Peak sun hours (कभी equivalent sun hours या daily peak solar insolation) बताते हैं आपकी site पर एक दिन में कितनी usable solar energy — 1,000 watts per square meter (W/m²) intensity के घंटों में expressed। वही 1,000 W/m² benchmark labs panel nameplate ratings के लिए use करते हैं। Long summer day में 14 daylight hours हो सकते हैं पर सिर्फ 5–6 peak sun hours — morning/evening light weaker। Winter failures बिना panels/batteries size करने के लिए raw daylight hours नहीं — वह single daily number चाहिए।
Worst-month value मिलने पर daily Wh WattSizing कैलकुलेटर में। Off-grid winter planning: Winter low-sun sizing।
Peak Sun Hours क्या हैं?
Peak sun hours पूरे दिन की changing sunlight को 1,000 W/m² “perfect sun” hours की एक equivalent number में compress करते हैं।
Panels STC under rated — field में sun rarely all day that angle/intensity। Planners day's energy add ÷ 1,000 W/m²।
उदाहरण: Roof को four hours perfect 1,000 W/m² जितनी total energy → 4 peak sun hours — real sun 10 या 14 clock hours up हो।
Equivalent Sun Hours और Peak Solar Insolation
| Term | मतलब |
|---|---|
| Peak sun hours | Daily solar energy ÷ 1,000 W/m², hours |
| Equivalent sun hours | Same metric |
| Peak solar insolation | W/m² या kWh/m²/day |
| PSH/day | Abbreviation |
5.2 kWh/m²/day ≈ 5.2 peak sun hours same period।
Off-grid sizing almost always worst month PSH — annual average नहीं। Northern Hemisphere December, Southern June drive array size।
Peak Sun Hours vs Daylight Hours
Interchangeable नहीं:
- Daylight: Sunrise to sunset clock time।
- Peak sun hours: Energy-based। Cloudy 12-hour day → 2–3 peak sun hours only।
Daylight hours से sizing → winter off-grid undersize। Irradiance-based PSH from map/calculator always।
Sizing Formula
Array Watts = Daily Energy Need (Wh) ÷ Peak Sun Hours ÷ System Efficiency
Typical system efficiency: 0.75 to 0.80 (controller, wiring, heat, soiling)।
Illustrative (Ohio cabin, December):
- Daily load: 2,400 Wh
- Worst-month PSH: 2.5
- Efficiency: 0.75
2,400 ÷ 2.5 = 960 Wraw960 ÷ 0.75 = **1,280 W**(~four 320 W panels)
Summer ~5.5 PSH → only ~581 W suggested — system fails Nov–Feb। Winter low-sun sizing।
Maps और Lookup Tools
| Tool | Best for | Read |
|---|---|---|
| NREL PVWatts | US addresses | Monthly Solar Radiation (kWh/m²/day) ≈ PSH |
| Global Solar Atlas | Worldwide | GHI maps, site data |
Steps:
- Address/coordinates enter।
- Monthly table (not annual alone)।
- Lowest month = off-grid design PSH।
- Real tilt/azimuth match mount।
Trees/chimneys micro-shading → real PSH below map।
Regional Seasonal Ranges (illustrative)
| Region | Summer | Winter | Annual |
|---|---|---|---|
| Southwest USA (Arizona) | 6.5–7.5 h | 4.0–5.0 h | 5.5–6.5 h |
| Northeast USA (New York) | 5.0–6.0 h | 2.0–3.0 h | 3.5–4.5 h |
| Australia (Queensland) | 6.0–7.0 h | 4.5–5.5 h | 5.0–6.0 h |
| Northern Europe (UK) | 4.5–5.5 h | 1.0–2.0 h | 2.5–3.5 h |
India sites: Global Solar Atlas coordinates; monsoon/cloud worst month often drives off-grid size।
ज़्यादातर गाइड skip
- Worst-month rule off-grid — annual average trap।
- System derate 20–25% — use 0.75–0.80।
- Mount angle — flat RV roof loses winter PSH।
- Load vs sun — daily Wh load + site PSH; electrical watts ≠ solar resource।
Practical Checklist
- PVWatts or Global Solar Atlas site data।
- Monthly table lowest month pick।
- Real tilt/azimuth if tool allows।
- Daily Wh load + autonomy days।
- Formula or WattSizing कैलकुलेटर with worst-month PSH।
FAQs
Peak sun hours simple terms?
Hours per day at 1,000 W/m² delivering same total energy your site receives। One PSH = one hour reference intensity।
Equivalent sun hours same?
Yes — different wording, same daily energy metric।
Peak solar insolation W/m²?
Insolation = power per area। Peak = STC 1,000 W/m² reference। Daily kWh/m²/day converts to PSH।
Peak sun hours in my area?
PVWatts US; Global Solar Atlas elsewhere — monthly radiation column।
Trustworthy peak solar hours map?
NREL, World Bank Global Solar Atlas — long-term weather models। Random blog maps without cited source avoid।
Same as daylight hours?
No — daylight clock; peak sun hours energy। 14 h summer day may yield 6 PSH।
Panels work outside peak hours?
Yes — morning/evening lower output baked into daily PSH total।
Summer or winter PSH?
Off-grid/year-round RV: winter worst month। Grid-tied net metering: annual OK for bill model; winter backup loads still need worst-month check।
Clouds effect?
Clear 5 PSH day → heavy clouds 1–2 equivalent। Worst-month historical data for reliability।
Panel temperature change PSH?
No — PSH describes site sunlight; hot cells reduce panel efficiency → still apply 0.75–0.80 system factor।
India monsoon sizing?
Use lowest monthly GHI/PSH from atlas — cloudy monsoon months often worst, not clear winter।
Tilt change peak sun hours how much?
5–15% swing when optimal tilt vs flat RV roof—re-run formula; do not reuse one city average for both mounts।
Battery sizing uses same PSH?
Array uses PSH; autonomy multiplies daily Wh—recovery after cloudy weeks still tied to low PSH; see how many batteries off-grid with same worst-month sun data।
India site lookup notes
Global Solar Atlas coordinates for India—monthly GHI, kWh/m²/day ≈ PSH। Western Ghats, Northeast, Kerala monsoon months sometimes worse than mild winter—never assume December worst without monthly table। Dust near dirt roads may need 0.75 efficiency factor, not 0.80。
Sources
- NREL – PVWatts Calculator
- World Bank – Global Solar Atlas
- U.S. DOE – Planning a Home Solar Electric System
अगला कदम: Worst-month PSH WattSizing कैलकुलेटर में — How many batteries off-grid और How many solar panels off-grid के साथ plan complete करें।
