Arun Diwakar
Desiccant Rotors International
& Bry-Air(Asia)
Dehumidification & Indirect
Evaporative Cooling
What is Moisture?
It is the water-vapour present in airaround us.
To understand or relate to moisture,we use the term RELATIVEHUMIDITY.
As the name suggests RH gives usa primary understanding of themoisture content in the air and is arelative term.
How do we control the RH in the surrounding
air?
Answer...
DESSICANT DEHUMIDIFICATION:
It is a process of removing excess moisture from the
surrounding air by using desiccants.
How does a
Desiccant Dehumidifier works?
Fresh Air in
Process Air out
React Air in
Wet Air out
Operating Principle of the
Desiccant Dehumidifier
Moisture-laden air entersthe unit through theprocess inlet and passesthrough the EcoDrymetal silicate fluteddesiccant synthesizedrotor, where the moistureis adsorbed.
The dry, dehumidified airis then delivered toconditioned area throughthe process outlet.
How does it work?
Rotation
Some typical applications
of
DEHUMIDIFIERS
Production & Processing Area
● Food (Snack & Health Food)
●Biscuits
●Chocolates/Candy
● Pharmaceuticals
●Breweries
● Safety Glass
● Sand Blasting
● Electronics
● Photographic Films etc.
Storage
● Turbine Storage
● Electrode Storage
● Bearing
● Precision components
● Electronics
● Food items
● Leather
● Seeds
● Sugar etc.
Packaging
● Hygroscopic Powders
● Dairy products
● Tea/Coffee
● Chemicals
● Fertilizer etc.
and many more...
Product Drying
● Foods
● Tea
● Coffee
● Cocoa
● Gelatine
● Soft Gelatin
● Capsules
● Yeast
● Seeds
● Silk
● Craft Paper Shells
Indoor Swimming PoolHumidity Control is Important in Indoor Swimming
Pool
• No mold & mildew on the wall / duct surfaces
• No fogging, condensation, rusting and rotting
• Reduction in annual maintenance costs
• Year round comfort conditions for humans beings
• Reduced injuries due to avoidance of slipping
and falling accidents due to wet floor
• Improved sanitation in indoor pool area through
elimination of overhead grill condensation
• Independent temperature and humidity control
Solution
Desiccant dehumidifiers offer simple and most economical solutions to humidity control .Dehumidifiers
remove excess moisture from the air inside the pool area by continuously circulating dry air and thus
controlling relative humidity between 50 to 60%. This prevents discomfort of swimmers and hampers
growth of microorganisms in the pool interior.
Cold StorageHumidity Control in Cold Stores using Sorption
Technologies
Typical Problems in Active Cold Storage
• Wet floors and ice build up on walls,
floors and conveyors
• Ice build up on evaporator coils.
• Frost build up near the loading docks
• Fog in the loading dock
• Moisture absorption by cardboard
cartons etc which causes cartons to
soften and sag, making them unstable
and hazardous to workers as well as un-
markable
• Extra cost for defrosting and frosting
Source – Direct Floral Source International, Schaumburg, Illinois
Moisture ingress in the docking area due to:
• Frequent opening of the doors
• Fresh air
• Permeation due to walls
• People load
Source – Direct Floral Source International, Schaumburg, Illinois
A Schematic Representation
• Product load
• Cracks
• Wet surface
• Wall opening
A more effective and practical
solution is to have a
“Dehumidified Air Curtain”
Cold Storage
Solution
•Major benefits realized thru humidity control in Cold Stores using sorption technologies are:• Reduced occupational injuries due to avoidance of slipping and falling and pallet mover accidents due to
wet/icy floor
• Reduction in annual operational costs
• Reduction in dock evaporator defrosts
• - Summer defrost schedules can be set back to winter schedules
• Independent temperature control
• Attractive Payback Period
• Improved sanitation in warehouse thru elimination of overhead condensation, snow, and ice
• Labor cost reduction due to avoidance of chipping ice off floors, racks or products
• Increased productivity as well as worker’s safety
• Increased shelf life
• Lower power consumption
• Easy to install and use
• Increased life of infrastructure
Cold Storage
Archives, Museums and Library
Preservation in Archives, Museums and Library
through Humidity Control
Humidity Control prevents:
• Warping
• Mildew Growth
• Fungus Growth
• Decay of Paper/Documents/Books
• Decay Films/Photographic material
• Decay of Paintings
• Corrosion on metals
• Decay of Leather goods, Wooden items etc.
PROBLEM IDENTIFIED
• Preserving books, historic documents, paintings,
photographs from the ravages of time.
• Books, historic documents, photographs and art
works are all hygroscopic because they have paper
as the organic base material.
