200+ engineering definitions, formulas, code references, and design guides — written by solar engineers, for solar engineers.
Six clusters of solar engineering knowledge, organized by discipline.
Core PV design, performance, and electrical fundamentals.
NEC, UL, IEEE, ASCE, Title 24, and AHJ requirements.
MNRE, CEIG, DISCOM, ALMM, BIS, and state-level approvals.
PVsyst, Helioscope, Aurora, SAM, HOMER, and Meteonorm.
P50/P90, LCOE, IRR, capacity factor, and yield modeling.
Modules, inverters, connectors, racking, and disconnects.
The most-searched solar design fundamentals.
Maximum Power Point Tracking — how inverters maximize array yield.
Single Line Diagram — the heart of every solar permit submission.
The single number that defines real-world plant health.
Cold-Voc and hot-Vmp checks against the MPPT window.
Rear-side energy contribution from albedo and ground reflectance.
NEC 690.12 module-level shutdown for firefighter safety.
Quantifying near and far obstructions on annual yield.
DC and AC conductor sizing for <2–3% drop targets.
The codes and standards that govern every solar permit.
The master article for solar PV systems in the National Electrical Code.
Interconnected power production source rules — 120% rule and beyond.
Wind, snow, and seismic loads governing rooftop and ground-mount structural design.
California net billing tariff that reshaped residential payback math.
California utility interconnection standard governing inverter behavior.
Interconnection of distributed energy resources with the grid.
The simulation and design platforms that ship most commercial designs.
Industry-standard simulation tool for bankable energy yield reports.
Fast layout and yield modeling — the commercial designer's default.
LIDAR-based residential design with built-in shading and finance.
NREL's open-source PV + financial model — granular and conservative.
Hybrid renewable system design including storage and diesel.
TMY weather data source used in PVsyst and most simulation tools.
Deep-dive references — formulas, design rules, code citations, and worked examples.
The complete engineering reference: algorithms, multi-MPPT design, string sizing math, NEC and UL compliance, and how PVsyst models it.
California's shift to net billing, the export rate impact on residential payback, and how design strategy adapts.
New wind tunnel coefficients, snow load updates, and the practical implications for rooftop and ground-mount design.
How to read a PVsyst loss diagram, what to validate before signing off, and the common modeling pitfalls.
Latest editorial revisions and code updates.
Every term in the glossary, in alphabetical order.
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Common questions about how the Heaven Designs glossary works.
Monthly digest of glossary updates, NEC and ASCE changes, India regulatory shifts, and new engineering guides. No spam.
