Natatorium Control

Transcript

TM POOLPAK Technical Library PoolPak™ Technical Library Series www.poolpak.com Natatorium Control Description of Design and Operation of the PoolPak™ MPK System In order to control a natatorium environment and structurally maintain a building, the following functions must be provided: • • • • Ventilation to satisfy health and safety code requirements. Space heating to maintain a comfortable environment for the occupants and minimize evaporation. Dehumidification to prevent condensation from destroying the building. Pool water heating to make the pool enjoyable to swimmers. The PoolPak™ unit provides these functions and does so at the lowest operating cost. This manual includes a step-by-step narrative of the PoolPak™ MPK’s control functions and features. Automatic Control of Air and Water Temperatures and Humidity An integral part of the PoolPak™ system is a proven microprocessor control which automatically senses and maintains comfort conditions. Sensors detect changes in natatorium air temperature and humidity, quickly regulating supply air conditions to meet set point comfort levels even during periods of unusually heavy pool use. The PoolPak™ unit continuously monitors pool water temperature and adds heat as necessary. To prevent condensation on walls and windows, the system automatically adjusts humidity in response to changes in wall or window surface temperature. As seasons or weather conditions change, PoolPak™ controls alter its method of operation accordingly. Throughout the year, PoolPak™ units think “efficiency” and automatically selects the least expensive energy source for pool air and water heating needs. Prevention of Building Damage Effective control of humidity and temperature conditions in the indoor pool environment eliminates condensation on interior surfaces. Laden with pool chemicals, this condensation encourages mold, mildew, paint blistering/peeling and rust. Steel supports, lockers, light fixtures and hardware along with heating and air conditioning systems can quickly corrode beyond repair. In many cases, reinforcement steel embedded in concrete can be seriously damaged or weakened by the percolating effects of pool chlorine and moisture condensation. The installation of PoolPak™ equipment significantly reduces routine maintenance costs while preventing structural damage. Reduction in Energy Costs PoolPak™ units dramatically reduces energy costs in two important ways: • • By recovering exhaust air heat and returning it to the indoor pool environment. Closely controls indoor air conditions so minimal outside air is necessary to heat it. PoolPak™ units offer significant advantages compared to either conventional heating and ventilation natatorium systems, which waste energy and money by exhausting large volumes of indoor air, or to improperly applied dehumidifiers that may provide inadequate control. MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control Application of Heat Pump Technology Through the use of heat pump technology, PoolPak™ units automatically performs the following eight functions: • • • • • • • • Dehumidification/Humidity Control Natatorium Space Heating Heating, Cooling and Dehumidifying Economizing Pool Water Heating Proper Ventilation Control Recovery of Reusable Heat Natatorium Space Cooling Wall Condensate Prevention Smart Air Management With the PoolPak™ MPK, PoolPak™ International introduces a new standard feature for optimal ventilation control called Smart Air Management™. With the use of VFD's, air flow monitoring stations, and advanced Instant Command (ICC) control logic, the MPK will maintain ideal airflow conditions in every mode of operation. To learn more about this feature, see page 4. FUNCTIONAL DESCRIPTION OF SYSTEM Primary Function The primary function of the PoolPak™ system is to provide environmental control of the space through the use of heat pump technology. Heat from the warm, humid pool air is recovered for reuse while the air is dehumidified and cooled. The recovered heat is then used to heat the supply air and, if necessary, the pool water. Refrigerant-Side Operation (see Figure 1) The PoolPak™ system draws in warm, moist air from the pool enclosure. This air passes through the evaporator (dehumidification) coil and gives up heat energy to the refrigerant which is in a cool, liquid state. This exchange of energy causes the air temperature to fall below its dew point, resulting in moisture condensation on the evaporator coil. The moisture formed