Improved differential control for solar heating systems

Kicsiny, Richárd; Farkas, I.

doi:10.1016/j.solener.2012.08.003

Cited by 30 publications

(9 citation statements)

References 12 publications

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“…This system requires the use of a pump that is turned on during the day for fluid circulation and off during the night to prevent reverse circulation. reported in [4,7,8,9,10,11,12,13], with results suggesting that SWHS connected in an open loop configuration result in a higher rate of energy transfer from the input loop to the load when compared to SWHS connected in a closed loop configuration.…”

Section: Swhs Connections and Configurationsmentioning

confidence: 97%

“…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: 99%

“…Existing approaches to energy maximization through mass flow rate control are reported in [4,7,9,8,10,11,12,13,25]. In particular, [7] investigates optimal flow control of a closed-loop SWHS with one and two serpentines used for heat exchange in the storage tank.…”

Section: Flow Rate Optimizationmentioning

confidence: 99%

“…In [12,13] the application of block orientated type mathematical modeling is applied to the SWHS with pumps. In this paper two different types of bang bang control are used.…”

Section: Flow Rate Optimizationmentioning

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: Swhs Connections and Configurationsmentioning

confidence: 97%

Section: Problem Formulationmentioning

confidence: 99%

Section: Flow Rate Optimizationmentioning

confidence: 99%

“…In [12,13] the application of block orientated type mathematical modeling is applied to the SWHS with pumps. In this paper two different types of bang bang control are used.…”

Section: Flow Rate Optimizationmentioning

confidence: 99%

See 2 more Smart Citations

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

2016

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“…Well-established techniques developed in 1970s-1980s, such as on-off ("bang-bang") or modulating ("differential") control, are usually implemented in commercial controllers. Refinements of proportional control are proposed in [26], and complex algorithms are more and more commonly found in the literature, for example using optimal control to determine the correct primary flow rates to maximize energy gain, whilst meeting user-defined tank temperatures with minimum energy usage in the secondary loop of the system [27]. Valdiserri [28] includes on-off control in the TRNSYS simulation of solar water heating systems located in seven European cities, analyzing the effect of night switch-offs.…”

Section: Introductionmentioning

confidence: 99%

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

Piana

Grassi

Socal³

2020

Energies

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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.

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Dynamic Modelling of a Thermal Solar Heating System

Boaventura‐Cunha

Ferreira

2022

Innovations in Bio-Inspired Computing and Applications

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Improved differential control for solar heating systems

Cited by 30 publications

References 12 publications

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

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

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

Dynamic Modelling of a Thermal Solar Heating System

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