scholarly journals A New Method to Determine the Annual Energy Output of Liquid-Based Solar Collectors

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4586 ◽  
Author(s):  
Zukowski ◽  
Radzajewska

One of the most effective ways to reduce greenhouse gas emissions is the widespread use of solar panels. A new approach to estimating the annual energy output ESC of liquid-based solar thermal collectors is presented in this paper. The main parameters of the surrounding environment that affect the energy yield from solar water heating (SWH) systems are total solar radiation ES and outdoor air temperature θO. Here, two functions are developed that allow the specification of the ESC value based on these two previously determined factors. The article presents the subsequent stages that led to the development of this method. In the first step, the computer model of a solar domestic hot water (SDHW) system was built in the EnergyPlus environment. An object of the modeling procedure was the real solar installation located at Bialystok University of Technology. The database containing the annual energy output of the solar collectors, total solar radiation, and outdoor air temperature was developed based on the results of simulations made for 24 Polish cities. Then, the multiple regression method (implemented in Statistica v.13.1) was used to correlate these variables. Two contour graphs were also developed to determine the energy yield from solar collectors.

Author(s):  
Imants ZIEMELIS ◽  
Henriks PUTANS ◽  
Ilze PELECE ◽  
Andrejs SNEGOVS

Amount of presently mainly used fossil energy resources on the earth are limited and its impact on the earth environment is negative. Therefore, scientific research on replacing them with alternative energy like solar is important. Usually in practice, solar radiation for domestic water heating by solar collectors and production of electric energy by photovoltaic (PV) panels is used. Obtained by solar panels electric energy for water heating also can be use. The aim of the research is to make out the more preferable method for water heating by solar radiation particularly in weather conditions of Latvia. There are some advantages and disadvantages for each of them analyzed in the paper. Our research has shown that, at the same intensity of solar radiation, the efficiency of solar collectors is higher while the heated water temperature in the system’s hot water tank is lower, and at higher ambient air temperature as well, but opposite to this, efficiency of PV panels is higher at lower ambient air temperature. Electricity produced by PV panels, using an electric resistance heaters heat water independently of its temperature. The amount of heat energy transferred from a solar collector by heat carrier to the hot water tank depends on the temperature difference between the heat carrier and heated water. The method of investigation corresponds to the goal of investigation, the effectivity of solar collectors and solar panels of different design and construction has analyzed in the paper.


2018 ◽  
Vol 4 (3) ◽  
pp. 25 ◽  
Author(s):  
Daniel Ferrández ◽  
Carlos Moron ◽  
Jorge Pablo Díaz ◽  
Pablo Saiz

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.


2021 ◽  
Author(s):  
Kamyar Tanha

This thesis is focused on the performance of the two SDHW systems of the sustainable Archetype houses in Vaughan, Ontario with daily hot water consumption of 225 litres. The first system consists of a flat plate solar thermal collector in conjunction with a gas boiler and a DWHR. The second SDHW system consists of an evacuated tube collector, an electric tank and a DWHR. The experimental results showed that the DWHRs were capable of an annual heat recovery of 789 kWh. The flat plate and evacuated tube collectors had an annual thermal energy output of 2038 kWh and 1383 kWh. The systems were also modeled in TRNSYS and validated with the experimental results. The simulated results showed that Edmonton has the highest annual energy consumption of 3763.4 kWh and 2852.9 kWh by gas boiler and electric tank and that the solar thermal collectors and DWHRs are most beneficial in Edmonton.


Climate ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 26
Author(s):  
Jérémy Bernard ◽  
Pascal Kéravec ◽  
Benjamin Morille ◽  
Erwan Bocher ◽  
Marjorie Musy ◽  
...  

Shelters used to protect air temperature sensors from solar radiation induce a measurement error. This work presents a semi-empirical model based on meteorological variables to evaluate this error. The model equation is based on the analytical solution of a simplified energy balance performed on a naturally ventilated shelter. Two main physical error causes are identified from this equation: one is due to the shelter response time and the other is due to its solar radiation sensitivity. A shelter intercomparison measurement campaign performed by the World Meteorological Organization (WMO) is used to perform a non-linear regression of the model coefficients. The regression coefficient values obtained for each shelter are found to be consistent with their expected physical behavior. They are then used to simply classify shelters according to their response time and radiation sensitivity characteristics. Finally, the ability of the model to estimate the temperature error within a given shelter is assessed and compared to the one of two existing models (proposed by Cheng and by Nakamura). For low-response-time shelters, our results reduce the root mean square error by about 15% (0.07 K) on average when compared with other compensation schemes.


