Calculator Inputs
Example Data Table
| Scenario | DC Size | Inverter AC | DC/AC Ratio | Daily Delivered | Daily Clipping Loss | Loss % |
|---|---|---|---|---|---|---|
| School rooftop | 12.00 kWdc | 10.00 kWac | 1.20 | 64.92 kWh | 1.80 kWh | 2.70% |
| Warehouse carport | 25.00 kWdc | 20.00 kWac | 1.25 | 138.38 kWh | 5.17 kWh | 3.60% |
| Utility block | 100.00 kWdc | 90.00 kWac | 1.11 | 643.00 kWh | 2.13 kWh | 0.33% |
Formula Used
1) Net peak before clipping
Net Peak = DC Array Size × Irradiance Multiplier × Performance Ratio × (1 − Temperature Loss) × (1 − Soiling Loss) × (1 − Wiring and Mismatch Loss)
2) Daylight power curve
The calculator models solar production through the day using a sine profile:
P(t) = Net Peak × sin(π × t / Daylight Hours)
3) Clipped power
Delivered Power = min(P(t), Inverter AC Rating)
4) Energy and loss
Daily energy is summed across the selected time interval. Clipping Loss = Unclipped Energy − Delivered Energy. Loss % = (Clipping Loss ÷ Unclipped Energy) × 100.
This method gives a practical construction-stage estimate for inverter sizing and array oversizing reviews. Real projects should still be checked with detailed irradiance and temperature datasets.
How to Use This Calculator
- Enter the planned DC module capacity in kWdc.
- Enter the inverter AC nameplate capacity in kWac.
- Add effective daylight hours for the representative day.
- Set irradiance multiplier above 1.00 for stronger conditions.
- Enter performance ratio and project losses.
- Choose analysis days for the study period total.
- Click the calculate button.
- Review the result cards, graph, and export files.
Frequently Asked Questions
1. What is solar clipping loss?
Solar clipping loss happens when the PV array could produce more power than the inverter can pass to the AC side. The excess is limited, so some potential energy is not delivered.
2. Why oversize a DC array if clipping occurs?
A larger array often improves morning, afternoon, winter, and cloudy-period production. Small clipping during high-output periods can still be economically worthwhile if total yearly energy increases enough.
3. What DC/AC ratio is common?
Many projects use ratios near 1.1 to 1.35, but the ideal value depends on climate, tariff structure, equipment cost, interconnection limits, and available roof or land area.
4. Does this calculator replace detailed energy modeling?
No. It is a fast planning tool for design comparison and construction-stage checks. Final decisions should also consider weather files, module temperature behavior, degradation, and site-specific shading.
5. What does the irradiance multiplier represent?
It scales output relative to standard array capacity. Values above 1.00 simulate very strong solar conditions, while values below 1.00 reflect weaker irradiance or non-ideal operating periods.
6. Why include temperature, soiling, and wiring losses separately?
These losses help construction teams and designers test realistic field conditions. High heat, dirt buildup, and wiring or mismatch losses can materially reduce peak power and change expected clipping.
7. What does clipping hours per day mean?
It is the estimated time during which modeled PV output exceeds inverter capacity. Longer clipping windows usually indicate stronger oversizing or stronger site conditions near midday.
8. Can this help with construction value engineering?
Yes. It helps compare inverter sizes, array oversizing strategies, and expected lost energy before procurement. That makes it useful during budget reviews and constructability discussions.