US20090114212A1

US20090114212A1 - Hybrid solar panel

Info

Publication number: US20090114212A1
Application number: US12/246,172
Authority: US
Inventors: Lin-Shu Wang
Original assignee: Research Foundation of State University of New York
Current assignee: Research Foundation of State University of New York
Priority date: 2007-10-06
Filing date: 2008-10-06
Publication date: 2009-05-07

Abstract

Disclosed is an apparatus and method for improved efficiency in the collection of solar energy, in which an energy conversion device is provided that includes a first zone for converting received solar energy into thermal energy, the first zone having a Fresnel lens, and a heat absorption layer with heat collectors embedded therein. The energy conversion device also includes a second zone positioned at a lower level of first energy zone for converting received solar energy into electrical energy utilizing a photovoltaic cell.

Description

PRIORITY

This application claims priority to U.S. Provisional Application No. 60/997,861, filed Oct. 5, 2007, and to U.S. Provisional Application No. 60/982,559, filed Oct. 25, 2007, the contents of each of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Conventional photovoltaic (PV) panels generate electrical energy directly. Conventional concentrated solar thermal power (CSP) plants extract heat energy from sunlight, but require a separate apparatus to utilize the heat energy, such as a Rankine-cycle plant to convert the heat energy into the electrical energy. CSP plants, which employ huge arrays of mirrors to concentrate solar energy, are centralized powerplants, which do not have the flexibility and modularity of PV panels. Although the CSP conversion is generally more efficient than use of photovoltaic panels, the recent development of concentrated solar photovoltaic (CPV) cells matches the CSP conversion efficiency of light energy into power.
CPV can operate at more than twice the efficiency than non-concentrated PV cells. CPV's also reduce the amount of required PV cell material, which is the most expensive part of a solar panel. However, CPV's only convert direct sunlight and waste approximately half of the available energy in diffuse sunlight.
Importantly, the photovoltaic conversion efficiency depends on the concentration factor and the temperature of PV cells; higher efficiency is obtained at higher concentration factor and lower PV cell temperature. Concentration method of CPV enables creating separate zones of different temperatures in a solar panel.
The present invention overcomes the shortcoming of losing diffuse sunlight in conventional solar concentration technologies by providing a hybrid solar panel (HSP) design that captures diffuse sunlight and at the same time creates two temperature zones within the panel, providing rooftop CPV's harnessing heat and power, both usable in building applications. CPV technology represents a step forward on the issue of conversion efficiency and at the same time the issue of cost of conventional PV technology. The present invention further improves CPV technology and provides a technological foundation for a zero energy building with the potential of decreasing the nation's total housing energy consumption.

SUMMARY OF THE INVENTION

The hybrid solar panel of the present invention overcomes the shortcomings of conventional systems by converting direct sunlight into electricity and collecting the unconverted direct sunlight and the diffuse sunlight as heat in a single solar panel.
In the present invention, an energy conversion device and method are provided that include a refractive lens, a heat absorption layer containing a plurality of heat collectors, a plurality of insulators, a first zone positioned between and including the lens and heat absorption layer for converting received solar energy into thermal energy, wherein the first zone includes the plurality of insulators, and a second zone is positioned between the plurality of insulators for converting received solar energy into electrical energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows direct sunlight entering into the a single collector of the energy conversion device 100 of the present invention;

