At Compact Engineering, our aim is to improve the energy efficiency of our dryers.
Energy efficiency does not happen by chance but by design
There are a number of factors that determine the overall efficiency of an infrared dryer or heater and first amongst them is the wavelength of the infrared.
- At Compact Engineering, we manufacture our own lamps, which are designed to deliver infrared at 1.35 microns at full power.
- At this wavelength, the infrared is able to penetrate deep into the sheet and heat the sheet evenly throughout.
- In independently run tests, Compact’s emitters were determined to have a heat transfer efficiency of over 59%. That is to say, in excess of 59% of the power from the transformer was measured as a heat gain by the sheet.
- Under comparable conditions, the industry standard lamps show an efficiency of just 38%.
Secondly, having generated the infrared using our specially developed lamps, the infrared has to be guided onto the sheet surface.
- For this we use gold-plated reflectors that reflect over 99% of the primary energy from the lamps and also reflect any energy that is initially reflected by the sheet.
- Managing the reflected radiation is important, as any infrared that escapes from the dryer is lost to the drying or heating process.
- Reflector design and construction is therefore, a significant contributor to overall energy efficiency.
Thirdly, to protect the lamps and reflectors and to assist in effective cooling,
- Compact use hydroxyl-free quartz tubes or plates, depending upon the dryer design. The advantage of using ‘pure’ quartz is that it absorbs very little infrared energy resulting in more of the Infrared being available to heat the sheet.
- The quartz does not get hot so there is no fire risk, which is a major safety feature.
A fourth consideration is the active management of the boundary layer.
- This ensures that the energy added to the sheet by the infrared is removed as the water in the sheet is evaporated.
- Compact’s range of dryers will often produce a lower sheet temperature as the sheet exits the dryer, than when the sheet came into the dryer.
- This does not mean that we are not getting the energy into the sheet, but that we are promoting rapid and controlled evaporation.
Typically under identical conditions, Compact dryers remove twice as much water per kilowatt consumed, as that of competing dryers.
