Stulz ULTRASONIC User manual

AIRCONDITIONING
ULTRASONIC / ENS
TECHNICAL MANUAL - ENS
INDEX 71.1-2
Edition 2.97
Copyright STULZ GmbH 02/1997
Û

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TABLE OF CONTENTS
Page
1. Operation 4
2. Technical Data ENS Series 5
2.1 Humidifier Path 6
2.2 Dimensioned Drawings 7
2.3 Description 9
3. Capacity Calculation for Ultrasonic Humidifiers11
3.1 Questionnaire Ultrasonic Humidifiers 18
4. Control System 20
4.1 Set-up of ON/OFF Control 21
4.2 Set-up of Proportional Control 26
4.3 Function of Proportional Adapter 31
4.4 Connecting Lines between the Humidifiers 34
and the Control System
4.5 Electrotechnical Information ENS 1200-9600 36
ON-OFF

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TABLE OF CONTENTS
Page
4.6 Electrotechnical Information ENS 14-18 37
5. Assembly, Start-up and Limitations 38
5.1 Assembly ENS Series 39
5.2 Installation Examples for Humidifiers ENS 60
5.3 Start-up of Humidifiers ENS 63
5.4 Precautions during Operation 65
6. Accessories 67
6.1 Data Sheet SafetyTransformers 67
6.2 Information Regarding the Conductimeter 68
7. CE - EMC law
7.1 Information about the EMC law 70
according to CE-guidelines

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1. Operation
STULZ Ultrasonic humidifiers operate on the principle of ultrasonic nebuliza-
tion. A 48 V a.c. voltage is rectified on an oscillator circuit and transferred into
a high frequency signal of 1.65 MHz. This signal is transmitted to an oscillator
(transducer) installed in the water bath, which then transfers this signal into
high frequency automatic vibrations. The built-in oscillators are so-called
thickness oscillators which in accordance with the signal of 1.65 MHz applied
change their thickness 1.65 million times per second.
Thesurfaceofthetransduceroscilla-
tes at such a high speed that the
water cannot follow because of its
inertia of masses; therefore, imme-
diately after the unit has been swit-
ched on, a water column is genera-
ted above the oscillators. During the
negative amplitude of the oscillator,
an instantaneous vacuum is produ-
ced because of the fact that the
watercannotfollowthefasteroscilla-
tor movements. Cavitation produ-
ces bubbles, which are "catapulted"
to the edge of the water column du-
ring the course of the positive ampli-
tude and which collide there with
great force. During this procedure,
finest water particles are being ato-
mized at the edge of the water co-
lumn. Due to the focussing of the
sound waves, cross waves are pro-
duced directly underneath the water
surface, in the centers of which
smallest water droplets are separa-
ted and generate a mist, which is
immediately absorbed from the air
stream.
OPERATION

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TECHNICAL DATA ENSTYPE
2. Technical Data ENS Type
The Ultrasonic humidifier type ENS operates on the principle of utrasonic
nebulization.Thehumidifierisintendedforinstalledincompactair-conditioning
units, box-type units and intake air ducts.
Itcontainsthenebulizationmoduleswithwatersupplyvalve/solenoidvalveand
float switch.
Type ENS ENS ENS ENS ENS ENS ENS ENS ENS ENS
1200 2400 3600 4800 6000 7200 8400 9600 14 18
Output 1.2 2.4 3.6 4.8 6.0 7.2 8.4 9.6 14 18
(l/h) 2x7.0 2x9.0
No. of 2 4 6 8 10 12 14 16 24 30
Oscillators
Trans- Primary: 110V / 208V / 230V / 400V / 460V ±15 V
former 50/60 Hz
Secondary: 12V / 24V / 36V / 42V / 48V / 52V
No. Power 65 125 185 240 310 375 435 495 750 960
(W)
Transf.Out. 160 160 320 320 320 500 500 500 1300 1300
(VA)
Weight 1.5 2.2 2.9 3.6 4.3 5.1 5.8 6.5 11 13
(kg)
Dimension 220 340 460 580 700 820 940 1060 785 950
L (mm)
Dimension 120 240 360 480 600 720 360 480 730 895
P, P1, P2 (480) (480)
(mm)
Subject to technical modifications./* output at: water level 40mm, air temp. 26°C, water temp.
26°C, voltage 48V.
Working condition: Air temperature 8°C bis 40°C, relative humidity below
90%
Water supply: The feed water supplied into the humidifier must be
<20µS/cm. Water pressure should be between 0.2 bar
and 6 bar. The water temperature should be between
5°C abd 40°C.

