Indoor Pool Design and Dehumidification Vijayanand Periannan Regional Sales Manager October 9, 2014 vijay.periannan@munters.com

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

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 50-60% 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.

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

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.

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

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

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

Typical Mechanical Dehumidifier OUTSIDE AIR RETURN AIR EXHAUST AIR

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

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

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

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

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

Typical Munters Fresh Air Pool Unit

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

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

MUNTERS UNIT PERFORMANCE VS CONVENTIONAL POOL UNIT

DETROIT, MI

CONVENTIONAL UNIT

MUNTERS UNIT

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

Summer Design

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.

Change Over Condition

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%

WINTER

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%

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

CONVENTIONAL UNIT

MUNTERS UNIT

Summary of Operating Costs

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

Avoiding Mechanical Cooling/Dehumidification

DIRECT EVAPORATIVE COOLING FOR POOLS?

Pool Exhaust Air Heat Extraction Using a Heat pump

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

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

ARNE HANNA AQUATIC CENTRE, WASHINGTON

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)

Newton Wave Pool - Surrey, BC

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

Pool Unit Construction

Exterior Walls

Base Frame

Coated Floor

Epoxy Coated Fan Assemblies

Coated Coils

All Aluminum Dampers

Controls

Wiring Methods

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

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

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

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

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

Seresco Unit OUTSIDE AIR RETURN AIR EXHAUST AIR

MUNTERS UNIT

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

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.

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%

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

Questions