Thermal Model of a Dish Stirling Cavity-Receiver

Gil, Rubén; Monné, C.; Bernal, Nuria; Muñoz, M.; Moreno, Francisco Grimaldo

doi:10.3390/en8021042

Cited by 22 publications

(11 citation statements)

References 19 publications

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“…Beyond this value, the temperature decreases because the effect of heat losses particularly radiation in the receiver is greater than the amount of solar radiation intercepted. This behavior is close to the results found by other authors [15][16][17] who also showed increased radiation loss with increasing receiver aperture diameter. Beltran et al [16] found that the aperture diameter of the cavity reaches a point of maximum efficiency when the aperture diameter is equal to 0.13 m which corresponds to a receiver aspect of ratio of 1.5.…”

Section: Effect Of the Aspect Ratiosupporting

confidence: 81%

“…Beltran et al [16] found that the aperture diameter of the cavity reaches a point of maximum efficiency when the aperture diameter is equal to 0.13 m which corresponds to a receiver aspect of ratio of 1.5. Gil et al [17] found with a heat loss coefficient of 12 W m −2°C−1 , the receiver best aspect ratio is 1.9 which is close to our case. Prakash et al [18] found that the convective loss values increase with opening ratio or exposure ratio while the aspect ratio is equal to 1.…”

Section: Effect Of the Aspect Ratiosupporting

confidence: 75%

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Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

Mbodji

Hajji

2017

Energ Sustain Soc

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Background: In an ever-changing world where needs increase daily due to economic growth and demographic progression, where prices are unstable, where reserves are running out, where climate change is topical, the energy issues are increasingly marked by the question of sustainability. In many developing countries, wood and subsidized butane are the main sources of energy used for cooking in households. The use of solar energy in domestic cooking becomes unavoidable. Several models of solar cookers have been proposed, but most of them dealt with box and oven types of solar cookers without storage. Methods: This paper presents a dynamic thermodynamic model of a parabolic solar cooking system (PSCS) with heat storage, along with a comparison of the model solution with experimental measurements. The model uses various thermal resistances to take into account heat transfer between the different parts of the system. Results: The first experimental setup consists of a parabolic concentrator (0.80-m diameter and 0.08-m depth) and a 1.57-l cylindrical receiver. The second experimental setup is composed of a parabolic concentrator (1.40-m diameter and 0.16-m depth), the same receiver, and a 6.64-l heat storage. Tests were carried out in Rabat, Morocco, between April 24 and July 10, 2014, and between May 15 and June 18, 2015. Synthetic oil is used as a transfer fluid and a sensible heat storage. Conclusions:Comparison between predicted and measured temperatures shows a good agreement with a relative error of ± 4.4%. The effects of important system design and operating parameters were also analyzed. The results show that a 50 W m −2 increase of the daily maximum solar radiation increases the storage temperature by 4°C and a 5% increase of the receiver reflectance or absorptance improves the maximum storage temperature by 3.6 and 3. 9°C, respectively. Optimizing the aspect ratio of the receiver to 2 gives a maximum storage temperature of 85°C. Increasing the thermal fluid mass flow rate from 0 to 18 kg h −1 , or the receiver thermal insulation from 0.01 to 0. 08 m, increases the maximum storage temperature by 65 and 17°C, respectively.

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Section: Effect Of the Aspect Ratiosupporting

confidence: 81%

Section: Effect Of the Aspect Ratiosupporting

confidence: 75%

Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

Mbodji

Hajji

2017

Energ Sustain Soc

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“…where ρ is the clean mirror reflectance (which also incorporates the losses due to slope mirror errors), cle is a factor which takes into account the mirror cleanliness, γ is the intercept factor of the collector and is the effective cavity receiver absorptance [48].…”

Section: Energy Balance Of the Dish-stirling Systemmentioning

confidence: 99%

A validated energy model of a solar dish-Stirling system considering the cleanliness of mirrors

Buscemi¹,

Brano²,

Chiaruzzi³

et al. 2020

Applied Energy

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Solar systems based on the coupling of parabolic concentrating collectors and thermal engines (i.e. dish-Stirling systems) are among the most efficient generators of solar power currently available. This study focuses on the modelling of functioning data from a 32 kWe dish-Stirling solar plant installed at a facility test site on the University of Palermo campus, in Southern Italy. The proposed model, based on real monitored data, the energy balance of the collector and the partial load efficiency of the Stirling engine, can be used easily to simulate the annual energy production of such systems, making use of the solar radiation database, with the aim of encouraging a greater commercialisation of this technology. Introducing further simplifying assumptions based on our experimental data, the model can be linearised providing a new analytical expression of the parameters that characterise the widely used Stine empirical model. The model was calibrated against datacorresponding to the collector with clean mirrors and used to predict the net electric production of the dish-Stirling accurately. A numerical method for assessing the daily level of mirror soiling without the use of direct reflectivity measures was also defined. The proposed methodology was used to evaluate the history of mirror soiling for the observation period, which shows a strong correlation with the recorded sequence of rains and dust depositions. The results of this study emphasise how desert dust transport events, frequent occurrences in parts of the Mediterranean, can have a dramatic impact on the electric power generation of dish-Stirling plants.

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“…Thermal efficiency of the heat receiver is studied and validated in [5]. A thermal model of a cavity receiver is developed for optimization in [6] where radiative exchange is evaluated using the radiosity method. The authors in [7] show that the global energy efficiency ranges between 19% and 26%, which can be achieved through optimal design based on a modified Iwamoto model of a Stirling engine and a solar prediction model.…”

Section: Introductionmentioning

confidence: 99%

Particle Swarm Optimization-Based Power and Temperature Control Scheme for Grid-Connected DFIG-Based Dish-Stirling Solar-Thermal System

Li¹,

Xiong²,

Su³

et al. 2019

Energies

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Variable-speed operation of a dish-Stirling (DS) concentrated solar-thermal power generating system can achieve higher energy conversion efficiency compared to the conventional fixed-speed operation system. However, tuning of the controllers for the existing control schemes is cumbersome due to the presence of a large number of control parameters. This paper proposes a new control system design approach for the doubly-fed induction generator (DFIG)-based DS system to achieve maximum power point tracking and constant receiver temperature regulation. Based on a developed thermo-electro-pneumatic model, a coordinated torque and mean pressure control scheme is proposed. Through steady-state analysis, the optimal torque is calculated using the measured insolation and it serves as the tracking reference for direct torque control of the DFIG. To minimize the tracking error due to temperature variation and the compressor loss of the hydrogen supply system, four optimal control parameters are determined using particle swarm optimization (PSO). Model-order reduction and the process of the pre-examination of system stability are incorporated into the PSO algorithm, and it effectively reduces the search effort for the best solution to achieve maximum power point tracking and maintain the temperature around the set-point. The results from computational simulations are presented to show the efficacy of the proposed scheme in supplying the grid system with smoothened maximum power generation as the solar irradiance varies.

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Thermal Model of a Dish Stirling Cavity-Receiver

Cited by 22 publications

References 19 publications

Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

A validated energy model of a solar dish-Stirling system considering the cleanliness of mirrors

Particle Swarm Optimization-Based Power and Temperature Control Scheme for Grid-Connected DFIG-Based Dish-Stirling Solar-Thermal System

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