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Humidifier Path
The length of the humidifier path is dependent on different factors.
- even distribution of the mist in the airflow
- air temperature
- relative air humidity
- air speed
Thefollowingdiagramforthedetermationofthehumidifierpathcontainsstandard
values dependent on the most important parameters. (Air temperature 18°C to
24°C). The tolerance is approx. ± 0.5 m.
If noplaceisavailableforthehumidifierpath,useofamistcollectorispossible.The
smaller the distance to the mist collector, the larger the loss effect of the humidifier
and the more water is drained off into the pan, which has to be drained off for
hygienic reasons. Another possibility to reduce the humidifier path is the employ-
ment of a proportional control. With this control, the output of the humidifiers is
reduced dependent on the requirements in more than 90% of the operating time
and therefore reduces the humidifier path, saves the oscillators and maintains an
even distribution of the mist even in operation under partial load.
TECHNICAL DATA ENS SERIES
2.1

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TECHNICAL DATA ENS SERIES
Dimensioned Drawings
Unit Assembly ENS 1200-9600
Dimensions L, P, P1, P2 refer to page 5 "Dimensions"
Legend
1 Water supply module
2 Nebulizing module
3 Mist collector
4 Electric supply*
5 Cable socket
6 Water supply line*
7 Safety overflow
8 Water drain
9 Installation base
*
to be supplied by customers
2.2

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Unit assembly ENS 14-18
TECHNICAL DATA ENS SERIES
Dimensions L, P refer to page 5 "Dimensions"
Legend:
1 Water supply module l 7 Water supply line*
2 Mist collector 8 Safety overflow
3 Metal plug 9 Water drain
4 Cable 10 Installation base
5 Metal plug 11 Check valve*
6 Cable *
to be supplied by customers

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TECHNICAL DATA ENS SERIES
2.3
Unit Description
Safety Appliances
Automatic feed water control with solenoid valve and float switch. Preventive
protectionagainstdry-running;if waterlevelfallsbelowaset level,floatswitch
and relay are automatically activated in order to cut off power supply. The
thermostatwill automaticallycutoffpower supplyif temperatureinthehumidi-
fier gets higher than the setpoint.
Forfurtherprotection,fuses and varistorshave been installed to protectthe
electronic parts.
Description of main components
1. Humidifier ENS 1200-9600
Thehumidifierconsistsofwatertanksthatarelinkedtogetherandusedforthe
nebulization and control of the water supply. The nebulization module is
equipped with oscillation converters. The tank, built-in for control of water
supply, is equipped with all necessary devices for supply and control, such as
relay, solenoid valve and float switch.
2. Humidifier ENS 14-18
Utrasonic nebulization modules, the solenoid valve and the float switches are
installed in a stainless steel casing.
3. Nebulization Module
Oscillators and amplifying circuits are installed at the bottom of each of these
compact units. 48 Volt a.c. are being applied to an oscillating circuit and are
amplified to high frequency performance, so that the oscillator (transducer) is
set to automatic vibrations. The generated ultrasonic waves are then directed
to the water surface and, as a result, the water is being atomized.

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TECHNICAL DATA ENS SERIES
4. Water Supply Solenoid Valve and Float Switch
In order to achieve optimum nebulization of the water, the water level in the
tanks has to be kept as constant as possible. To meet these requirements, a
solenoid valve and a float switch are used for automatic water supply. If the
waterlevel inthetankfallsbelowthestandardlevel,thefloatswitchwillturnto
ON and the solenoid valve opens to fill the tank with water.
As soon as the standard water level has been reached, the float switch will
turn to OFF again and the solenoid valve is closed.
5. Relay (externally installed in control box) and Float Switch (dry-
running Protection)
Should the humidifier be operated with a water levelin the tank being too low,
the oscillator will be damaged. To avoid any dry-running, a float switch is
inserted. If the water level falls below the safety level - for any reason
whatsoever,thefloatswitchturnstoOFF, activatestheexternalrelay whichis
installed on the supply board and cuts off the electric power supply to the
oscillators.

