What weather and irradiance data does Design Studio use?

Design Studio uses weather and solar irradiance input data to run its simulation engine, which converts a panel layout into a projected annual energy yield for the project location.

What panel and inverter brands are available?

The module library includes three domestic ALMM-eligible Tier-1 manufacturers pre-loaded in the engine, with additional brands available via the Solmarkt Marketplace.

How are ROI, IRR, and payback calculated?

Financial assumptions used for ROI, IRR, and payback period calculations are documented on this page, covering the methodology behind every financial projection Design Studio generates.

How does Design Studio handle PM Surya Ghar subsidy calculations?

Design Studio applies the PM Surya Ghar subsidy logic documented in this specification, covering how the applicable central subsidy is calculated as part of a project's financials.

What standards and compliance references does Design Studio use?

The standards and regulations referenced in the Design Studio product and documentation are listed under Compliance and Standards References.

How accurate are these specifications?

This page documents only what can be confirmed from the engine, with a dedicated Note on Accuracy section covering data sources and assumptions.

Solmarkt Design Studio

Technical Specifications

What irradiation data? Which methodology? Which assumptions? This page documents exactly what powers every yield estimate, financial output, and subsidy calculation in Solmarkt Design Studio — only what we can confirm from the engine, honestly.

Rows marked Unconfirmed are features not yet implemented or details pending internal verification. We do not invent data sources or methodology claims for this audience.

Weather & Irradiance Input

The solar resource assumption used to drive all energy-yield calculations.

1/3 confirmed

Weather Data Source

— (Details on request)UnconfirmedNo external API or named irradiance database is called in the current engine. Yield is computed from a fixed peak sun-hour constant.

Peak Sun Hours Assumed

4.2 h/dayA single representative constant applied to all designs regardless of location. Source: hardcoded in the EPC Design Studio engine.

Location-Specific Irradiance Look-up

— Not implementedUnconfirmedThe current engine does not perform a per-coordinate or per-city irradiance query. A single national average is applied.

Simulation Engine & Methodology

How the Design Studio converts a panel layout into a projected annual yield.

4/6 confirmed

Yield Formula

Annual kWh = System kW × 4.2 h/day × 365 days × Net EfficiencyDeterministic single-diode-free model. Net Efficiency is derived from the base yield factor minus shading loss.

Base Yield Factor (Performance Ratio)

85 %Captures wiring, inverter, temperature, and soiling losses in aggregate. Applied uniformly to all designs.

Shading Model

Grid-cell obstruction count → proportional loss factor, capped at 30 %Users mark shaded cells on the rooftop grid; the ratio of shaded to total cells drives a shading loss percentage up to a 30 % maximum.

Effective Performance Ratio with Shading

max(50 %, 85 % − shading loss %)A lower-bound floor of 50 % ensures the model does not produce degenerate outputs for heavily-shaded layouts.

Hourly / Monthly Simulation

— Not implementedUnconfirmedThe engine is an annual-aggregate model. Sub-monthly or hourly yield profiles are not computed in the current version.

Temperature Coefficient Correction

— Not implementedUnconfirmedThe current engine does not apply a site-specific temperature coefficient (Pmax TC). Included in the base yield factor in aggregate.

Module Library

The solar panel brands and specifications available in the Design Studio engine.

3/4 confirmed

Available Brands

Waaree Energies, Adani Solar, Vikram SolarThree domestic ALMM-eligible Tier-1 manufacturers pre-loaded in the EPC Design Studio. Additional brands available via the Solmarkt Marketplace.

Available Wattage Classes

450 Wp, 540 Wp, 600 WpMono PERC technology for all three wattage classes.

Module Technology

Mono PERC (all pre-loaded classes)Bifacial, TopCon, and other technologies available in the Marketplace but not yet in the embedded design engine.

External Module Database

— Not integratedUnconfirmedThe engine uses a curated list of three brands, not a full external component database. Live Marketplace product listings supplement this for procurement.

Inverter Library

Inverter sizing and cost assumptions used in BOQ and financial calculations.

2/3 confirmed

Sizing Rule

Inverter size = ⌈System kW × 1.1⌉ kW10 % over-sizing applied to the DC system size to set the minimum inverter AC rating.

Available Size / Cost Tiers

≤ 3 kW, ≤ 5 kW, ≤ 10 kW, > 10 kW (indicative cost brackets)The engine uses four price brackets, not a model-level database. Actual pricing from live Marketplace vendors overrides these for procurement.

Inverter Brand / Model Database

— Not integratedUnconfirmedThe current design engine contains no inverter brand or model list. Brands such as Solis, SMA, and Growatt are available via the Solmarkt Marketplace.

