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Title: A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

Abstract

A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. Thismore » paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.« less

Authors:
; ;  [1]
  1. Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)
Publication Date:
OSTI Identifier:
22608562
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1754; Journal Issue: 1; Conference: ICME 2015: 11. international conference on mechanical engineering, Dhaka (Bangladesh), 18-20 Dec 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 14 SOLAR ENERGY; ABSORPTION; AIR FLOW; APERTURES; CAPACITY; CAVITIES; FLOW MODELS; FLOW RATE; FLUID MECHANICS; HEAT TRANSFER; MIXTURES; NUMERICAL ANALYSIS; SILICON; SILICON CARBIDES; SOLAR CELLS; SOLAR FLUX; SOLAR PARTICLES; SOLAR RECEIVERS; THERMAL EFFICIENCY

Citation Formats

Sarker, M. R. I., E-mail: islamrabiul@yahoo.com, Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com, and Beg, R. A.. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles. United States: N. p., 2016. Web. doi:10.1063/1.4958431.
Sarker, M. R. I., E-mail: islamrabiul@yahoo.com, Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com, & Beg, R. A.. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles. United States. doi:10.1063/1.4958431.
Sarker, M. R. I., E-mail: islamrabiul@yahoo.com, Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com, and Beg, R. A.. 2016. "A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles". United States. doi:10.1063/1.4958431.
@article{osti_22608562,
title = {A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles},
author = {Sarker, M. R. I., E-mail: islamrabiul@yahoo.com and Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com and Beg, R. A.},
abstractNote = {A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.},
doi = {10.1063/1.4958431},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1754,
place = {United States},
year = 2016,
month = 7
}
  • The main objective of this work was to evaluate the behavior of porous materials, when treated as volumetric receivers under concentrated solar radiation. For this reason various porous metallic and ceramic materials have been tested as potential receivers for concentrated solar radiation. The experimental investigation showed that their efficiency was depending on both materials parameters and flow conditions. In this work, a variety of foam materials such as Ni and Ni alloy, inconel, copper, aluminum and SiC with different open cell porosity were tested as potential media to be used as volumetric receivers and heat exchangers. However, since the resultsmore » were similar, for space economy, only the results of two of them, nickel and inconel were presented in detail and compared with each other. (author)« less
  • The heat transfer and absorption characteristics of an external receiver pipe under unilateral concentrated solar radiation are theoretically investigated. Since the heat loss ratio of the infrared radiation has maximum at moderate energy flux, the heat absorption efficiency will first increase and then decrease with the incident energy flux. The local absorption efficiency will increase with the flow velocity, while the wall temperature drops quickly. Because of the unilateral concentrated solar radiation and different incident angle, the heat transfer is uneven along the circumference. Near the perpendicularly incident region, the wall temperature and absorption efficiency slowly approaches to the maximum,more » while the absorption efficiency sharply drops near the parallelly incident region. The calculation results show that the heat transfer parameters calculated from the average incident energy flux have a good agreement with the average values of the circumference under different boundary conditions. For the whole pipe with coating of Pyromark, the absorption efficiency of the main region is above 85%, and only the absorption efficiency near the parallelly incident region is below 80%. In general, the absorption efficiency of the whole pipe increases with flow velocity rising and pipe length decreasing, and it approaches to the maximum at optimal concentrated solar flux. (author)« less
  • Current literature on solar air collectors emphasizes satisfactory heat transfer between the absorber and the flowing air as being a major factor in overall performance. Heat transfer in the airflow passages, usually in or near the transitional flow range, is also influenced by entrance effects. The present study experimentally examines a back-corrugated absorber-convector comprised of a rectangularly corrugated plate attached to the back side of a flat absorber plate with a high temperature, high strength adhesive. 8 refs.
  • Current literature on solar air collectors emphasizes satisfactory heat transfer between the absorber and the flowing air as a major factor in overall performance. Heat transfer in the airflow passages, usually in or near the transitional flow range, is also influenced by entrance effects. The present study experimentally examines a back-corrugated absorber-convector composed of a rectangularly corrugated plate attached to the back side of a flat absorber plate with a high-temperature, high-strength adhesive. The upper surface is subjected to a heat flux from a blanket-type electric heater which simulates solar irradiation. The corrugated-plate configuration creates two parallel airflow channel types.more » The two channels have different geometries and, therefore, may have different heat transfer characteristics. An apparatus was designed to determine the local convective heat transfer coefficients along each of the channels. The results show that the back-corrugated absorber-convector has much better thermal performance than the simple flat-plate absorber-convector, primarily because of the increased convective heat transfer area.« less
  • A method of determining the heat-transfer coefficient of the side walls of a solar water heater with a metal (steel) frame insulated from the heatreceiver by means of a ..pi..-shaped rubber sealing gasket is proposed.