The present relates to solar panels, and more particularly to autonomous solar panels for use in winter conditions.
The development of photovoltaic technology has evolved over the last thirty years and is now one of the most promising sources of alternative energy in areas conducive with high levels of uninterrupted solar capacity. Concurrently, as a result of natural resources being limited and unable to last forever, it is the implementation of sustainable so-called “green” energy that has the capacity to fulfill our energy needs now and in the future.
Solar photovoltaic panels have been made and marketed to accommodate weather in states and countries that have an abundance of sunshine and limited winter weather conditions given that the panels must remain clear and clean at all times to maximize the solar energy output. Locations with winter weather precipitation (snow, frost, sleet, ice, hail) including higher latitude areas have had many challenges given the reduced energy produced and cost effectiveness of this green technology. Contrary to common knowledge, photovoltaic energy is enhanced under cold winter temperatures.
A number of designs have been used to address at least some of the aforesaid problems. One design described in PCT application PCT/US2010/000803 (WO 2010/107491) to Ball et al. for “Photovoltaic Module with Heater” is a roof mounted solar panel with a heater in which heating filaments embedded in, or located on, a transparent panel are connected to an external power source operable using a switch to selectively heat and melt snow that has collected on the solar panel. Another design described in PCT application PCT/US2010/032832 (WO 2010/127037) to Kaiser et al for “Solar Power Systems Optimized for use in Cold Weather Conditions” is a system in which electrical energy is supplied to a load based on solar energy. The system includes a mode select switch which permits switching between one mode, where a solar cell supplies electrical energy to a load, and a second mode, where a power supply supplies energy to the solar cell so that it generates heat.
Thus, there is a need for an improved solar panel cleaning device which provides reliable solar energy power in areas that may have winter conditions, which would reduce or negate the effective energy output.
Features of the discovery will be apparent from a review of the disclosure, drawings and description below.
The present relates generally to framed and frameless autonomous winterized solar photovoltaic panels that can effectively produce year round energy on a reliable and consistent basis thereby reducing our carbon footprint. This can be achieved by diverting a small portion of stored photovoltaic panel power to at least one heat and/or mechanical energy generator to effectively remove winter precipitation in an autonomous manner. The mechanical energy aspect can also be used year round to remove dust and other undesirable material.
Accordingly, there is provided an autonomous solar panel for use in winter conditions, the panel comprising:
at least one energy transfer member associated with the solar panel;
at least one sensor in communication with the energy transfer member;
a power supply connected to the energy transfer member; and
a network interconnecting the energy transfer member, the sensor, and the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the solar panel, a portion of stored power in the power supply activates the energy transfer member so as to remove the winter precipitation from the solar panel.
In one example, the solar panel includes a solar panel cover, the energy transfer member is a heater which is embedded within the solar panel cover. The heater is a serpentine heating wire which is disposed substantially across the entire solar panel cover.
In one example, the network includes a heater switch connecting the power supply to the sensor. The network includes a controller connecting the sensor to the heater switch. The power supply is a battery. The network includes a charger connecting the solar panel to the battery. A load switch connects to the charger. A user load connects to the load switch.
In one example, the solar panel includes a winter precipitation sensor and a temperature sensor. The solar panel includes a solar panel cover and a solar panel voltaic array, and the temperature sensor sandwiched therebetween, the controller connects to the temperature sensor. The network includes a user heater voltage supply connected to the load switch.
In another example, the network includes a user load connecting a controller to a solar panel voltaic array of the solar panel. The network includes a supplemental heater switch connecting the controller to a heater supplement supply. The network includes a remote display connected to the controller.
In yet another example, the energy transfer member includes at least one vibration assembly. The solar panel includes a solar panel cover and a solar panel voltaic array, and the vibration assembly being sandwiched therebetween. The vibration assembly is located at the periphery of the solar panel. The solar panel includes four vibration assemblies, two of which are spaced apart and located at a top edge of the solar panel, the other two being spaced apart and located at a bottom edge of the solar panel.
