CASE50 · Buildings · Fenestration simulation
Comparing window area, glazing shading coefficient and curtains in an office model
The same building model isolates three fenestration changes. Their annual energy-cost impacts are interpreted with thermal transfer, solar gain and daylighting kept distinct.
01 · CASE ANALYSIS
Fenestration is more than facade area
Windows affect heat transfer, solar gain and useful daylight. Window-to-wall ratio, U-value, shading coefficient and visible transmission answer different performance questions.
The source changes one fenestration condition at a time; it does not identify a universal optimum window ratio.
02 · CASE ANALYSIS
Window-area comparison
Reducing the window ratio from 63% to 40% changed annual cost from approximately KRW 3,114 million to KRW 3,060 million. The reported reduction was KRW 54 million/year, or 1.7%.
Electricity and gas cost fell by approximately KRW 47 million and KRW 7 million/year respectively.
| Scenario | Annual cost (KRW million) | Change | Rate |
|---|---|---|---|
| Common baseline | 3,114 | — | — |
| Window ratio 63% → 40% | 3,060 | −54 million/year | −1.7% |
| SC 0.33 → 0.75 | 3,405 | +291 million/year | +9.3% |
| Curtains: none → 50% | 3,083 | −31 million/year | −1.0% |
03 · CASE ANALYSIS
Glazing and curtain comparisons
Changing SC from 0.33 to 0.75 increased modeled annual cost to KRW 3,405 million: KRW 291 million/year or 9.3%. Electricity cost rose 7.8% and gas cost 32.5%.
Applying curtains at the source’s 50% condition reduced cost to KRW 3,083 million: KRW 31 million/year or 1.0%. Curtain material and use schedules affect transferability.
04 · CASE ANALYSIS
Interpret the result without inventing a cause
Higher SC can increase solar heat gain, but the full electricity/gas response depends on hourly heat balance and HVAC. The source result does not prove one sole causal mechanism.
Treat U-value, solar control and visible transmission separately. Evaluate orientation, glare, comfort, daylight controls and construction cost when choosing a real facade.
| Variable | Principal interpretation |
|---|---|
| WWR | Amount of glazing relative to wall area |
| U-value | Temperature-driven thermal transfer |
| SC / SHGC | Solar heat-gain control; distinct source notation |
| VT / VLT | Visible light and daylighting |
| Curtain state | Material, position and operating schedule |
05 · CASE ANALYSIS
Compare complete alternatives
Combine feasible glazing, window area, shading and lighting-control choices in a fresh model run. Do not add these single-case percentages.
CASE49 and CASE50 share the virtual-office scenario study. Their values are related design comparisons rather than independent realized savings projects.
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