Airconditioning with the Hemmes-system























Schematic drying before heatrecovery













Schematic drying after heatrecovery




Description of the patented systems

The Hemmes-system is based on using two high efficiency heatexchangers : one is used in the dehumidification section to transfer sensible heat (free reheating) and the other is used for heat or cold recovery from the return air. The cooling is obtained by using indirect evaporative cooling; evaporating water in the return air before and during the passage of  the heatexchanger.

Below we describe the dehumidifier  and the two patented Hemmes systems : drying before and after heatrecovery.



Schematic of the dehumidifier

This type of dehumidifier is certainly not new but very badly known in the field of airconditioning. That´s the reason we have dedicated a special chapter to this way of drying.


The Hemmes system with dehumidification before heat or cold recovery

Ideal for a very stable supply temperature

The  possible bypasses of the dehumidifier and the bypass of the second heatexchanger are not drawn.

In the mollier diagram we used a setpoint of 5 degree Celsius for the dewpoint which can easily be obtained with a DX-cooler and shows the possibilities of the system to dry and cool without low supply temperatures.




The Hemmes system with dehumidification after  heat or cold recovery

When you want to have the possibility for low supply temperatures as well, this schematic offers the possibility to bypass the dehumidifier-heatexchangerafter the cooler. This bypassing is the same as lowering the  temperature efficiency of the heatexchanger and when bypassing further the known schematic of a normal cooler is obtained. And when you start with a high efficiency heatexchanger in the dehumidifier you have high supply temperatures (up to 100% drying effect) 




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