In one example, the network is configured such that in response to the sensor sensing the accumulation of winter precipitation on the solar panel, the portion of stored power in the power supply activates the vibration assembly to vibrate the solar panel so as to remove the winter precipitation therefrom. The vibration assembly is a vertical vibration assembly and includes a vertical vibration actuator, a vertical vibration plunger, and a resilient vibrator lever connected to the solar panel cover. The network includes a vibrator switch connecting a controller to a voltage supply to activate the vibration actuator.
In an alternative example, the vibration assembly is a horizontal vibration assembly and includes a vibration actuator, a vibration plunger, a cam lever, and a resilient vibrator lever connected to the solar panel cover. The network includes a vibrator switch connecting a controller to a voltage supply to activate the vibration actuator.
In one example, a frame holds together the solar panel cover and the solar panel voltaic array. The solar panel further includes a solar panel frame heater. The frame heater includes a plurality of heater elements connected to a frame heater switch, the heater elements extending substantially along the bottom of the frame.
In one example, the power supply includes a plurality of batteries located between the underside of the solar panel and a panel tilt mount on which the solar panel and batteries are mounted.
In another example, the power supply includes a plurality of batteries located in or on the side of a vertical post connected to a panel tilt mount on which the solar panel is mounted.
In another example, the power supply includes a plurality of batteries located between the underside of the solar panel and a frame mount on which the solar panel is mounted.
In another example, the power supply includes a plurality of batteries located separately from the solar panel.
In one example, the power supply includes a plurality of batteries located between the underside of the solar panel and a roof mount on which the solar panel is mounted.
In one example, the sensor includes one or more light emitting devices which illuminate the solar panel upper outer surface and a light sensing device which senses the reflection caused by winter precipitation.
In one example, a temperature sensor is located on the inner surface of the solar panel cover to determine when winter precipitation is possible and to determine when the panel cover has been sufficiently heated.
In another aspect, there is provided an autonomous solar panel for use in winter conditions, the panel comprising:
a power supply connected to the heater element; and
a network interconnecting the heater element, the sensor, and the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the solar panel, a portion of stored power in the power supply activates the heater element so as to heat the solar panel to remove the winter precipitation therefrom.
In another aspect, there is provided an autonomous solar panel for use in winter conditions, the panel comprising:
a vibration assembly associated with the solar panel;
at least one sensor in communication with vibration assembly;
a power supply connected to the vibration assembly; and
a network interconnecting the vibration assembly, the sensor, and the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the solar panel, a portion of stored power in the power supply activates the vibration assembly so as to vibrate the solar panel to remove the winter precipitation therefrom.
In another aspect, there is provided an autonomous solar panel for use in winter conditions, the panel comprising:
In yet another aspect, there is provided an autonomous solar panel cleaning system for use in winter conditions, the panel comprising:
a controller;
at least one energy transfer member associated with the solar panel;
at least one sensor in communication with the energy transfer member;
a power supply connected to the energy transfer member; and
a network interconnecting the controller, the energy transfer member, the sensor, the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the solar panel, a portion of stored power in the power supply activates the energy transfer member so as to remove the winter precipitation from the solar panel.
In another aspect, there is provided an autonomous solar panel system for use in winter conditions, the system comprising:
a master solar panel having an master energy transfer member associated therewith;
a plurality of slave solar panels, each panel having a slave energy transfer member associated therewith;
at least one sensor in communication with the master solar panel;
a master controller connected to the master solar panel;
a plurality of slave controllers, each slave controller being connected to the respective slave solar panels;
a power supply connected to each of the master and the slave energy transfer members; and
a network interconnecting the energy transfer members, the sensor, the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the master solar panel, a portion of stored power in the power supply activates the master and the slave energy transfer members so as to remove the winter precipitation from the master and the slave solar panels.
In another aspect, there is provide a circuit comprising:
a solar panel;
at least one energy transfer member associated with the solar panel;
at least one sensor in communication the energy transfer member;
a power supply connected to the energy transfer member; and
a network interconnecting the energy transfer member, the sensor, and the power supply, the network being configured such that in response to the sensor sensing an accumulation of winter precipitation on the solar panel, a portion of stored power in the power supply activates the energy transfer member so as to remove winter precipitation from the solar panel.