is collected by the unitís condensate drain system. After passing through the evaporator coil, the refrigerant becomes a cool gas. The refrigerant enters the unit's compressor, where it is compressed into a hot gas. While in the compressor, the refrigerant absorbs the energy used to operate the compressor. This hot gas refrigerant then travels either through an air reheat coil, the pool water condenser or to an optional auxiliary air condensing heat exchanger, which may be either air or water cooled. If air heating is required, the air reheat coil is used. The hot refrigerant exchanges energy with the cooler, dehumidified air coming from the evaporator coil. This causes the temperature of the air to rise for heating. If pool water heating is required the hot gas flows into a pool water condenser, where it adds energy to the incoming pool water. This heats the pool water while the refrigerant is condensed into a warm liquid. If space cooling is required, the refrigerant flows to the auxiliary air conditioning condenser bypassing the air reheat coil and pool water condenser and allowing cool air from the evaporator coil to provide space cooling. MKW07-NATCONTROL-20140721 2 PoolPak™ Technical Library TM Natatorium Control Air-Side Operation The PoolPak™ system provides outside air ventilation to satisfy minimum air ventilation requirements during occupied periods per ASHRAE standard 62.1.The MPK unit can include an outside air damper (MS), a factory mounted exhaust fan (MSE), or an exhaust and purge fan (MSEP). MSEP models have an economizer function that can modulate up to 100% exhaust air and outside air. This operation allows the unit to use outdoor ambient conditions if they are favorable for free heating, cooling, or dehumidification. For a more detailed description of economizer and smart economizer operation, see the respective control mode pages. The PoolPak™ unit has been designed two best recycle the energy from the return air during mechanical dehumidification. In cooling modes for units employed with an exhaust fan (MSE & MSEP models), warm natatorium air is exhausted before the evaporator coil. On the other hand, in heating modes for units employed with purge fans (MSEP models), warm natatorium air is exhausted after the evaporator coil. This allows the unit to capture the exhaust air heat energy for heating before exhausting the air to ambient. Figure 1. PoolPak™ Natatorium Environmental Control System Schematic (MSEP) OUTSIDE AIR H T EXHAUST AIR GLYCOL PUMP HEAT RECOVERY OPTION T TO AIR-COOLED CONDENSER OR WATER-COOLED CONDENSER (OPTIONAL) S OUTSIDE AIR AIRFLOW MEASUREMENT SYSTEM EXHAUST FAN COLD SURFACE TEMPERATURE SENSOR EXTERNAL TO MPK OPTIONAL AUX HEATING COILS (HOT WATER, STEAM, GAS FURNACE, OR ELECTRIC) OR AUX COOL COILS (CHILLED WATER COIL) FT S VFD COMPRESSOR WARM RETURN AIR FROM POOL S OUTSIDE AIR DAMPER FT VFD MD T T T SUPPLY AIR H H EVAPORATOR COIL (HEAT RECOVERY COIL) EXPANSION VALVE FT MD RECIRCULATION DAMPER VFD PURGE FAN(S) FT CONDENSER REHEAT COIL SUPPLY FANS PURGE/EXHAUST AIR RECEIVER FROM AIR-COOLED CONDENSER OR WATERCOOLED CONDENSER (OPTIONAL) LEGEND HOT LIQUID REFRIGERANT HOT GAS REFRIGERANT COLD LIQUID REFRIGERANT COLD GAS REFRIGERANT T TEMPERATURE SENSOR H RELATIVE HUMIDITY SENSOR MD MOTORIZED DAMPER POOL WATER CONDENSER COOL POOL WATER WARM POOL WATER FT 4-20mA AIRFLOW TRANSDUCER (CFM) VFD VARIABLE FREQUENCY DRIVE (FAN SPEED CONTROL) AUXILIARY POOL WATER HEATER (BY OTHERS) S SOLENOID VALVE 3 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control Airflow Monitoring and Control The best way to control building pressure is by measuring and controlling airflow rates. The PoolPak™ system employs a factory mounted VFD on the supply fan array, exhaust fan, and purge fans to modulate airflow. The controller receives feedback from fan inlet measuring stations and the outdoor air measuring station to continuously monitor the outside air, exhaust air, purge air, and supply air flows. These components and ICC controller logic provide Smart Air Management ™. By tracking the airflow rate of the exhaust fan and outdoor air intake, a consistent building pressure can be maintained. See Figure 2 below for reference. The ICC takes the outside air flow measurement and controls the speed of the exhaust fan. This control maintains a constant return air flow/supply air flow differential whether the system is operating at the minimum outdoor airflow rate or maximum outdoor airflow rate (ie. economizer mode). To determine the