Indoor Swimming Pools: The Technologies 20 th November 2017 Amnon Holland BE Eng, M.AIRAH www.esbsconsult.com.au 1
Agenda The driver Code Compliance of Ventilation The Technologies - Heat exchange and heat recovery Smart BMS strategies: Variable speed control of fans and pumps The basics Afterhours pool hall temperature and humidity setback Condensation mitigation when pushing limits with setback Implementation Working with the BMS contractor 2
Code Compliance of Ventilation Large volumes of exhaust air are required when the facility is occupied Equals the amount of outdoor air must be introduced Highly energy intensive in cold climate like Canberra This + Filtration pumping is the main reason for high energy intensity in aquatic centres 3
Heat Exchange Technologies The opportunity Application 1 Pool Hall Summary of heating inputs: 0 C 28 C 28 C Heating from Boiler or Heatpump + Heat Recovery 27 C Heating from Boiler or Heatpump 4
Heat Exchange Technologies Pool Hall In Summer Natural ventilation (i.e. Motorised louvres or doors pool operators), Mechanical Extract or a Combination Heat wheels Switch off when ambient is close to inside Plate HEX/ Run-around coil bypass (or more simply Separate fan) High volumes of air to flush pool hall 35 C 30 C 30 C 27 C 5
Heat Exchange Technologies The opportunity Application 2 Entry Foyers & Amenities (Toilets) Must Air to Air plate type. Often can be an in ceiling unit. Select variable speed fans Exhaust Constant Volume Supply Can be ramped back 0 C 6 C 20 C 26 C Foyer Toilets 6
Heat Exchange Technologies The Ideal Scenario Full recirc (no outdoor air) No heating OA and minimal fan power High RH (reduce pool water and heat loss) Pool hall T is setback several degrees below water temperature (night) Pool water heating If Heatpumps Run during the day with warmer ambients, float the pool up to 0.5 C higher If Condensing boilers reset the flow temperature below 60 C afterhours (when high temps are likely not required), and float the pool 0.5 C higher Considerations Warm up, dry out period before patrons arrive 7
Heat Exchange Technologies 1: Air to Air Plate Heat Exchangers There are 3 main technologies, 2 commonly used Different manufacturers products Crossflow ~70% Peak Eff. Counterflow ~80% Peak Eff. Importance of Filters Cold climate considerations 8
Heat Exchange Technologies 1 Ctd. Considerations Size and bulk Co-located supply and exhaust ducts Heating source HW coil or HP Controls Always ensure all 4 airstreams have temp sensors very cheap Check BMS contractor has allowed for variable speed hardware (VFDs, pressure sensors not switches) Sensible vs Latent media 9
Heat Exchange Technologies 2: Rotary Heat Wheels Counterflow (80% Eff) in nature and cleanable Speeds, Install & Maintenance 0 C 22 C 6 C 28 C 10
Heat Exchange Technologies 3: Run around coils Rarely used Efficiency (between 45-70%) is highly dependant on water flow control More compact, and useful where the intake and exhaust air streams are apart More prone to corrosion/ degradation than HEX units with plastic cores in pool environments 11
Heat Exchanger Performance Verification Periodic measuring of performance is essential. 1. Measure airflows Exhaust should be 0-20% greater than Supply 2. Measure temperatures (TRA TOA)/(TRA-TSA) > 65% 12
Smart BMS Strategies Variable speed control of fans and pumps The basics first: Unecessary throttling (valves) Controls issues Pressure switches and sensors need to be suitable for new variable flow envelope Otherwise...system reliability Conservation of mass (airflow), cant just apply to one fan in isolation What minimum code ventilation rates need to be maintained during occupied times? In response to what? Zone temp or Humidity, but need checks 13
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Occupied Unoccupied Occupied Smart BMS Strategies 15
Smart BMS Strategies 16
Smart BMS Strategies System Lockout Door switches on external doors When opened for >10mins locks out LPHW Heating coil, fans still run Traffic lights on the BMS main screen (monitored by pool attendant) lights up Green = Okay, when ambient conditions are favorable 17
Smart BMS Strategies In-slab heating Control Generally controlled by running pump, with inlet temperature via mixing valve Most comfortable and energy form of heating, as heating is localised rather than heating all air. New pools needs insulation under pool apron slab Even though BCA does not cover. Control Weather compensation based Commissioning requires experimenting during start of heating season 18
Smart BMS Strategies Variable speed control of fans and pumps The basics first: Unecessary throttling (valves) Controls issues Pressure switches and sensors need to be suitable for new variable flow envelope Otherwise.. Conservation of mass (airflow), cant always apply to one fan in isolation. In response to what? Zone temp or Humidity, but need checks 19
Working with the Team Achieving objectives Include interactive workshops with BMS contractor early in the project before engineering is commenced. Attendees: FM/ Operation staff Mechanical maintenance contractor Clients key staff Technical Consultant Allow for a fixed amount of hours for tuning during DLP Clearly identify the expectations tuning required 20
Thank You Amnon Holland BE Eng, M.AIRAH, www.esbsconsult.com.au 21