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TECHNICAL CHARACTERISTICS Str. 1/16

TECHNICAL CHARACTERISTICS OF AIR CONDITIONING CHAMBERS


CONTENTS 1. Basic characteristics of air conditioning chambers

2. Structure and integral elements

2.1 Heat exchangers

2.2 Recuperators

2.3 Droplet eliminators

2.4 Ventilators

2.5 Filters

2.6 Dampers

2.7 Sound dampers

3. Dimensions and shape of head cross-section

4. Criteria for the selection of the dimensions and type of air conditioning chamber

5. Types of air processing

6. Makes and marking of air conditioning chambers

7. Technical information and calculation

8. Used standards

9. Simbols


1. BASIC CHARACTERISTICS OF AIR CONDITIONING

CHAMBERS

• Wide range of application from 1.000 m3/h to 85.000 m3/h.

• Selection among 18 standard cross sections in all model variants, with regard to purpose, mounting location and installation method.

• Simple mounting; easy interconnection of individual elements into a whole, adaptability to available space, possibility to bring in sections divided into elements, as well as mounting thereof on the spot (in case of narrow transport routes).

• Quality made housings are characterized by flat and smooth surfaces while all sharp edges and angles have been avoided.

• Small possibility of condensate appearing at the housing due to good heat insulation and tightness of housing.

• Long life cycle thanks to the use of stainless materials for the production of housings. All sealed materials are aging-resistant.

• Simple and easy maintenance and easy access to all incorporated elements during servicing and cleaning of the chamber.

• Possibility to choose the system of the waste air heat usage, whether it be with plate recuperator or with two glycol heat exchangers mutually interconnected by a pipe loop with a pump.

• The operation of air conditioning chamber with variable air quantity, at buyer’s demand, is possible by the use of two-speed motors or frequency invertors, which ensure continuous regulation of air quantity.

• High quality level of all built in elements, together with technical support and spare parts.

• Possibility to select optimal system, special structure and make, according to buyer’s requirements.

• Air conditioning chamber can be equipped with complete belonging regulation equipment, which is necessary for the automatic operation of the chamber.


2. STRUCTURE AND INTEGRAL ELEMENTS • The base of the air conditioning chamber is characterized with adequate carrying

capacity; it is made of sufficiently thick galvanized sheet metal profiles, and adapted to be positioned on the rubber ribbed shock absorbing pads 40 mm thick, which prevent vibration transfer from air conditioning chamber to building structure. Incorporation of a sufficiently high drain trap is ensured by the design.

• Housing frame of air conditioning chamber is a disassembly structure made of drawn (reinforced) aluminum profiles and angles, composed of highly rigid aluminum casting, having a special form and additional corrosion protection.

There may be four different dimensions of aluminum profiles and angles, depending on the size and purpose of air conditioning chambers.

Profiles and angles for hygienic model of air conditioning chambers represent a special variant thereof.

• Coverings have a sandwich structure, consisting of outside and inside galvanized sheet metal, with heat and sound insulating material between them. By special demand, coverings can be painted in desired color.

Insulation material can be: - Two-component polyurethane compound, density 40 kg/m³ , in three depths - Mineral wool, density 75 kg/m³, in two available depths.

Floor coverings, made with mineral wool, if needed, may have additional reinforcements in order to improve stiffness.

INS

UL

AT

ION

M

AT

ER

IAL

Dep

th

(mm

)

PURPOSE OF CHAMBER COVERING

INSIDE GALVANIZED

SHEET METAL (mm)

OUTSIDE GALVANIZED SHEET METAL

(mm)

K (W/m2 0C)

STANDARD COLOR

PO

LY

UR

ET

HA

NE 25

za unutrašnju ugradnju

do 40.000 m3/h ≠ 0.6

plastificirani ≠ 0.6 mm

0.75 RAL 9006 RAL 5012

40 za spoljašnju

ugradnju do 40.000 m3/h

≠ 0.6 plastificirani

≠0.6 0.5

RAL 9006 RAL 5012

50 preko 40.000 m3/h ≠ 0.6 plastificirani

≠0.6 0.4

RAL 9006 RAL 5012

MIN

ER

AL

W

OO

L 40 do 40.000 m3/h ≠ 0.8

plastificirani ≠ 1

0.81 RAL 9006 RAL 5012

50 preko 40.000 m3/h ≠ 0.8 plastificirani

≠ 1 0.66

RAL 9006 RAL 5012


• Sealing of coverings is ensured with a sealing self-adhesive tape 4 mm thick, and in hygienic model, with the use of rubber packing.

