1. Indoor Pool Design and Dehumidification
Vijayanand Periannan Regional Sales Manager October 9, 2014

2. Summary
Indoor pool design and operation criteria
Conventional mechanical dehumidifier design
Munters pool dehumidification unit design
Comparison of the two systems at various operating conditions
Annual operating cost savings using the Munters unit
Munters pool dehumidification units at various location in USA
Munters unit construction features

3. Control of space temperature & relative humidity
The successful design & operation of an indoor pool project requires all of the following:
Control of space temperature & relative humidity
Design air temperature equal to or slightly higher than water temperature
Design relative humidity %
4-8 air changes/hour
Pool space pressure negative compared to the surrounding area
Minimum ventilation - 0.5cfm/sqft of pool and deck area + 8cfm per person in the spectator area
CDC has issued a new Model Aquatic Health Code (MAHC) for public review. This code proposes 2-3 times more outdoor air than ASHRAE-62.

4. 84-86°F / 40-60% 82-84°F E/A O/A Recirc S/A R/A 4-8 Air Changes
Min 0.5 CFM
Per ft^2 pool +deck
+8 CFM/person
O/A
E/A
E/A > O/A = Negative Pressure
Recirc
S/A
R/A
4-8 Air Changes
Per Hour
Infiltration
84-86°F / 40-60%
H20
82-84°F

5. Windows and other surfaces to be washed with dry supply air.
The successful design & operation of an indoor pool project requires all of the following:
Air movement at low velocities over the pool desired to control chloramines from stagnating.
Low velocity is desired to reduce evaporation rate and chilling effect on bathers.
Windows and other surfaces to be washed with dry supply air.

6. 80% 20% IDEAL AIR DISTRIBUTION R/A DUCT S/A DUCT S/A DUCT
In addition to a distributed
high return trunk, it is also desirable
to have one low return/exhaust
to reduce the concentration of heavy
chloramines that tend to
build up over the pool and deck
20%
S/A DUCT
S/A DUCT

7. So, how do we start? Determine Space and Water Parameters
Calculate Evaporation Rate
Add Load from People / Ventilation / Other
Determine required Leaving Air Temp/DP
Determine Air Changes

8. Pool Dehumidification Methods
Outdoor Air
Outdoor Air with Exhaust Heat Recovery
Mechanical System with DX or Chilled Water
Combination Ventilation/Heat Recovery/Mechanical
Desiccant

9. Typical Mechanical Dehumidifier
OUTSIDE AIR
RETURN AIR
EXHAUST AIR

10. Typical Mechanical Dehumidification Systems
Uses mechanical refrigeration to:
Dehumidify the pool space
Provide sensible cooling
As a result, compressors will operate for most part of the year
Always uses minimum outdoor air even when it is ideal for free dehumidification

11. Hot gas heat of rejection is used to:
Typical Mechanical Dehumidification Systems
Hot gas heat of rejection is used to:
Reheat dehumidified air leaving cooling coil
Heat pool water
Reject to remote condensing unit

12. Typical Mechanical Dehumidification Systems
Has a single supply fan
Usually requires a separate exhaust fan for maintaining negative space pressure

13. Consider…
Introduction of fresh air, in a controlled manner, will positively control indoor pool humidity when the outdoor air is at, or below the required supply air dew point.
Template
November 7, 2018November 7, 2018

14. Munters Design Approach
Take advantage of the drying effect of ambient air when possible for pool dehumidification.
Our DDC controller regulates the amount of outside air brought in to optimize the energy consumption while making sure the IAQ is not compromised.
In much of the U.S., O/A can provide all of the required dehumidification
Pre-condition outside air by using energy recovery to further reduce operational costs
Face and bypass dampers for supply temperature control
Use mechanical cooling for dehumidifying and space cooling only when required, NOT ALL THE TIME

15. Typical Munters Fresh Air Pool Unit

16. Munters Unit Uses More than Minimum OA when it can Better IAQ
Lower Chloramines smell
Superior Swimmer Comfort
Less Odors from other sources, I.e. locker rooms, into adjacent rooms

17. Why Energy Recovery? Lots of OA is Great for the IAQ,
however it costs Money to heat it up.
Energy Recovery reduces that cost!
Wide array of ER available – Flat Plate HX, Heat Pipe, etc

18. MUNTERS UNIT PERFORMANCE VS CONVENTIONAL POOL UNIT

19. DETROIT, MI

20. CONVENTIONAL UNIT

22. MUNTERS UNIT

25. MODULATING OUTDOOR AIR HEAT RECOVERY SYSTEM
MODULATES
TO MAINTAIN
SPACE NEGATIVE
PRESSURE
SUMMER
ECONOMIZER
EXHAUST
EXHAUST
N.C.
N.C.
RETURN FAN
RETURN
BLOW-THRU
DESIGN
Recirculation
N.O.
OUTDOOR
AIR H
S/A
N.C. C
SUPPLY FAN
Heat Exchanger
HOT WATER
COIL OR INDIRECT
FIRED GAS HEAT
MODULATES
TO CONTROL SPACE
HUMIDITY

26. Summer Design

30. Comparison
Munters unit uses 10,000 cfm Outside Air vs Conventional unit with 2,750 cfm Outside Air
Munters unit requires 23.8 tons of refrigeration vs Conventional unit requires 29.7 tons of refrigeration
Munters Unit: More O/A with less energy consumption.
Better IAQ and a smaller ACCU size with Munters unit.
Munters unit reduces reheat requirements in summer. Conventional unit uses 56mbh of reheat in summer.

