KONGRESS KGH – DECEMBER 2018 BEOGRAD SERBIA SIMON HARTLES – EXPORT DIRECTOR COOL-SPACE EVAPORATIVE COOLING
KONGRESS KGH – DECEMBER 2018
BEOGRAD SERBIA
SIMON HARTLES – EXPORT DIRECTOR COOL-SPACE EVAPORATIVE COOLING
CONTENTS
PART 1: FUNCTIONALITY OF EVAPORATIVE COOLING: HOW IT WORKS IN PRINCIPLE
NATURAL COOLING
HOW IT WORKS IN PRACTICE HOW IT IS RECREATED IN PRACTICE
COOLING EFFECT AND HUMIDITY
EXPECTATION OF PERFORMANCE
ENERGY IMPACT CONSUMPTION OF ELECTRICITY & WATER
Cf. AIR CONDITIONING
CONTENTS
PART 2: DESIGNING A SYSTEM REQUIREMENTS OF VENTILATION
FIXED COOLING
PORTABLE COOLING
PART 3: APPLICATIONS APPROPRIATE USES
APPLICATION EXAMPLES
INAPPROPRIATE USES
LEGIONELLA RISK
PART 4: QUESTIONS
PART ONE
EVAPORATIVE COOLING: DEFINITION
AND FUNCTIONALITY
NATURE’S COOLING SOLUTION
34℃ (DB) INLAND
ON THE SEA
IT’S 22℃
WHAT’S HAPPENING?
WATER VAPOUR IN AIR
Wind / Breeze
SUSPENDED WATER VAPOUR DISPLACES HEAT
35.0 ℃ DB
21.0℃ WB
ATHENS, GREECE
Summer Peak ave
Resultant temp 22.0℃
90% RH
PORTABLE EVAPORATIVE COOLER
HOW IT WORKS
• The fan draws
hot air in
HOW IT WORKS
• Hot dry air is
drawn through
the thick moist
Media pad
HOW IT WORKS
Water evaporates
through the
passing air –
displacing heat
HOW IT WORKS
• Result is a mist
less discharge –
cooling people
and spaces
COOLING EFFECT - BEOGRAD
33.7 ℃ DB
21.2℃ WB
BEOGRAD, SERBIA
Summer Peak ave
85% RH
Resultant temp 23.0℃
COOLING CALCULATION DRY BULB TEMPERATURE (DB): 33.7 ℃
WET BULB TEMPERATURE (WB): 21.2 ℃
PAD EFFICIENCY 85%
DISCHARGE TEMP = DB–0.85(DB-WB)
RESULT = 23.0℃ DISCHARGE TEMP.
COOLING EFFECT - BEOGRAD
33.7°C to
23.0°C = 10.7°C
cooler
10°C Cooling in Beograd
HOW MUCH DOES IT COOL?
EVAPORATION CALCULATION CALCULATE MOISTURE CONTENT OF AIR:
MEASURE FROM PSYCHROMETRIC CHART:
DB 33℃ / WB 21℃ = 10.8 g/KG OF DRY AIR
DB 23℃ / WB 21℃ = 15 g/KG OF DRY AIR
INCREASE IN MOISTURE 4.2 g/KG OF DRY AIR (IM)
M³/H x (g/1000 IM) x (KG of 1 m³ AIR) x (KG/L WATER)
16,600 M³/H x 0.0042 x 1.293 x 1 = 89
89 LITRES PER HOUR EVAPORATION RATE
ENVIRONMENTAL IMPACT• NO CFCs OR HFCs
• AIR, WATER SINGLE PHASE ELECTRICITY• < 6 AMPS
• 4 WATTS
• ELECTRICITY 8 KWH PER YEAR
• EQUIVALENT COOLING POWER KW• Heat lost = 0.28 m3/s x 1.005 kJ/(kg
K)[absorption] x 1.205 kg/m3 x (delta T) K (actually C) [density]
• FOR 16,500 M³/H AND 10℃ ∆T= 55 KW COOLING
• HOW MUCH WOULD A 55 KW DX AIRCON SYSTEM COST TO RUN?
