Ind ustrial -sized, cost-e f f ectiv e e vaporat iv e co ol er s
Single Sta ge, Two Sta ge and Hybrid Coolers
Lower operational costs
Complete fresh air system
Smaller electrical connection
From household to industrial capacity
Increased cooling efficiency (COP up to 12)
Cheaper to install than conventional air-conditioning
Typical application allows a design delta T of 6 °C while with Single Stage evaporative cooling, the corresponding delta T is 3 °C.
Tel: +27 (0)12 259 3857 | E-mail: [email protected] | www.protekcooling.co.za | Postnet suite 118, Private Bag X0001, Ifafi, 0260
P r o ducts
H o w d o es i t wo r k ?
Single stage compact
Evaporative cooling evaporates water in order to cool air. Normally the
lowest temperature that can be achieved with evaporative cooling is wet
bulb temperature.
Large volume single stage unit for
industrial applications require low
cost bulk cooling.
Two stage
Large capacity unit with the capacity
of exceptionally low supply air
temperatures with only water
cooling.
With two stage cooling, we do two things that improves the efficiency of
this process:
1.We lower the wet bulb temperature by dry cooling air before we
evaporate water into it.
2.We also cool the water in a cooling tower before we cool the air in
the primary tower.
The result is a product that cools air to typically 2 °C below wet bulb
temperature.
A hybrid cooler containers an additional DX coil and inverter compressor,
thereby providing the capability to cool incoming air to as low as 10 °C.
Hybrid
A two stage unit with mechanical
cooling/heating additionally for
complete control over cost effective
operation.
E v i d en c e th at eva p o r ati v e c o o li n g i s c o s t
effec ti v e
R el e vant calcul at ions
Single stage
Supply air temperature: Tsa=Tdb-0.9*(Tdb-Twb) (1)
RH ~ 60 %
Typically: 21-23 °C
Two stage
Supply air temperature: Tsa=Tdb-1.18*(Tdb-Twb) (2)
RH
Typically: 17.5-19.5 °C
Hybrid
Supply air temperature: 10-16 °C
Figure 1: Electrical energy consumption for different units sorted by the
kWh, from highest supply air temperature (left) to lowest (right).
In the figure above, the electrical energy consumption is calculated for
historical temperature data for a specific location. It can clearly be seen
that using water to cool air is much more cost effective than using DX
only.
Figure 2: Horizontal axis is supply air temperature per year, sorted by the
hour from highest (left) to lowest (right).
It can also be seen from the supply air temperatures that in many
locations (e.g. Johannesburg South Africa), the supply air temperature for
the Two Stage cooler is nearly sufficient to provide air for a whole year
below 18 °C.
P s y chrometrics
U n i t d es c r i p ti o n
Single stage compact
A three sided single stage module with a 100mm
paper packs and forward curved centrifugal fan,
all manufactured in 3CR12 steel.
Basic single module
Two stage and hybrid unit sizes up to 11m3/s have
1 sump, a pump and horizontal cooling tower.
Double module
Hot air starts at ambient conditions (Tdb/TWb 30/20 °C) at point 1.
Single stage
Water is evaporated into air until 90% of the wet bulb depression
is reached (90% of the difference between dry bulb and wet bulb
temperature). Single stage air has very little ability to do cooling work
(point 3 to 5 on the graph).
Two stage
Units above 11m3/s have a double sump, two
pumps and a vertically discharging cooling tower.
Primary air is discharged horizontally and
perpendicularly to the outside air inlets.
Hybrid
An inverter compressor is used to provide mechanical cooling and/or
heating to the unit. This unit needs to be sized to the sensible cooling/
heating requirements of the solution.
With two stage air is first cooled from point 1 to 2 (dry cooling). This is
typically 80% of the wet bulb depression possible.
The outdoor coil, compressor and fan is detached and placed alongside
the unit.
Water is then absorbed in the air (to point 3) and the final product has
significant cooling ability left. Note that the RH of the final product is also
correspondingly lower than that of single stage.
Insulation
Hybrid
Material
After the dry cooling (point 1 to 2), air is then mechanically cooled to
point 4. Note that this air is very flexible and can produce both a low RH
and low room temperature.