• When they absorb moisture, they provide a base for
micro-organisms to multiply and breed, causing
irreparable damage.
SOLUTION
• Dehumidifiers provide a low humidity
environment which prevents microbial attack.
The dry air is often enough for preservation
without necessarily involving temperature control.
Archives, Museums and Library
HospitalsCritical areas in Hospitals that require
temperature & humidity control
• Operation Theatre Rooms (18°C~22°C @
50%RH)
• Imaging Department: X-Ray room, MRI, CT
Scanner, Mammography, Ultra Sound,
Fluoroscopy, Angiology, Tomography. (22°C ~
24°C @ 50%RH)
• Pathology Department : Dark Room, Biology
lab, Chemical lab, Immunology, Hematology
(22°C~24°C @ 50%RH)
“Not A New Concept”
In fact it's the oldest known method of cooling hot & dry air to make
living or working spaces more comfortable.
In ancient times, People hung wet materials, so that wind could
blow through it to create a cooling effect.
Cooling of water in clay pot is perfect example of evaporative
cooling.
Max Cool Pads are
uniform for even air-flow
Switching helps bonding of
engineered fibers to netting. Reduce
sagging and adds lots of strength.
What is Evaporative Cooling?
Water removes heat from our body 7 times faster than air. So when we get out of the pool our body is wet, because the water at the surface of our body begins to evaporate and evaporation causes cooling.
Why do swimmer feels cold after emerging
from pool?
&Air Water
Evaporative Cooling using 2 Natural Elements
Extracted from ASHRAE Standard 55 - 2013
THERMAL ENVIRONMENTAL CONDITIONS FOR HUMAN OCCUPANCY
Adaptive Comfort
Adaptive Approach - The fundamental concept is to stretch the
range of comfort temperature. Adaptive Approach also shows
that the ambient outside air temperature is the most important
parameter that affects the Comfort Temperature.
It has been widely accepted that by applying a suitable
combination of temperature, humidity, air movement, air
cleanliness and dress protocol, that it is possible to find human
comfort over a wide range of temperatures.
By accepting comfort temperatures around 26 - 30 deg C - with
higher air changes and allied with enhanced air movement,
most of the occupants can be kept within the comfort zone,
while achieving substantial energy savings.
Adaptive Comfort
What is Evaporative Cooling ?
Direct Evaporative Cooling
Water evaporates directly into the air stream, thus reducing the air
temperature while humidifying the air.
Outdoor Air
Hot & Dry Supply Air
Cool & Fresh
Water
Psychometric Representation
Direct Evaporative Cooling
DBT
Mo
istu
re C
on
ten
t
1
2
Constant Wet Bulb
Enthalpy
RH %
Direct Evaporative Cooling
1000 CFM - 100000 CFM
Indirect Evaporative Cooling ( IDEC) Single Stage
Outdoor Air
Hot & DrySupply Air
Cool & Fresh
WaterExhaust
Secondary Air
Stream
D
RI
C
oo
l
M
od
ul
e
Indirect Evaporative Cooling
Psychrometric Representation
DBT
Mois
ture
Conte
nt
12
Constant Wet Bulb
Enthalpy
RH %
DBT
Mois
ture
Conte
nt
Constant Wet Bulb
Enthalpy
RH %
Indirect Evaporative Cooling ( IDEC) Two Stage
Two-stage evaporative air cooling ( DCM + ECM)
Warm Air Cool Air Cooler AirD
RI
C
oo
l
M
od
ul
e
Secondary Air Stream
Primary Air Stream
Exhaust
Psychometric Representation
Two-stage evaporative air cooling ( DCM + ECM)
DBT
Mois
ture
Conte
nt
12
Constant Wet Bulb
Enthalpy
RH %
3
Indirect Evaporative Cooling ( IDEC) Three Stage
Three-stage evaporative air cooling for RH Control Application
Warm Air
Primary Air
Stream
Cool Air Cooler Air
Secondary Air
Stream
Exhaust
Conditioned Air
DRI
Cool
Mod
ule
IDEC Vs DEC
1 - Outdoor Air Condition
1-2 Supply Air Condition at outlet of Direct Cooler
2-3 Room Temperature achieved with direct cooler
DBT
Mois
ture
Conte
nt
Constant Wet Bulb
