decide if greenhouse heating is needed for the next day. Using measured temperatures from the preceding days and considering the minimum and maximum temperatures given by the weather forecast, it was possible to accurately compute the temperature for the next day. Pumpkin, eggplant and tomato seeds were used in this study. A solar system was used to heat the air inside a greenhouse at night using an air–water–air heat exchanger and make a comparison with an unheated greenhouse. The performance of the solar collector and methods of heat exchange were tested. It was shown that the solar energy collected was sufficient for warming a nursery greenhouse overnight. The system operated with a hot water flow rate of 0.647 L/min and an air flow rate of 9.21 m3/min and could maintain the greenhouse temperature between 16 and 20°C. The quantity of heat collected and delivered by the solar system from incident solar radiation was about 50% in a day. Heating the air inside the greenhouse at night produced 100% germination for all seedlings. In comparison, in the unheated greenhouse the germination ratio was 100, 93 and 27% for pumpkin, eggplant and tomato respectively. The germination ratio outside the greenhouses was 100% for pumpkin, 67% for eggplant and zero for tomato.

scholarly journals Demand-Side Optimal Sizing of a Solar Energy–Biomass Hybrid System for Isolated Greenhouse Environments: Methodology and Application Example

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3724
Author(s):  
Juan D. Gil ◽  
Jerónimo Ramos-Teodoro ◽  
José A. Romero-Ramos ◽  
Rodrigo Escobar ◽  
José M. Cardemil ◽  
...  
Keyword(s):  
Solar Energy ◽  
Storage System ◽  
Farming Systems ◽  
Design Parameters ◽  
Biomass Boiler ◽  
Sustainable Solutions ◽  
Fuel Prices ◽  
Energy Hub ◽  
Growing Seasons ◽  
Solar Field

The water–energy–food nexus has captured the attention of many researchers and policy makers for the potential synergies between those sectors, including the development of self-sustainable solutions for agriculture systems. This paper poses a novel design approach aimed at balancing the trade-off between the computational burden and accuracy of the results. The method is based on the combination of static energy hub models of the system components and rule-based control to simulate the operational costs over a one-year period as well as a global optimization algorithm that provides, from those results, a design that maximizes the solar energy contribution. The presented real-world case study is based on an isolated greenhouse, whose water needs are met due to a desalination facility, both acting as heat consumers, as well as a solar thermal field and a biomass boiler that cover the demand. Considering the Almerian climate and 1 ha of tomato crops with two growing seasons, the optimal design parameters were determined to be (with a solar fraction of 16% and a biomass fraction of 84%): 266 m2 for the incident area of the solar field, 425 kWh for the thermal storage system, and 4234 kW for the biomass-generated power. The Levelized Cost of Heat (LCOH) values obtained for the solar field and biomass boiler were 0.035 and 0.078 /kWh, respectively, and the discounted payback period also confirmed the profitability of the plant for fuel prices over 0.05 /kWh. Thus, the proposed algorithm is useful as an innovative decision-making tool for farmers, for whom the burden of transitioning to sustainable farming systems might increase in the near future.

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