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The two air conditions are entered into the h-x digram (point A and point B
Draw a vertical line from A to edge measurement "x" point C
Draw a vertical line from B to edge measurement "x" point D
Then calculate the humidifier output:
>Point C = 2.8 g/kg air
>Point D = 6.4 g/kg air
>Difference = 3,6 (g Water)/(kg air) ( D - C )
>Multiply the predetermined air volume (10.000 m³/hour)
with the average air density (1,18 kg/m³)
10.000 m³/hour x 1,18 kg/m³ = 11.800 kg/hour
>Multiply the difference of the water content in the air with
the air weight/hour
3,6 g/kg x 11800 kg/hour = 42.480 g/hour
humidifier output = 42,5 kg/hour
Themostfavorabletypeofcombinations isnowchosenfromthedelivery
range. The most frequent selection criteria are:
>Length of the ENS humidifier at the predetermined depth
of the air treatment.
>Number of ENS humidifiers, because of number of fixing
fixing divices, water supply lines and electric control.
In the example given, 2 off ENS 14 have been chosen. ( 3 x 14 kg/hour =
42 kg/hour )
CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
Capacity Calculation for Ultrasonic Humidifiers
Basis of the capacity calculation for ULTRASONIC humidifiers is the que-
stionnaire listed under chapter 3.1. Provided that this questionnaire has been
completely been filled in, it will contain all data necessary for the calculation.
Example 1:
3.
LE = Air intake before humidification = 31.5°C / 10% r.h.
LA = Air outlet after humidification = 18.0°C / 50% r.h.
Air volume = 10.000 m³/hour
Thesevalueshavetobechosenforthemostunfavorableconditions,which
usually exist in winter at lowest outer temperatures.
1.
2.
3.
4.
5.

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CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
6. Determine the net cross section and the air speed in the duct or air
treatment unit
>Determine the free cross section for the air treatment unit from
manufacturers' information.
For the calcualtion example: Height: 1100 mm
Depth: 1300 mm
Height x deptch = 1.1 m x 1.3 m = 1.43 m² cross section
>Determine the reduction of the free cross section caused by the
humidfiers
Example:
1,43 m² - (3 x 0,137) = 1,02 m²
= free cross section under
consideration of the three
humidifiers ENS 14
>Determine the air speed
Air volume (m³/h) / 3600 = m³/s
m³/s
free cross section (m²)
Example:
10.000 m³/h
3.600
2,78 m³/s
1,02 m²
The calculated air speed of 2,73 m/s is within the permissible
limits of 1,5 - 3 m/s.
Type
ENS 1200
ENS 2400
ENS 3600
ENS 4800
ENS 6000
ENS 7200
ENS 8400
ENS 9600
ENS 14
ENS 18
C.Sectiont
0,035 m²
0,053 m²
0,072 m²
0,091 m²
0,11 m²
0,129 m²
0,148 m²
0,166 m²
0,137 m²
0,166 m²
= m/s
= 2,78 m³/s
= 2,73 m/s

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CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
(6.4 - 2.8)g/kg x 10000 m³/h x 1.18 kg/m³ = 42480 g/h
= 42.5 kg/h

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7. Determination of the Humidifier Path
The length of the humidifier path is dependent on different facors:
- Even distribution of the mist in the airflow
- Air temperature
- Air relative humidity
- Air speed
Thefollowingdiagramforthedeterminationofthehumidifierpathcontains
experience values dependent on the most important parameters. The
diagram is valid for the temperature range from 18°C to 24°C.
Should no place be available for the humidifier path, the use of a mist
collector is possible. The smaller the distance to the mist collector, the
largerthelosseffectofthehumidifierandthemorewaterisdrainedoffinto
the pan, which has to be drained off for hygienic reasons.
CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS

