Cover Your A$$ets Solar Panel Protection Project Team: Krista Miller Sohaib Hasan John Helme

What is the problem? Passive solar panels collect energy in the form of heat. In warm weather, it is possible for the temperature of these panels to exceed a desirable limit.

One solution is to “dump” hot water and add cold water. Normal Solutions Another solution is to use a “large” thermal like a swimming pool or the earth. These options are not always viable.

Problem Statement The maximum temperature that a passive solar panel can reach must be controlled. The temperature control system must work without using additional water. When not active, the control system shall not interfere in the efficiency of the solar panels. Solution Constraints: The solution must:  Work on any number of panels.  Have both an automatic and manual control.  Have user adjustable temperature setting.  Have a maximum cost of $200 per panel.

Summary of Solutions SolutionResolves Problem Economically Feasible Conserves Energy Uses Electro- mechanical systems Dump heat into ground YesNo Sterling Engine No – limited heat dissipation UnknownYes Seebeck Device No – limited heat dissipation NoYes Energy Blocking Yes NoYes

Solution Statement Blinds will be automatically positioned to cover a solar panel before the panel temperature reaches a critical level. Each solar panel will: Have a complete and independent blind system. Have adjustable temperature controls. Be controlled by a single override control.

Microcontroller Position Sensors 1-3 Temp Sensor M Increment Motors Manual Override Power Motor Controller System Diagram

Mechanical System Diagrams Solution allows for some ‘play’ with the universal joint – won’t bind as easily.

Mechanical Linkage Constructed From:  Pulley or Gear  2 machined rectangles used for spacing  Connector to Solar Panels (pre-made)  Screws …but will it hold up to our motor forces?

Stress Tests: Affect of a Motor on Assembly Parts Machined from Aluminum & Galvanized Steel Safety Factor: >200 for each piece Deformities: Shown on a 5000:1 scale

Cover Heavy Duty Premium White Tarp  Blocks Sunlight  Water-resistant  Rot-proof  Dust-proof.

DC Motors & Motor Driver: Motor  Denso  12V, 3.3A  163 RPM  100 oz in torque Motor Provides: 100oz*in = 2.84 N*in Motor Requirements: Torque = F*radius Torque Test: 2.0N starting 1” Radius = 2.0 Nm Torque 1.0N continuing 1” Radius = 1.0 Nm Torque

Electrical System Diagram Power Supply Signal Amplification Microcontroller Signal Conditioning/CJC

Electronics Overview Open Limit Switch (in back) Covered Limit Switch Mid Position Limit Switch Microcontroller  Freescale HCS08 10bit A2D converter Ease of use Inexpensive Available Code Position Switches  SPST Momentary Roller Switch

State Diagram Motor close Motor open Reference Variables Standard close temperature s.close.ref Critical close temperature c.close.ref Standard open temperature s.open.ref These values will be set using potentiometers on the controller circuit. Sensors Sensor Variable Panel open pos.open Panel 1/2 open pos.hw Panel closed pos.clsd Temperature temp Override Controls Control Variable Open or.open Close or.clsd

Budget for Major and Minor Components

Schedule, Personnel Assignments, Milestones

Summary Problem: The temperature of the solar panels must not exceed a maximum temperature. Solution Constraints:  Must work on any number of panels.  Must have both an automatic and manual control.  Must have a maximum cost of $200 per panel. Solution: Solar panels will be automatically covered when they reach a set temperature. Solution Constraints:  Controller and motor for each panel.  Open, close and power off override controls.  Demonstration system estimated cost of $185.