• Connecting of the coverings

- Fixed – non-removable coverings are fixed with bolts in plastic expansion shields, whereby the number of bolts should be sufficient to ensure the connections that would endure the overpressure which is present in some parts of air conditioning chamber;

- Removable coverings are fixed with aluminum locks mounted on the housing frame;

- Coverings in the form of doors with hinges, sight glass and locks, that enable good tightening, are fitted on filter and ventilator sections.

• Easy building-in, mounting, or dismantling the individual functional elements of air conditioning chamber, is carried out by positioning of sliders, supports and partitioning elements in the housing, which are made of galvanized sheet metal, and they, at the same time, direct the air through air conditioning chamber.

2.1 Heat exchangers

• Calculation and selection of a heat exchanger is performed with the software package GÜNTNER, with the possibility to choose the thermal dynamic parameters of the medium, as well as the very geometry of the exchanger, so that it would be maximally adapted to the requirements.

• Standard make of all heat exchangers, which are built in air conditioning chambers, whether they be coolers, evaporators, heaters used for heating pipe systems, steam heaters or condensers, is the following:

Copper tubes ∅ (10, 12 or 16 mm) finned with aluminum lamella, with the most frequent pitch of 2 to 4 mm;

By expanding the copper tubes, close contact with the lamella collar is enabled, and by this, an excellent conductivity is also achieved;

Frames of exchanger are made of galvanized sheet metal;

Collecting pipes of exchanger (heater and cooler) can be made of copper or steel. Connections on exchangers up to 2 inches are threaded (in compliance with JUS), and those greater than 2 inches are flanged;

Collecting pipes of evaporator and condenser are made of copper and they are always soldered;

Penetrations of tube connections (adapters) of the heat exchanger through the housing are sealed with rosettes.

At the suitable spots on the heat exchanger, connections for air vent and empting are located.

2.2 Recuperators

• For the sake of energy saving (significant decrease of required heating capacity) heat recuperators are used to transfer waste air heat to fresh hear.


• There are two possible variant of recuperators: - Plate recuperators, which are calculated and selected according to the software

package of the firm “HEATEX”, whereby recuperation ratio (up to 75%) and the available effort are taken into consideration. In addition, a by-pass regulation shutter is built in to protect the heat recuperator from freezing;

- Variant with circulation system of water and glycol mixture in a closed loop of two heat exchangers with a pump.

2.3 Droplet eliminators

• They are located in all the spots where the transition of droplets into another section has to be prevented, and this may be behind the cooler, evaporator and plate recuperator.

• Lamellae are made of galvanized sheet metal, and they are mounted together with plastic spacers.

• They can be easily pulled out of the housing.

2.4 Ventilators

• Ventilators in air conditioning chambers are centrifugal, radial, with two-side intake, from manufacturer “NICOTRA”, chosen with the use of their software package.

• For total pressure losses of around 800 Pa, ventilators with forward curved blades are used.

• For total pressure losses higher than the above specified values, ventilators with backward curved blades are used.

• The basic criterion for the selection of ventilator size is maximum efficiency in the ventilator’s operating point, also meaning the lowest electric motor power needed for the ventilator drive and the lowest noise level.

• Ventilator is, together with electric motor, pulleys and belts, positioned on the common support, which is, through vibration absorbers, placed on the chamber housing.

• On the other hand, pressure side of the ventilator is connected through a flexible connection with the housing (plasticized tarpaulin fabric with flanges made of Al profiles).

