## Saturn UV LED UV power comparison with Arc lamp UV

At Saturn UV we like to look at things both logical and scientifically. In order to compare like for like we have to make several logical assumptions.

## Assumptions:

· Arc lamp technology has about 4% UV output in the spectrum required. Can be referred to as output efficiency

· LED UV has 100% in the spectrum required. +/- 5%

· LED output efficiency is about 50%

· Whilst LED UV is always referred to as watts per sq/cm output, Arc lamps are always referred to as watts/linear cm output.

· These calculations below are based on a LED array 3.5cm wide and 20 cm long. However it can be under stood that even an arc lamp has an array output width of around 3.5cm ( even if it is focused) so these two UV sources can be compared almost like for like without consideration of substrate pass speed.

· Useful wave length output for Current Arc lamp curing technology 230-270nm

· Useful wave length for LED UV 375- 415

## Arc and LED UV comparison

Arc lamp rated at 160 watts/cm
4% x 160 = 6.4 watts per cm at 230-270 nm

LED UV array rated at 12 watts per sq/cm on an array 20cm x 3.5 cm
Total Power Consumption for unit =1646W
Power input per linear cm = 1646/20 = 82 watts
Efficiency of power at 50% = 41 watts UV output at 395nm

Technology           Linear Watts input           Linear Watts output             Wave length
Arc Lamp                      160                                        6.4                                      230-270 nm
LED UV                            82                                        41                                        395 +/-5%

## Saturn UV comparison of Electrical usage for LED UV and Arc lamp UV

At Saturn UV we like to look at things both logical and scientifically. In order to compare like for like we have to make several logical assumptions.

Assumptions:

· Printer running 2 shifts, 40 hours a shift.
· Factory open for 40 weeks per year.
· Printing uptime of machine 60% ( In other words UV is only used for 60% of the time)
· Printer is using a 6 colour label press 250mm wide.
· UV is after each colour.
· Arc lamps are on during printing pauses at around 10% power as they take serval minutes to re start.
· Printing Pauses rather than stops, When lamps are Off, could account for an additional 10% of lamp running time. (@10% power)
· A 250mm Arc lamp at 160 watts per cm
· LED UV is strictly ON/OFF
· LED array approximately 82 watts total input power per linear cm. ( approximately equivalent to 12watts per sq cm when running at 60M per min)
· Cooling of both systems is required but considered to be calculated equal for both systems.
· Cost of electricity UK £ 0.17 per kW hr
· Standing charge not used in this calculation as this would be paid even if no production was run.
Arc Lamp UV and LED UV comparison

Arc lamp
Running hours per year = 40hrs x 2 shifts x 40 weeks x 60% up time= 1,920 running hours
Total system kWs = 160 watts per cm x 25cm x 6 units = 24kWs
Running hours 1,920 hrs per year
Running kWs = 1,920hrs x 24 kWs = 45,080 kW hrs
Stand by kWs = 10% of total hours (3200 per year) @10% power = 320hours x 2.4kWs = 768 kW hrs
Total kW hrs = 46,848
Electrical Cost: 46,848 x £0.17 = £7,964.16

LED UV
Running hours per year = 40hrs x 2 shifts x 40 weeks x 60% up time = 1,920 running hours
Total system kWs = 82 watts per cm x 25 cm x 6 units = 12.3 kWs
No Stand by time.
Total kW hrs: 1,920 hrs x12.3 kWs = 23,616 kW hrs
Electrical Cost: 23,616 kW hrs x £0.17 = £4,014.72

Conclusion:
LED provides an electrical cost saving of:
£7964.16 – £4,014.72= £3,949.44per year
A Reduction in kW hrs Arc 46,848 – LED 23616 = 23,232 kW hrs which may keep you under the total business level of 100kW which would otherwise lead to the legal installation of a Half Hour meter and subsequent electrical tariffs.

## At Saturn UV we like to look at things both logical and scientifically. In order to compare like

Assumptions:

· Arc lamp technology has about 4% UV output in the spectrum required. Can be referred to as output efficiency
· LED UV has 100% in the spectrum required. +/- 5%
· LED output efficiency is about 50%
· Whilst LED UV is always referred to as watts per sq/cm output, Arc lamps are always referred to as watts/linear cm output.
· These calculations below are based on a LED array 3.5cm wide and 20 cm long. However it can be under stood that even an arc lamp has an array output width of around 3.5cm ( even if it is focused) so these two UV sources can be compared almost like for like without consideration of substrate pass speed.
· Useful wave length output for Current Arc lamp curing technology 230-270nm
· Useful wave length for LED UV 375- 415

Arc and LED UV comparison
Arc lamp rated at 160 watts/cm
4% x 160 = 6.4 watts per cm at 230-270 nm

LED UV array rated at 12 watts per sq/cm on an array 20cm x 3.5 cm
Total Power Consumption for unit =1646W
Power input per linear cm = 1646/20 = 82 watts
Efficiency of power at 50% = 41 watts UV output at 395nm

Technology   Linear Watts input     Linear Watts output  Wave length

Arc Lamp          160                                6.4                         230-270 nm

LED UV                  82                                       41                         395 +/-5%

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