ERGONOMIC IMPACT
PART TWO
DESIGNING A SYSTEM
AIR CHANGE RATES & VENTILATION
EVAPORATIVE COOLING REQUIRES VENTILATION
TYPES OF VENTILATION IN A BUILDING:
NATURAL
OPEN WINDOWS/ DOORS, STACK EFFECT, WIND IMPACT
MECHANICAL
FAN INPUT/EXTRACT AXIAL OR DUCTED
BOTH MECHANICAL & NATURAL
AIR CHANGE RATES & VENTILATION
AIR CHANGE RATES DENOTE AS ACH AIR CHANGE RATE PER HOUR
NATURAL VENTILATION OPEN WINDOWS/ DOORS, STACK EFFECT, WIND IMPACT
RULE OF THUMB:
0.5 AIR CHANGES/HR IS USED FOR TIGHT (SEALED) BUILDINGS
1/HR FOR MODERATE
2/HR FOR LOOSE ONES (OLD OR WITH ALL WINDOS AND DOORS OPEN)
MECHANICAL FAN INPUT/EXTRACT AXIAL OR DUCTED
DETERMINED BY SYSTEM PERFORMNACE
AIR CHANGE RATES & VENTILATION
AIR CHANGE RATES & VENTILATION
SOURCE: CIBSE GUIDE: FROM NUAIRE GUIDE TO VENTILATION 2011 REF. 671552
DESIGN FOR A FACTORY FULL COVERAGE:
TAKE VOLUME OF THE BUILDING X RECOMMENDED AIR CHANGE RATE
EXAMPLE: FACTORY: 100M X 30M X 7M = 21,000M³
RECOMMENDED ACH: 8
VENTILATION REQUIREMENT = 168,000 M³/H
COVERAGE CONSIDERATION RE QUANTITY OF COOLERS TOTAL VENTILATION/APPLIANCE AIR VOLUME
E.G. 168,000M³/H / 18,000 M³/H = 9 UNITS
USE FIXED THROUGH THE ROOF EVAPORATIVE COOLER
DESIGN FOR A FACTORY FIXED COOLERS
DUCTED OR PLENUM HEADS TO DISTRIBUTE AIR INTO
SPACE AT LOW LEVEL
DESIGN FOR A FACTORY
FULL COVERAGE NOT ALWAYS REQUIRED SPOT COOLING ONLY
INSTALLATION COSTS CAN BE PROHIBITIVE
PHYSICAL INSTALLATION OF FIXED COOLERS CAN BE IMPRACTICAL BE AWARE OF PROCESSES WITHIN THE BUILDING
CONSIDER USING PORTABLE COOLERS
DESIGN FOR A FACTORY
PORTABLE COOLERS APPLIED BY RECOMMENDED
AREA COVERAGE – RE FROM MANUFACTURERS
EXAMPLE BY APPLIANCE:
45,000 M³/H: 600 M²
16,500 M³/H: 300 M²
5,000 M³/H: 100 M²
DESIGN FOR A FACTORY
PORTABLE COOLERS – KEY CONSIDERATIONS:
CHECK VENTILATION RATE:
KEEP ALL AVAILABLE WINDOWS /DOORS OPEN
∴ ASSUME NATURAL VENTILATION RATE OF 2 X ACH
EXAMPLE TO COOL FACTORY 100M X 30M X 7M
AREA OF 1500M ONLY
IN THIS AREA X 8 ACH – 84,000 M³/H
DESIGN FOR A FACTORY
PORTABLE COOLERS – KEY CONSIDERATIONS:
EXAMPLE TO COOL FACTORY 100M X 30M X 7M
AREA OF 1500M ONLY
IN THIS AREA X 8 ACH – 84,000 M³/H
TO KEEP COMFORT HUMIDITY < 60% RH IN SPACE
IDEAL TO HAVE FRESH AIR AT AROUND 40% MIN OF TOTAL
ACH
NATURAL VENTILATION IN THIS EXAMPLE IS 42,000M²/H
50%
DESIGN FOR A FACTORY
PORTABLE COOLERS – KEY CONSIDERATIONS:
EXAMPLE TO COOL FACTORY 100M X 30M X 7M
AREA OF 1500M ONLY
IN THIS AREA X 8 ACH = 84,000 M³/H
DIVIDE REQUIRE ACH BY APPLIANCE RATING E.G.