• Ventilator drive – in addition to ventilators with pulley drive, ventilators with directly coupled motor and free rotation ventilators are also used (ventilators without helical housing).

• Electric motors in air conditioning chambers are three-phase synchronous motors, B-3, with protection IP54.

• Four-pole motor are the most frequently used ones, while six-pole and two-pole motors are used a little less frequent, whereas eight-pole motors are used in exceptional cases.

• In accordance with JUS ISO 5291 standard for power transfer from motor axle to ventilator axle the following is used:

- Two-part V-pulleys (rim + elastic bushing) with one, two or three grooves of the type SPZ, SPA, SPB, SPC;

- V-belts 10, 13, 17, 22 for the pulley profiles Z, A, B, C.


2.5 Filters

• Capability of one or more stages of filtration, depending on the facilities for which air conditioning chambers are used.

• For each air conditioning chamber, incorporation of at least class G3 filter is recommended.

• Coarse filters, G3 and G4, can be zig-zag or bag type filters. • Fine filters, class F5 to F9, are bag filters. • Among the other types, the following filters can be built in on demand::

- Absolute filters, class H10 to H13; - Filters with activated carbon cartridges for separation of hazardous gases and odours; - Metallic filters for grease separation.

2.6 Dampers

• Frame with flanges and aluminium lamellae. • Swivelling of lamellae is very easy, thanks to the gear system made by injection of

ABS plastics, and it is carried out through the brass square 12 x 12 mm. • Capability of extremely good sealing by means of rubber profiles. • Damper drive can be manual drive (with handles made of Al casting) or motor drive. • Possibility of easy establishment of the coupled drive in mixing sections.

2.7 Sound dampers

• Acoustical curtains of the damper have a frame made of galvanized sheet metal, wherein the mineral wool plates are placed, representing an efficient absorbing material. External surfaces of the plates are protected against falling of the small parts (particles).

• Damper acoustical curtains are installed into the air conditioning chamber as a compact whole.

• The most frequent type of sound damper is with the depth of curtain d = 100 mm, while the distance between acoustic-damping curtains is s = 50 mm (33% free cross section).

• Standard lengths of curtains, depending on the desired damping ratio at 250 Hz are: 600 mm, 900 mm, 1200 mm and 1500 mm.

D (dB) 15 18 22 26

L (mm) 700 1040 1400 1640

3. DIMENSIONS AND SHAPE OF HEAD CROSS-SECTION

• The dimensions of head cross-section are determined by air quantity that should be processed by air conditioning chamber.

• During determining the dimensions, maximum speeds of air circulation through the light cross section of air conditioning chamber are taken into consideration, all in accordance with fitting of the standard filter dimensions.


CH

AM

BE

R T

YP

E

DIMENSIONS OF HEAD CROSS SECTION

LIGHT CROSS SECTION OF

HEAT EXCHANGER

DIMENSIONS AND NUMBER

OF FILTERS

A A1 H H1 H2 L B

592

x 5

92

490

x 5

92

287

x 5

92

K - 1 592 650 437 520 580 400 350 1 K - 2 592 650 637 720 780 400 550 1 K - 3 782 840 637 720 780 600 550 1 1 K - 4 982 1040 637 720 780 800 550 2 K - 5 1192 1250 637 720 800 1000 550 2 K - 7 1192 1250 842 930 1010 1000 750 2 2 K - 9 1192 1250 1042 1130 1210 1000 950 4

K - 12 1277 1335 1247 1335 1415 1050 1150 4 2 K - 15 1582 1640 1257 1355 1435 1370 1150 2 4 K - 20 1792 1850 1457 1555 1635 1550 1350 3 3 3 K - 25 1792 1850 1657 1755 1835 1550 1550 3 6 K - 30 1792 1850 1857 1955 2035 1550 1750 9 K - 35 2072 2130 1857 1955 2035 1800 1750 9 3 K - 40 2392 2440 1857 1955 2035 2100 1750 12 K - 50 2970 3080 1850 2000 2100 2700 1750 15 K - 60 2970 3080 2250 2400 2500 2700 2150 10 10 K - 70 3565 3675 2250 2400 2500 3300 2150 12 12 K - 80 3565 3675 2450 2600 2700 3300 2350 24


