The Science & TechnologyOf

Humidification

Scott Herr (HygroMatik)&

Steve Ehrman (AC Equipment Reps)

Humidification can be divided into:

Comfort humidification

Better atmosphere in buildings where humans live and work.

In some countries minimum humidity levels are determined by law

Process humidification

Humidification in production facilities in order to produce and process products and keep high quality standards

SPA & Wellness applications

Steam baths, Hamman ancient Roman bath, healing clay baths, etc.

Humidification can be also divided into:

Isothermic humidification

With Steam

Adiabatic humidification

Evaporation /spraying of water

with additional cooling effect

Why Humidify?

Just ask these questions of any building or process:

1. HYGROSCOPIC MATERIALS?Materials that absorb moisture and may change dimension as the cells of

the material swell or shrink. The goal is to stabilize the materials by stabilizing the humidity.

2. STATIC ELECTRICITY?When humidity falls below 35%, there is not enough moisture in the air or

in surface films to ground the charges.

3. HEALTH & COMFORT?Dry air pulls moisture from everything, including mucous membranes,

resulting in discomfort and cracks that allow contaminants easier access to the body.

Why Humidify?Hygroscopic Materials...

Printing - Up to 90% reduction of scrap. Eliminates solvent fires. Faster run.Concrete Curing -Every nuclear power plant built used humidification for curing concrete.

Why Humidify?Hygroscopic Materials...

Museums - Proper humidity control is far more important than temperature control. Contact Lenses - Dry air makes them lose moisture and curl, making them very uncomfortable.

Why Humidify?Static Electricity...

X-rays - static discharge can give false readings and images.Microchips - static discharge of only 10 volts destroys chips. Avg. static discharge = 5,000 V.

Why Humidify?Static Electricity...

Bowling - 5 points higher pin scores in humidified alleys.Gunpowder & Flammables - Any flammable material can be set off by someone with an Angora sweater.

Why Humidify?Health & Comfort...

Sick Building Syndrome

• Outgassing• Dust Count

Hospitals & Operating Rooms

• Plastic Surgery• Organism Levels

Comfort Level

• Dry Skin• Contact Lenses• Mucous Membranes

Respiratory Ailments

• Body Adjustment• Asthma

Why Humidify?Health & Comfort...

How Much Humidity?Questions needing answers:

Inside level of temperature & humidity?Outside design temperature & humidity?Cubic size of the area to be humidified?CFM volume of exhaust or makeup air?Volume of any hygroscopic materials?

Size of A/C system. Economizer?How many people in 24 hours?

How Much Humidity?Calculations:

• Determine grains of moisture/ft3 of air at design temperature and humidity

• Determine grains of moisture/ft3 of air at outside temperature and humidity

• Determine largest volume of outside air• Run this formula:

Lbs/hr = (ft3/hr) x (gr/ft3 design - gr/ft3 outside)7,000 gr/lb

°FGrains

per Cu Ft °FGrains

per Cu Ft0 0.475 60 5.7955 0.609 65 6.845

10 0.776 70 8.05515 0.984 75 9.44820 1.242 80 11.0425 1.558 85 12.8730 1.946 90 14.9435 2.376 95 17.2840 2.863 100 19.9545 3.436 105 22.9550 4.106 110 26.3455 4.889 115 30.13

Pitfalls of Humidification

Load CalculationsBuilding Design

Boiler Treatment Chemicals - IIHCMineral Dust, Effects, Elimination

Improper InstallationMaintenance of Systems

The Wrong Humidifier in the Wrong Place

How to Humidify

• Isothermic:o Electrode Steam Humidifierso Heater Element Steam Humidifierso Gas-Fired Steamo Direct Discharge Steamo Steam to Steam Conversion

• Adiabatic:o Pressure Atomizing Humidifierso Air/Water Atomizing Humidifiers

Electrode Steam• Metal electrodes immersed in water tank• Current flowing between electrodes produces heat• Periodic refill & drain to control mineral concentration• Eventual cleaning/replacement of steam cylinder & electrodes

Electrode Steam

Time (Min)

100 %

128 %

105 %

95 %

0 %

• Initial fill & warm up• Overcurrent reduction, start to boil• Fill/boil cycles shorten with mineral build-up• Drain to reduce concentration & repeat

Electrode Steam• Maintenance

Element Steam

• Able to operate on any quality of water including R/O

• Precision: +-1%RH• Able to avoid drains

during test runs• Water level is constant,

controlled by level control

• Floats to be eliminated in 2018

• Metal heating elements immersed in water tank• Elements heat the water into steam• Periodic refill & drain to control mineral concentration• Eventual cleaning of steam cylinder & elements

Element Steam• Maintenance

Water Quality

0 - 100 125- 200 200 - 800 800 - 1250

Electrode type (HY, C, MS)

Heater type (HL)

Electrodes with larger surface Cylinder Star

• Choosing the right humidifier• Lowest cost = electrode• Best water tolerance = element• Highest precision = element• Fastest response = electrode

General Function

Steam from existing system- Pressure 5 - 58 PSI- Max. 356°F

Control signal to the actuator-Electrical or pneumatic-0-10V; 4-20mA; 2.9-14.5PSI

Sensor signal to the BMS

Start up safety switch-Switchover point at 176°F-Releases actuator power supply

Condensate drain

Actuator Power supply

Direct Steam

Direct SteamJacketed Steam Manifolds:• Multiple manifolds for shorter absorption distance• Heated manifolds reduce condensate, avoid contamination

Multi-PipeNozzle Steam Manifolds:• Multiple manifolds for shorter absorption distance• Nozzles prevent condensate discharge• Higher condensate production• Insulated manifolds can reduce some duct heat gain and

condensation.