Enthalpy
14
2
3
5 6
15 20 25 30 35 40 45
1-4 Firsts stage of Indirect Cooler
4-5 Second stage of Indirect Cooler
5-6 Room Temperature achieved with IDEC
City : Doha
Outdoor Air
Month DBT (°C) WB (°C)
Typical Design
46.00 30.00
Jan 28.20 17.40
Feb 32.10 17.80
March 35.8 18.2
April 40.5 19.9
May 42.3 21.9
June 43.7 22.1
July 44.9 23.4
Aug 45 23.3
Sept. 41.6 23
Oct. 38.5 22.6
Nov. 34.1 19.7
Dec. 30 18.8
Level-2 (Direct)
Supply Air
DBT (°C) WB (°C)
33.2 30
19.02 17.40
19.95 17.80
20.84 18.20
22.99 19.90
24.96 21.90
25.34 22.10
26.63 23.40
26.56 23.30
25.79 23.00
24.99 22.60
21.86 19.70
20.48 18.80
Level-3 (Indirect)
Supply Air
DBT (°C) WB (°C)
34.32 27.44
20.42 14.6
20.95 13.76
21.72 13.08
24.02 14.24
25.98 16.74
26.42 16.64
29.85 18.94
30.90 18.8
28.58 19.13
26.58 19
22.87 15.92
21.94 16.05
Level-3 (IDEC+DEC))
Supply Air
DBT (°C) WB (°C)
28.12 27.44
15.76 14.6
15.20 13.76
14.81 13.08
16.20 14.24
18.59 16.74
18.60 16.64
21.12 18.94
21.22 18.8
21.02 19.13
20.52 19
17.31 15.92
17.23 16.05
Temperature Analysis - Doha,Qatar
Typical Design
46 30 33.2 30 34.32 27.44 28.128 27.44
July 44.9 23.426.63 23.40 29.85
18.9421.12
18.94
August 45 23.3 26.56 23.30 30.90 18.8 21.22 18.8
Sports / Stadium Seating arena / Indoor stadiums / Training Areas.
Possible Application
Religious Places
Possible Application
Automobile Service Centers
Possible Application
Warehouses & Godowns
Possible Application
IDEC as an Energy Saving system to compliment the Conventional
Airconditioning Systems.
Treated Fresh Air Systems....(Once thru Systems)
(For commercial buildings having a conventional air conditioning system & involving
Treated fresh air AHU's.)
First Stage Indirect Cooling + Chilled Water or DX cooling coil for 100% Fresh Air
Applications.
• For DX application, the Unit can be offered to work with any commercially available
Condensing unit. Humid working air being discharged from IDEC can be allowed to
pass over DX Air cooled condenser coil thereby achieving reduction in discharge
temperature & power consumption.
IDEC can also be integrated into Conventional Air Conditioning Applications.
IDEC for Pre -Cooling of Fresh Air
(Conventional Air Conditioning)
Indirect Evaporative Cooling (DCM + Cooling Coil)
Warm Air
Primary Air Stream
Secondary Air Stream
Exhaust Water
Pre-Cool Air Conditioned Air
DRI
Cool
Mod
ule
(Indirect + ECM) vis-a-vis Conventional Air Conditioning.....
Low Capital CostPower SavingLow Running Cost
RH RegulationDoor & Window can be left open Good IAQ & 100 % Fresh Air
Advantages of IDEC
Advantage of IDEC as Pre-Cooler for Fresh Air
Summer Conditions /Air quantity - 17000 CMH
Location
Outdoor Air
Conditions
(**)
Desired
ConditionCooling
Coil
Load (tons)
Power
Consumption (kw)
Supply Air
Conditions
after IDECCooling
Coil
Load (tons)
Saving Cooling
Coil Load (tons)
Power
(kw)
Power
(kw)DBT °C/WBT
°CDBT °C/RH
%DBT °C/WBT
°C
Dubai 46/30 15/95 93.3 83.9733.2/27.17
71.87 19.84 64.68 19.29
Riyadh 46 /21.2 15/95 50.2 70.31 27.9/15.34 29.32 20.9 41.05 29.26
Kuwait 49/30 15/95 93 83.70 33.8/26.62 67.8 70 61.02 22.68
**- At Summer Design Conditions
IDEC offers many advantages for Cooling Applications.
It offers a very viable alternative to Cool Large Spaces in Middle East
Conditions without Mechanical Cooling.
Significantly lower resultant room temperature & Moisture addition as
compared to Single Stage Direct Coolers.
IDEC also can be applied to Conventional Air Conditioning Equipment
as pre-cooling device for fresh air cooling purpose wherever Energy
recovery from Exhaust Air is not possible.
Summary...
Indirect Direct Evaporative Cooling Systems
Indirect Direct Evaporative Cooling Systems
Indirect Direct Evaporative Cooling Systems
THANK YOU
ARUN DIWAKAR
MANAGER SALES
DESSICANT ROTOR INTERNATIONAL