Passionate Passivity

Photovoltaic Technologies
Photovoltaic panels are composed of a silicon semiconductor material, in order to effectively collect incident solar radiation. (See Figure 3.) Electrons within the material are contacted, generating movement within the silicon atoms that produce electrical energy.

Presently, negative-type silicon is the most efficient conductor in photovoltaic technology. Silicon atoms have fourteen electrons each, arranged in three different shells: two filled, and four valence electrons in the third. An atom fills the four remaining electron spaces of the outer shell by sharing electrons with neighbouring atoms, thus forming the crystalline structure of the photovoltaic panel. Impurities in the silicon material are inserted to also fill remaining electron spaces. This allows for one proton and electron to remain, as the phosphorous atom contains five electrons to complete four spaces. As a result, weaker chemical bonds allow for simpler electron separation during incident solar radiation collection. With numerous photovoltaic cells consisting of such material, photovoltaic panels can be constructed to optimize collection of solar energy. (See Figure 4.)

Figure 3: A standard photovoltaic solar panel.
(Source: The Solar Energy Company)

Figure 4: The above left shows the internal components of a photovoltaic cell.
The above right shows the internal components of a photovoltaic panel.
The lower depicts an array of photovoltaic panels in arrangement.
(Source: Massachusetts Technology Collaborative Renewable Energy Trust)

Active Tracking Methods
Active tracking methods of photovoltaic panel arrangement are electrically-operated, either directly from the photovoltaic panel, or a main battery. (See Figure 5.) Thus, photoelectric sensors are used in combination with an electronic control that activates electrical motors in order to position the photovoltaic panel tracker in a manner perpendicular to the solar radiation angle. Presently, an advantage of using active tracking is the high precision of the electrical motors, coupled with a dual-axis ability that allows the tracker to follow the daily east-west and seasonal north-south directions of the radiation.

Active tracking is also effective in conditions with drastic climate variations. However, active trackers are inefficient due to their demanding mechanical considerations, as well as their consumption of energy proportional to the photovoltaic panel size and geographic location. Due to the usage of electricity, active photovoltaic trackers are more susceptible to lightning damage. Additionally, from a financial perspective, active tracking methods are initially more costly than passive tracking methods. Furthermore, constant mechanical repairs will increase the net cost of an active tracker, compared to the minimal repairs required for a passive tracking system over a longer period of time.

Figure 5: A conventional active photovoltaic panel tracking system.
(Source: The Solar Energy Company)

Passive Tracking Using Thermal Liquids
Present passive trackers consist of two copper tubes strategically mounted on the east and west sides of the photovoltaic panel, in areas of shading. The copper tubing is filled with a chlorofluorocarbon (CFC) or hydrochlorofluorocarbon (HCFC) compound capable of vapourizing at low temperature environments. When solar radiation exposure increases the temperature one side of the photovoltaic panel, the compound in the copper tubing vaporizes. As the gaseous state of the compound occupies more area internally, the liquid state of the compound is shifted to the heavier, shaded area of the tracker. This thermal process is controlled by the aluminium shadow plates. This mass transfer process adjusts the balance of the photovoltaic panel system, causing it to rotate to the west. (See Figure 6.)

As the vapourization of the CFC or HCFC content shifts accordingly to the direction of exposure to solar thermal energy, the passive photovoltaic panel tracks the direction and motion of the solar radiation. The system remains in the western direction at times of minimized exposure to solar radiation, with a dependence on early-hour solar radiation in order to return to the eastern direction. Standard passive tracking systems also require infrequent manual adjustments for the north-south direction depending on the season, as the system is not designed in a dual-axis manner.

Figure 6: The tracking movement of the standard passive photovoltaic panel system, using chlorofluorocarbon and hydrochloroflurocarbon vapourization, throughout the time span of one day’s exposure to solar radiation.
(Source: Zomeworks Corporation)

Hydraulic Restrictor Controls
Hydraulics systems function using a virtually incompressible fluid, such as water, in order to transmit forces from one location to another within the system. Force can be defined as a push or pull exerted against the total area of a specific surface, and pressure is the amount of force applied to each unit area of the specific surface, capable of exertion in one, several, or all directions. In hydraulics systems, force can be calculated as the product of pressure and area. When applied to the end of a column of confined liquid, a force is transmitted straight through to the column’s other end, remaining undiminished in every direction throughout the column. This causes pressure.

This concept is based upon Blaise Pascal’s Law, which states that an increase in pressure at any point in a confined area results in an equal increase at every other point of the container. Thus, a force that is applied to one section of an enclosed liquid at rest will be transferred throughout the entire liquid with an equal amount of force. The force acting on a system is directly proportionate to its area.

Because of temperature fluctuations, liquids expand and contract. At high temperatures in closed areas, liquids expand, exerting pressure on the sides of the container. When given space, the minor thermal expansion in liquids can be harnessed in contribution to hydraulic system movement.

(This website details preliminary work for Passionate Passivity, corresponding with the Calgary Youth Science Fair in March 2008. Significant project changes and design modifications have been made to Passionate Passivity since the creation of this website. To ensure intellectual property protection, final work spanning from approximately June 2007 to April 2008 will be first presented at the Intel International Science and Engineering Fair (ISEF) in May 2008. This website should not be utilized as a reference for Eden Full's ISEF 2008 research.)


