Transmissive CPV Module With Spectrum Splitting and Cell Cooling
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Solution Overview
Problem
Conventional concentrating photovoltaic (CPV) systems face challenges in maintaining low cell temperatures for efficient photovoltaic performance while capturing high thermal output temperatures, leading to inefficiencies in spectrum splitting and thermal energy utilization.
Innovation Solution
A transmissive, spectrum-splitting concentrating photovoltaic (tCPV) module using III-V triple junction solar cells that absorbs UV and visible light for electricity generation while allowing infrared light to pass through for thermal energy capture, combined with active or passive cooling systems to manage temperature and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If concentrating approaches are used to reduce PV area and improve efficiency, then electricity conversion efficiency is improved, but cell temperature increases which reduces performance and reliability
Solution Approach 1:
The solar spectrum is segmented into different wavelength ranges using spectrum splitting optics. UV and visible light (above-bandgap) are directed to PV cells for electricity generation, while infrared light (below-bandgap) is directed to thermal receivers for heat capture. This segmentation allows the PV cells to operate with reduced thermal load since they only absorb the portion of sunlight that generates electricity, not the full solar spectrum that would otherwise heat them.
Solution Approach 2:
Spectrum splitting optics act as an intermediary between the concentrated sunlight and the PV cells. These optical elements selectively direct different wavelength ranges to different targets, mediating the interaction between sunlight and the PV/thermal system. This intermediary function enables the PV cells to receive only the beneficial above-bandgap radiation while excluding much of the thermal infrared radiation.
2Power
If conventional CPV systems capture high thermal output temperatures, then thermal energy utilization is improved, but PV cell temperature increases leading to efficiency loss
Solution Approach 1:
The solar spectrum is segmented into different wavelength ranges using spectrum splitting optics. UV and visible light (above-bandgap) are directed to PV cells for electricity generation, while infrared light (below-bandgap) is directed to thermal receivers for heat capture. This segmentation allows the PV cells to operate with reduced thermal load since they only absorb the portion of sunlight that generates electricity, not the full solar spectrum that would otherwise heat them.
Solution Approach 2:
Different regions of the solar spectrum are treated differently: above-bandgap radiation is converted to electricity by PV cells while below-bandgap radiation is captured as heat by thermal receivers. This local quality approach applies different conversion mechanisms to different portions of the incident radiation, optimizing both electrical and thermal output while maintaining PV cell temperature control.
3Productivity
If spectrum splitting is used to separate UV/visible light for PV and IR light for thermal capture, then energy utilization efficiency is improved, but system complexity increases
Solution Approach 1:
The tCPV module integrates multiple functions into a single system: it simultaneously performs concentrated photovoltaic electricity generation and concentrated solar thermal energy capture through the transmissive module design. The same optical concentration system serves both PV and thermal functions, reducing the need for separate tracking and concentration systems that would increase complexity.
Solution Approach 2:
The PV module and thermal receiver are merged into a single integrated system where the PV module is positioned within the thermal receiver assembly. This merging allows shared structural support, shared optical concentration elements, and coordinated thermal management, reducing overall system complexity compared to separate PV and CSP systems.
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 tCPV module achieves an overall energy conversion efficiency of 43.5% for in-band light and 75% transmission efficiency for out-of-band light, allowing for flexible thermal output from 100°C to 570°C, suitable for various industrial and commercial applications.
Implementation Method 1
ultraviolet (UV) and visible light is directly absorbed and converted to electricity
Implementation Method 2
The lateral heat conducting layer may be comprised of a transparent material with high thermal conductivity
Implementation Method 3
The one or more heat sinks may be positioned in an orientation selected from the group comprising flushed, flared, or inverted, radially surrounding the one or more lateral heat conducting layers
Implementation Method 4
infrared (IR) light will pass through the cells and module to be captured by a solar thermal receiver
Data Source
AI summary
A spectrum splitting, transmissive concentrating photovoltaic (tCPV) module is proposed and designed for a hybrid photovoltaic-solar thermal (PV/T) system. The system may be able to fully utilize the full spectrum of incoming sunlight. By utilizing III-V triple junction solar cells with bandgaps of approximately 2.1 eV, 1.7 eV, and 1.4 eV in the module, ultraviolet (UV) and visible light (in-band light) are absorbed and converted to electricity, while infrared (IR) light (out-of-band light) passes through and is captured by a solar thermal receiver and stored as heat. The stored heat energy may be dispatched as electricity or process heat as needed. The tCPV module may have an overall power conversion efficiency exceeding 43.5% for above bandgap (in-band) light under a standard AM1.5D solar spectrum with an average concentration ratio of 400 suns. Passive and/or active cooling methods may be used to keep cells below 110° C. while transmitting >75% of out-of-band light to the thermal receiver, which may attain thermal energy capture at temperatures as high as 500° C. or more. A transparent active cooling system may improve the CPV module efficiency by about 1% (absolute) relative to a passive cooling system by reducing the maximum cell working temperature by about 16° C.