In one example, the solar panel is for use with a pipeline carrying a fluid energy source.
In one example, in which the pipeline includes a pipeline fluid spill monitoring device and system.
In another example, the solar panel is integrated into conventional and non-conventional building materials including: plastic, composite, polycarbonate, or petroleum based solar cells, the materials being superimposed, sprayed, or painted on surfaces or woven into fabric.
In yet another example, the solar panel is for use with a roadside and highway emergency notification device and system.
In still another example, the network is configured such that in response to the sensor sensing the accumulation of dust or other material on the solar panel, the portion of stored power in the power supply activates the vibration assembly to vibrate the solar panel so as to remove the material therefrom.
In order that the discovery may be readily understood, embodiments of the discovery are illustrated by way of example in the accompanying drawings.
Further details of the AWSP and its advantages will be apparent from the detailed description included below.
We have designed an autonomous system for photovoltaic solar panels to operate efficiently in all winter weather conditions. The system is equipped with components to sense and remove winter precipitation such as snow, frost, ice and sleet, to maximize and restore panel performance to peak solar energy output levels. The system provides at least one type of energy transfer in the form of heat and/or panel cover shaking to remove the winter precipitation from the panel surface. This shaking can also be used year round to remove dust and other material from the panel surface. The panels can independently remove the winter precipitation through solar powered energy that is stored in a self-contained solar powered battery compartment. This may be supplemented by AC/DC power supply. The system maximizes solar energy output of the solar panels and effectively provides a higher level of efficiency throughout the entire daylight hours in a cost effective manner. Under extreme winter conditions, the system may simultaneously or sequentially employ both the solar panel surface heating and the solar panel surface shaking to remove the winter precipitation during a cleaning cycle.
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Other heater elements 34 that can be used to transfer heat may include the following non-limiting examples:
1. Infrared heater elements with focusing reflectors below or above the cover glass;
2. Microwave energy focused on the glass (requires a special glass able to absorb microwave energy at low temperatures);
3. Hot air passing under or in the panel cover by pressurized force or convection;
4. Snow and ice melt solvent such as glycol applied to the panel glass; and
5. Heating coil heater utilizing resistive element/wire, hot air or hot liquid.
The photovoltaic panel output is fed to the battery charger. The battery charger is designed for photovoltaic applications and is commercially available. The battery charger tailors the charge rate for the battery 27 for optimal charging. When the photovoltaic panel output is greater than the battery charging requirement, the charger transfers the excess photovoltaic output via its load switch to user load, which can be an electric utility grid and/or a local load for the user. The integrated charger/load switch is typically used, but alternate methods whereby controller 38 monitors the state of the battery charge and activates a separate load switch, or a smart load switch monitors the battery charge, can also be used. Typical batteries used include a sealed type such as an absorbed glass mat (AGM) or gel battery which can be charged at low temperatures and have a long life. More compact high energy types, for example, nickel metal hydride (NiMH), lithium hydride (LiH), and the like, may become suitable. When the controller 38 determines that snow, sleet or ice removal is required, it activates the switch to feed battery power to the panel heater and optional frame heater.
It should be noted that the system may be powered using any type of electrochemical device that can be used to store energy. One example of an alternative energy store is an electrochemical battery that is fueled by electrolytes rather than lithium ions.
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When the vertical vibration is required, the controller 38 switches the vibrator switch 76 on to feed the battery or user the heater voltage supply to the vibrator actuator 70. This causes the vibrator actuator plunger 72 to move in, which moves the solar panel cover down, thereby bending the vibrator spring lever 74. The controller 38 then switches the vibrator switch 76 off. The vibrator plunger 72 relaxes, allowing the vibrator spring lever 74 to move solar panel cover back to its rest position. Little motion damping is provided, so the cover motion will oscillate about its rest position. The controller 38 continues to switch the vibrator switch 76 on and off for the programmed vibration time at the natural oscillation frequency of the vibrator spring lever 74 and the solar panel cover combination to maximize the motion amplitude. The vibration actuator plunger 72 which moves out instead of in when power is applied is also a suitable approach.
