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CFD simulation of airflow in a new receiver concept for solar tower

Cheilytko Andrii, Nohutcu Oguzhan, Schwarzbözl Peter, Broeske Robin Tim

Journal of New Technologies in Environmental Science

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2023

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Vol. 7, nr 3

83--98

EN

Open cavity solar receivers play an important role in concentrated solar power (CSP) systems and hold great promise, particularly in scenarios where their ability to absorb high fluxes at very high temperatures yields beneficial results. This intense concentration of sunlight can be used to produce electricity through various means, such as generating steam to drive a turbine. The efficiency of the open volumetric receiver concept relies heavily on the air return ratio (ARR) which refers to the proportion of air recirculated and returned to the receiver. A high ARR contributes to high receiver efficiencies, as with rising ARR, the reused part of the enthalpy of warm air increases. This paper deals with the design and simulation of a new receiver concept with a conical cavity and square cross-section. The objective is to identify the most effective design arrangement for the square-cone structure, considering different depths, that maximizes both the air return ratio (ARR) and thermal efficiency. The findings demonstrate that increasing the depth of the mentioned receiver leads to a rise in the ARR, up to a certain threshold which can reach values up to 94.53%, beyond which there is a subsequent decline in efficiency. Furthermore, this study examined how varying the amount of air passing through a specific section of the receiver across a defined area, along with the temperature changes in these sections, affected its operational efficiency.

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A new idea to increase the convective efficiency of a solar tower air receiver by creating a controlled vortex

Cheilytko Andrii

Journal of New Technologies in Environmental Science

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2023

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Vol. 7, nr 2

46--55

EN

Concentrated solar energy as a source of renewable energy has a high potential for solving the current energy crisis. The solar tower receiver is a crucial element of solar energy conversion efficiency. To increase the convective efficiency of the solar tower receiver, the idea of creating a vortex is proposed. The vortex is created either in the plane in front of the receiver, for flat receivers, or in the internal volume of the receiver, for cavity-type receivers. The calculation formulas for calculating the parameters of the controlled vortex are proposed and computer modeling is performed to determine the effectiveness of the proposed idea. The results of computer modeling confirmed the physical possibility of the controlled vortex formation in the receiver space and visually show the flow structure. Also, the general dependence of the air return coefficient in the VoCoRec receiver on the flow twist was found. Conclusions are drawn on the satisfactory results obtained and on the improvement of the existing model of the controlled vortex.

3

New developments of solar energy utilization in the aspect of EU directives

Barwicki J., Kuboń M., Marczuk A.

Agricultural Engineering

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2017

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Vol. 21, No. 2

15--24

EN

Photovoltaic systems are very efficient concerning proper utilization of solar radiation. However, the nanotechnology solution can replace the photovoltaic by the use of new production technology to lower the price of solar cells to one tenth. Sun provides nearly unlimited energy resource, but existing solar energy harvesting technologies are quite expensive and cannot compete with fossil fuels. The central part of Poland, which represents about 50 percent of the area, gives solar radiation at the level of 1000 kWh·m-2/year. Other new developments, which can help improve existing efficiency of solar systems are: diatoms utilization, artificial photosynthesis, nanoleaves and rotation solar towers.

PL

Układy fotowoltaiczne są bardzo wydajne pod względem właściwego wykorzystania promieniowania słonecznego. Jednakże rozwiązania nanotechnologiczne mogą zastąpić fotowoltaikę dzięki wykorzystaniu nowej technologii produkcji, w celu obniżenia ceny ogniw słonecznych do jednej dziesiątej. Słońce dostarcza prawie nieograniczone zasoby energii, ale istniejące technologie jej pozyskiwania są dość kosztowne i nie mogą konkurować z paliwami kopalnymi. W centralnej części Polski, która stanowi około 50 procent powierzchni, promieniowanie słoneczne osiąga poziom 1000 kWh·m-2/rok. Innymi nowymi rozwiązaniami, które mogą przyczynić się do poprawy istniejącej efektywności systemów słonecznych są: wykorzystanie sztucznej fotosyntezy, nanotechnologii, czy też wprowadzenie obrotowych wież słonecznych.