Near-Blackbody Thermal Receiver Cavity for Solar Heat Loss Reduction
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Solution Overview
Problem
Concentrating solar power systems face low thermal efficiencies due to radiant and convective heat losses from high-temperature thermal receivers, particularly those using air or solid particles as heat transfer media, which limits their operational temperature and efficiency.
Innovation Solution
A thermal receiver design featuring external and internal panels configured to form a cavity with channels for heat transfer media, where radiation is absorbed and reflected multiple times to minimize energy loss, with angled portions to intercept radiation and reduce direct impingement on the back panel, enhancing energy absorption and reducing thermal losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperature operation (above 650°C) is implemented using air or solid particles as heat transfer medium, then operating temperature is improved, but thermal efficiency deteriorates due to radiant and convective heat losses
Solution Approach 1:
The receiver is divided into multiple discrete panels (e.g., 3-5 panels) arranged in a cavity configuration. Each panel is independently positioned and can be optimized for specific functions such as radiation absorption, reflection, and heat transfer. This segmentation allows better control of thermal paths and reduces unwanted heat losses while maintaining high operating temperatures.
Solution Approach 2:
The patent implements a nested cavity structure where panels are positioned within an outer shell, creating internal cavities. The heat transfer medium flows through channels within the panels, which are nested within the overall receiver assembly. This nested configuration traps radiant energy within the cavity, reducing radiant heat losses to the environment while maintaining high temperatures for efficient energy conversion.
2Device complexity
If conventional receiver designs are used, then device simplicity is maintained, but thermal efficiency deteriorates due to direct radiation impingement on back panel causing heat losses
Solution Approach 1:
The patent introduces asymmetric positioning of panels within the receiver cavity, with panels angled at specific orientations (e.g., 45-degree angles) relative to the incoming radiation. This asymmetric arrangement prevents direct radiation from impinging on the back panel, redirecting energy toward the heat transfer medium channels instead. The asymmetric design optimizes radiation trapping while maintaining relatively simple structural implementation.
Solution Approach 2:
The patent transitions from a conventional two-dimensional panel arrangement to a three-dimensional cavity configuration with panels positioned at various angles and depths. This dimensional change creates multiple reflection paths for incoming radiation, allowing energy to be trapped and redirected within the cavity volume rather than directly striking the back panel. This spatial optimization reduces radiant heat losses without significantly increasing structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves thermal efficiencies exceeding 90% at temperatures above 650°C, minimizing radiant and convective losses and maximizing energy transfer to the heat transfer fluid, thereby improving the overall efficiency of concentrating solar power systems.
Implementation Method 1
radiation is absorbed and reflected multiple times to minimize energy loss
Implementation Method 2
radiation is absorbed and reflected multiple times to minimize energy loss
Implementation Method 3
minimizing radiant and convective losses
Implementation Method 4
transfers that heat as thermal energy to a heat transfer fluid
Data Source
AI summary
An aspect of the present disclosure is a receiver for receiving radiation from a heliostat array that includes at least one external panel configured to form an internal cavity and an open face. The open face is positioned substantially perpendicular to a longitudinal axis and forms an entrance to the internal cavity. The receiver also includes at least one internal panel positioned within the cavity and aligned substantially parallel to the longitudinal axis, and the at least one internal panel includes at least one channel configured to distribute a heat transfer medium.