16,500M³/H = 5 UNITS
CHECK COVERAGE PER UNIT AT 300M² = 1500M²/H
DESIGN FOR A FACTORY
PORTABLE COOLERS – KEY CONSIDERATIONS:
POSITION COOLERS BY OPEN WINDOWS AND DOOR
BI-DIRECTIONAL BLOWING IF POSSIBLE
ALLOW 1 M BEHIND UNIT CLEARANCE
BEWARE OBSTRUCTIONS
Design Considerations
PART THREE
APPLICATIONS IN PRACTICE
AUTO WORK SHOPS
FACTORIES
AVIATION HANGARS
WAREHOUSES
CONSTRUCTION SITES
RESTAURANT AND TERRACES
HOTEL GARDENS
MARQUEES
OUTDOOR EVENTS
SPORTS TRAINING CENTRES
EQUINE BARNS
EVAPORATIVE CANNOT BE USED IN: AREAS THAT REQUIRE NO HUMIDITY
DATA CENTRES ETC.
CLEAN ROOM AREAS THAT PRECLUDE DUST MOVEMENT
AREAS THAT REQUIRE TEMPERATURE CONTROL TO 0.5℃ SET POINT
WEATHER INFLUENCES TEMP ACHEIVED
AREAS OR BUILDINGS THAT ARE SEALED; HAVE NO WINDOWS, DOORS OR VENTILATION SYSTEM
IS THERE A RISK OF LEGIONELLA? SOURCE: ASHRAE JOURNAL (USA) 1995
EVAPORATIVE COOLERS POSE LITTLE RISK WITH LEGIONELLA SPREAD :
LEGIONELLA BECOME ACTIVE IN STANDING WATER BETWEEN 37°C AND 41°C
WATER IN AN EVAPORATIVE COOLER RARELY EXCEEDS 24℃ AND IF BEING CONNECTED TO A MAINS FEED, WATER IN COOLERS WILL RARELY EXCEED 20℃.
IS THERE A RISK OF LEGIONELLA? SOURCE: ASHRAE JOURNAL (USA) 1995
UNITS SHOULD BE RUN DRY EVERYDAY AS AN EXTRA
PRECAUTION. REPLENISHING WATER REGULARLY
THEREFORE IS A GOOD THING
USING A BIOCIDE IS AN EXTRA PRECAUTION
RECOMMEND THE USE OF REFRESH™ TABLETS FROM
RECTORSEAL
IS THERE A RISK OF LEGIONELLA? SOURCE: ASHRAE JOURNAL (USA) 1995
LEGIONELLA REQUIRE AN AEROSOL OF BETWEEN 1
AND 5 MICRONS TO BE CARRIED AND PENETRATE
INTO THE LUNGS.
THE DROPLET PRODUCED BY MEDIA TYPE COOLERS ARE
FAR LARGER AND THEREFORE CANNOT PHYSICALLY
CARRY THE LEGIONELLA BACTERIA
IS THERE A RISK OF LEGIONELLA? SOURCE: ASHRAE JOURNAL (USA) 1995
THE THREAT IS NEGLIGIBLE BASED ON THE ABOVE.
ALTHOUGH GOOD PRACTICE IS ALWAYS THAT
STANDING WATER IS AVOIDED IN VERY HOT
CONDITIONS.
PART FOUR
QUESTIONS?
REFERENCES• CVB2/16 CIBSE GUIDE B2: VENTILATION AND DUCTWORK 2016.
• NUAIRE GUIDE TO VENTILATION. SEPTEMBER 2011 DOC REF. 671552.
• PAUL R. PUCKORIOUS, PATRICIA T. THOMAS & ROBERT L.
AUSPURGER;
• ”WHY EVAPORATIVE COOLERS HAVE NOT CASUED LEGIONNAIRES
DISEASE”. ASHRAE JOURNAL (USA) 1995.