H o w to desig n a sol ut io n for yo ur
bui lding
There are two methods to size units:
Manual
Determine the cooling load in w/m2 for your building. Use the following
calculation to size the appropriate unit:
Qload = 60 w/m2 as Room Sensible Heat (e.g. 1000 m2)
Tdb/Twb = 30/20 °C
Tsa = 18.2 °C (for two stage cooling)
Troom = 24 °C
dT = 5.8 °C
Altitude = 1 400 m
ρair = 1.0 kg/m3
Cp = 1.005 kJ/kg/K
Q = m*Cp*dT(3)
m = 60/1.005/5.8*1.0 m3/s
m = 10.3m3/s (unit size)
Automated
Protek also has an automated tool with which we can calculate an
appropriate solution. You need to provide us with:
1.The location of the building.
2.The facade load per m2 for cooling and heating.
3.The number of people, energy required for lights and equipment.
We will then size a unit based on the last years temperatures for the
nearest location for which we have historical temperature data.
International units are made of 25 mm double skin with Polyurethane
foam injected panel insulation.
International units inner skin is 304 Stainless Steel and non-insulated
surfaces are all 304 Stainless Steel. South African units are completely
manufactured in 3CR12 corrosion resistant steel.
Primary fan
International units have a high quality galvanized double inlet, double
width primary fan with a final transparent epoxy surface coating
and rubber mounted. South African units have a high quality fan
manufactured completely in 3CR12.
Secondary fans
Secondary fans are standard IP54 rated 4 pole electrical motors with
cast aluminium impellers.
Pumps
Own design, Sealless, Polyprop injection moulded pumps.
Evaporative media
Evaporative media is 100 mm or 300 mm deep cellulose paper
impregnated with insoluble anti­rot salts and rigidifying saturants,
with a saturation efficiency of 90% at 3m/s face velocity. No moisture
carry­over up to 4m/s.
Coils
Cooling coils will be suitably sized copper/aluminium or copper/copper
where required.
Filtration
Filters specification is 50 mm washable wireframe filters with 90%
ASHREA arrestance.
Controls and switch board
Sizes
Switchboard is 3 Phase 400V IP54 rated to 10kA current, with
electrical motor protection for over/under current/voltage, phase
failure and rotation.
Compact single stage: 9-22 m3/s (only available in South Africa)
Two Stage: 3-22 m3/s
Hybrid: 4-22 m3/s
All units are sized for max 250Pa external static pressure.
Optional VSDs may be ordered for variable volume supply and
cooling tower air. The controller is a Carel PCO series controller.
Optional sensors for the unit includes:
1.Low water indicator
2.Duct static pressure sensor
3.Supply air/room temperature sensor.
Delivery dates
South African delivery is typically 4-6 weeks
International delivery is typically 12 weeks
Shipping configuration
International units modular and shipped in containers.
Return air plenum
South African clients may order a return air plenum, all
manufactured in 3CR12 with a tight sealing return air damper and
appropriately sized modulating (or non) damper motors.
Warranty
Exclusions
Installation by a contractor is required.
Commissioning by a contractor is required.
For modular units, assembly by the contractor is required.
All units are guaranteed to be free of manufacturer’s defects for
12 months from shipment.
Support and maintenance
Units to be cleaned and checked monthly (filters washed and
sumps cleaned). Maintenance contracts in South Africa is possible
for fully maintained solutions.
our Clients
We have more than 1600 units operating in South Africa with a variety of blue chip clients that include:
Food and beverage
Retail
Entertainment
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• Lost City
• Times Square
• Gallagher Estates
Heineken
Coca-Cola
Clover
Dairy Belle
Nestlé
Manufacturing
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BMW
Nissan
Audi
Porsche
Knorr-bremse
Ford
Nampak
SASOL
Medical
• Onderstepoort
• Steve Biko Hospital
Makro
Kalahari Mall
Kudube Shopping Center
Italtile
Food Lover’s Market
Spar
Shoprite
MTN
Offices
• Nedbank
• Strathavon
• Sandton City
Government
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Department of Environmental Affairs
Development Bank of SA
SA Mint
Eskom
Constitutional Court
Aviation
• Comair
• Walvis Airport
Educational
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Tshwane University of Technology
University of Pretoria
Qua-Qua University
University of Johannesburg
University of Stellenbosch
Mining
• Zimplats
• ISCOR
Tel: +27 (0)12 259 3857 | E-mail: [email protected] | www.protekcooling.co.za | Postnet suite 118, Private Bag X0001, Ifafi, 0260