Solar Engineering Glossary

Q: What is a solar engineering glossary?

A reference library of standardized definitions, formulas, and design rules used by solar engineers, EPCs, designers, AHJs, and PE-stamping professionals. Heaven Designs maintains a 200+ term glossary spanning PV design, US and India codes, software, components, and engineering math.

Q: Who is this glossary for?

EPC engineers, solar designers, electrical and structural engineers, permit coordinators, AHJ reviewers, utility interconnection teams, NABCEP candidates, engineering students, and decision-makers researching unfamiliar terms.

Q: How often is the glossary updated?

Every term is reviewed at least annually. High-priority entries (NEC updates, ASCE revisions, NEM rule changes, ALMM updates) are refreshed within 30 days of the source change. The "Recently Updated" panel above shows the latest revisions.

Q: Do the definitions cover both US and India regulations?

Yes. Every applicable term includes a US compliance section (NEC, UL, IEEE, ASCE, Title 24) and an India regulatory section (MNRE, CEIG, DISCOM, ALMM, BIS, CEA) where relevant.

Q: Are the formulas safe to use in actual design work?

The formulas and worked examples are accurate and reference current code editions, but glossary content is educational. Final design decisions should be reviewed by a licensed PE familiar with the project's AHJ and utility requirements. Heaven Designs offers PE-stamped solar design packages that handle that for you.

Q: Can I link to specific glossary entries?

Yes, every term has a permanent URL at /glossary/[slug]/. Educators, EPCs, and authors are welcome to link to entries; attribution is appreciated but not required.

Q: How do I suggest a missing term?

Send the term plus a short note on why it matters to service@heavendesigns.in. The editorial team reviews suggestions monthly and adds high-impact terms to the publication queue.

200+ engineering definitions, formulas, code references, and design guides, written by solar engineers, for solar engineers.

200+

Engineering Terms

Browse by Category

Six clusters of solar engineering knowledge, organized by discipline.

Solar Engineering

Core PV design, performance, and electrical fundamentals.

US Solar Codes

NEC, UL, IEEE, ASCE, Title 24, and AHJ requirements.

India Regulations

MNRE, CEIG, DISCOM, ALMM, BIS, and state-level approvals.

Solar Software

PVsyst, Helioscope, Aurora, SAM, HOMER, and Meteonorm.

Engineering Math

P50/P90, LCOE, IRR, capacity factor, and yield modeling.

Solar Components

Modules, inverters, connectors, racking, and disconnects.

Popular Engineering Terms

The most-searched solar design fundamentals.

View all engineering terms →

MPPT

Maximum Power Point Tracking, how inverters maximize array yield.

SLD

Single Line Diagram, the heart of every solar permit submission.

Performance Ratio (PR)

The single number that defines real-world plant health.

String Sizing

Cold-Voc and hot-Vmp checks against the MPPT window.

Bifacial Gain

Rear-side energy contribution from albedo and ground reflectance.

Rapid Shutdown

NEC 690.12 module-level shutdown for firefighter safety.

Shading Analysis

Quantifying near and far obstructions on annual yield.

Voltage Drop

DC and AC conductor sizing for <2-3% drop targets.

Popular Code References

The codes and standards that govern every solar permit.

View all US codes →

NEC 690

The master article for solar PV systems in the National Electrical Code.

NEC 705

Interconnected power production source rules, 120% rule and beyond.

ASCE 7-22

Wind, snow, and seismic loads governing rooftop and ground-mount structural design.

NEM 3.0

California net billing tariff that reshaped residential payback math.

Rule 21

California utility interconnection standard governing inverter behavior.

IEEE 1547

Interconnection of distributed energy resources with the grid.

Popular Software Tools

The simulation and design platforms that ship most commercial designs.

View all software →

PVsyst

Industry-standard simulation tool for bankable energy yield reports.

Helioscope

Fast layout and yield modeling, the commercial designer's default.

Aurora Solar

LIDAR-based residential design with built-in shading and finance.

SAM

NREL's open-source PV + financial model, granular and conservative.

HOMER

Hybrid renewable system design including storage and diesel.

Meteonorm

TMY weather data source used in PVsyst and most simulation tools.

Featured Engineering Guides

Deep-dive references, formulas, design rules, code citations, and worked examples.

18 min

MPPT, Maximum Power Point Tracking

The complete engineering reference: algorithms, multi-MPPT design, string sizing math, NEC and UL compliance, and how PVsyst models it.

14 min

NEM 3.0 vs NEM 2.0, What Changed and Why

California's shift to net billing, the export rate impact on residential payback, and how design strategy adapts.

16 min

ASCE 7-22 for Solar Structural Engineers

New wind tunnel coefficients, snow load updates, and the practical implications for rooftop and ground-mount design.

12 min

PVsyst Project File Anatomy

How to read a PVsyst loss diagram, what to validate before signing off, and the common modeling pitfalls.

A-Z Glossary Directory

Every term in the glossary, in alphabetical order.

Glossary FAQ

Common questions about how the Heaven Designs glossary works.

What is a solar engineering glossary?