Description:
Manual L4 ES HP; L4 ES HP W
Document Number:
1004289
Created By:
MSHN
Revision Approval Date:
2019-06-28
Revision:
A
© Corroventa Avfuktning AB
5 (42)
21.
The dehumidifier must not be used with accessories other than those described in this manual
or approved by Corroventa Avfuktning AB.
Contact the supplier of this dehumidifier for further advice on the safety and use of the product.
Relative humidity and its impact on materials
All air contains a greater or lesser degree of moisture. We can’t see it with the naked eye until it appears
in the form of small water drops against a cold metal or glass surface for example. However, before it is
visible, moisture is already causing problems by affecting materials and manufacturing processes,
causing corrosion and growth of micro-organisms.
Air moisture is measured and usually given in relative humidity (% RH). It is a measurement of how much
water vapour the air contains over how much it can hold in total at a given temperature and pressure.
The higher the temperature, the more water the air can hold, but it is the relative humidity that is
calculated and must be controlled to prevent corrosion or mould growth.
At 100% RH the air is saturated, and the moisture falls in the form of small water droplets. Steel
corrodes at 60% RH and at 70% RH there is a risk of mould. A rule of thumb is that 50% RH is a good
climate for most materials.
How to select dehumidification technology for a given
situation
The adsorption principle has the advantage of not having the same temperature dependence as
condensing dehumidification. Adsorption also works way below freezing, whilst condensing drier
capacity decreases sharply with decreasing temperature, which is illustrated in the graph below to the
left.
An adsorption dehumidifier with air-cooled condenser like L4 ES, bridges these properties by working
within a large area, including the primary area of the condensing drier. In other words, it is the best
option for room drying at low temperatures, ideal for emergency damage and construction
dehumidification.
As a general tip when choosing the technique for the relevant drying situation, it can be said that
adsorption dehumidification is the primary choice for drying in unheated spaces or when material drying
is required. The latter is justified by the adsorption dehumidifier producing dehumidifier air, i.e. provides
a greater difference between the incoming and outgoing air's moisture content calculated in grams per
cubic metre (ΔX), which can be seen using the graph to the right below and which is decisive for the rate
of drying. Layered structures are dried by the machine being installed, with the turbine, for suction or
pressure drying.