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CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
As the dimensioning of the humidifier output is always made for the most
unfavorableoperating status,thehumidifier is over-dimensioned inup to 90%
of the operating time. (In a comfort air conditioning unit, the dimensioning is
made for the lowest temperature in winter, which usually occurrs during the
night and usually does not last for more than 10 hours/year).
A proportional control reduces the output to more than 90% of the operating
time of the humidifier according to demand and thus reduces the humidifier
path, andtherefore saves the oscillatorsandmaintains an even distribution of
the mist also in operation under partial load.
2. Example Humidification of an office room
Humidification of an office room with Ultrasonic humidifiers installed in the air
intake duct (recirculating operation with outer air portion)
- Volume flow VL= 2000 m³/h
- Outer air condition in winter LW= -10 °C / 90 % r.h.
- Desired ambient temperature LR= 20 °C / 60 % r.h.
- Outer air portion 50%
The air conditions LWandLRare drawninto the h-x diagram and both points
are connected with each other.

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CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
The mixing point for the outer air percentage 50% is half of the connecting
straight line between LWand LR. From the mixing point M and from LRa
perpendicularisdrawnattheupperedgeoftheh-xdiagram.Onbasisofthe
perpendicular line at point M, a water content of 5.2 g/kg and, at point LR
of 8,8 g/kg can be determined.
This results in an ∆x of 8.8 g/kg - 5.2 g/kg = 3.6 g/kg. This means that 3.6 g
of water per kg hourly recirculated air have to be provided.
The mass of the hourly recirculated air results from the volume flow (2000
m³/h) multiplied by the specific weight ρof the air
(1,20 kg/m³).
VLx ρ= 2000 m³/h x 1,20 kg/m³ = 2400 kg/h
As 3,6 g of water have to be added hourly per kg of air, the output of the
humidifier can be calculated as follows:
2400 kg/h x 3.6 g/kg = 8640 g/h

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CAPACITY CALCULATION FOR ULTRASONIC HUMIDIFIERS
Note:
STULZ ULTRASONIC humidifiers atomize water into smallest water dro-
plets (< 0,001 mm).
The mist (aerosols) generated takes away heat from the ambient air (enthal-
py) and changes its state of aggregation from liquid to gaseous. Because of
this"adiabatic"behavior(heatabsoptionfromtheambientair),theambientair
in cooled down.
Example:
- Air conditon before humidification: Temperature 25 °C
relative humidity 30 %
- Moisture addition of ∆x= 3 g/kg
Condition of the air after humidification: Temperature 18 °C
relative humidity 70 %

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3.1
QUESTIONNAIRE FOR ULTRASONIC HUMIDIFIERS
Questionnaire for Ultrasonic humidifiers
For planning of a STULZ ULTRASONIC humidification system, please
make use of the questionnaire shown in the following.

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KLIMATECHNIK GmbH

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CONTROL SYSTEM
4. Control System
For operationof the Ultrasonic humidifiers, an external control box has to be
provided. Together with the transformer required for operation, contactor
relays, the main switch, strip terminals and the proportional adapter, if requi-
red, controller or theconductimeter have to be integrated into the control box.
Control of the humidifiers can either be ON/OFF control, continuous or
proportional control. The control system should be suitably adapted to the
project in question.
When the control box is wired, the suppressor diodes provided to protect the
oscillators have to be connected in parallel with the oscillator boards. For all
types, the provided contactor for the bath response (level indicator of water
tank) has to be additionally used and to be connected with the RC module
provided. Other contactors would destroy the float switch.
Incorrect wiring of the control box may cause damage to the humidifier; the
control boxes should therefore be wired in accordance with the wiring dia-
grams provided.
The parts provided by STULZ are identified by "*" in the wiring diagram.
The regulations of the local electric supply companies have to be observed.
ConcerningtheCErequirementsfortheEuropeanCommunitypleaserefer to
page 70 - 73. The components mentionned on page 70 - 73 must be inserted
in the wiring diagrams of this chapter.