Data Sources & Methodology

This calculator uses a simplified annual yield estimation method combined with dynamic data inputs.

1. Data Sources

• Collector Parameters: Real-time data fetched from Solar Keymark database (via Duurzaam Loket). Coefficients ($\eta_0, a_1$) are used to adjust performance relative to a standard reference collector.
• Meteorological Data: Typical Meteorological Year (TMY) data sourced from PVGIS (EU) or NREL (US) depending on location coordinates.

2. Performance Calculation

Annual energy production ($E_{solar}$) is estimated using a reference specific yield approach adjusted for collector quality and storage:

$$ E_{solar} = A_{total} \cdot Y_{specific} \cdot f_{eff} \cdot f_{storage} $$

• $A_{total}$: Total Aperture Area ($N \cdot A_{single}$)
• $Y_{specific}$: Location-based reference yield (kWh/m²/year) derived from GHI.
• $f_{eff}$: Efficiency factor ($\eta_0 / 0.73$), rewarding higher optical efficiency.
• $f_{storage}$: TES Performance boost (1.0 - 1.15x) based on Volume-to-Area ratio ($V/A$).

Solar Fraction: $$ SF = \frac{min(E_{solar}, HeatDemand)}{HeatDemand} $$

3. Financial Assumptions

• Hardware Cost: $\approx \$200/m^2$ base + efficiency premium. TES cost varies by material (Water $\approx \$1.5/L$).
• Total CAPEX: $1.6 \times HardwareCost$ (Includes 60% markup for installation, piping, controls).
• OPEX: $1.5\%$ of Total CAPEX annually.

4. Financial Metrics

LCOH (Levelized Cost of Heat):

$$ LCOH = \frac{\sum_{t=0}^{N} \frac{I_t + M_t}{(1+r)^t}}{\sum_{t=0}^{N} \frac{E_t}{(1+r)^t}} $$

Simple Payback Period: $$ SPP = \frac{Total \ Investment}{Annual \ Saving} $$

5. References & Standards

• Collector Testing: Solar Keymark Network (EN 12975 standards) used for $\eta_0, a_1$ coefficients.
• Meteorological Data: EU JRC PVGIS (TMY) for solar irradiance and temperature data.
• LCOH Methodology: Based on IEA SHC Task 54 guidelines for Levelized Cost of Heat.
• Emission Factors: IPCC 2006 / DEFRA standard for Natural Gas ($0.205 \ kgCO_2/kWh$).