Sovereignty Module: Capture the Light
Complete Solar Energy, Passive Heating, Solar Cooking, and Photovoltaic Guide
The sun delivers 1,000 watts per square meter to Earth's surface. Free, silent, and eternal. This campaign covers every way to harvest solar energy from passive building design to solar cookers to photovoltaic electricity.
Chapter 1: Solar Energy Applications
| Application | Technology | Complexity | Cost | Output |
|---|---|---|---|---|
| Passive solar heating | Building design (windows, mass) | Low (design phase) | Free | Heating (50-100% of needs) |
| Solar water heating | Black pipe/tank in sun | Low | Low | Hot water (120-160F) |
| Solar cooking | Reflective cooker or box oven | Low | Very low | Cooking temperature (250-400F) |
| Solar dehydration | Screened box with airflow | Very low | Very low | Food preservation |
| Solar distillation | Glass/plastic over water basin | Low | Low | Clean water (1-4 liters/day per m²) |
| Solar electricity (PV) | Photovoltaic panels + batteries | High | High | Electricity (100-400W per panel) |
| Solar pumping | PV + DC pump | Moderate-high | Moderate | Water pumping |
| Concentrated solar (thermal) | Mirrors/lenses focusing sunlight | Moderate-high | Moderate | High heat (metal melting possible) |
Chapter 2: Passive Solar Building Design
| Principle | Implementation | Effect |
|---|---|---|
| South-facing windows (N. Hemisphere) | Large windows on south wall, small on north | Captures winter sun, minimal summer gain |
| Thermal mass (heat storage) | Concrete/stone/water inside building | Absorbs heat by day, releases at night |
| Insulation | Thick walls, ceiling insulation | Retains captured heat |
| Overhang (summer shade) | Roof overhang sized to block summer sun | Summer: shaded. Winter: sun enters (lower angle). |
| Cross ventilation | Operable windows on opposite walls | Summer cooling without energy |
| Earth sheltering | Building into hillside or berming | Constant 55F earth temperature moderates extremes |
| Trombe wall | Dark masonry wall behind glass, south-facing | Absorbs and radiates heat into building |
| Clerestory windows | High windows above roofline | Brings light deep into building, stack ventilation |
Overhang calculation: For latitude 40°N, overhang = window height x 0.42. This blocks summer sun (high angle) while admitting winter sun (low angle). Adjust multiplier for your latitude.
Chapter 3: Solar Water Heater Construction
| Type | Temperature | Complexity | Materials | Freeze Protection |
|---|---|---|---|---|
| Black bucket/barrel in sun | 100-130F | Very low | Black container | Drain in winter |
| Batch heater (breadbox) | 120-150F | Low | Black tank in glazed box | Drain or insulate |
| Flat plate collector | 140-180F | Moderate | Black pipe in insulated glazed box | Drain-back or antifreeze |
| Evacuated tube | 160-200F+ | High (purchased) | Glass vacuum tubes | Inherent (vacuum insulates) |
| Thermosiphon | 120-160F | Low-moderate | Collector below tank (natural circulation) | Drain in winter |
Simplest system: Black garden hose coiled on south-facing roof or ground. Sun heats water in hose. Connect to elevated tank (gravity feed). 100-130F water for washing, bathing. Free hot water 8+ months per year in temperate climates.
Chapter 4: Solar Cooker Types
| Type | Temperature | Cook Time | Materials | Portability |
|---|---|---|---|---|
| Panel cooker (funnel) | 250-350F | 2-4 hours | Cardboard + aluminum foil + black pot | High |
| Box cooker (oven) | 300-400F | 1.5-3 hours | Insulated box + glass lid + reflectors | Low |
| Parabolic cooker (dish) | 400-700F | 30-60 minutes | Reflective dish (satellite dish + mirror film) | Low |
| Fresnel lens | 500-2000F+ | Minutes | Large magnifying lens (old TV screen) | Low |
Box cooker construction: Insulated box (cardboard + newspaper/straw insulation + inner box). Glass or clear plastic lid (double-glazed = better). Interior painted black. Reflective flap(s) direct additional sunlight in. Place black pot inside. Reaches 300-400F on sunny day.
Chapter 5: Solar Electricity (Photovoltaic) Basics
| Component | Function | Sizing Rule |
|---|---|---|
| Solar panel | Converts sunlight to DC electricity | Watts = daily Wh needed / peak sun hours / 0.75 |
| Charge controller | Prevents battery overcharge/damage | Amps = panel watts / battery voltage x 1.25 |
| Battery bank | Stores energy for night/cloudy days | Ah = daily Wh / voltage / 0.5 (50% depth of discharge) |
| Inverter (if AC needed) | Converts DC to AC (120V/240V) | Watts = largest AC load x 1.5 |
| Wiring | Connects components | Size for <3% voltage drop |
| Fuses/breakers | Safety (overcurrent protection) | At each connection point |
Example system: 4 LED lights (10W each) + phone charging (10W) + small fan (20W) = 70W. Used 6 hours/day = 420 Wh/day. With 5 peak sun hours: need 420 / 5 / 0.75 = 112W panel. Battery: 420 / 12V / 0.5 = 70 Ah (12V battery).
Chapter 6: Solar Still (Water Purification)
| Step | Action | Details |
|---|---|---|
| 1 | Dig pit (3-4 feet diameter, 2 feet deep) | In sunny location |
| 2 | Place collection container in center of pit | Cup, jar, or pot |
| 3 | Fill pit around container with contaminated water, wet vegetation, or moist soil | Source of moisture |
| 4 | Cover pit with clear plastic sheet | Seal edges with soil/rocks |
| 5 | Place small stone in center of plastic (directly above container) | Creates low point for drip |
| 6 | Sun heats pit, water evaporates, condenses on plastic, drips into container | Distillation process |
| 7 | Collect 1-4 liters per day (depending on sun and moisture) | Pure distilled water |
Solar still produces pure water from any source: saltwater, contaminated water, urine, or moisture in soil/vegetation. Slow but requires zero energy input and no filters.
Reference Card
- South-facing windows (N. Hemisphere): captures winter sun, overhang blocks summer sun
- Thermal mass (concrete, stone, water) inside building stores heat for nighttime release
- Overhang depth = window height x 0.42 (for latitude 40°N, adjust for your location)
- Black container in sun = free hot water (100-130F) for 8+ months per year
- Solar box cooker reaches 300-400F: cooks anything an oven can (just slower)
- Solar still: 1-4 liters pure water per day from any moisture source (zero energy)
- PV sizing: daily Wh needed / peak sun hours / 0.75 = panel watts needed
- Battery bank: daily Wh / voltage / 0.5 = amp-hours needed (50% max discharge)