A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

Sung, Taehong; Yoon, Sang Youl; Kim, Kyung Chun

doi:10.3390/en8077058

Cited by 28 publications

(13 citation statements)

References 21 publications

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“…Three variables were considered appropriate for the analysis of this study. These variables, global horizontal irradiance (W/m 2 ), diffuse irradiance (W/m 2 ) and temperature ( C o ), have been identified in several studies (Iqbal, 2012;Sung et al, 2015;An et al, 2017;Opálková et al, 2018) as important measures in solar radiation assessments, hence the decision to select them. Modelled data was collated using Meteonorm, a software package that uses trade-restricted algorithms to simulate solar resource data subject to specific settings (Remund et al, 2014).…”

Section: Equipment and Databasementioning

confidence: 99%

Inferential based statistical indicators for the assessment of solar resource data

Clohessy

Sharp

Hugo

et al. 2019

J. energy South. Afr.

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The drive to reduce fossil fuel dependency led to a surge in interest in renewable energy as a replacement fuel source, which provided research opportunities for vastly different domains. Statistical modelling was used extensively to assist in research. This study applied two statistical techniques that can be used in conjunction or independently to existing methods to validate solar resource data simulated from models. The case study, using a database from a Southern African Universities Radiometric Network, provided illustrative benefits to the methods proposed, while comparing them with some of the validation methods currently used. It was demonstrated that profile analysis plots are easy to interpret, as deviations between modelled and measured data over time are clearly observed, while traditional validation scatter plots are unable to distinguish these deviations.

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Section: Equipment and Databasementioning

confidence: 99%

Inferential based statistical indicators for the assessment of solar resource data

Clohessy

Sharp

Hugo

et al. 2019

J. energy South. Afr.

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“…Solar irradiance is modelled here using the work of Sung et al, which was validated against data taken from Anatolia-Rancho Cordova, California [41]. This model allows for both long and short term weather induced variations, see equations (29) and (30).…”

Section: Comments On Turnaround Efficiency and A Case Study Applicatimentioning

confidence: 99%

“…In these equations, I ETI is the maximum extraterrestrial solar irradiation, d n is the day within the year (samplings in mid July are considered here), ψ z is the zenith angle (in degrees), t is a specific time in the day (expressed in hours), t rise is the sunrise time, and t set in the sun set time. The following model parameters are assumed to be representative of California, M = 0.76, a 1 = 0.1, b 1 = 7, c 1 = 1, a 2 = 0.5, b 2 = 40, c 2 = 2, and d n = 180 [41].…”

Section: Comments On Turnaround Efficiency and A Case Study Applicatimentioning

confidence: 99%

A series hybrid “real inertia” energy storage system

Rouse

Garvey

Cárdenas

et al. 2018

Journal of Energy Storage

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The wide scale market penetration of numerous renewable energy technologies is dependent, at least in part, on developing reliable energy storage methods that can alleviate concerns over potentially interrupted and uncertain supplies. Many challenges need to be overcome, not least among them is allowing capacity for the wide range of time scales required to ensure grid stability. In thermal power plant, high frequency/short duration demand fluctuations, acting at the milliseconds to several seconds time scale, are addressed passively by the inertia of the grid. Here, grid inertia can be thought of as the mechanical inertia of spinning steel in steam and gas turbines. This allows time for active control measures to take effect at the tens of second to hours time scale and for the system to recover without a supply frequency deviation that is noticeable to the customer. It is of paramount importance that, as thermal plant is retired, renewable energy generation and storage systems account for the loss of this inertia. In the literature, strategies to address the loss of "real" inertia have often relied on emulation rather than actual replacement. The present work focuses on the preliminary development of a novel energy storage system that makes use of real inertia to address short term supply/demand imbalances while simultaneously allowing for extended depths of discharge. The concept looks to combine flywheel and compressed fluid energy stores in order to power a synchronous generator. By combining these energy storage technologies through a differential drive unit, DDU, it is anticipated that the benefits of high system inertia can be exploited in the short term while allowing energy to be continually extracted from the flywheel in the long term during storage discharge. The use of a DDU makes the present design particularly novel and distinct from other hybrid systems. In essence, this inclusion allows energy to be extracted entirely from the flywheel, inducing "real" inertia, or entirely from the secondary store, inducing "synthetic" inertia, or some combination of the two. Fundamental sizing calculations for a 50MW system with 20MWh of storage capacity are presented and used to design a suitable control system that allows for the operation of both primary flywheel and secondary compressed fluid energy stores. The transient behaviour of the system is simulated for several charge/discharge time profiles to demonstrate response stability for the system. Comments on system turnaround efficiency, which is dependent upon loading history but for the intended applications can be considered to be greater than 90% are also made here, along with a case study application to an isolated Californian solar powered grid.

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“…Sunlight radiation modeling is a trend based on accurate measurement. Measurement and modeling of solar radiation is important for many systems and applications [24,25]. Our sunlight model was formulated by extracting the sunlight radiation values in the paper discussed above [21].…”

Section: Modeling Of Tomato Greenhouse Cultivationmentioning

confidence: 99%

Optimizing Greenhouse Lighting for Advanced Agriculture Based on Real Time Electricity Market Price

Mahdavian

Wattanapongsakorn

2017

Mathematical Problems in Engineering

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The world’s growing demand for food can be met by agricultural technology. Use of artificial light to supplement natural sunlight in greenhouse cultivation is one of the most common techniques to increase greenhouse production of food crops. However, artificial light requires significant electrical energy, which increases the cost of greenhouse production and can reduce profit. This paper models the increments to greenhouse productivity as well as the increases in cost from supplemental electric lighting, in a situation where the greenhouse is one of the elements of a smart grid, a system where the electric energy market is dynamic and prices vary over time. We used our models to calculate the optimum values for supplemental light and the required electrical energy for HPS lamps in the greenhouse environment, using cherry tomato cultivation as a case study crop. We considered two optimization techniques: iterative search (IS) and genetic algorithm (GA). The two approaches produced similar results, although the GA method was much faster. Both approaches verify the advantages of using optimal supplemental light in terms of increasing production and hence profit.

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A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

Cited by 28 publications

References 21 publications

Inferential based statistical indicators for the assessment of solar resource data

Inferential based statistical indicators for the assessment of solar resource data

A series hybrid “real inertia” energy storage system

Optimizing Greenhouse Lighting for Advanced Agriculture Based on Real Time Electricity Market Price

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