Fläkt Woods
3099 US 03.02
19
Specifications are subject to alteration without notice
PUMA (A–F) Rotary heat exchanger
TECHNICAL HANDBOOK
Control of rotary heat exchangers
Either on/off or continuously variable control can be em-
ployed for controlling the rotor speed.
If on/off control is employed, the temperature effici-
ency will be either zero or a maximum.
In continuously variable control, the rotor speed is var-
ied from rest to maximum speed in a continuous manner.
The temperature and moisture efficiencies as a function
of the rotor speed are shown in Chart 6.
During periods when no heat recovery is required, the
rotor speed will be so low that the efficiency will be close
to zero, although the rotor will still be purged.
For particulars of selecting the drive equipment for
on/off or continuously variable speed, refer to separate
instructions from Munters International Inc.
Chart 6
Example. Heat recovery - Variable speed
The heat exchanger rotor speed is controlled steplessly by
temperature sensors for constant supply air temperature,
constant room temperature or constant exhaust air tem-
perature.
0
10
20
30
40
50
60
70
80
90
0
20
40
60
80
100
Verkningsgrad
η
%
100
% av max. varvtal
η
t
η
x
Hygroskopisk rotor
Kompositrotor
Rum
RC-T
RC
RPM
DM
~
Ingår i PUM
Fig. 13
RC
RPM
DM
ST
SV
RC
T
DT
K
= Varvtalsregulator
= Spjällreglermotor
= Reglercentral för temperatur
= Kontaktor
= Drivmotor för värmeväxlare
= Ventilreglermotor
= Temperaturgivare
= Differenstermostat
Room
Included in PUM
Efficiency
η
, %
% of max. speed
= Speed
controller
= Temperature control unit
= Heat exchanger drive motor
= Damper
motor
= Temperature sensor
= Proportional thermostat
= Differential thermostat
= Contactor
Composite rotor
Hygroscopic rotor
Fig. 12.
If the air is admitted at an angle to the rotor face
In systems in which the air impinges on the rotor face at
an angle as shown in Fig. 12, the rotor could start to turn
because of this inclined angle of flow. This may cause
undesirable heat recovery due to the rotor rotating even
when the heat exchanger is shut down.
In such installations, guide vanes should be fitted at
the rotor inlet in order to deflect the air so that it will
flow at right angles to the rotor face.
If the heat exchanger is located on the delivery side of
the fan, a space should always be provided between the
fan outlet and the rotor to enable the air leaving the fan
outlet to distribute itself evenly over the whole of the
rotor area.
Control Systems
Project design advice