Home	Problem Problem and Purpose Background Objectives Variables Hypothesis	Conventional Materials Procedure Observations Managed Data Discussion	Designed Design Materials Procedure Observations Managed Data	Conclusion Analysis Conclusion Applications Sources of Error Future Directions	Credits
Background
*Photovoltaic Technologies* Photovoltaic panels are composed of a silicon semiconductor material, in order to effectively collect incident solar radiation. (See Figure 3.) Electrons within the material are contacted, generating movement within the silicon atoms that produce electrical energy. Presently, negative-type silicon is the most efficient conductor in photovoltaic technology. Silicon atoms have fourteen electrons each, arranged in three different shells: two filled, and four valence electrons in the third. An atom fills the four remaining electron spaces of the outer shell by sharing electrons with neighbouring atoms, thus forming the crystalline structure of the photovoltaic panel. Impurities in the silicon material are inserted to also fill remaining electron spaces. This allows for one proton and electron to remain, as the phosphorous atom contains five electrons to complete four spaces. As a result, weaker chemical bonds allow for simpler electron separation during incident solar radiation collection. With numerous photovoltaic cells consisting of such material, photovoltaic panels can be constructed to optimize collection of solar energy. (See Figure 4.) Figure 3: A standard photovoltaic solar panel. (Source: The Solar Energy Company) Figure 4: The above left shows the internal components of a photovoltaic cell. The above right shows the internal components of a photovoltaic panel. The lower depicts an array of photovoltaic panels in arrangement. (Source: Massachusetts Technology Collaborative Renewable Energy Trust) *Active Tracking Methods* Active tracking methods of photovoltaic panel arrangement are electrically-operated, either directly from the photovoltaic panel, or a main battery. (See Figure 5.) Thus, photoelectric sensors are used in combination with an electronic control that activates electrical motors in order to position the photovoltaic panel tracker in a manner perpendicular to the solar radiation angle. Presently, an advantage of using active tracking is the high precision of the electrical motors, coupled with a dual-axis ability that allows the tracker to follow the daily east-west and seasonal north-south directions of the radiation. Active tracking is also effective in conditions with drastic climate variations. However, active trackers are inefficient due to their demanding mechanical considerations, as well as their consumption of energy proportional to the photovoltaic panel size and geographic location. Due to the usage of electricity, active photovoltaic trackers are more susceptible to lightning damage. Additionally, from a financial perspective, active tracking methods are initially more costly than passive tracking methods. Furthermore, constant mechanical repairs will increase the net cost of an active tracker, compared to the minimal repairs required for a passive tracking system over a longer period of time. Figure 5: A conventional active photovoltaic panel tracking system. (Source: The Solar Energy Company) *Passive Tracking Using Thermal Liquids* Present passive trackers consist of two copper tubes strategically mounted on the east and west sides of the photovoltaic panel, in areas of shading. The copper tubing is filled with a chlorofluorocarbon (CFC) or hydrochlorofluorocarbon (HCFC) compound capable of vapourizing at low temperature environments. When solar radiation exposure increases the temperature one side of the photovoltaic panel, the compound in the copper tubing vaporizes. As the gaseous state of the compound occupies more area internally, the liquid state of the compound is shifted to the heavier, shaded area of the tracker. This thermal process is controlled by the aluminium shadow plates. This mass transfer process adjusts the balance of the photovoltaic panel system, causing it to rotate to the west. (See Figure 6.) As the vapourization of the CFC or HCFC content shifts accordingly to the direction of exposure to solar thermal energy, the passive photovoltaic panel tracks the direction and motion of the solar radiation. The system remains in the western direction at times of minimized exposure to solar radiation, with a dependence on early-hour solar radiation in order to return to the eastern direction. Standard passive tracking systems also require infrequent manual adjustments for the north-south direction depending on the season, as the system is not designed in a dual-axis manner. Figure 6: The tracking movement of the standard passive photovoltaic panel system, using chlorofluorocarbon and hydrochloroflurocarbon vapourization, throughout the time span of one day’s exposure to solar radiation. (Source: Zomeworks Corporation) *Hydraulic Restrictor Controls* Hydraulics systems function using a virtually incompressible fluid, such as water, in order to transmit forces from one location to another within the system. Force can be defined as a push or pull exerted against the total area of a specific surface, and pressure is the amount of force applied to each unit area of the specific surface, capable of exertion in one, several, or all directions. In hydraulics systems, force can be calculated as the product of pressure and area. When applied to the end of a column of confined liquid, a force is transmitted straight through to the column’s other end, remaining undiminished in every direction throughout the column. This causes pressure. This concept is based upon Blaise Pascal’s Law, which states that an increase in pressure at any point in a confined area results in an equal increase at every other point of the container. Thus, a force that is applied to one section of an enclosed liquid at rest will be transferred throughout the entire liquid with an equal amount of force. The force acting on a system is directly proportionate to its area. Because of temperature fluctuations, liquids expand and contract. At high temperatures in closed areas, liquids expand, exerting pressure on the sides of the container. When given space, the minor thermal expansion in liquids can be harnessed in contribution to hydraulic system movement. (This website details preliminary work for Passionate Passivity, corresponding with the Calgary Youth Science Fair in March 2008. Significant project changes and design modifications have been made to Passionate Passivity since the creation of this website. To ensure intellectual property protection, final work spanning from approximately June 2007 to April 2008 will be first presented at the Intel International Science and Engineering Fair (ISEF) in May 2008. This website should not be utilized as a reference for Eden Full's ISEF 2008 research.)
Copyright © Eden Full, 2008. All rights reserved. Contact: spacecamper@gmail.com.