4. CRITERIA FOR THE SELECTION OF THE DIMENSIONS AND TYPE OF AIR CONDITIONING CHAMBER

The dimensions and type of air conditioning chamber are determined with two independent criteria or specified data:

1. Quantity of the air that should be processed by an air conditioning chamber determines the dimension of the head cross section of air conditioning chamber;

2. Required functional units of air conditioning chamber, i.e. types of air processing, determine the type of air conditioning chamber.

• During creation of selection diagrams, based on the air quantities that should be processed by air conditioning chamber, the following maximum allowed speeds of air circulation across light cross section of heat exchanger and light cross section of air conditioning chamber (i.e. at filters) are adopted:

- Air speed through the light cross section of cooler This is the most strict criterion and maximum speed amounts up to 3 m/s. There are two cases: 1. For air speeds up to 2.4 m/s through the cooler, droplet eliminators are not

being built into chamber; 2. For air speeds between 2.4 m/s and 3 m/s through the cooler, droplet

eliminator is being built into chamber.

- Air speed across the heater cross section Less strict criterion for air speed is adopted for heaters, so that maximum speed amounts up to 3.6 m/s. This criterion applies when air conditioning chamber does not contain air cooler section as its integral part.

- Air speed across the light cross section of air conditioning chamber, i.e. across the filters, is up to 2.4 m/s. If air conditioning chamber does not contain exchangers as its integral parts, then maximum speed at the light cross section of the air conditioning chamber can be up to 4 m/s.

• Selection diagrams for the dimensions of air conditioning chamber are given in two variants:

VARIJANT I Selection diagram depending on the permitted speed at the light cross sections of exchangers


VARIJANT II Selection diagram depending on the permitted speed at the light cross section of chamber, i.e. at filters

5. TYPES OF AIR PROCESSING

With appropriate airflow and quality (temperature, humidity, cleanliness,), the essence of the air conditioning system is to achieve the desired comfort parameters in the air-conditioned space. This is accomplished by combination of the basic procedures of air processing, various possibilities of air guidance and by application of various automatic systems.

• Ventilation - Air exhaust - Air feed - Variant with two ventilators for air feed and air insertion and extraction with mixing section

• Filtering - With one stage of filtration - With two stages of filtration

• Heating - Heating with hot water - Heating with low pressure steam - Electric heaters

• Cooling - Cooler with cool water - Exchanger – direct expansion

• Heat recuperation - Plate recuperator - Two glycol exchangers in closed -

loop with pump

• Moisturizing - With steam - isothermal moisturizing - Adiabatic moisturizing

• Demoisturizing

Damping


6. MAKES AND MARKING OF AIR CONDITIONING CHAMBERS


7. TECHNICAL INFORMATION AND CALCULATION

7.1 Fan curves

• Change of fan speed with duct system unchanged

If the fan speed changes while the duct system remains unchanged, the fan’s working point moves from point 1 (V1, ∆Ptot1) to point 2 (V2, ∆Ptot2).

V (m3/h)- air flow, ∆Ptot (Pa)- total pressure, Pw (kW)- drive power, n (0/min) – fan speed, η (%)–efficiency

The following apply:

• Effect of changing pressures on a system’s working point

A system always runs at the point of intersection between the fan curve at speed n and the system curve. Point 1: Design point (V1, ∆Ptot1)

If the actual pressure is ∆p higher than the design pressure, working point 2 is the intersection of n and a parallel through 1´.

The efficiency -η and the power consumption- Pw change.

The following apply:

2

1

2

1

n

n

V

V =

22

2

1

2

1

2

1

=

=∆∆

V

V

n

n

Ptot

Ptot

33

2

1

2

1

2

1

=

=V

V

n

n

Pw

Pw

η1 = η2 = cnstant.