desired air flow rates, the controller must be programmed with setpoints for the desired supply air flow, the desired return air flow, the minimum outdoor air flow, and minimum mixed air temperature allowed. During minimum outdoor air ventilation, the controller controls the outside air and recirculation air dampers to maintain the minimum ventilation air requirement. During economizer mode, the controller modulates the outside air flow and exhaust air flow to maintain space conditions. Figure 2. Airflow Monitoring and Control Schematic OUTSIDE AIR EXHAUST AIR OUTSIDE AIR FLOW MEASUREMENT SYSTEM EXHAUST FAN FT OUTSIDE AIR DAMPER VFD FT MD RECIRCULATION DAMPER WARM RETURN AIR FROM POOL VFD SUPPLY AIR PURGE FANS MD FT FT VFD PURGE/EXHAUST AIR ICC LEGEND FT 4-20mA AIRFLOW TRANSDUCER MD MOTORIZED DAMPER WITH FEEDBACK SIGNAL VFD VARIABLE FREQUENCY DRIVE (FAN SPEED CONTROL) MKW07-NATCONTROL-20140721 4 SUPPLY FANS PoolPak™ Technical Library TM Natatorium Control MPK CONSTRUCTION FEATURES Figure 3. MPK Component Isometric Hot Gas Reheat Coil • Provides reheat using recycled compressor heat • Supplies up to 80% of space heating requirement Mixing Box Optional Integral Air-Cooled Condenser • Eliminates remote ACC • Lowers Installation Cost Extruded Modular Framing and Panels • Extruded structural system for rigidity • Aluminum skins provide corrosion protection and light weight • Diamond plate floor for corrosion resistance • 2" foamfilled panels provide high strength and no exposed insulation Exhaust Fan • Low pressure drop • Precise blending of ventilation and return air • Airside economizer provides free cooling, heating and dehumidification Auxiliary Air Heating • Supplemental space heating • Available with hot water, gas, steam and electric heating sources • Electro-GuardTM coil coating • Direct drive • High efficiency with low noise • Low maintenance Return and Outside Air Filters • Available with up to MERV 13 filters • Improved IAQ Purge Fans Refrigeration Circuit Compressor Modules • Individual circuits • Each compressor module managed by an integrated stand-alone controller • Modular refrigeration system design • Redundancy • Evaporator coil available with Electro-Guard PlusTM coating • Four stages capacity loading • Constant refrigerant tube velocity and oil management • Each stage with own compressor and coils • Maxiumum sensible cooling capacity • Available with nominal and high sensible cooling coils • • • • Dual Direct drive fans VFD controlled High efficiency with low noise Purge cycle Air Measuring Stations • Accurate measurement and control of all air flows • Process grade sensors HIGHEST QUALITY CONSTRUCTION FOR LONG LIFE The MPK is built to withstand the corrosive indoor pool environment. The new design features include all-aluminum interior, extruded aluminum framing and a fully drainable tread-plate floor for extra protection. A self-flashing base prevents water from entering between the unit and curb. The 2” double wall construction with foam panels ensures minimal heat loss and maximum sound attenuation. The MPK maintains many standard features like compressors and TXVs outside of the corrosive air stream, a cleanable pool water condenser option and high performance coatings in critical areas. The MPK like other PoolPak™ systems are built in the USA and designed to operate efficiently for longer than the average industry rating of 15 years. 5 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control CONTROL FUNCTIONS TABLE OF CONTENTS Ventilation Mode 07 Purge Mode 08 Economizer Psychrometrics & Set Points 09 Economizer Modes 10 Cooling and Dehumidifying Economizer 11 Heating Economizer 12 Heating and Dehumidifying Economizer 13 Summer Ventilation Mode 14 Heating Via Heat Recovery 15 Heating/Auxiliary 16 Smart Economizing 18 Dehumidification 19 Wall Condensate Prevention 20 Pool Water Heating 22 Flywheel Air Conditioning 24 Remote or Integral Air-Cooled Condenser Air Conditioning 26 Remote Water-Cooled Condenser Air Conditioning 27 Integral Chilled Water Coil Air Conditioning 28 Selection and Specifications 29 MKW07-NATCONTROL-20140721 6 PoolPak™ Technical Library TM Natatorium Control VENTILATION MODE In the lower portion of the figure below is the natatorium (see figure 4). To its right is the pool filter, circulation pump and auxiliary pool water heater. Above it is a MPK enviromental control system. To emphasize that the PoolPak™ unit is a totally factory-packaged environmental control system including all the refrigeration components