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Documentation

Methodology, formulas, and key assumptions behind each TerraNomadHub calculator. All tools produce estimates — always validate with a professional engineer.

Overview & Disclaimer

TerraNomadHub calculators are engineering estimation tools. They apply standard industry formulas and publicly documented coefficients to user-provided inputs to produce planning estimates. All calculators run entirely in your browser — no data is sent to our servers.

Important: All results are estimates based on generalized models. Local conditions, micro-climate variations, equipment specifications, installation quality, and regulatory requirements can significantly alter real-world outcomes. Always have your design reviewed by a licensed professional engineer before construction or major equipment purchases.

SolarPowerNomad

Calculates off-grid photovoltaic system requirements including panel count, battery bank sizing, charge controller specifications, and estimated payback periods.

Core Methodology

Daily energy demand (Wh/day) is calculated from appliance loads and usage hours. This is divided by Peak Sun Hours (PSH) — a location-specific value representing equivalent full-sun hours per day — to determine required panel capacity:

Panel Capacity (W) = Daily Demand (Wh) ÷ PSH ÷ System Efficiency

Battery capacity is sized to cover a user-defined number of Autonomy Days (days without sun), accounting for Depth of Discharge (DoD) limits to preserve battery life.

Battery Capacity (Ah) = Daily Demand × Autonomy Days ÷ System Voltage ÷ DoD

Key Assumptions

  • Default system efficiency factor: 0.75–0.85 (accounts for wiring losses, inverter losses, temperature derating);
  • PSH values sourced from NASA POWER / PVGIS reference datasets;
  • Lead-acid battery DoD default: 50%; Lithium (LiFePO4): 80%;
  • Payback calculation uses current average grid electricity pricing and does not account for battery replacement cycles.

RainCatchNomad

Estimates annual and monthly rainwater yield from catchment surfaces, sizes storage tanks, and calculates drought autonomy periods.

Core Methodology

Harvestable volume is calculated using the standard rainwater harvesting formula:

Yield (L) = Rainfall (mm) × Catchment Area (m²) × Runoff Coefficient × Filter Efficiency

Monthly yield is compared against monthly household consumption (derived from occupant count × per-capita daily usage) to identify surplus and deficit months. Tank size is recommended based on the longest projected deficit period.

Key Assumptions

  • Roof runoff coefficient: 0.75–0.90 depending on surface type (metal roofing, tiles, EPDM);
  • First-flush diverter assumed (10–25L wasted per rainfall event);
  • Default per-capita consumption: 50–80 L/day (potable + non-potable combined);
  • Rainfall data is user-supplied; local ARSO/meteorological data is recommended.

FoodStockNomad

Plans long-term food storage by calculating caloric and macronutrient requirements, storage volumes, rotation schedules, and weight estimates for various dietary profiles.

Core Methodology

Caloric requirements are estimated using the Mifflin-St Jeor equation adjusted by an activity factor. Total calories are then distributed across food categories (grains, legumes, fats, sugars, proteins) based on the selected dietary profile:

Storage Weight (kg) = (Daily Calories × Storage Days) ÷ Calories per kg of food category

Volume estimates use typical bulk food densities. Rotation schedules are derived from shelf-life data (hermetically sealed, oxygen-absorber packed conditions).

Key Assumptions

  • Shelf life data based on freeze-dried and properly sealed bulk storage; actual shelf life varies significantly with storage temperature and humidity;
  • Caloric density values sourced from USDA FoodData Central;
  • Activity factor default: 1.55 (moderately active); adjustable in calculator;
  • Volume calculations assume standard food-grade 5-gallon bucket storage (≈18.9L).

ThermalCoreNomad

Calculates building heat loss, insulation requirements, firewood cord estimates, and thermal mass sizing for passive solar and wood-heated structures.

Core Methodology

Heat loss is calculated using the U-value method across all building envelope components:

Heat Loss (W) = Σ [U-value × Area × ΔT] + Ventilation Losses

Annual heating demand is integrated over Heating Degree Days (HDD) for the location. Firewood requirements are derived from wood species BTU values and assumed stove efficiency.

