Energy Cost Analysis and Optimization of Open, Closed and High Humidity Hoods and Related Air Systems, 2006 TAPPI Papermaker’s Conference
This paper studies three typical paper machine hood configurations (e.g. open hood, closed hood, high humidity hood) and compares the relative operating costs of each in terms of the dryer section air systems. Optimization of the air systems can return significant energy savings resulting in an improved "cost per ton" index. For the case study, the conventional hood proved to be 43% less costly to operate compared to a canopy type hood.
The high humidity hood is 55% more cost affective than the canopy hood, and 22% more energy efficient than the conventional hood. In terms of hood heat recovery potential, the canopy hood "heat recovery performance index" (annual savings $/m2 surface area) is approximately $437/ m2 of heat recovery surface area, compared to $518/ m2 and $744/ m2 for conventional and high humidity hoods respectively.
There are significant cost savings potential with the high humidity hood compared with other hood technologies.