and control hardware/software, everything within the ”walls” of the unit is factory-mounted and supplied with the MPK system. The PoolPak™ control function to be discussed on each figure is listed on the left side of the page. The PoolPak™ components that pertain to that PoolPak™ control function are displayed in the schematic. The air and pool water temperatures are represented by different colors. The temperature/color “thermometer” is displayed on the right side of the figures. Ventilation is required to satisfy the ASHRAE ventilation standard 62.1, which states a natatorium must be supplied with 0.5 cfm/square foot of pool and deck area. The ventilation function is provided via the: • Exhaust and Supply Fans • Outside Air and Recirculation Air Dampers The supply fan brings air from the natatorium into the PoolPak™ unit. In the mixing box a certain amount of air is relieved by the exhaust fan such that the required amount of ventilation air can be introduced to the space via the outside air damper and supply fan. The return air that is not exhausted is recirculated via the mixing box’s bypass damper. The PoolPak™ MPK supplies approximately 5% - 10% less airflow than is returned by the return fan to maintain negative pressure in the natatorium. ASHRAE Std 62.1 Requires 0.48 CFM (9.06 CMH) of OA per Ft2 (m2) of pool and deck area. Figure 4. Ventilation Main Pool Pump Filter Auxiliary Pool Water Heater 7 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control PURGE MODE (MSEP) There may be occasions when the pool operator wants to exhaust 100% of the return air and purge the pool room with 100% outside air, such as when shocking the pool water. To accomplish the purge function, PoolPak™ MPK exhaust and purge fans are modulated to 100% and the recirculation damper is moved to the 0% open position. If the design engineer wants to provide the purge function to his customer, the designer must be sure the supplemental space heating system’s capacity is capable of heating 100% outside air on a design winter day to the desired space temperature (see figure 5). Figure 5. Purge Mode If Purge Mode is used, be sure to size auxiliary heat to handle 100% OA on design winter day. 100% OA when shocking to relieve hazardous gases coming off of the pool. MKW07-NATCONTROL-20140721 8 PoolPak™ Technical Library TM Natatorium Control ECONOMIZER PSYCHROMETRICS PoolPak™ MPK ICC controls compare the condition of the return air to the set-point quadrants on the psychrometric chart. Depending in which quadrant the return air dry bulb and dew point temperatures are, the ICC controls determine if the space requires heating, cooling and/or dehumidification. When the air coming back from the natatorium in the: In the PoolPak™ control system, the psychrometric chart is stored in the memory. The set-points are entered into the controller by the building operator. On the psychrometric chart, the set-points (84°F and 60% RH) are indicated by the point where the 84°F dry bulb line and 60% relative humidity line intersect. The PoolPak™ controls convert the DB and RH setpoints to DB and Dew Point (DP) setpoints. PoolPak™ controls use these two set-points to divide the psychrometric chart into quadrants along the vertical 84° dry bulb line and the horizontal absolute humidity point or 70° F dew point line. Figure 5 illustrates how the psychrometric chart is divided into the four quadrants. • Upper right quadrant - the space is too hot and too humid. • Bottom right quadrant - the space is too hot but the humidity is okay. • Upper left quadrant - the space is too cold and too humid. • Bottom left quadrant - the space is too cold but humidity is okay. SET POINTS - DRY BULB AND DEW POINT All conventional dehumidiers control to DB and %RH. E.G., 84˚F DB and 60% RH set point. PoolPak™ units control to dew point and DB. E.G., 84˚F DB and 70˚F DP set point. Figure 6A. Set Points If RA here, space too cold, too humid If RA here, space too hot, too humid Dew Point Humidity Ratio lbw / lba 82˚F / 28˚C 0.030 80˚F / 27˚C 0.028 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C 55˚F / 13˚C 50˚F / 10˚C 80% 60% 40% 0.012 If RA here, space too cold, humidity OK If RA here, space too hot, humidity OK 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 20% 0.000 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 9 100˚F/38˚C 110˚F/43˚C 120˚F/49˚C MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control ECONOMIZER MODES PoolPak™ units first stage of control is to utilize the economizer