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

Excellent background to the application The solar panels at the VTC Alternative Energy Building use ethylene glycol as the thermal conductor. Ethylene glycol will begin to break down at temperatures near 250°F.

Clear Identification of the Problem Problem: The temperature of the ethylene glycol in the solar panels must not exceed 250°F. Solution Constraints:  Must work on any number of panels.  Must have both an automatic and manual control.  Have a maximum cost of $200 per panel.

Solution Statement Blinds or screens will be automatically positioned to cover a solar panel before the panel temperature reaches a critical level. Each panel will have an complete and independent blind system. The blind system for multiple panels can be controlled by a single override control.

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

Above is a picture of how the solar panel cover will be mounted on the existing panels. Excellent Mechanical System Diagrams

Cover Heavy Duty Premium White Tarp  6 oz per Square Yard  1200 Denier  UV Treated For Longer Protection  12 Mil Thickness  14x14 Weave Count  Water-resistant  Rot-proof  Dust-proof.

DC Motors & Motor Driver: Motor  Denso  12V, 3.3A  163 RPM  100 oz in torque Motor Driver  H Bridge

Excellent Temperature Sensing Diagram Type K Thermocouple  Self Powered  Simple  Rugged  Inexpensive  Wide Temperature Range Thermocouple Processing/Conditioning

Excellent 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

Excellent State Diagram Start 0 Open0 0 1 Idle1 0 Idle 0 0 Idle½ 0 Open½ 0 1 Close 1 0 Start 0 Close½ 1 0 Motor close Motor open p.open<>1 else p.open=1 else pos.hw=1 else or.open=1 or temp<s.open.ref or.clsd=1 pos.clsd=1 temp>s.clos.ref or temp>c.clos.ref or or.clsd=1 pos.hw = 0 temp<s.open.ref or.open=1 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 temp>s.close.ref

Budget for Major and Minor Components

Informative Schedule, Balanced Personnel Assignments, Milestones

Excellent Summary Problem: The temperature of the ethylene glycol in the solar panels must not exceed 250°F. 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 the temperature of the ethylene glycol reaches 220°F. Solution Constraints:  Controller and motor for each panel.  Open, close and power off override controls.  Demonstration system estimated cost of $185.