Steam dispersion systems can increase the flexibility in system design and afford opportunities previously not possible particularly in challenging applications says Dave Mortimer, national sales manager for Vapac Humidity Control
DESPITE the significant advances in humidification technology, steam absorption has always posed a number of hurdles. However, recent developments in rapid steam absorption systems not only tackle the problems but also save money and use a shorter air-handling footprint too.

The lack of humidity and its effects are well documented. When the atmosphere of a building becomes too dry, its occupants display symptoms such as dry eyes and sore throats. Dry air also leeches moisture from a building’s fabric and over a period of time cracks in plaster on walls and ceilings develop, paintings crack and excessive amounts of static electricity are produced.



Adding moisture to the air offers many benefits but understanding a building’s requirements and those of its occupants is critical to ensure that the correct humidification system whether adiabatic or isothermal is designed.

The two types operate quite differently. Adiabatic systems reduce temperature and increase moisture content. During this process the % RH will also increase. Isothermal humidification increases moisture content and increases the %RH without increasing or decreasing the temperature, but a length of the air stream is required for the moisture addition to be absorbed.

A number of elements affect how quickly an air stream absorbs moisture. The higher the relative humidity that is produced the more difficult the problem. Lower temperature systems and high air speed can also be significant factors.

When a humidifier is required and is an after-thought and the conditions inside the air handler or ductwork are not the same as the design, what do you do about absorption length?

There are a number of factors to consider that impact absorption:

• Duct or air handling temperature – cool air absorbs far less than warm air therefore a longer absorption distance is required

• The moisture content of the air

• The amount of moisture addition

• Air speed

Retro-fitting kit is always a costly exercise and humidification is no exception. For effective absorption, a manifold needs to be sited so that steam is introduced at a point where there is enough straight and unimpeded ductwork downstream. However, a building’s structural constraints, along with short ductwork may not be suitable for conventional steam pipes to work effectively and air handlers already in-situ are quite likely to lack the necessary space.

The boffins at Vapac have come up with an innovative solution, a multiple-tube steam dispersion system, which is far more effective than using single duct tube or conventional steam pipe injection systems. The frame-like construction of Vapasorb is composed of a bank of multiple tubes, evenly spaced that provides instantaneous steam evenly distributed into the air stream.

The compactness of the frame means that it can be installed either directly inside existing duct systems or inside air handlers making it ideal for retrofitting applications too.



Manufactured using welded stainless steel construction, Vapasorb is the first generation of steam dispersion devices that uses hole-forming technology as opposed to nozzle inserts to extract the condensate-free steam from the centre of the tubes. Its design eliminates the need for inefficient jacketed tubes, expensive stainless steel nozzles and/or unreliable plastic inserts.

Units can be custom-designed in a wide range of sizes to address specific needs and this allows for infinitely variable tube spacing and numbers of holes per tube. This together with counter flow steam injection can meet even the shortest absorption requirements.

Vapac Humidity Control

01732 863447