cycle. The economizer cycle is divided into the following modes: COOLING ECONOMIZER In this mode, the return air condition is in the bottom right quadrant (too hot, but humidity is okay). If the outside air is in either the upper left or lower left quadrants (outside air is cooler than return air), then the PoolPak™ controls will slowly modulate the exhaust and purge fans while opening the outside air damper and close the recirculation damper to introduce 100% cool outside air into the space (see Figure 6B). Then Economizer if OA in these quadrants (air is cool) If RA in this quadrant Dew Point Humidity Ratio lbw / lba 82˚F / 28˚C 0.030 80˚F / 27˚C 0.028 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C 55˚F / 13˚C 0.012 50˚F / 10˚C 80% (Too hot, but humidity OK) 60% 40% 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 20% 0.000 Figure 6B. Cooling Economizer 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 100˚F/38˚C 110˚F/43˚C OA Cool RA too hot, RH OK MKW07-NATCONTROL-20140721 10 120˚F/49˚C PoolPak™ Technical Library TM Natatorium Control COOLING AND DEHUMIDIFYING ECONOMIZER In this mode, the return air condition is in the upper right quadrant (too hot, and too humid). If the outside air is in either the lower left quadrant (outside air is cooler and dryer than return air), then the PoolPak™ controls will slowly modulate the exhaust and purge fans while opening the outside air damper and close the recirculation damper to introduce 100% cool outside air into the space. If RA in this quadrant (Too hot, too humid) Dew Point Humidity Ratio lbw / lba 82˚F / 28˚C 0.030 80˚F / 27˚C 0.028 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C Then Economizer if OA in this quadrant (cool & dry) 80% 60% 40% 55˚F / 13˚C 0.012 50˚F / 10˚C 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 20% 0.000 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 100˚F/38˚C 110˚F/43˚C 120˚F/49˚C Figure 6C. Cooling and Dehumidifying Economizer OA Cool, dry RA too hot, too humid 11 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control HEATING ECONOMIZER In this mode, the return air condition is in the bottom left quadrant (too cold, but humidity is okay). If the outside air is in either the upper right or lower right quadrants (outside air is warmer than return air), then the PoolPak™ controls will slowly modulate the exhaust and purge fans while opening the outside air damper and modulate closed the recirculation damper to introduce up to 100% warm outside air into the space. Then Economizer if OA in these quadrants, OA warmer than RA If RA in this quadrant 80% 60% Humidity Ratio lbw / lba 82˚F / 28˚C 0.030 80˚F / 27˚C 0.028 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C 55˚F / 13˚C 0.012 50˚F / 10˚C (Too cold, humidity OK) 40% Dew Point 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 20% 0.000 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 100˚F/38˚C 110˚F/43˚C 120˚F/49˚C Figure 6D. Heating Economizer OA Warm RA too cold, RH OK MKW07-NATCONTROL-20140721 12 PoolPak™ Technical Library TM Natatorium Control HEATING AND DEHUMIDIFYING ECONOMIZER In this mode, the return air condition is in the upper left quadrant (too cold and too humid). If the outside air is in the lower right quadrant (outside air is warmer and dryer than return air), then the PoolPak™ controls will slowly modulate the exhaust and purge fans while opening the outside air damper and modulate closed the recirculation damper to introduce up to 100% warm outside air into the space. The PoolPak™ controls will look to see if the outside air is cooler than the return air. Humidity is not a concern in this situation. If RA in this quadrant (Too cold, too humid) Then Economizer if OA in these quadrants, 80% 40% Humidity Ratio lbw / lba 82˚F / 28˚C 0.030 80˚F / 27˚C 0.028 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C 55˚F / 13˚C 0.012 50˚F / 10˚C OA warmer and dryer than RA 60% Dew Point 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 20% 0.000 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 100˚F/38˚C 110˚F/43˚C 120˚F/49˚C Figure 6E. Heating and Dehumidifying Economizer OA Warm,dry RA too cold, too humid THE BOTTOM LINE The PoolPak™ unit's first stage of control is to use its economizer, NOT turn on a compressor. Since the fans are already running, it makes more sense to just open the unit's dampers to maintain conditions. 