07-ENERGY-MOC

⚡ Energy Systems: Complete Map

Mission: Design, build, and operate renewable energy systems that provide reliable power for communities, from household to bioregional scale.

🎯 System Architecture Overview

DISTRIBUTED ENERGY ARCHITECTURE
├── Generation
│   ├── Solar PV (photovoltaic panels)
│   ├── Solar Thermal (heat directly)
│   ├── Wind (turbines, vertical-axis)
│   └── Hydro (micro, run-of-river)
│
├── Storage
│   ├── Battery (LiFePO4, lead-acid)
│   ├── Thermal (water tanks, phase-change)
│   └── Mechanical (flywheel, compressed air)
│
├── Distribution
│   ├── DC systems (12V, 24V, 48V)
│   ├── AC systems (120V, 240V, 3-phase)
│   └── Microgrids (local balancing)
│
└── Consumption
    ├── Loads (appliances, machinery)
    ├── Smart management (demand response)
    └── Interconnection (grid-tie, islanding)

📚 Foundation: Energy Basics

Energy-Fundamentals

Power (watts), energy (watt-hours), efficiency
Load calculation (how much do you actually need?)
Duty cycle and demand profiles
Losses in wiring and conversion

Key Insight: Most systems are over-sized because people guess wrong. Load-Audit-Methodology must happen first.

☀️ Solar Systems (Most Accessible)

Solar-PV-Fundamentals

How photovoltaic cells work (electron-hole pairs, current)
Panel specifications (Voc, Isc, Pmax, efficiency curves)
Temperature effects (hotter = less efficient)
Series vs. parallel: voltage and current trade-offs

Solar-Site-Assessment

Shade analysis (solar pathfinder tools, manual assessment)
Roof orientation optimization
Seasonal variation (winter vs. summer output)
Microclimate factors (reflection, wind, dust)

Deliverable: Solar-Assessment-Template with annual production estimates

PV-Array-Design

String sizing (voltage headroom for regulators)
Panel selection matrix (cost vs. efficiency vs. reliability)
Combiner boxes and breakers
Grounding strategy (equipment + personnel safety)

Charge-Controller-Selection

PWM (Pulse Width Modulation): Simple, 70-85% efficiency
- Use for: Small systems (<2kW), 12V/24V banks
- Cost: $100-300
- Example: Victron-PWM-Controller
MPPT (Maximum Power Point Tracking): 95%+ efficiency
- Use for: Medium-large systems (2kW+), multi-string, 48V+
- Cost: $300-1500 per unit
- Example: Victron-MPPT, Epever-Tracer, Renogy-Wanderer

Decision: MPPT pays for itself in ~3-4 years through extra generation if you have >4kW array

Battery-Selection-for-Solar

Lead-Acid (Flooded)

Cost: $100-200/kWh
Lifespan: 5-10 years
DoD (Depth of Discharge): 50% recommended
Maintenance: Watering, equalization
Use: Budget-conscious, established tech

Lead-Acid (AGM/Gel)

Cost: $150-300/kWh
Lifespan: 5-10 years (similar to flooded)
DoD: 50% still recommended
Maintenance: Minimal
Use: RVs, boats, when no watering possible

LiFePO4 (Lithium Iron Phosphate)

Cost: $300-600/kWh (dropping annually)
Lifespan: 10-20 years (3000-10000 cycles)
DoD: 100% usable (no degradation from deep discharges)
Maintenance: None (BMS handles everything)
VERDICT: 2024 forward, this is the only rational choice despite upfront cost

Decision Matrix: Battery-Selection-Spreadsheet

Inverter-Sizing

Modified Sine: Cheap ($200-500), may interfere with sensitive devices
Pure Sine: Better ($500-2000), compatible with everything
Sizing rule: 1.5-2x peak load (inrush current for motors)
Example: 10A fridge start = 2000W, need 3000W+ inverter

Popular Models: Victron-Phoenix, Victron-Multiplus, Epever-Hybrid

Wiring-Sizing-and-Protection

Wire gauge by current and distance (use tables in Electrical-Safety-Handbook)
Breakers and fuses (properly sized, never oversized)
DC disconnect switches (visible, accessible, redundant)
Grounding electrode system (rod in ground, bonding)

Critical: Under-wiring causes fires. Over-protect is impossible.

💨 Wind Systems

Wind-Resource-Assessment

Wind speed data (use NREL database, personal anemometer)
Height matters: 10m tower = 2x more wind than 5m
Terrain factor (sheltered, open, hilltop)
Probability of sustained winds (not just gusts)

Reality Check: Most residential areas don't have sufficient wind. Test before investing.