31. Change Over Condition

34. Comparison
Munters unit uses 10,000 cfm outdoor air vs Conventional unit with 2,750 cfm outdoor air
Munters unit requires no refrigeration cooling vs Conventional unit requires 26.1 tons of refrigeration
Munters unit requires 226 mbh of gas heat vs Conventional unit requires 316 mbh of refrigeration
Even though Conventional unit uses 7,250 cfm of warmer return air, overcooling for dehumidification results in additional reheat.
Heat exchanger reduces gas heat requirement by about 30%

35. WINTER

38. Comparison
Munters unit requires 214 mbh of gas heat vs Conventional unit requires 412 mbh of gas heat
Munters Unit: Heat exchanger provides 198 mbh of free winter heat
Heat exchanger reduces gas heat requirement by 48%

39. Operating Costs Analysis
Detroit, MI Bin Data
10,000 CFM Supply Air
ELECTRICITY COST: $0.13/KW-HR
HEATING COST: $0.8/THERM

40. CONVENTIONAL UNIT

41. MUNTERS UNIT

42. Summary of Operating Costs

43. Munters Unit Advantages
Lower Electricity and Gas Heat Consumption
More Outdoor Air and Hence better IAQ
Longer Compressor Life and Less Maintenance
Conventional Unit with Smaller E/A Fan HP Does Not Mean Overall Lower Unit Energy Consumption

44. Avoiding Mechanical Cooling/Dehumidification

45. DIRECT EVAPORATIVE COOLING FOR POOLS?

48. Pool Exhaust Air Heat Extraction Using a Heat pump

50. Pool Water Heating Option with Munters Unit
DX coil in the E/A air stream after the heateto extract heat out of the high quality humid air.
The Compressor operating at 110F condensing and 45F SST has an
operating efficiency of 0.75KW/ton
COP refrigeration based heat pump = heat output / energy input
COP = 5.9 (COP of Heat Pump Only)
Rejecting the heat to the condenser in the supply air stream for reheat
Rejecting any additional heat to the pool water

51. Modulating Outdoor Air, Dual Heat Recovery System
EXHAUST
Modulating Outdoor Air, Dual Heat Recovery System
Evaporator HX
Bypass 4
84F/55%
RETURN AIR FROM POOL SPACE D X 3
Recirculation
EXHAUST FAN
N.O. H 2 1
S/A
OUTDOOR
AIR
SUPPLY FAN
Heatpump (Air Heater)
Bypass

52. ARNE HANNA AQUATIC CENTRE, WASHINGTON

54. Refrigeration Piping Schematic
3-way modulating
Hot Gas Diverting
Valve
Pool Water OUT
Hot Gas
Heating Coil
(Condenser 2)
Coaxial HX
(Condenser 1)
Mix of O/A,
Preheated by
Air-to-air HX,
And recirculation air
Heated
S/A to Space
Pool Water IN
Exhaust Air
(After HX)
TXV
DX Coil
Scroll Compressor(s)

55. Newton Wave Pool - Surrey, BC

57. Munters Heat Pump Advantages
CONVENTIONAL SYSTEM
Munters unit can provide heating whenever required. Conventional unit can provide heating only when cooling is on.
Most of the condenser heat is wasted in reheating the overcooled air
Conventional unit cannot provide pool water heating in winter when heating is most required.
Munters unit extracts heat from the exhaust air. Heatpump will provide heat in much colder ambient conditions.
MUNTERS SYSTEM

58. Pool Unit Construction

59. Exterior Walls

60. Base Frame

61. Coated Floor

63. Epoxy Coated Fan Assemblies

64. Coated Coils

65. All Aluminum Dampers

66. Controls

67. Wiring Methods

69. Fresh Air Pool
Plate Heat Exchanger, with / without refrigeration
Western Markets

70. Wringer Pool
Wringer and Wringer Plus configurations for pools
Able to integrate building exhaust
Larger Sizes, over 200 lbs/hr
Humid markets
Custom options, pool hot water heating, controls

71. DryCool Humid ambient conditions DX operated at higher temperatures
Condenser heat used for Reactivation
No overcooling
Lower supply dewpoint results in less supply airflow and fan power

72. Fresh Air Pool Success Story
RIO GRANDE POOL
Fresh Air Pool Success Story

73. Location: Albuquerque, NM Basis of Design : Seresco
Size : 20,000 cfm
Basis of Design : Seresco

74. Seresco Unit
OUTSIDE AIR
RETURN AIR
EXHAUST AIR

75. MUNTERS UNIT

77. R/A
O/A
* OUTSIDE AIR DEWPOINT IS LOWER THAN R/A
* OUTSIDE AIR ENTHALPY IS LOWER THAN R/A
* WHY NOT TAKE ADVANTAGE OF THIS AND BRING IN MORE O/A
* WE CAN REDUCE ENERGY CONSUMPTION AND IMPROVE IAQ

78. Summer Design : 97F/60F
Munters unit uses 6,768 cfm Outside Air vs Conventional unit with 4,820 cfm Outside Air
Munters unit requires 20 tons of refrigeration vs Conventional unit requires 32 tons of refrigeration
Almost 40% reduction in refrigeration tons.
Munters Unit: More O/A with less energy consumption.
Better IAQ and a smaller refrigeration size with Munters unit.

79. Winter Design : 18F/14.4F
Munters unit requires 259 mbh of HW heat vs Conventional unit requires 539 mbh of HW heat
Munters Unit: Heat exchanger provides 280 mbh of free winter heat
Heat exchanger reduces HW heat requirement by 52%

80. OPERATING COSTS ANALYSIS
Albuquerque, NM Bin Data
20,000 CFM Supply Air
ELECTRICITY COST: $0.09/KW-HR
HEATING COST: $0.5/THERM

82. Questions