Financial Assumptions (ROI / IRR / Payback)

The financial model inputs and methodology behind every proposal's return calculations.

7/8 confirmed

Simple Payback Period

Net Project Cost ÷ Annual Grid Savings (₹)Grid savings = Annual kWh × user-entered grid tariff (₹/kWh). Default tariff: ₹8.50/kWh.

Grid Tariff Input

User-configurable slider (default ₹8.50 / kWh)Entered by the EPC engineer per project. No automatic DISCOM tariff look-up.

Panel Degradation (25-Year Basis)

8 % aggregate over 25 years (× 0.92 scalar)A single scalar applied to the 25-year cumulative generation estimate. Year-by-year degradation curve is not modelled.

O&M Cost Assumption

15 % of net project cost over project lifetimeFlat percentage; not broken down by year or component type.

LCOE

(Net Cost + Lifetime O&M) ÷ 25-Year Cumulative GenerationOutput in ₹/kWh. Reflects project-specific cost and subsidy inputs.

IRR Methodology

Lookup-table approximation based on annual savings ÷ net cost ratioFour ratio bands map to four IRR values (5.2 %, 11.5 %, 19.8 %, 26.2 %, 32.4 %). This is an indicative estimate, not a full DCF calculation.

EMI Calculation

Standard reducing-balance EMI formulaInputs: down payment, loan tenure (years), annual interest rate (default 9.5 % p.a.). Loan amount = Net cost − down payment.

Inflation / Tariff Escalation

— Not modelledUnconfirmedThe current engine assumes a flat grid tariff for the project lifetime. Escalation modelling is not implemented.

PM Surya Ghar & Subsidy Logic

The central government subsidy slab and state-level rebate engine used in project financials.

7/8 confirmed

Central Subsidy — Up to 1 kW

₹30,000PM Surya Ghar: Muft Bijli Yojana central government slab.

Central Subsidy — Up to 2 kW

₹60,000Cumulative (₹30,000/kW for first 2 kW).

Central Subsidy — 3 kW and above

₹78,000 (ceiling)Capped at ₹78,000 for all residential systems 3 kW or larger.

State Rebate — Gujarat

Up to ₹20,000 (₹5,000/kW)Applied in addition to central subsidy. Capped at ₹20,000.

State Rebate — Maharashtra

Up to ₹15,000 (₹3,500/kW)Capped at ₹15,000.

State Rebate — Delhi

Up to ₹10,000 (₹2,500/kW)Capped at ₹10,000.

Other States

— Not implementedUnconfirmedOnly Gujarat, Maharashtra, and Delhi state rebates are modelled in the current engine. Other state schemes are not yet included.

Subsidy Applicability

Residential rooftop installations (qualifying criteria per MNRE guidelines)Commercial and industrial systems are not eligible for PM Surya Ghar central subsidy.

Compliance & Standards References

Standards and regulations referenced in the Design Studio product and documentation.

5/7 confirmed

Electrical Safety Reference

NEC (National Electrical Code) & local safety codesCited in the Electrical Design stage of the workflow as the basis for String Sizing and DC/AC layout outputs.

ALMM (Approved List of Models & Manufacturers)

Module brand choices limited to ALMM-eligible domestic manufacturersWaaree, Adani Solar, and Vikram Solar are all ALMM-listed. The Marketplace surfaces ALMM compliance status on vendor listings.

Net Metering

DISCOM net-metering capacity guidelines referenced in Site Add-ons workflowEarthing layout and cable sizing outputs are documented as complying with local net-metering connection guidelines. GERC has updated MSME net-metering capacity to 1 MW.

MNRE Guidelines

PM Surya Ghar subsidy slabs follow MNRE Muft Bijli Yojana programme rulesSubsidy logic is based on publicly notified MNRE slab rates. Confirm current notified rates before client-facing use.

BIS Certification

BIS-certified products surfaced in Marketplace listingsBIS compliance status is displayed on individual vendor product listings. The design engine itself does not enforce a BIS filter.

CEA (Central Electricity Authority) Standards

— Not explicitly referenced in current engineUnconfirmed

IEC / IS Standards (Module/Inverter)

— Not explicitly referenced in current engineUnconfirmed

A Note on Accuracy

This page reflects the calculation engine as implemented. Where fields are marked Unconfirmed, the feature is either not yet built or pending internal documentation. Subsidy slabs are based on publicly notified MNRE programme rates; EPC engineers should confirm current notified rates before using them in client-facing documents. For enterprise deployments requiring verified methodology documentation, contact the Solmarkt team.

See the Engine in Action

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