Numerical investigation of natural convection of cavity receiver for low power application

Ngo, L.C.; Bello‐Ochende, Tunde; Meyer, Josua P.

doi:10.1080/15435075.2016.1161628

Cited by 10 publications

(6 citation statements)

References 14 publications

(9 reference statements)

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“…Its performance may be enhanced by attaching fins on the surface of cavity receiver by improving working fluid side heat transfer coefficient, as reported by Strumpf et al [31]. At higher operating temperatures, e.g., from 400 to 1000 K, the variation of convective energy loss with reference to receiver tilt angle is almost non-linear, while it is quite linear closer to 400 K, according to Ngo et al [32]. The effect of receiver tilt angle on an energy loss by convection from a receiver is stronger at higher operating temperatures.…”

Section: Introductionmentioning

confidence: 79%

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Experimental investigations on thermal performance characteristics of a solar cavity receiver

Bopche

Kumar

2019

Int J Energy Environ Eng

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The experimentation is carried out to examine the influence of receiver aperture/opening ratio (receiver's aperture diameter to the maximum diameter ratio, d/D), glass cover thickness and inclination angle of cavity receiver on its collection efficiency for various flow rates of ordinary water as a working fluid. Experimental tests have been conducted at lower incident energy, i.e., at lower cavity wall temperatures (less than 200 °C). The aperture ratio examined encompasses values as 0.46, 0.6, 0.7, and 0.93 for water flowing at flows of 0.8, 0.65, 0.5, and 0.4 LPM that corresponds to Reynolds numbers (Re) of 1880, 1525, 1175, and 938, respectively. The glazing thicknesses of 6, 4, and 2 mm were provided at an aperture. A modified cavity-type receiver is made inclined at angles 90°, 60°, 45°, and 30° (with 90° as down-facing receiver opening and 30° as close to sideway-facing of receiver opening). The tests have been conducted for cavity surface temperatures ranging from 90° to 180 °C. It is observed that an aperture ratio of 0.6 demonstrates maximum receiver performance for the values of Reynolds number studied, while the receiver performance exhibited reducing trend with reduction in receiver tilting angle from 90° to 30°.Keywords Modified cavity receiver · Aperture/opening ratio · Collection efficiency · Inclination Non-dimensional numbers d/D Ratio of receiver's aperture diameter to the receiver maximum diameter ∕D Glazing thickness ratio Gr Grashof number Nu Nusselt number N RC Radiation-conduction number = T 4 w D 2 (Tw−Tamb)kf Re Reynolds number T R Temperature ratio = T amb T w o Angle ratio Symbols Surface absorptivity δ Thickness (m) Emissivity of the surface Receiver collection efficiency or receiver performance parameter

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Section: Introductionmentioning

confidence: 79%

“…Its contribution change is insignificant between receiver inclination angles of 75° and 90°. Its contribution increases with receiver aperture size [32].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigations on thermal performance characteristics of a solar cavity receiver

Bopche

Kumar

2019

Int J Energy Environ Eng

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“…Due to high temperature difference between the atmosphere and the receiver, it is not recommended to consider the Boussinesq approximation. 3,26 The air in the computational domain is assumed to be incompressible and an ideal gas. Based on these assumptions, the density of the working fluid is determined using the Equation ( 6), which is considered as the effect of temperature changes.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Numerical analysis of convective heat loss from a cylindrical–hemispherical receiver using a glass cover and an air curtain

Kumar,

Karmakar,

Mondal

2024

Heat Trans

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It is imperative to mitigate the convective heat loss from the receiver to improve the overall efficiency of the parabolic dish concentrator. In this study, the reductions of convective heat loss from the cylindrical‐hemispherical receiver are numerically analyzed and the model was validated by the experimental data from literature. In the first case, the impact of the glass cover on convective heat loss is examined under conditions of both natural and forced convections at various receiver orientations (γ = 0°, 30°, 60°, and 90°). Numerical results clearly demonstrate that the use of a glass cover significantly reduces the intrusion of surrounding air into the receiver cavity which leads to an enhancement of the stagnation zone inside the cavity and, as a consequence, a noticeable reduction in convective heat loss is observed. To perform analysis of the receiver with glass cover under forced convective condition, the wind velocities over the receiver are considered in the range of 1–6 m/s. The maximum reduction of convective heat loss using the glass cover is achieved to be 58.44% with wind velocity of 5 m/s at γ = 60°. In the second case, the influence of air curtain at the receiver aperture under natural convective heat loss conditions is analyzed. The analysis incorporates three variables: receiver orientation (γ = 0°–60°), nozzle width ( = 0.002–0.004 m), and nozzle outlet velocity ( = 0.5–3.5 m/s). The results show that the air curtain minimizes the outflow of receiver inside air and results in an improvement in the stagnation zone inside the cavity. The maximum effectiveness of the air curtain is found to be 43.2% at nozzle width of = 0.004 m and nozzle velocity of = 1.5 m/s at receiver orientation of 60°. It is also noteworthy that the optimal nozzle velocity decreases with the increase of nozzle widths.

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“…Thermodynamic analysis of the proposed system is performed by the EES program [13]. The thermodynamic calculations of the general system and subsystems are determined in this section.…”

Section: Thermodynamic and Economic Analysismentioning

confidence: 99%

“…The useful heat gain of the concentrating solar system can be calculated by applying the famous Hottel-Whillier equation [13].…”

Section: Wind Turbine [17]mentioning

confidence: 99%

Thermoeconomic Analysis of Solar Chimney and Wind Turbine Application to Help Generate Electricity in a Trigeneration Cycle

Khorram

Mirzaee

Jafarmadar

2022

IJEE

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The main purpose of this study is to evaluate the thermodynamic and economic performance of using a solar chimney and wind turbine to help generate electricity in a multigeneration system. The proposed system is designed to generate power, heating, cooling, hot water, and steam. Parametric studies were conducted to evaluate the effects of various parameters such as Brayton cycle turbine inlet pressure, organic Rankine cycle turbine inlet temperature, solar radiation, wind speed, and absorption refrigeration cycle evaporator temperature on the system efficiency. The effects of these parameters on the energy, exergy, and economic efficiencies of the whole system were investigated. The results showed that the highest energy efficiency and total exergy of the multigeneration system were 22.12% and 11.4%, respectively. Also, the total power generation capacity of the studied system was calculated to be 2103 kW. The results also depicted that the highest rate of exergy destruction for the main components of the system is found in the parabolic dish solar collector. Increasing the turbine inlet pressure, the average wind velocity of the wind turbine and, evaporator temperature increasing of absorption refrigeration cycle has a positive effect on the efficiency of the proposed system.

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Numerical investigation of natural convection of cavity receiver for low power application

Cited by 10 publications

References 14 publications

Experimental investigations on thermal performance characteristics of a solar cavity receiver

Experimental investigations on thermal performance characteristics of a solar cavity receiver

Numerical analysis of convective heat loss from a cylindrical–hemispherical receiver using a glass cover and an air curtain

Thermoeconomic Analysis of Solar Chimney and Wind Turbine Application to Help Generate Electricity in a Trigeneration Cycle

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