Key Assumptions

  • Default air change rate: 0.5 ACH (well-sealed construction);
  • Wood BTU values: beech/oak ≈ 28–30 GJ/cord; softwoods ≈ 18–22 GJ/cord;
  • Stove efficiency default: 75–80% (modern certified wood stove);
  • HDD data is user-supplied or estimated from climate zone selection.

DataLinkNomad

Configures off-grid connectivity solutions including satellite internet, VHF/UHF radio range estimation, and local mesh network planning.

Core Methodology

Radio range is estimated using the Friis transmission equation and terrain-adjusted models. Line-of-sight (LoS) distances use the radio horizon formula:

Radio Horizon (km) ≈ 3.57 × (√h_tx + √h_rx) where h = antenna height (m)

Satellite bandwidth planning uses published provider data (Starlink, Iridium, etc.) with per-device allocation modeling. Local mesh network coverage assumes IEEE 802.11 standards with obstacle derating.

Key Assumptions

  • Radio horizon assumes flat terrain; hills, forests, and buildings will reduce actual range;
  • Satellite latency and availability figures are based on published provider specifications and may vary by location and congestion;
  • Mesh network range defaults: 2.4GHz ≈ 150m open air; 5GHz ≈ 50m open air.

BioCycleNomad

Sizes composting toilet systems, greywater filtration, and biomass recycling loops based on occupant count and waste generation rates.

Core Methodology

Composting toilet sizing uses standardized waste volume generation rates per person per day. Composting volume accounts for bulking agent ratio and decomposition reduction factor:

Composting Volume (L/yr) = Persons × Daily Waste (L) × 365 × Bulking Ratio × (1 - Reduction Factor)

Greywater treatment sizing is based on flow rates (liters per person per day), treatment technology type (constructed wetland, sand filter, biofilter), and local infiltration capacity of the soil.

Key Assumptions

  • Average human waste volume: ≈1.5L/person/day (feces + urine);
  • Composting reduction factor: 70–90% volume reduction over 12–18 months;
  • Greywater flow: 60–100 L/person/day (showers, sinks, laundry);
  • Constructed wetland sizing: 5–7 m² per person (horizontal subsurface flow);
  • Local regulatory requirements for greywater and composting systems vary widely; always verify with local authorities.

OffGridNomad

The unified master calculator that aggregates outputs from all other modules into a single resilience dashboard, identifying resource gaps and system interdependencies.

Core Methodology

OffGridNomad collects key outputs from each subsystem calculator (energy surplus/deficit, water autonomy, food days stored, thermal comfort factor, etc.) and weights them into a composite Resilience Index (RI) score:

RI = Σ (Subsystem Score × Category Weight) ÷ Total Possible Score × 100

Category weights are configurable to reflect the user's priorities and geographic context. The dashboard highlights critical vulnerabilities (scores below threshold) and recommends priority investments.

Key Assumptions

  • Default category weights: Energy 30%, Water 25%, Food 25%, Thermal 10%, Waste 10%;
  • The RI score is a planning heuristic, not a certified resilience standard;
  • System interdependencies (e.g. water pump powered by solar) are simplified; detailed design should account for these explicitly.

Units & Conventions

All TerraNomadHub calculators use SI (metric) units as the primary standard, with optional imperial unit display where applicable. Key conventions:

  • Energy: Watt-hours (Wh), Kilowatt-hours (kWh), Gigajoules (GJ);
  • Power: Watts (W), Kilowatts (kW);
  • Volume: Liters (L), Cubic meters (m³);
  • Area: Square meters (m²);
  • Mass: Kilograms (kg), Metric tons (t);
  • Temperature: Degrees Celsius (°C);
  • Rainfall: Millimeters (mm);
  • Currency: Estimates shown in EUR; conversion to local currency is the user's responsibility.