Although an electromechanical vibrator is shown, other vibrators can be used if they have suitable motion and force characteristics, and include, for example, piezoelectric vibrators and an electric motor with an unbalanced flywheel. The electric motor would require being switched on and off only at the start and end of the programmed vibration time.
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Another option is to coat the upper frame and cover glass with a non-stick translucent material such as a silicone based film. This is a facilitator for the vibrators, allowing the snow, sleet or ice to slide off with a shorter vibration cycle, or under some circumstances, with no vibration cycle.
Alternatively, the winter precipitation or other material may be mechanically removed using a selection from the following:
1. A motorized scraper system such as a windshield wiper style (articulated or not articulated), or a blade moving vertically or horizontally across the panel cover on tracks located on the panel edge;
2. Blowing high pressure air at the panel cover glass;
3. Rotating the panel to an upside down position briefly; and
4. Covering the panel when snowing or icing starts, flipping the cover back to the retracted position when the sun is available.
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The upper part of the cam lever 88 has a cam profile to achieve the desired panel cover frame vertical motion and mechanical advantage. Removing power to the actuator 70 causes the panel cover frame weight and the vibrator spring lever force to move the cam lever 88 and the actuator plunger 72 back towards their rest position. For a pull type actuator, the actuator plunger 72 is attached to the cam lever 88, and the cam lever 88 is mounted in mirror image position such that the panel cover is moved up when the actuator plunger pulls on the cam lever.
Other variations which achieve vertical motion from a horizontally mounted vibrator can also be used such as, for example, methods whereby the actuator plunger slides a wedge under the vibrator spring lever. The wedge's height versus distance profile is selected to achieve the desired panel cover frame 1 vertical motion and mechanical advantage.
When activated, the vibrators can cause some or all of the snow, sleet or ice to “avalanche” off the panel, substantially reducing the power required for removal.
In a typical example, four actuators, one actuator at each corner of the panel, are activated synchronously. Asynchronous activation, other locations such as vibrators as part of the panel mount that shakes the entire panel horizontally or vertically, and a different number of actuators can also be used.
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A suitable option with likely lower cost is feeding the output from two or more panels into a common larger capacity battery and charger. This option could be combined with common larger capacity heater and/or vibration relays instead of individual heater and/or vibration relays in the solar panel.
It should be noted that although the solar panels are illustrated as mounted on angled mountings, the solar panels may also be mounted in horizontal orientations. It is also to be noted that the solar panels may be mounted on motor vehicles such as trucks, cars, motorcycles, recreational vehicles and the like. Furthermore, it is also to be stated that the solar panels may be integrated into the body of, or mounted on: trains, buses, subway cars, or motor vehicles such as trucks, cars, motorcycles, recreational vehicles and the like; whereby one or more of the energy transfer members in conjunction with one or more of the sensors may be implemented to facilitate winter precipitation removal.
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In addition to winter precipitation, the precipitation sensor may be similarly activated to detect other material on the panel surface and thereby activate cleaning using just the vibration energy member. The temperature sensor would then be used to distinguish between winter precipitation and other material.
Other sensors that may be implemented as alternative options for this winter precipitation sensing technology are illustrated below. These alternative sensors, although viable, are not presently as effective as the developed LED sensor design noted herein:
These noted sensors can be implemented in one or more panels or in a separate smart sensor box to service many panels (including a solar park) at the same time.
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In the example illustrated, a three panel installation includes one master panel 12A and two slave panels 12B. A person skilled in the art will recognize that any number of slave panels can be connected to the master panel, subject to practical installation limits in heater supply wire lengths and the like.
Generally speaking, multiple panel installations will require some spatial separation between adjacent panels, in case the shaking is not synchronized because either the solenoids have response variations, or adjacent panels may be connected to different controllers
Furthermore, the multiple panel installation can be extended to the use of a surrogate, in which the cover, vibrators, heater, master controller 38A and sensors are located in a non-photovoltaic assembly which representatively performs snow and/or sleet and/or ice and/or or hail removal, and the master controller 38A commands slave controllers 38B on the photovoltaic panels.