Steam to Steam• Avoids treatment chemical discharge• Produces atmospheric steam

Gas-Fired Steam• Useful where electric costs are high, gas cheap• Larger, heavier, more maintenance• Must locate near wall for flue venting• Lower accuracy of control

Atomizing• Can replace boilers• More difficult to apply safely• Requires more space

WinterHumidification

Atomizing• Useful where evaporative cooling can also be used

Atomizing• How water is atomized: pressure vs air

Project: blood Centre in Linz / Austria

• 3.500 m² / 37760 ft² total area• Stem cells and tissues are produced from organs • cleanrooms with classes A to D GMP-Standards

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Case study ATOMIZING

Situation on site

• 8 Air handling units, isotherm humidification

• 11 Steam humidifiers installed

• Total air volume: 135.000 m³/h / 79458 cfm

• humidification load: 780 kg/h / 1719 lbs/h

• Reachable humidity: 45% r.h.

• Total energy costs $ 473.000/ year

• Costs for air-conditioning $ 246.000/ year

• Costs for isothermal air humidification $ 105.600 /year

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ATOMIZINGCase study

Basic conditions /requirements on site :• Comply with ÖNORM H6020:

• „air treatment device for medical applications “

• Similar to VDI 6022

• Keep Specific room climate and humidity

• Since 2007 alternatives to isothermal systems are allowed if

equivalency is approved.

• Specific water treatment to comply with hygienic requirements on site

• Duration of the project 18 Months

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ATOMIZINGCase study

Result:

• Equivalency HPS to isotherm systems was approved

by an recognized independent external expert for

Hospital Hygiene and confirmed by the Austrian

authorities.

• 8 Air handling units, were converted to HPS,

2 additional 2 AHU‘ were equipped with HPS ->

10 AHU equipped with adiabatic humidification

• Total humidified air volume 158 000 m³/h 93000 cfm

• Total humidification capacity 1 100 kg/h / 2425 lbs/h

• Future Project: HPS for adiabatic exhaust air cooling

in combination with heat exchanger in preparation

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ATOMIZINGCase study

The cost effectiveness of the HPS

Operating costs for air humidification – previous state:Energy costs for isothermal air humidification: 105894 $ p.a.Maintenance: 8250 $ p.a.

Operating costs for air humidification – new state:Energy costs for adiabatic air humidification: 2 524 $ p.a.Energy costs for pre-warming the air: 14867 $ p.a.Maintenance costs: 1540 $ p.a.

Savings in operating costs by using the HygroMatikHigh pressure nozzle system: 94964 $ p.a.

Total investment costs: 160600 $

Amortization: 1.69 years

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ATOMIZINGCase study

Atomizing• Stainless steel section should be used• Turbulators or air mixers shorten absorption distance• Mist eliminators prevent wetting

Atomizing• Stainless steel section should be used• Turbulators or air mixers shorten absorption distance• Mist eliminators prevent wetting• Nozzles arranged for best evaporation

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Hygienic without additives!• High efficient humidifier with less waste water

• All used material hygienically approved (inert components, i.e. materials that give no breeding ground for bacterial /legionella. (Tested by independent institute –ILH in Berlin)

• Installation according hygienic aspects (acc to VDI 6022), this norm states that all components have to be removable for cleaning, this is the case for HDS)

• The System is completely self drainable. In case the unit is in stand by, all hoses, manifolds and nozzles will be self drained automatically. This prevents standing water in the system and eliminates bacteriological growth and development of legionellaAddionally

• Stand-By flushing by default every 24h (adjustable between 2h and 48h), i.e. fresh demineralised water is used to flush the pump, high pressure hoses, manifolds and nozzles. After flushing the system is completely drained to prevent formation of bacteria and legionella, hence no standing water in the system. This function also complies with VDI 6022

• Water sample tap that can be flamed (for disinfection purposes) to get a water sample from the system. The water then can be checked. This is a special requirement for very sensitive clean room applications and hospitals.

ATOMIZING

Signal input

Pressure

10 VDefault : 5% = 0,5V

Default : 12,5% Control

range, here: 1,25 V

57,6 l/h 12.67 gal/h 229 l/h 50.37 gal/h

Control range4.07gal/h to 229 l/h 50.37 gal/h 18,5 l/h

32 l/h 7.03 gal/h

Default : 25% Control range,

here: 2,5 V37

75 bar /1087 psi

25 bar 362 psi

115,2 l/h 25.34 gal/h

Default : 50% Control range,

here: 5,0 V

18,5 l/h 4.07gal/h 33,3 l/h 7.32gal/h 66,6 l/h 14.65gal/h 133,2 l/h 29.3gal/h

ATOMIZING• Proper control should involve staging / modulation• Arrange for good low end precision• Use nozzles that adjust to pressure range

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An enthalpy based control of adiabatic humidifier is the best solution.

The easiest solution is an exhaust condition based control.

Be careful with post heating solutions. Post heating needs a higher humidity during

humidification process which causes a higher water loss

ATOMIZING• Enthalpy control is advantageous

The Science & TechnologyOf

Humidification

Scott Herr (HygroMatik)&

Steve Ehrman (AC Equipment Reps)