FIG. 2 provides an enlarged view of a photovoltaic zone of FIG. 1; and

FIG. 3 shows diffuse insolation of sunlight onto a collector surface of a plurality of collectors at an upward zero-angle position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of preferred embodiments of the invention will be made in reference to the accompanying drawings. In describing the invention, explanation about related functions or constructions known in the art are omitted for the sake of clearness in understanding the concept of the invention, to avoid obscuring the invention with unnecessary detail.
The present invention provides a hybrid energy conversion device for maximizing the amount of energy extracted from solar power. In a preferred embodiment, the apparatus of a preferred embodiment of the present invention includes, as shown in FIGS. 1-3, a first zone 102 for converting received solar energy into thermal energy and a second zone 204 for converting received solar energy into electrical energy. FIG. 1 shows direct sunlight entering into the energy conversion device 100 of the present invention and FIG. 3 shows a plurality of collectors of the present invention arranged side by side to provide an extended light collecting surface.
In a preferred embodiment of the present invention, an upper boundary is provided of the first zone 102, with the upper boundary preferably provided by a refractive Fresnel lens 110 that focuses the sunlight onto the PV zone 240. A heat absorption layer 130 and Fresnel lens 110 define the first zone 102.
In a preferred embodiment, the first zone 102 is occupied by ambient air, with the Fresnel lens forming a boundary of a double-layered exterior cover, evacuated to operate in a vacuum.
In an alternate embodiment, heat absorption layer 130 and a collector side 152 of the hybrid energy conversion device are curved to form a reflective mirror to direct sunlight onto photovoltaic (PV) zone 240, which acts as a collector of electric power via operation of a PV cell 241 therein.
The heat absorption layer 130 contains a plurality of heat collectors 136, preferably pipes filled with fluid that flows through and absorbs solar energy. In a preferred embodiment, once heated by the solar power, the fluid leaves the first zone 102 where the heat is removed from before the fluid returns to the plurality of heat collectors 136. It will be appreciated that the heat collectors 136 may also be heat pipes, within which fluid forms a closed loop for transport of absorbed solar energy to a condenser-end.
A plurality of insulators 149 thermally protect the PV zone 240 from the heat absorption layer 130. To maximize the operational efficiency of the PV 241, the PV zone 240 includes upper and lower conduits 242 and 246 provide air coolant and water coolant 244 and 248, respectively. The cover of 242 is 243, which in a preferred embodiment are made of optical materials configured to block long wavelength radiation.
A receiving area of the hybrid solar panel is preferably made of small areas of high-performance PV cells, which convert radiation energy into electrical power, surrounded by larger areas of radiative absorbing and heat conducting surfaces, which convert radiation energy into heat and distribute the heat. The solar panel includes thermal management unit and heat transporting elements, as well as the control (both thermally for temperature controls and dynamically for tracking control. It will be recognized that the whole hybrid energy conversion panel can be mounted onto an arm that tracks the movement of the sun, either in one or two dimensions. Alternatively, each individual collector within a panel can be tracked to follow the movement of the sun.
While the invention has been shown and described with reference to certain exemplary embodiments of the present invention thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and equivalents thereof.

Claims

1. An energy conversion device comprising:

a refractive lens;

a heat absorption layer containing a plurality of heat collectors;

a plurality of insulators;

a first zone positioned between and including the lens and heat absorption layer, the first zone for converting received solar energy into thermal energy, wherein the first zone includes the plurality of insulators; and

a second zone is positioned between the plurality of insulators, the second zone for converting received solar energy into electrical energy.

2. The device of claim 1, wherein the second zone is thermally cooled.

3. The device of claim 1, wherein the plurality of insulators of the second zone consist of two insulators positioned on opposite sides of a photovoltaic cell.

4. The device of claim 1, wherein the lens is a Fresnel lens.

5. The device of claim 1, further comprising a one-axis tracking device.

6. The device of claim 1, further comprising a two-axis tracking device.

7. The device of claim 3, wherein a plurality of the energy conversion devices adjacently housed in a panel, including a double-layered cover having a vacuum between layers thereof.

8. The device of claim 1, wherein the heat collectors are heat pipes.

9. The device of claim 1, wherein the second zone is conditioned with water coolant in a lower conduit and air coolant in an upper conduit.

10. The device of claim 1, wherein the upper conduit includes an optical cover to block infrared radiation.

11. The device of claim 1, wherein the first zone operates in a vacuum.

12. A method for energy conversion, the method comprising:

diffracting sunlight in a refractive lens;

absorbing, in a heat absorption layer containing a plurality of heat collectors, solar heat;

within a first zone positioned between and including the lens and heat absorption layer, converting received solar energy into thermal energy, wherein the first zone includes the plurality of insulators; and

within a second zone positioned between the plurality of insulators, converting received solar energy into electrical energy.