Everything You Ever Wanted to Know About Humidification · HEALTH • Many claims of humidification...

EVERYTHING YOU EVER WANTED TO KNOW ABOUT

HUMIDIFICATION

By Jeff Boldt

PRESENTER

Jeff Boldt

• Director of Engineering, KJWW• Author - AEDG for Large

Hospitals• Member ASHRAE 90.1 and

189.1• 62.1 – 55 – GPC-36• PE - Mechanical• PE - Fire Protection• Nearly MS - Acoustics• boldtjg@kjww.com

(Search “Jeff Boldt nerd”)

WHY HUMIDIFY?

HEALTH

• Many claims of humidification promoting health

• Many based on the 1985 Sterling Study– I believe the conclusions of that study are not

supported by the details in the report

• Healthcare codes reduced minimum from 30% to 20% in most spaces (a few exceptions)

COMPUTERS

• ASHRAE expanded

the operational

ranges greatly

MATERIAL PRESERVATION

• Organic materials expand with >RH

– Not absolute humidity

– Expand more across grain

• Gym floors

• Carriage Museum

• Artwork

• Material cracking

STATIC ELECTRICITY

• Formerly a big issue in ORs

– Ether is no longer used as an anesthetic

– ORs now require 20-60% RH

• More problematic with carpet

HUMIDIFICATION ISSUES

WINDOW CONDENSATION

• Condensation

– Windows

– Inside walls

CONDENSATION PREDICTION

• Windows have a Condensation Resistance Factor (CRF)

CONDENSATION PREDICTION

• Windows

PSYCHROMETRICSPSYCHOMETRICS

MADISON

PHOENIX

SWAMPCOOLERS

File Not Saved

BAROMETRIC PRESSURE: 29.004 in. HG

PSYCHROMETRICCHARTNormal TemperatureI-P Units

860 FEET

Weather Data Location:

MADISON_DANE_CO_REGIONAL_ARPT_ISIS, WISCONSIN, USA

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

DRY BULB TEMPERATURE - °F

0 5 10 15 20 25 30

35

40

45

50

55

55

60

60

EN

TH

AL

PY

- B

TU

PE

R P

OU

ND

OF

DR

Y A

IR

0

5

10

15

20

25

30

35

40

45

50

ENTH

ALP

Y -

BTU

PER P

OUND O

F DRY A

IR

SATU

RATI

ON T

EM

PERATU

RE -

°F

.05

.1

.15

.2

.25

.3

.35

.4

.45

.5

.55

.6

.65

.7

.75

.8

.85

.9

.95

1

1.05

1.1

1.15

1.2

1.25

1.3

VA

PO

R P

RE

SS

UR

E -

IN

CH

ES

OF

ME

RC

UR

Y

0

10

20

25

30

35

40

45

50

55

60

65

70

75

80

85

DE

W P

OIN

T T

EM

PE

RA

TU

RE

- °

F

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

1.00

0.95

0.90

0.85

0.80

0.75

0.70

0.65

0.60

0.55

0.50

0.45

0.400.350.300.250.20SENSIBLE HEAT RATIO = Qs / Qt

SE

NS

IBL

E H

EA

T R

AT

IO =

Qs /

Qt

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

15%

25%

2%

4%

6%

8% RELATIVE HUMIDITY

10% RELATIVE HUMIDITY20%

30%

40%

50%

60%

70%

80%

90%

-50

05

510

1015

1520

2025

25

30

30

35

35

40

40

45

45

50

50

55

5560

6065

65 70

7075

75

80

80

85 WET BULB TEM

PERATURE - °F

85

90

13.0

14.0

15.0

VO

LU

ME

- CU

.FT

. PE

R L

B. D

RY

AIR

HU

MID

ITY

RA

TIO

- G

RA

INS

OF

MO

IST

UR

E P

ER

PO

UN

D O

F D

RY

AIR

0

1.0 1.0

-

2.0

4.08.0

-8.0-4.0-2.0-1.0-0.5

-0.4

-0.3

-0.2

-0.1

0.10.

