In the competitive marketplace of today one of the many tools for success is the reduction of energy consumption without a sacrifice in product quality or delivery. The printing industry inherently understands the potential savings to be added to the bottom line by decreasing energy consumption. This industry is generally a large consumer of both electric and natural gas for production processes. The majority of the industry utilizes some form of continuous web processing to combine ink with paper and create a finished product. The heat generated during this process still falls under the category of "waste heat" in many facilities. Large amounts of outside air and/or mechanical cooling in many companies are utilized to eliminate excess process heat. It is common knowledge the important role humidification control plays in printing. It is sometimes "not so" common knowledge how to approach the addition of humidity to the printing facility without increasing overall energy consumption. The benefits of adiabatic humidification can be extremely effective in many cases. In the printing facility, steam humidification adds enthalpy (potential energy) to an air handling system. The alternative approach, with an adiabatic form of humidification, utilizes the excess process heat for evaporation. This compatibility follows the line of constant enthalpy on the psychrometric chart to an overall energy savings for the plant.
Figure 1 represents a starting condition of 80 deg. F. and 15% RH (Point A). Room design conditions of 70 deg. F. and 58% rh (Point B) are required for the pressroom. The supply air discharge must be at 57 deg. F. and 90% RH (Point C) to obtain room design conditions. To accomplish this with steam humidification, mechanical cooling must be used to drop the return air temperature to 57 deg. F. (Delta of 23 deg. F. across the coil). In many VAV systems more outside air may also be introduced which in turn creates an increase in the overall humidification load due to the increase of cold, dry, outside air. Both circumstances will add energy costs. Steam humidification will then be utilized to raise the humidity level to 90% to meet supply air discharge requirements and room design conditions. In this case the steam represents an increase in enthalpy of 5.6 btu’s / lb of dry air. This increased enthalpy reflects an increased demand on cooling at an additional cost to the facility. By utilizing adiabatic humidification, in this example, the supply discharge temperature of 57 deg. F. and 90% RH (Point C) can be obtained through evaporative cooling across the humidifier. The room design will also be achieved without an increase in enthalpy and without the additional requirement for mechanical cooling or outside air. The energy savings in this example and many others can be substantial and must not be overlooked.
The benefits of utilizing adiabatic humidification in printing as well as many other industries are easy to recognize from the previous example. The technologies available to accomplish this task vary greatly. From the very basic evaporative type humidifiers to the latest supersonic vacuum implosion nozzle systems, adiabatic humidification has come a long way and is now becoming the technology of choice. There are still many applications where the advantages of steam humidification cannot be ignored and should be utilized, but printing facilities usually benefit more from following the line of constant enthalpy with a form of adiabatic humidification. |
The MC is not an ultrasonic fogging nozzle. It is not a modified paint spray nozzle. These types of nozzles may be fine for use in greenhouses, amusement parks and movie sets where heavy fog is desired, but in a duct system where wetting can lead to bacterial and viral contamination, or over sensitive production areas, a light, highly controlled, easily evaporated mist is mandated. In short, if you want to film "The Creature of the Fog" use a fogger. If you want safe, reliable indoor humidity control, use the MC!