Extended ordinary differential equation models for solar heating systems with pipes

Kicsiny, Richárd; Nagy, József; Szalóki, Cs.

doi:10.1016/j.apenergy.2014.04.108

Cited by 21 publications

(11 citation statements)

References 31 publications

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“…It should be noted that SWHS configurations similar to that shown in fig.3.1 have been considered in other studies. More notably, similar systems where considered in [8,12,13,27]. What physically differentiates our system from the studies noted above is the circulation fluid and the type of exchanger used the systems primary loop.…”

Section: Problem Formulationmentioning

confidence: 98%

“…When compared to measured results from a physical system, the results of this model show lower absolute error values than those of the other models that do not take system thermal losses into account. The results of [27] highlight the importance of considering system thermal losses in order to increase the accuracy of any model. In attempt to further the work that has been developed by the previous authors, this study focusses on the design and optimization of a model that will characterise a SWHS consisting of an array of solar collectors, two energy storage tanks and connecting pipes.…”

Section: Connecting Pipe Parametersmentioning

confidence: 99%

“…There are existing studies that have shown that characterising system losses as a part of the SWHS model can Department of Electrical, Electronic and Computer Engineering University of Pretoria provide a more realistic and accurate representation of the performance of a SWHS. In [27] for instance, extended differential equations are used to model a SWHS consisting of a solar collector, heat exchanger, energy storage tank and connecting pipes. The developed model considers pipe thermal losses and simply illustrates the temperature distribution over the components of the SWHS.…”

Section: Connecting Pipe Parametersmentioning

confidence: 99%

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Optimal flow control of a forced circulation solar water heating system with energy storage units and connecting pipes

2016

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Degree:Master of Engineering (Electrical Engineering)Keywords: Flat plate solar collector, flow rate optimization, maximum energy extraction, system thermal losses, thermal comfort.Solar water heating systems (SWHS) have fast become a suitable alternative to conventional water heating systems due to growing energy demands. A SWHS generally consists of a solar collector (which is used to convert solar radiation to heat), a water storage tank, and a flow control device such as a pump in the case of forced circulation SWHS. Extensive research and analysis on the operation and performance of these systems has been conducted, and results show that optimal flow control is an important factor that can be used to improve the performance and efficiency of SWHS.This study focuses on pump flow rate optimization for forced circulation SWHS with pipes.The system analyzed consists of an array of flat plate solar collectors, two storage tanks (one for the circulation fluid and one for the water), a heat exchanger, two pumps, and connecting pipes which are considered as one of the components of the SWHS so as to account for their thermal effects. The proposed model is developed using mainly the first and second laws of thermodynamics. The model is used to maximize the difference between the energy extracted from the solar collector and the combined sum of the energy extracted by the heat exchanger and corresponding energies used by the pumps in the primary and secondary loops. The objective function maximizes the overall system energy gain whilst minimizing the sum of the energy extracted by the heat exchanger and energy used by the corresponding pumps in the secondary loop to conserve the stored energy and meet the user requirement of water tank temperatures.The model is solved using the fmincon solver in MATLAB's optimization toolbox. When compared to other flow control techniques, in particular the most suitable energy efficient control strategy, the results of this study show a significant increase in the system's overall energy gain. The results also illustrate the effects of system pipe thermal losses for the different control strategies, hence highlighting the importance of developing a model that takes such losses into account so as to improve the overall accuracy of the model. Sonenergie-waterverwarmingstelsels (SWV) het vinnig 'n geskikte alternatief vir konvensionele waterverwarmingstelsels geword, weens die groeiende vraag na energie. 'n SWV bestaan gewoonlik uit 'n sonkollektor wat gebruik word om sonstraling om te skakel na hitte, 'n opgaartenk vir water, en 'n vloeibeheertoestel soos 'n pomp, in die geval van geforseerde sirkulasie SWV. Uitgebreide navorsing en ontleding op die werking en prestasie van hierdie stelsels is uitgevoer en die resultate toon dat die optimale vloeibeheer 'n belangrike faktor is wat gebruik kan word om die prestasie en doeltreffendheid van SWV verbeter. OPSOMMINGHierdie studie fokus op die optimering van die vloeitempo van 'n pomp vir geforseerde sirkulasie sonenergie-waterverwarmingste...

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Section: Problem Formulationmentioning

confidence: 98%

Section: Connecting Pipe Parametersmentioning

confidence: 99%

Section: Connecting Pipe Parametersmentioning

confidence: 99%

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Optimal flow control of a forced circulation solar water heating system with energy storage units and connecting pipes

2016

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“…Assim os resultados obtidos através da simulação indicaram que parâmetros como o comprimento do coletor, afetam significativamente a temperatura de saída de água e que esta temperatura não é sensível à velocidade do vento. Utilizando a modelagem matemática a parâmetros concentrados, Kicsiny et al (2014) propuseram quatro modelos matemáticos, sendo dois linearesbásico e estendido e dois não linearesbásico e estendido. Sabendo que o modelo estendido leva em consideração os efeitos causados pela tubulação, e o básico não, foram feitas simulações para os modelos lineares (básico e estendido).…”

Section: Revisão Da Literaturaunclassified

“…Como hipóteses simplificadoras foi considerado que as temperaturas ( , , ℎℎ , ℎ , 1 , 1 , 2 , 2 ) são homogêneas e variam com o tempo, mistura perfeita, e que as perdas por radiação são desprezíveis. O modelo matemático utilizado foi baseado no trabalho de Kicsiny et al (2014) sendo que foram implementadas algumas modificações com a finalidade de se aproximar ao máximo a um sistema de aquecimento real.…”

Section: Materiais E Métodosunclassified

Sistema de aquecimento solar de água: simulação e análise

Tavares¹,

Sousa

2019

RBCTI

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Devido ao crescente aumento na demanda energética mundial, a busca por novas fontes de energia renováveis tem se tornado um dos principais desafios para a sociedade atual. O Brasil é um país privilegiado em termos de radiação solar, devido a isso, vem-se investindo no uso de aquecedores solares visando reduzir o consumo de energia elétrica e outras fontes de energia não renováveis. Partindo deste pressuposto, este trabalho propõe a simulação e análise do modelo matemático de sistemas de aquecimento de água utilizando coletores solares como fonte de energia. Foram avaliados dois modelos distintos: básico (sem efeito da tubulação) e estendido (com efeito da tubulação) e os cenários simulados levaram em consideração a convecção forçada (com o vento) ou convecção natural e o isolamento do sistema. Os resultados obtidos mostram que o vento possui uma grande influência tanto na eficiência quanto nas temperaturas atingidas. A eficiência foi reduzida em 58%, e a temperatura reduziu aproximadamente 5°C, quando há convecção forçada. Mesmo assim, ambos os sistemas são eficientes para o aquecimento de água na região do Triângulo Mineiro, chegando a eficiência de 53% e a temperatura máxima da água de aproximadamente 80oC.

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