2

0.3

0.4

0.5

0.6

0.8

-2000

-1000

0

500

1000

1500

2000

3000

5000

-

SENSIBLE HEAT Qs

TOTAL HEAT Qt

ENTHALPY

HUMIDITY RATIO

h

W

File Not Saved

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

BAROMETRIC PRESSURE: 29.004 in. HG

PSYCHROMETRICCHARTNormal TemperatureI-P Units

860 FEET

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

File Not Saved

BAROMETRIC PRESSURE: 29.004 in. HG

PSYCHROMETRICCHARTNormal TemperatureI-P Units

860 FEET

Weather Data Location:

MADISON_DANE_CO_REGIONAL_ARPT_ISIS, WISCONSIN, USA

-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130

DRY BULB TEMPERATURE - °F

0 5 10 15 20 25 30

35

40

45

50

55

55

60

60

EN

TH

AL

PY

- B

TU

PE

R P

OU

ND

OF

DR

Y A

IR

0

5

10

15

20

25

30

35

40

45

50

ENTH

ALP

Y -

BTU

PER P

OUND O

F DRY A

IR

SATU

RATI

ON T

EM

PERATU

RE -

°F

.05

.1

.15

.2

.25

.3

.35

.4

.45

.5

.55

.6

.65

.7

.75

.8

.85

.9

.95

1

1.05

1.1

1.15

1.2

1.25

1.3

VA

PO

R P

RE

SS

UR

E -

IN

CH

ES

OF

ME

RC

UR

Y

0

10

20

25

30

35

40

45

50

55

60

65

70

75

80

85

DE

W P

OIN

T T

EM

PE

RA

TU

RE

- °

F

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

1.00

0.95

0.90

0.85

0.80

0.75

0.70

0.65

0.60

0.55

0.50

0.45

0.400.350.300.250.20SENSIBLE HEAT RATIO = Qs / Qt

SE

NS

IBL

E H

EA

T R

AT

IO =

Qs /

Qt

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

15%

25%

2%

4%

6%

8% RELATIVE HUMIDITY

10% RELATIVE HUMIDITY20%

30%

40%

50%

60%

70%

80%

90%

-50

05

510

1015

1520

2025

25

30

30

35

35

40

40

45

45

50

50

55

5560

6065

65 70

7075

75

80

80

85 WET BULB TEM

PERATURE - °F

85

90

13.0

14.0

15.0

VO

LU

ME

- CU

.FT

. PE

R L

B. D

RY

AIR

HU

MID

ITY

RA

TIO

- G

RA

INS

OF

MO

IST

UR

E P

ER

PO

UN

D O

F D

RY

AIR

0

1.0 1.0

-

2.0

4.08.0

-8.0-4.0-2.0-1.0-0.5

-0.4

-0.3

-0.2

-0.1

0.10.

2

0.3

0.4

0.5

0.6

0.8

-2000

-1000

0

500

1000

1500

2000

3000

5000

-

SENSIBLE HEAT Qs

TOTAL HEAT Qt

ENTHALPY

HUMIDITY RATIO

h

W

File Not Saved

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

BAROMETRIC PRESSURE: 29.004 in. HG

PSYCHROMETRICCHARTNormal TemperatureI-P Units

860 FEET

Chart by: HANDS DOWN SOFTWARE, www.handsdownsoftware.com

HUMIDIFICATION METHODS

EVAPORATIVE (ADIABATIC)

• Pad – Residential, greenhouse, dry

climates

– Not legal in hospitals

• Spray– Commercial – mostly dry

climates

– Not legal in hospitals

• Ultrasonic & Infrared– Computer room units mostly

– Not legal in hospitals

THINK ABOUT YOUR CONDITIONS. WHICH ONE WILLWORK FOR YOU?

STEAM

• Boiler Steam– Inexpensive

– Low maintenance

– Less space needed

• Clean Steam– No potential carcinogens

– Maintenance depends on feed water

– http://www.esmagazine.com/articles/95728-humidification-options-amines-and-the-impacts-of-ashrae-standards-621-and-170

BOILER CHEMICALS

• Health Risk

• POTENTIAL carcinogens

• 62.1 = FDA boilerchemical limits

– No air monitoring

– WHEA fought hard for this

• Maintenance• Without amines,

condensate pipes rust swiftly

• Neutralizing amines protect condensate pipes– Cyclohexylamine– Morpholine– DEAE

• RO reduces blowdown, chemical costs, corrosion

Should they be used for humidification?

