Solar Receiver Natural Circulation to Cut Pressure Drop
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Solution Overview
Problem
Current solar concentration systems with tower central receivers require drive pumps to recirculate the working fluid, leading to significant pressure drops, which limits their efficiency and scalability compared to fossil fuel-based systems that utilize natural circulation.
Innovation Solution
A novel design employing natural circulation within the solar receiver system, utilizing larger tube diameters and strategic component configurations to facilitate fluid recirculation without pumps, minimizing pressure drops and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drive pumps are used to recirculate working fluid in solar receivers, then fluid circulation is achieved, but pressure drops increase significantly
Solution Approach 1:
The invention extracts and eliminates the drive pumps from the solar receiver system by implementing a natural circulation design. The working fluid circulates through the receiver tubes and drum without mechanical pumping, using density differences between hot and cold fluid zones to drive flow. This removes the source of high pressure drops while maintaining effective fluid circulation.
Solution Approach 2:
The system enables self-service circulation where the working fluid automatically circulates through the receiver without external mechanical assistance. The natural circulation is driven by the density difference between heated fluid in the receiver tubes and cooler fluid in the drum, creating a self-sustaining flow that eliminates the need for pumps and reduces pressure losses.
2Ease of operation
If drive pumps are used for fluid recirculation, then circulation is maintained, but system efficiency decreases due to self-consumption
Solution Approach 1:
The invention removes drive pumps from the system, eliminating the auxiliary power consumption associated with mechanical recirculation. The natural circulation design allows the working fluid to circulate without external energy input, directly improving net electricity production by reducing self-consumption.
Solution Approach 2:
The invention replaces the mechanical pump system with a natural circulation mechanism driven by buoyancy forces. This substitution eliminates the need for mechanical energy input to maintain fluid circulation, converting a mechanically-driven system into a thermally-driven system that improves overall efficiency and net power output.
3Length of stationary object
If smaller receiver dimensions are used in solar towers, then tower height is reduced, but natural circulation becomes difficult to achieve
Solution Approach 1:
The invention modifies key parameters of the natural circulation system including increasing the drum diameter relative to tube dimensions, optimizing tube spacing and arrangement, and adjusting the receiver geometry to enhance density differences. These parameter changes enable sufficient natural circulation driving force even in compact tower configurations with reduced height.
Solution Approach 2:
The invention applies local quality optimization by designing specific receiver tube arrangements and drum configurations that maximize thermal gradients and density differences in localized zones. The receiver tubes are positioned and dimensioned to create optimal heating zones, while the drum geometry is optimized to enhance cooling and density stratification, enabling natural circulation in smaller overall dimensions.
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
This approach eliminates the need for recirculation pumps, reduces self-consumption, and increases net electricity production by leveraging the density difference between hot and cold zones to promote natural fluid ascent, thereby optimizing solar energy utilization.
Implementation Method 1
The invention describes both the design and the operating system of the receiver, which uses natural circulation as a method of supply of the working fluid to the system
Implementation Method 2
The proposed innovation seeks to exploit one of the physical properties of the working fluid (density) in the operating conditions which, under a proper configuration of the circuit components (equipment elevations, lengths and diameters of tubes), can result in the natural circulation phenomenon
Implementation Method 3
solar radiation is concentrated by using heliostats in a receiver located on top of a tower (in the focus of the optical system) and where it is transformed into thermal energy by the absorption of heat from the working fluid
Data Source
AI summary
The invention relates to a solar receiver with natural circulation for generating saturated steam, which uses water/steam as a heat-transfer fluid and includes a combined circuit for fluid recirculation (forced circulation and natural circulation). The system comprises: water-walls which receive the radiation on the surface thereof and inside which the working fluid changes phase; riser pipes through which the water/steam mix exiting the pipes of the receiver rises towards the drum; downpipes through which the recirculation water descends from the drum to the receiver; and a support pump in order to increase the incident power in the receiver and start up the plant when necessary.