One example, which enhances the usefulness of the AWSP system, can be found in the solar panel based powering of pipeline fluid spill monitoring devices and systems. Advantageously, the use of the AWSP means that the pipeline leak detection device and system can be used year round, and is particularly useful where the pipelines cross through areas that are prone to heavy winter precipitation. The AWSP could be retrofittable into existing pipeline monitoring systems thereby providing year round autonomous power.
Another example, which enhances the usefulness of the AWSP system, can be found in the solar panel based powering of roadside and highway emergency notification systems. Such systems are typically located in remote areas away from sources of power. Their continued operation in winter is particularly critical, since even a common event such as running out of gas can result in death from exposure to cold temperatures. AWSP panels can provide continued autonomous power even when snow and ice storms are prevalent.
The use of the device can be extended into other seasons whereby the vibration assembly would be implemented in non-winter seasonal use to clean off dust, sand, rocks, and dirt by shaking or vibrating the materials off the panel and frame surfaces on a programmed basis or in conjunction with a rain sensor where the advent of rain or dew would be sensed and utilized to remove the materials in conjunction with the vibration.
There is also the ability to extend the use of the device to all seasons by combining this device and system with that of the Solar Power Autonomous Cleaning Device (application of previously filed U.S. patent application Ser. No. 13/507,954, filed on Aug. 9, 2012) such that this device and system would be combined and integrated together with the Solar Power Autonomous Cleaner into the manufacturing process of photovoltaic panels whereby they would be used together to facilitate year-round cleaning. This combination would allow for the Solar Power Autonomous Cleaning Device to house its cleaning facets at the top of a photovoltaic panel to permit the avalanching of winter precipitation in the winter season.
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When winter temperatures exist, the controller 38 periodically activates the snow, sleet and ice sensor 24. The radiation sources 118 (LEDs) are switched on and the output of the radiation sensor 120 (photo transistor) is read. Then the LEDs are switched off and the radiation sensor 120 is read again. If there is no snow, sleet or ice, the difference between the two readings is small and caused by minor dirt on the glass and the fact that the glass is not perfectly translucent. Snow and sleet produces a large difference, while ice produces a smaller but still very usable difference.
The sensor 24 is more sensitive at low ambient illumination conditions when the LED light is stronger than the ambient light. The LED light has insufficient strength for a clear panel cover in daylight sun between approximately 9 AM and 3 PM. Any snow or ice that requires removing will block the ambient light, and will likely be accompanied by clouds that will further reduce the illumination. LED strength will then be sufficient. If the LED light has insufficient strength, snow and ice removal will not be scheduled by the controller, but the illumination on the photovoltaic array will be sufficient to produce a useful output.
The controller's programmed strategy is to sense snow, sleet and ice throughout the day and night and if present, schedule removal in the morning. For the user heater supply and heater supplement options, more frequent removals can be scheduled if more electrical power is available.
The minimum energy strategy for snow, sleet and ice removal uses gravity and the solar panel's tilt angle. Climates with a long winter are typically at higher latitudes where the panel tilt angle is higher, facilitating precipitation removal. The controller's programmed strategy is to turn on the heater and monitor the temperature sensor. When the glass temperature rises to the snow, sleet or ice melting temperature, and then rises more slowly, the bottom layer of snow, sleet or ice is melting. The adhesion of the snow, sleet or ice to the cover glass is substantially reduced by the thin layer of melt next to the cover glass. At this point, the vibrators are activated to avalanche the snow or ice off the cover glass. If the illumination sensed by the snow, sleet and ice sensor does not then indicate a rise, shorter heating and vibration cycles are activated until either the illumination rises or a programmed energy consumption budget is reached. The removal cycle will be halted if the illumination rises during the heating cycle before the vibrators are activated, indicating that the snow, sleet or ice has avalanched off due to its own weight.
This strategy works best with a thick snow blanket. Thick snow is a better insulator which minimizes heat loss to the ambient air while the cover glass is being heated. This strategy does not work as well with thin sleet or ice, but thin sleet or ice allows a useful solar panel output and is easily removed by the sun.
