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Electricity from waste heat applied e.g. to photovoltaic structure

IP.com Disclosure Number: IPCOM000201667D
Publication Date: 2010-Nov-17
Document File: 5 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Abstract

PV solar modules / devices are directly exposed to the sun. This not only generates electricity within the solar device but also heat. The elevated temperature in the PV solar device typically has the effect of performance degradation. There are solutions available to cool PV solar devices and modules. The cooling mainly is made using water or air cooling. It would be much better to use the waste heat from solar devices to generate direct electricity while cooling the device to achieve better performance. The solution as outlined below is not restricted to PV cell solutions only but can also be used in any heated device environment.

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Electricity from waste heat applied e .g. to photovoltaic structure

Description of the waste heat solution

The core idea is it to use so-called magnetic switches to generate the electricity. Permanent magnets (e.g. hard bias) create a magnetic field. This field is guided by flux guides to the thermo magnetic device by soft magnetic material (e.g. NiFe 45/55). The flux guides also collects the heat to transport it to the thermo magnetic device. The figure below shows a side view of a PV solar cell with magnetic switch cooling on the rear side.

PV-Structure
Si-Wafer

Thermo-Mag- Structure

Figure 1: PV solar cell side view, including magnetic switch application

The base idea is it to generate a permanent magnet field which in combination with the elevated heat activates the magnetic switches to generate the electricity. The switches open and close at a certain frequency, determined by setup and temperature. The heat is transferred to the back by the alumina layer, which also is the back surface field of the PV solar cell.

Magnetic Switches

Hard-Magnetic-

Permanent-Magnets

Soft-Magnetic-Yoke

Red arrows = heat / energy flow

Figure 2: backside view on the magnetic cooling device

The detailed structure to generate electricity is shown in the figure below.

Al-backplane

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magnetic switch

AC

soft magnetic yoke

hard magnet

Figure 3: inductive cycle closed by magnetic switch generating electricity through waste heat

The magnetic switch is closing the magnetic yoke through thermo-magnetic effect. The magnetic field induces a current in the coil. The switching causes an AC current which should be transferred into DC before merging with other power sources.

The heat flow through the solar device as well as the magnetic setup generates electricity as well as reduces the temperature in the PV solar device. The heat from the sun is transferred to the Al backplane which works as a head spreader. The flux guides (soft magnetic yoke) collects the heat from the backplane and transfers it to the thermo magnetic structure (see figure 1 & 2). Inside the thermo magnetic structure the heat flows through the converter unit (magnetic switch) and creates electricity. From the thermo magnetic structure the heat flows to the heat sink which dispenses the remaining heat to the air. The figure below shows a side view of the entire setup mounted on a PV solar cell.

PV-Structure Si-Wafer Al-heat-Spreader

sun

Red arrows = heat / energy flow

permanent-Magnets softmagnetic yoke

Thermo-Mag- Structure

Converter unit: heat electricity

heat sink

air air air

Figure 4: side view of the whole setup on a PV solar cell

The mounting of the cooling device can be implemented into the PV solar cell process. The cooling setup can be specific build for high sun intensity geo's, like dessert areas etc. The heat sink could be the module back side where the solar cell is be mounted on.

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An alternative structure could be as follows. Permanent magnet (e.g. hard b...