ENERGY SOURCES

HEAT OF THE AIR (ADIABATIC)

• Pads, sprays, ultrasonic, maybe IR

• Called “adiabatic”

• Not legal for hospitals

• Common in dry climates and computer room units

ELECTRIC

• Low first cost

• High operating cost

– Natural gas ~35% the cost of electricity

• High maintenance cost

• Difficult to control accurately except for deluxe modulating units

NATURAL GAS

• Relatively low first cost

• Maintenance depends on design

• Good option for clean steam at multiple distant locations

STEAM

• Traditional

• Jacketed

• Smaller tubes

• Need summer shutoff

• Short Dispersion

• Large diameter tubes

• No automatic shutoff needed

HOW MUCH HUMIDITY DO YOU NEED?

WISCONSIN CODE

• ASHRAE Standard 170-2008 Addendum d– 20% for most healthcare areas

• Surgery

• Delivery

• Procedure

• Endoscopy

– 30% for a few areas• Intensive Care

• NICU

• Newborn Nursery

WHAT IS THE BEST LOCATION?

• Upstream of cooling coil?

– Eliminates water in duct risk

– After HC so air is low RH

– Low velocity can be an issue

• Has anyone experienced this? Email me!

• Downstream of fan?

– High velocity = short dispersion

MY OPINION

• Between Preheat Coil and Cooling Coil

– Prevents water droplets going down ducts

– Low RH normally for good absorption

STEAM HUMIDIFIER TYPES

JACKETED BAYONET HUMIDIFIER

Need automatic shutoff valve!

SHORT DISPERSION HUMIDIFIER

DESCRIPTION

• Bayonet tubes are ~212°F

• They cause unwanted air heating

• Short absorption manifolds have large surface area and intensify the problem

• Up to 5°F of heat added

INSULATED BAYONETS

ADVANTAGES OF INSULATED BAYONETS

• Energy efficiency

• Less water waste

– Treated water waste

• Better control of discharge air temperature

• Complies with energy codes

– 90.1-2010

– IECC-2012

DISADVANTAGES OF INSULATING BAYONETS

• Higher first cost

• Can be more difficult to clean

• Must be rated for use in the airstream

• Potential wear and tear of insulation

STAINLESS STEEL SHELL WITH AIR GAP

Stainless steelshielding

¼” Air-gap

Foam strips

Cool Airflow

Hot Steam

Nortec- R = 0.66 - 70% condensate

reduction

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0 500 1000 1500 2000 2500

Loss

es

(lb

s/h

r) p

er

Lin

ear

Fo

ot

of

Tub

e

Duct Velocity (ft/min)

50°F Standard

60°F Standard

70°F Standard

80°F Standard

50°F Insulated

60°F Insulated

70°F Insulated

80°F Insulated

Stainless Steel Shell with Air Gap

ELASTOMERIC INSULATION

Elastomeric- R = 0.74- Flame Spread – 25- Smoke Spread – 45- Thickness – 0.5 in- 70% condensate

reduction

PVDF INSULATION

PVDF- R = 0.56- 1/8 inch thick- 75% reduction in

condensate- 0/0 flame/smoke

rating

THERMAL INSULATING COATING

• Ceramic spray-on coating

• Approximately 0.03” thick

• R-Value of 0.045

• Durable and easy to clean

DISPERSION TUBE HEAT LOSS

R-VALUE

• ASHRAE 90.1 6.5.2.4.3 Humidification system dispersion tube hot surfaces in the airstream of ducts or air handling units shall be insulated with a product with an insulating value of at least R-0.5.

KJWW PERSPECTIVE

• Worth the added cost for new construction

• Will save energy if implemented and maintained

• Should be considered for all projects

• Required for 90.1-2010 or later and LEED v4

• Insulation type should be evaluated for each project for cost, longevity, and R-value

CONTROL OPTIONS

• Return Air

– Slow response

– Need limits on supply RH

• Supply Air with Return RH Reset

– My favorite option

– Fast response

– No wet filters

MAINTENANCE HEADACHES

WATCH FOR IMPROPER PITCH

WATER TREATMENT

• RO reduces TDS

– 90-95% reduction in TDS (including hardness)

– Surface water vs. well water

• Madison = 18-20 grains of hardness

• TDS = hardness + other minerals (sodium)

WATER TREATMENT

• Softening

– One 2+ (calcium) replaced by two 1+ (sodium)

– “Naturally” soft water is not like softened water

WATER TREATMENT

• Legionella and Infection

– No issue for steam humidifiers

– No recorded Legionnaires from swamp coolers

Q & A

Jeff Boldt

– boldtjg@kjww.com

– (608) 221-6709 direct

– (608) 658-5750 mobile

– www.KJWW.com