The energy required is near zero at 0° C., and increases linearly as the ambient temperature drops below 0° C. At −10° C., a standard 1.6 square meter panel requires approximately 900 watts for 5 minutes for each removal cycle. At −20° C., this increases to 900 watts for 10 minutes for each removal cycle. Five −20° C. removal cycles are budgeted to allow for multiple precipitation days before the sun is available to power the solar panel and recharge the battery. This requires a 100 amp-hour battery pack.
On a sunny day, the standard panel will produce approximately 6 amperes at 30 VDC. The battery charger will use approximately half that output for approximately 5 hours to restore the battery to useful capacity. After that, the charge current is reduced by the charger until the battery is fully charged.
The system will function down to −40° C., but to make most of the panel's output energy available to the user, the controller strategy below −20° C. is to use the vibrators only should the option be implemented in the panel. The energy consumption demand for the vibrator system is small, and at that temperature, the precipitation is usually powder snow, which avalanches easily. As the temperature drops, battery charging and output efficiency decreases.
An option available is a remote display 54 connected to the controller 38. When the display 34 is turned on, the controller 38 sends useful status information such as panel voltage and current, battery voltage, panel temperature, recent ice and snow removal events, and any faults detected. The user can also enter mode commands based on predicted weather to optimize the snow and ice removal strategy, to include mode commands for master/slave multiple panel installations. The display 54 and controller 38 are on a bus cable, allowing the display to transfer information with multiple controllers.
It is to be understood that the device and system described herein are readily adaptable to other photovoltaic configurations such as an integrated dual pane assembly comprising a top pane of conductive glass and a bottom pane of photovoltaic glass, and an integrated assembly where the conductive and photovoltaic glasses are integrated into a laminate, and where photovoltaic capability is integrated into conventional and non-conventional building materials (in a horizontal or vertical manner) such as siding, atrium panels, greenhouse roofs, walls, decks, roof shingles or where solar cells are embedded in conventional or non-conventional materials and all for the purpose of obtaining solar power. The term conventional and non conventional building materials includes but is not limited to: plastic, composite, polycarbonate, or petroleum based solar cells, that are superimposed, sprayed, or painted on surfaces or woven into fabric whereby there is a manipulation of matter on a atomic and/or molecular scale and subsequent macroscale products or molecular nanotechnology is implemented therein.
The device and system described herein need a minimal amount of the solar panel's output energy to autonomously remove snow, frost, sleet, and/or ice precipitation. Once the solar panel upper cover is at the melting temperature, the snow, frost, sleet and/or ice adhesion substantially reduces, find the winter precipitation slides off or may be avalanched off using the vibrators option. Conventional techniques require additional energy to melt winter precipitation. At an ambient temperature of −20° C., the energy required for the said system is 360 kilojoules for a one centimeter snow water equivalent (SWE) snow or ice per panel square meter, compared to 3660 kilojoules for conventional techniques. The energy required for the system reduces linearly to zero at 0° C., compared to reducing to 3300 kilojoules for said conventional techniques. Conventional high efficiency solar panels generate about 125 watts per square meter at standard temperature, increasing to about 150 watts per square meter at −20° C. For a typical five day winter cycle of three days of sun and two days of winter precipitation, the solar panel will generate about 9000 kilojoules if the winter precipitation is removed.
In an example, a design budget whereby it snows for five days in a row comprises five removal attempts (one per day) during the five day cycle at −20° C., where battery charging efficiency is 40 percent. The energy drawn from the panel is (360×5)/0.40=4500 kilojoules, or half the panel's capacity. As the ambient temperature approaches 0° C., the available panel capacity approaches 100 percent as the energy drawn for removal approaches zero.
The technology supports a green environment, reducing dependence on fossil fuels by making solar panel use effective in winter climates. The usage includes but is not limited to commercial solar parks and residential applications seeking to effectively increase and/or maximize solar panel energy output or establish electricity generation in winter for locations that would never have been contemplated for solar panel use prior.
Although the above description relates to a specific preferred embodiment as presently contemplated by the inventor, it will be understood that the AWSP in its broad aspect includes mechanical and functional equivalents of the elements described herein.
This application is a continuation-in-part (CIP) application of previously filed U.S. patent application Ser. No. 13/507,958, filed on Aug. 9, 2012, to which priority is claimed, the entire contents of which are hereby incorporated by reference.