Small-Wind-Turbines

Horizontal-Axis (HAWT): More efficient, needs yaw system
Vertical-Axis (VAWT): Omnidirectional, lower efficiency, quieter
Micro-turbines: <5kW, residential scale

Popular Models: Bergey-Excel, Southwest-Windpower

Wind-Tower-Safety

Height required for wind resource
Structural engineering for wind load
Setback requirements (property lines, building distance)
Grid interconnection rules

💧 Hydro Systems

Micro-Hydro-Viability

Flow measurement (l/min or gallons/minute minimum)
Head (vertical drop, often more important than flow)
Power formula: Power (watts) = Flow (l/min) × Head (meters) × 0.163

Example: 50 l/min through 10m head = 81.5W (small, but 24/7!)

Hydro-Site-Development

Intake design (no harm to aquatic life, legal requirements)
Penstock routing (gravity feed, minimal friction loss)
Powerhouse location
Return to stream

Hydro-Turbine-Types

Pelton: High head, very efficient
Turgo: High head, medium flow
Crossflow: Medium head and flow (most versatile DIY)
Banki: Similar to crossflow, easier to build
Propeller: Low head, high flow

🔋 Battery Storage Deep Dive

LiFePO4-Chemistry-and-BMS

Cell-level management
Balancing (why it matters)
Temperature monitoring
CAN bus and integration
DIY assembly (cells + BMS) vs. pre-made

Recommendation: Battle-Born-Batteries or assemble with Orion-BMS for custom systems

Thermal-Energy-Storage

Hot water tank (simplest, effective)
Phase-change materials (ice storage, salt hydrate)
Insulation requirements (R-value, thermal mass)
Seasonal thermal storage (buried, underground)

Mechanical-Storage

Pumped hydro (if you have elevation + water)
Compressed air (less efficient, mechanical simplicity)
Flywheels (very efficient, low roundtrip loss, safety concern)

⚙️ System Integration

Microgrids-and-Local-Balancing

Islanding capability (work without main grid)
Load prioritization (essential vs. nice-to-have)
Demand response (shift loads to peak solar)
Frequency and voltage stability

Grid-Tie-Systems

Net metering (sell excess back)
Anti-islanding protection (safety requirement)
Equipment certification (UL, IEC standards)
Interconnection agreements (utility rules)

Off-Grid-Autonomy

No utility fallback = oversizing required
Battery sufficient for worst month
Backup generation (diesel/biodiesel, propane)
Load management culture (winter discipline)

📊 System Sizing Methodology

Step 1: Load-Audit

Category          | Device        | Watts | Hours/Day | Wh/Day
─────────────────────────────────────────────────────
Refrigeration    | 12V fridge    | 80    | 10       | 800
Lighting         | LED 10W × 4   | 40    | 5        | 200
Electronics     | Laptops, USB  | 100   | 6        | 600
Heating         | Space heater  | 1500  | 2        | 3000
─────────────────────────────────────────────────────
DAILY TOTAL                                          | 4600 Wh

Use Load-Audit-Template and actually measure (kill-a-watt meter).

Step 2: Peak-Load-Calculation

Simultaneous maximum draw = inverter size
(Fridges and heaters don't usually run together, but size for worst case)

Step 3: Array-Sizing

Wh/Day ÷ Peak Sun Hours (your location) = Array Capacity
4600 Wh ÷ 4.5 hours (Florida) = ~1.2 kW array
4600 Wh ÷ 3.0 hours (Colorado) = ~1.5 kW array

Location Data: NREL-Solar-Data-by-City, PVWatts-Calculator

Step 4: Battery-Bank-Sizing

Days of Autonomy × Daily Load ÷ DoD = Battery Capacity
3 days × 4600 Wh ÷ 0.9 (LiFePO4) = 15.3 kWh

Step 5: Component-Selection

Panels: ÷ highest rated (Bifacial, high-efficiency)
Controller: 1.25× array current rating
Inverter: 1.5-2× peak load
Breakers/fuses: Protection-Sizing-Table

🔧 DIY Build Examples

12V-Off-Grid-Cabin

Scale: 4kW array, 10kWh battery, 3000W inverter
Cost: $8,000-12,000
Time: 40-60 hours
Difficulty: Medium

Load: Refrigeration, lighting, laptop, small tools. No heavy heating/cooling.

BOM: 12V-Cabin-BOM

48V-Community-Hub

Scale: 10kW array, 30kWh battery, 8kW inverter
Cost: $25,000-35,000
Time: 120+ hours
Difficulty: Hard (three-phase, multiple buildings)

Serves: Community center + workshop + 4 households

BOM + Wiring Diagram: 48V-Hub-Complete-Design

Grid-Tie-Residential

Scale: 5kW array, no battery, grid as storage
Cost: $7,000-10,000
Time: 20-40 hours
Difficulty: Medium (interconnection approval needed)

Advantage: Utility pays for excess, no battery maintenance