Natatorium Design:Natatorium Design:better building and gmechanical system

performance.

February 15, 2004 MoscowFebruary 15, 2004 Moscow

Design IssuesDesign Issues• Moisture Load

calculation• Air Distribution• Duct Design

• Condensation Control• Pool Water

Duct Design• Cooling

H i• Pool Water ChemistryE h Ai

• Heating• Energy recovery

• Exhaust Air• Outdoor Air

• Mechanical dehumidification

Design Criteria #1:Establish the

Space Dew Point

Everything vital to the poolEverything vital to the poolis based on this value.

Dew PointDew Point

100% 82ºF 50%RH62 º50%.62°

= 62 ºF DP70ºF 50%RH70ºF 50%RH= 50 ºF DP

82°

50 F DP82

AnyAny surfacesurface belowbelow

62°F will62 F will condense moisture

Why does water evaporate?Space dew point has a Vapor pressure

Water surface has a Vapor pressureW e su ce s V po p essu e

Why does water evaporate?Why does water evaporate?At 50% RH: Pw ~ 2 Pdp

(P

p

(Pdp) Vapor pressure of dew point

(Pw) Vapor pressure at water surface(Pw) Vapor pressure at water surface

Evaporation Rate Calculation

E i REvaporation Rate

Lb/h = 0.1 x A x ΔP x AF • A: Water Area; ft²

•ΔP: Δ Vapor pressure; inches Hg

•AF: Activity Factor (0.5 = Baseline)

E i REvaporation Rate

Lb/h = 0.1 x A x ΔP x AF Typical calculation has 2 scenarios:

• AF = 0.5 and space @ 50% (night)

• AF = 1.0 and space @ 60% (active)

Typical Design Conditions

Pool TypeAir

Pool TypeTemperature

Competition 78 to 85 °FDi i 80 t 85 °FDiving 80 to 85 °FElderly

Swimmers 84 to 90 °FSwimmersHotel 82 to 85 °F

Physical 80 to 85 °FyTherapy 80 to 85 °F

Recreational 82 to 85 °FWhirlpool/spa 80 to 85 °F

Typical Design Conditions

Pool Type Water Temperature

Activity FactorTemperature Factor

Competition 76 to 82 °F 0.65Diving 84 to 88 °F 0.65Diving 84 to 88 F 0.65Elderly

Swimmers 85 to 90 °F 0.8

Hotel 82 to 86 °F 0.8 – 1.0Physical Th 90 to 95 °F 0.65Therapy 90 to 95 F 0.65

Recreational 80 to 85 °F 1.0Whirlpool/spa 102 to 104 °F 1 0Whirlpool/spa 102 to 104 °F 1.0

Knowing the activity level inKnowing the activity level in advance is important

Similar to a pool ?Similar to a pool ?

H tHeat

Olympic Pool ExampleOlympic Pool Example

Water Area : 165 ft x 70 ft, 11550 ft²Water Temperature 77º FpAir Temp and RH 79º F - 50%Dew Point 58º FDew Point 58º FActivity Factor 1.0Evaporation Rate 490 lb/hHeat Loss due to 510 000 bt /hevaporation 510,000 btu/h

Olympic Pool ExampleOlympic Pool Example

Water Area : 165 ft x 70 ft, 11550 ft²Water Temperature 77º F 77º FpAir Temp and RH 79º F - 50% 82º F – 50%D P i t 8º 62º FDew Point 58º F 62º FActivity Factor 1.0 1.0Evaporation Rate 490 lb/h 425 lb/hHeat Loss due toHeat Loss due to evaporation 510,000 btu/h 450,000 btu/h

Energy Consideration:Energy Consideration:

Higher Air TemperaturesHigher Air Temperatures

R d tiReduce evaporation

Rule of Thumb:Air 2ºF warmer than water

C d i C lCondensation Control

1) Indoor surface temperature control

Remember: 62 ºF DP

Expensive WindowsExpensive Windows…….aren’t the answer.

• 85°F Space• -10°F Outdoors• A TRIPLE pane

window has a 57 °F inner surfaceinner surface temperature.

• A double pane pwindow has a 45 °F inner surface t t

Room dew point = 62 ºFtemperature.

C d i C lCondensation Control1) Inside surface temperature control

2) Moisture migration prevention) g p

High Temperature – High Vapor Pressure

Heat Migration

Vapor Migration

Low Temperature – Low Vapor Pressure

Hi h LowHighPressure

LowPressure

HighLow

ΔP > 10” WC!!