13 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control SUMMER VENTILATION MODE Summer Ventilation Mode permits the pool operator to open doors and windows in the pool facility to bring in fresh outside air. While the mode is named Summer Ventilation, this mode can be operated anytime of year. In northern climates, the summer months bring ideal outside air conditions for additional natural ventilation. This control function is available with both the PoolPak™ SWHP SR, SEP, and PoolPak™ MPK SEP models via a contact closure. Refer to the respective manual’s field wiring diagram for installation instructions. For the PoolPak™ MPK, when Summer Ventilation mode is enabled, the ICC control system uses the space doors and windows as its outside air intake by closing the unit's outside air damper while driving to full 100% exhaust mode through the exhaust and purge dampers at the PoolPak™ unit. The increase in negative pressure in the space causes an increase in airflow through any open windows or doors as seen in Figures below. Figure 7. Summer Ventilation Mode MKW07-NATCONTROL-20140721 14 PoolPak™ Technical Library TM Natatorium Control HEATING VIA HEAT RECOVERY To accomplish heating via heat recovery, a multi-stage refrigeration loop is included with PoolPak™ units consisting of: • Evaporator Coil • Compressor(s) • Condenser/Reheat Coil As the return air (space) temperature drops below set-point, the first stage of refrigeration is activated. The PoolPak™ unit will remove the latent and sensible heat in the return air as it passes through the evaporator. A portion of the cold air off the evaporator is exhausted from the mixing box to allow the ventilation air to be introduced into the space. The recovered latent, sensible and compressor heat are absorbed by the refrigeration system. This heat is put back into the supply air stream at the condenser/reheat coil which is down-stream of the outside air intake. As the space temperature continues to drop, the subsequent stages of the refrigeration system are activated and continue to heat the natatorium space. Thanks to PoolPak™ units extremely high heating coefficient of performance (COP) of 5, the heat recovery method of space heating is usually more economical than using a hot water, gas or electric system (see Figure 8). Figure 8. Heating via Heat Recovery Heat Recovery thermal efficiency COP = 5 15 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control HEATING/AUXILIARY When the refrigeration system cannot maintain the natatorium space temperature, such as on a heating design day, the last stage of heat is activated. The last stage of heat, an auxiliary heater (which can be low pressure hot water, steam, electric resistance or gas furnace) is turned on via the PoolPak™ control system. This last stage should be sized to have enough heating capacity to do the entire job of heating the natatorium. The last stage does not necessarily need to be located in the PoolPak™ unit. If the pool’s existing space heating system is in good condition, the PoolPak™ can bring it on as the last stage of heat (see Figures 9 and 10). In some circumstances where the cost of fossil fuels are significantly less per delivered BTU of heat, then the PoolPak™ controls can be programmed to utilize the auxiliary heating system as the first stage of heat (See Figure 11) rather than the Heating via Heat Recovery mode. Figure 9. Heat Recovery Heating and Auxiliary Hot Water Coil Heating Auxiliary Heat should be sized to handle 100% of building heat loss and ventilation heating load on design winter day MKW07-NATCONTROL-20140721 16 PoolPak™ Technical Library TM Natatorium Control Figure 10. Heat Recovery Heating and Auxiliary Gas Furnace Heating Gas Furnace Figure 11. “Auxiliary Air Heat First” Heating Mode 17 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control SMART ECONOMIZING (MSE/MSEP) The smart economizer operation is the simultaneous operation of the heat recovery and the economizer cycle in the space heating mode, allowing the PoolPak™ unit to take advantage of wider range of outside air conditions for space heating than the standard space heating economizer mode. When the refrigeration loop is running and the space is calling for heat, the air passing over the evaporator is being cooled to saturation. The PoolPak™ control system measures the condition of air leaving the evaporator with temperature and humidity sensors in the leaving-evaporator air stream. Remember there is also a temperature and humidity sensor located in the outside air stream. The PoolPak™ control system is constantly comparing the leaving-evaporator air and outside