UV Curing calculator

UV Cooling Requirement Calculator

Every UV cure system rejects a significant fraction of input power as heat — mercury rejects 65–80%, LED rejects 65–75% from the array body. That heat goes either into the chiller water loop or the exhaust airflow. This calculator sizes the cooling capacity needed (BTU/hr) so the chiller and exhaust system are spec'd correctly and the cell doesn't thermally shut down on the first hot summer day.

What this calculator does

  • Size chiller and exhaust capacity for a UV cure system from input power, the share of input that becomes heat to remove, and runtime.
  • Use it when laying out a new UV station's utilities — chiller GPM, exhaust CFM, ozone scrubber capacity — before the cell is ordered.
  • Returns the cooling capacity (BTU/hr and kW) needed to remove heat from a UV cure system, used to size chillers and exhaust.

Formula used

  • Estimated heat to remove (kW) = system input × heat-to-cooling fraction × runtime fraction
  • Cooling capacity (BTU/hr) = estimated heat × 3,412

Inputs explained

  • System electrical input: Total wall-plug power: lamp / LED + driver + controls.
  • Heat-to-cooling fraction: 0.65–0.80 for mercury (most of input becomes heat); 0.65–0.75 for LED (mostly array body heat).
  • Runtime per hour: Fraction of the hour the system is on; 1.0 = continuous, 0.3 = 30% duty cycle.

How to use the result

  • Use it during cell layout / utility design, before chiller and exhaust are ordered, and when troubleshooting a system that thermally derates in summer or after relocations.
  • Sizes the heat removal capacity, not the airflow or water flow specifics. Translate BTU/hr to chiller GPM (≈ BTU/hr ÷ 12,000 × 3 GPM/ton) and exhaust CFM with the system's vendor specs. Add 20–30% safety margin for ambient and elevation derating.

Common questions

  • Mercury vs LED — which needs more cooling? Mercury usually needs more total cooling because it stays on between parts (full hour) at 65–80% heat conversion. LED is more efficient and idles low, so total BTU/hr is often 40–60% lower even at the same UV output. The cooling case is one of the underappreciated advantages of LED retrofits.
  • How do I convert BTU/hr to chiller tons? 1 ton of cooling = 12,000 BTU/hr. So 80,000 BTU/hr ≈ 6.7 tons. Spec the chiller at this load + 25% margin (so ~8.5 tons here), and confirm GPM at the system's required water-side temperature delta (typically 10–20°F across the cure-cell loop).
  • What about exhaust requirements? Mercury lamps generate ozone (UV-C splits O₂); exhaust must be sized to dilute ozone below the OSHA PEL (0.1 ppm) and capture any ozone the system off-gases. Vendor data sheets quote required CFM. LED systems at >365 nm don't generate ozone — exhaust spec is mostly for substrate fume capture.
  • Why include a duty-cycle fraction? LED arrays often run at <50% duty (only on when parts are present). Sizing cooling for full continuous would oversize the chiller and waste capex. For mercury, set duty = 1.0 — the lamp idles on, so heat is continuous.

Last reviewed 2026-05-12.