Indoor Pool Design Considerations Colorado Springs, Colorado

Transcription

1 Indoor Pool Design Considerations Colorado Springs, Colorado September 20, 2018 Presentation by Eric S. Johnson, P.E. LifeMember, ASHRAE, Austin Chapter

2 DESIGN CONSIDERATIONS HUMIDITY CONTROL FOR INDOOR POOL FACILITIES

3 Natatorium Design: Better building and mechanical system performance

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5 February 15, 2004 Moscow

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11 5 Warning Signs in Your Natatorium Originally published in Private University Products and News magazine 1. "That indoor pool smell has always been here, it's normal." 2. "I just bought this equipment a year ago and it's already rusty!" 3. "My kids have to use inhalers at swim practice." 4. "It's raining in here, the windows and walls sweat." 5. "I have, so everything is fine."

12 Moisture Load calculation Condensation Control Pool Water Chemistry Exhaust Air Outdoor Air Air Distribution Duct Design Cooling Heating Energy Recovery Mechanical dehumidification

13 100% % 82ºF 50%RH = 62 ºF DP 82

14 Any surface below 62 F will condense moisture

15 (Pdp) Vapor pressure of dew point (Pw) Vapor pressure at water surface

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17 Lb/h = 0.1 x A x P x AF Typical calculation has 2 scenarios: AF = 0.5 and 50% (night) AF = 1.0 and 60% (active)

18 Pool Type Air Temperature Water Temperature Activity Factor Competition 78 to 85 F 76 to 82 F 0.65 Elderly Swimmers 84 to 90 F 85 to 90 F 0.65 Hotel 82 to 85 F 82 to 86 F Physical Therapy 80 to 85 F 90 to 95 F 0.65 Recreational 82 to 85 F 80 to 85 F 1.0 Whirlpool/spa 80 to 85 F 102 to 104 F 1.0

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20 Similar to a pool? Heat

21 Water Temperature Water Area : 165 ft x 70 ft, ft² Air Temp and RH 79º F - 50% Dew Point 77º F 77º F 58º F Activity Factor 1.0 Evaporation Rate Heat Loss due to evaporation 490 lb/h 510,000 btu/h

22 Water Temperature Water Area : 165 ft x 70 ft, ft² 77º F 77º F Air Temp and RH 79º F - 50% 82º F 50% Dew Point 58º F 62º F Activity Factor Evaporation Rate 490 lb/h 425 lb/h Heat Loss due to evaporation 510,000 btu/h 450,000 btu/h

23 Higher temperatures reduce evaporation Rule of Thumb: Air 2 F warmer than water

24 1. Indoor surface temperature control Remember: 62 F DP

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33 2. Moisture migration prevention

34 Low Pressure High Pressure

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38 Room dew point temperature control Inside surface temperature control Prevention of moisture migration through building materials Mechanical Dehumidifier Duct layout Building Design

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40 Pool water quality is the single biggest IAQ problem and it impacts the mechanical systems

41 1.Outdoor Air 2.Exhaust Air

42 Per Standard : 0.48 CFM per ft² of pool and deck area Add 7.5 CFM per spectator Add Spectator OA CFM to baseline Water parks: Double the OA!

43 Per Chapter 4 Applications: 0.05 to 0.15 WC negative pressure Rule of Thumb: 110% of OA

44 Trichloramines 4x heavier than air Source capture?

45 The heavier and denser Trichloramines will allow themselves to be pulled off the water surface

46 Air changes per ASHARE 4 6 per hour in a natatorium 6 8 per hour in a spectator area 8 per hour (occupied) in a water park Specify CFM needed to satisfy this requirement

47 Supply and Return location Supply air to where condensation is predictable Exterior windows Exterior doors Thermal bridging?

48 Supply and Return location Return location must complement supply duct layout Watch for short circuiting! This can effectively cut off 50%-75% of the room from supply air.

49 Air movement deck and water surface Stagnant air is an IAQ problem. The USOC wants some air movement at the water level where the swimmers breathe.

50 perimeter air supply can cause a desirable secondary airflow (10-30 fpm) at the water surface

51 In-floor perimeter air supply can cause a desirable secondary airflow (10-30 fpm) at the water surface

52 Duct Materials Galvanized Aluminum Fabric Avoid Stainless Steel! Ensure proper throw and direction from all diffusers

53 Duct Materials Galvanized Aluminum Fabric Avoid Stainless Steel! Ensure proper throw and direction from all diffusers

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55 Moisture Load calculation Condensation Control Pool Water Chemistry Exhaust Air Outdoor Air Air Distribution Duct Design Cooling Heating Energy Recovery Mechanical dehumidification

56 The space is generally F warmer Than a traditional room.

57 More btu/ft² heating Less btu/ft² cooling Don t forget Outdoor air in your load calculation. (~50% of heating load!)

58 More btu/ft² heating Less btu/ft² cooling Don t forget Outdoor air in your load calculation. (~50% of heating load!)

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60 Moisture Load calculation Condensation Control Pool Water Chemistry Exhaust Air Outdoor Air Air Distribution Duct Design Cooling Heating Energy Recovery Mechanical dehumidification

61 ΔT = ~ 100 ºF

62 PSIA Sensible + HC Latent Condensation Evaporation TH HC BTU/lb

63 Energy Recovery

64 Moisture Load calculation Condensation Control Pool Water Chemistry Exhaust Air Outdoor Air Air Distribution Duct Design Cooling Heating Energy Recovery Mechanical dehumidification Questions?

65 Thank You