HighPressure

LowPressure

Areas of Condensation ControlAreas of Condensation Control

• Room dew point temperature control

• ?p

• Inside surface t t t l

• ?temperature control

• Prevention of • ?moisture migration through building

• ?g g

materials

Areas of Condensation ControlAreas of Condensation Control

• Room dew point temperature control

• Mechanical Dehumidifierp

• Inside surface t t t l

Dehumidifier

temperature control

• Prevention of moisture migration through building g gmaterials

Areas of Condensation ControlAreas of Condensation Control

• Room dew point temperature control

• Mechanical Dehumidifierp

• Inside surface t t t l

Dehumidifier• Duct layout

temperature control

• Prevention of moisture migration through building g gmaterials

Areas of Condensation ControlAreas of Condensation Control

• Room dew point temperature control

• Mechanical Dehumidifierp

• Inside surface t t t l

Dehumidifier• Duct layout

temperature control

• Prevention of • Building Designmoisture migration through building

• Building Design

g gmaterials

“If There is a Pile of Manure in a Space. Do Not Try to Remove the Odor by Ventilation. Remove the Pile of Manure”

Pettenkofer (1858)

Pool water quality isPool water quality is the single biggestthe single biggest

IAQ problem and itIAQ problem and it impacts theimpacts the

mechanical systemsmechanical systems

Cause Effect

• Under Chlorination • Combined Chlorines

• High pH level or(foul odor)S l f i• High pH level or

high total alkalinityL H l l

• Scale forming

C i• Low pH level or low total alkalinity

• Corrosion

Corrosion & the IAQ problem:Corrosion & the IAQ problem:

Off-gassed gchloramines have a

strong attraction to the i b h idiairborne humidity.

Corrosion & the IAQ problem:Corrosion & the IAQ problem:

Chloramines = Corrosive Condensate

Addressing the IAQ problem:Addressing the IAQ problem:

Ultraviolet LightUltraviolet LightR d / li i tReduces/eliminates

chloramines!chloramines!

Addressing the IAQ problem:Addressing the IAQ problem:

Get Air to the

breathing zone!

Addressing the IAQ problem:Addressing the IAQ problem:

O d Ai Outdoor Air

Exhaust Air Exhaust Air

O d AiOutdoor AirS d d 62 2004Per Standard 62-2004:

- 0.48 CFM per ft2 of pool and (wet) deck area or-7.5 CFM per spectatorAdd S OA CFMAdd Spectator OA CFM to baseline.

Water parks: Double the OA!

Exhaust Air

Per Chapter 4 Applications:4 Applications:0.05 to 0.15” WC negative pressure.

R le of th mb: 110% of OARule of thumb: 110% of OA

Heat recoveryHeat recovery

ΔT = ~ 100 ºF

Th A f Ai Di ib iThe Art of Air Distribution

Air changes per ASHRAE4 6 h i i• 4 – 6 per hour in a natatorium

• 6 – 8 per hour in a spectator area• 8 per hour (occupied) in a water parkSpecify CFM needed to satisfy this p y y

requirement.

Th A f Ai Di ib iThe Art of Air Distribution• Supply air to breathing zone!

S l i t h d ti• Supply air to where condensation is predictable

• Exterior windows & Doors.• Return location must complement• Return location must complement

supply duct layout.

Th A f D D iThe Art of Duct DesignDuct Materials

• Galvanized – Aluminum – Fabric

• Avoid Stainless Steel!

Ensure proper throw and direction from all diffuserso a d use s

#1 HVAC Design issue#1 HVAC Design issue

Get Air to the

breathing zone!breathing zone!

Air delivered to the breathing zone?

Air delivered to the breathing zone?

DX Coil & Energy Recovery gy yLH:P lPool

Evaporation50%

.Moisture .Air off

Evaporator

Removed

Vapor Compression CyclePSIA

Condensation

EvaporationEvaporation

TH = LH + SH

BTU/lb

Vapor Compression CyclePSIA Latent

Condensation

EvaporationEvaporation

TH HC

BTU/lb

Vapor Compression CyclePSIA LatentSensible + HC

Condensation

EvaporationEvaporation

TH HC

BTU/lb

Mechanical Room as Return AirMechanical Room as Return Air Plenum

Locker Room as Return AirLocker Room as Return Air Plenum

Perhaps a pgood idea not t h thito have things

above the bove epool that need

iservice….

….. stick with approved electrical devices…..