Solar Energy ◽  
2004 ◽  
Author(s):  
Oleg P. Kovalev ◽  
Alexandr V. Volkov

During long-term time, the laboratory of non-traditional energetic is been busy with development and introduction of solar water heating systems for hot water supply. The systems with solar collectors of 40 m2 area have been developed and introducted. For estimation of their efficiency we should know flux density of solar radiation, proceeding to surface at the given place. However in Primorye Region at actinometrical watching only four meteostations in the Southern part are carrying out straight measurements of solar radiation flux, and the others record data which concern only solar radiation regime (the amount of solar radiation hours, relation of watching duration of solar radiation to possible duration, the amount of days without sun, etc.). We suggested the expression, which according to know data of solar radiation and cloudiness, recorded practically on all meteorological stations gives possibility to calculate for Primorye Region month sums of total radiation proceeding to horizontal surface. The comparison of estimated values with measured ones gives the error to 3...9% with regard to average many years values, and are in the range of variability of measured values for separate years. In Primorye Region more than 250 m2 of solar collectors were installed; and among them 150 m2 were developed with the laboratory, to position on 2003.11.01.   NOTE: This paper was presented at the 2004 International Solar Energy Conference and was inadvertently omitted from the 2004 ASME proceedings. The page range refers to the 2005 International Solar Energy Conference Print Proceedings, where it was subsequently published.


Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1272 ◽  
Author(s):  
Dorota Anna Krawczyk ◽  
Mirosław Żukowski ◽  
Antonio Rodero ◽  
Ruta Bilinskiene

A solar collector market is most European countries is at the stage of continuous development, however its expansion rate differs. It shows that much more factors than only the local solar radiation is important, including a technology progress, costs, local manufactures’ engagement, an economic government support or an environmentally consciousness raising relevant to a mitigating climate change. We conducted the analysis for a public office building, with a few toilets and a social room, used by 54 people. As a primary heat source for HVAC and DHW systems an oil boiler was used, whereas solar collectors were considered as an energy source for hot water preparation. The analysis was conducted for three locations of the building: Bialystok (Poland), Cordoba (Spain) and Kaunas (Lithuania), using a simulation software delivered within the framework of VIPSKILLS project. Theoretical hot water consumption was considered as 3–7 dm3/(day person) in compliance with national recommendations. It was found that beam solar radiation share in a total radiation balance was nearly twice higher in Cordoba than in Bialystok or Kaunas. The highest efficiency (44%) was estimated in Cordoba for solar collectors installed with the tilt angle between 45–50°. In case of Bialystok and Kaunas the efficiency was lower than in Cordoba and nearly equal 40–41% and the recommended tilt angle was in a range 30– 45°.


1998 ◽  
Vol 38 (4) ◽  
pp. 409 ◽  
Author(s):  
Ibrahim E. A. Elbatawi

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.


2014 ◽  
Vol 521 ◽  
pp. 37-40 ◽  
Author(s):  
Miroslav Rimár ◽  
Štefan Kuna ◽  
Marcel Fedák

The contribution deals with the climatic conditions in which a solar rotatable structure with flat solar panels was placed on the roof of the building in which the Department of Process Technique is located. There was designed a control system of the structure in order to achieve an increase in efficiency of solar panels. Presented are three ways of the rotatable structure positioning. During the first measurements, the data were obtained and recorded with a fixed position of the solar panels, the second measurements were carried out while the solar panels were rotating along the ecliptic without being dependent on the actual value of the solar radiation intensity, while with the third measurements the rotation was initiated depending on the intensity of the incident solar radiation on the collectors surface. The archived data obtained from individual measurements are presented in the graphs which show the advantage of solar panels rotation in terms of achieving higher temperatures of a solar fluid and a heat transfer medium of an accumulation tank.


2019 ◽  
Author(s):  
Ni Li ◽  
Arianna Fatahi ◽  
Dennis Lee ◽  
Jim Y. Kuo ◽  
He Shen

Abstract In comparison to fossil fuels, solar energy is a more sustainable option due to its high availability and less environmental impact. Improving the efficiency of solar farms has been a primary concern of solar energy research. Many studies focus on the control of the tilt angle of solar modules to maximize their solar radiation reception and energy generation. However, an increase in solar radiation is accompanied by an increase in module temperature, which is known to be a significant parameter that reduces the power generation efficiency. Wind is another influential factor that helps Photovoltaic systems maintain a low operating temperature by enhancing the rate of heat transfer. Therefore, solar radiation and wind behavior are both critical parameters that must be considered to optimize solar panel performance. In this paper, the effect of wind conditions on solar panel performance will be examined. The solar panel energy output model will be built by empirically considering the irradiation, ambient temperature, wind speed, and wind direction. The published weather data and energy output data for the year 2017–2018 have been collected from Antelope Valley Solar Ranch, located in Lancaster, California. Four models have been proposed and the results indicate that the model which incorporates the wind conditions has the highest accuracy in approximating the energy production of solar farms. Among the factors that affect the temperature of solar panels and further the efficiency of solar panels including solar irradiation, convection, conduction, wind plays a major role in convective heat transfer. Based on this model, the potential improvement of energy generation via introducing a horizontal installation angle and adjusting this angle monthly according to the wind conditions is further analyzed. These results will help designers improve the design of solar farms by taking into consideration the local weather conditions.


2018 ◽  
Vol 1 (1) ◽  
pp. 521-525
Author(s):  
Ceyda Aksoy Tırmıkçı ◽  
Cenk Yavuz

In this paper the number of solar modules of a 1kW solar energy system was determined by using the total solar radiation and the solar module energy output energy relation. The total solar radiation was correlated with the tilt angle of solar modules. Thus the optimum yearly tilt angle of solar modules was calculated and assumed that solar modules of the system were tilted at this angle. In conclusion the monthly average daily total solar radiation, optimum yearly tilt angle and the number of solar modules of the related system were established for the city.


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