7.2 Connector for Condensate Drain

Condensate drain is performed through the drain trap (U pipe) which is mounted on the very outlet of the Air Handling Unit. The height of U pipe must be appropriate in order to prevent suction of the drain condensate and its spraying in the air stream in the Air Handling Unit. Water must flow directly from the U pipe into side channel, and afterwards to the drains.

The height of the drain trap is defined according to the following:

p – total drop of pressure at the point of condensate drain.

Connect the drain trap to appropriate connection and charge it with water.

In the zone of overpressure

H1 (mm) = 35 mm

HS (mm) = (p /10) + 50

In the zone of underpressure

H1 (mm) = p / 10

HS (mm) = p x 0.075

Za ∆Ptot ≤ 1000 Pa

H1 (mm) = 35 mm

HS (mm) = 150 mm

Za ∆Ptot ≤ 1000 Pa

H1 (mm) = 100 mm

HS (mm) = 75 mm

Calculation of drain trap height


7.3 Temperature efficiency of the heat exchanger - recuperators

One of the most important ways to measure how well a heat exchanger performs, is to look at the temperature efficiency of the exchanger. The efficiency on the hot side of the exchanger is defined as:

intint

outtint

ch

hhh −

−=η

And the efficiency on the cold side as:

intint

intoutt

ch

ccc −

−=η

η is efficiency (1). t is temperature (°C). c is cold side and h is hot side. in is into the exchanger and out is out from the exchanger. When the fluid flows (actually the mass flow multiplied with the specific heat) are equal on both sides the efficiency will also be equal on both sides.


8. USED STANDARDS ISO/DIS 12100-1 (JUS EN 292-1) -Safety of machinery – Basic concepts, general principles for design- Part 1: Basic terminology methodology

JUS EN 292-2-Safety of machinery – Basic concepts, general principles for design- Part 2: Technical principles and specifications

JUS EN 294 - Safety of machinery – Safety distances to prevent danger zones being reached by the upper limbs.

JUS EN 418 -Safety of machinery – Emergency stop equipment, functional aspects- Principles for design

JUS EN 818 -Safety of machinery – Safety distances to prevent danger zones being reached by the lower limbs.

JUS IEC 60204 -1 -Safety of machinery – Electrical equipment of machines - Part 1: General requirements

EN 1886 – Ventilation for buildings – Air handling units – Mechanical performance

EN 13053 - Ventilation for buildings - Air handling units - Ratings and performance for units, components and section

VDI 3803, Air-conditioning systems - Structural and technical principles

DIN 7753-1, Endless narrow V-belts for mechanical engineering purposes; dimensions

DIN 7753-2, Narrow V-belts for industrial purposes; calculation of drives, power ratings

VDI 6022 – Hygienic requirements for ventilating and air conditioning systems and air-handling unit

JUS M.E2.011 – Boiler plants-Feed water and boiler water of steem generators of the group IV

JUS ISO 5291-Grooved pulleys for joined classical V-belts-Groove sections AJ, BJ, CJ i DJ (effective system)

JUS ISO 7005-1 -Metal flanges – Patr 1:Steel flanges

JUS N.M2.070 - Safety requirements – Electric fans – Particular technical conditions and test

JUS M.F4.001 - Fans – Terms, definitions and classification

JUS M.F4.002 - Safety requirements for fans

JUS M.E5.100 – Heat exchangers – Verification of thermal balance of water-fed or steam-fed primary circuits


9. SIMBOLS

WATER COOLING COIL EVAPORATING COIL ANTIFREEZE PROTECTION DROPLET ELIMINATOR SOUND ATTENUATOR UNIT WITH ONE DAMPER MIXING UNIT WITH TWO DAMPERS DOUBLE MIXING SECTION FILTERS

RADIAL FAN WATER COIL STEAM COIL CONDENSING COIL ELECTRIC HEATER PLATE HEAT EXCHANGER FILTERS CARBON FILTER ELECTRO FILTER ABSOLUTE FILTER

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