air conditions (see Figures 12 and 13). If the outside air is warmer and dryer than the leaving-evaporator air, the control system will automatically close the recirculation damper, modulate the exhaust and purge fans while opening the ouside air damper. This exhausts the cool, saturated air coming off the evaporator coil, while bringing in the dryer, warmer outside air and then will pass it over the condenser coil, heating this outside air with heat recovered in the evaporator Dew Point Humidity Ratio and compressor. This air is then sent to the lb / lb pool. Using the smart economizing cycle, a 82˚F / 28˚C 0.030 significant amount of heat energy is saved which can be used for pool water heating. If RA in this 80˚F / 27˚C 0.028 w The smart economizer may save an owner $2,000-$4,000 per year in energy that standard economizer-mixing boxes cannot. This smart economizing is only possible if (A) the dehumidifier has a mixing box, (B) it is located downstream of the evaporator and upstream of the condenser as we have shown here, and (C) contains control software that knows what action to take when the proper energy saving conditions occur. quadrant (too cold, too humid) Air condition leaving evaporator 80% 60% 40% 20% Smart Economizer if OA in this quadrant OA not in this quadrant, must activate refrigerant system 75˚F / 24˚C 0.024 70˚F / 21˚C 0.020 65˚F / 18˚C 0.016 60˚F / 16˚C 55˚F / 13˚C 0.012 50˚F / 10˚C 45˚F / 7˚C 0.008 40˚F / 4˚C 35˚F / 2˚C 30˚F / -1˚C 0.004 0.000 30˚F/-1˚C 40˚F/4˚C 50˚F/10˚C 60˚F/16˚C 70˚F/21˚C 80˚F/27˚C 90˚F/32˚C 100˚F/38˚C 110˚F/43˚C 120˚F/49˚C Figure 13. Smart Economizer Psychrometrics Figure 12. Smart Economizer Air Flow MKW07-NATCONTROL-20140721 Simultaneous operation of Heat Recovery and Economizer when space is calling for heat and outside air is warmer and dryer than air leaving the evaporator, but cooler than room temperature 18 a PoolPak™ Technical Library TM Natatorium Control DEHUMIDIFICATION For dehumidification, the following items are included in the PoolPak™: • Humidity Sensor in the Return Air Plenum Section • Drain Pan Covering the Entire Length of the PoolPak™ • Multi-Stage Refrigeration System When space humidity rises above the set-point, the PoolPak™ activates the first stage of the refrigeration system. The humidity is removed from the return air via the evaporator coil. The sensible and latent heat along with the compressor heat are recovered and made available for air reheat. As the humidity continues to rise, additional stages of the refrigeration system are activated. The second stage is usually required when the pool is being moderately used. When the pool is being heavily used and the evaporation rate is extremely high, the PoolPak™’s final stage is activated. This final stage always has enough moisture removing capacity to keep the relative humidity below the desired set point. Moisture collected during the dehumidification process can be returned to the pool via the filter system (if allowed by code) or drained to the sewer. Over the period of a year, a pool’s worth of water can be recovered with the condensate. The condensate is chemically like the pool water from which it came. The condensate is biologically dead. Figure 14. Dehumidification Modulating capacity allows for excellent part load performance Approximately 1 pool’s worth of water per year recovered with condensate 19 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control WALL CONDENSATE PREVENTION One of the more significant control features of the PoolPak™ unit is its ability to prevent condensate from forming on certain walls of the natatorium. This benefit is accomplished by mounting a temperature sensor in the natatorium on the inside of a wall that will encounter the lowest natatorium temperatures. The best location for this sensor is on the inside of a window frame door frame of a north-facing wall or a skylight. As the outdoor temperature drops, the interior temperature drops. This condition is monitored by the wall sensor. When the cold surface temperature approaches the condensing temperature (or dewpoint) of the air in the natatorium, the PoolPak™ controls automatically reset the humidity set-point downward in order to lower the dewpoint of the air. By lowering the air’s dewpoint, condensate is prevented from forming on the natatorium walls. This space dew-point-temperature-setpoint reset is best illustrated in Figures 15 and 16. In Figure 15, the outside temperature is 60˚F and the interior surface temperature of the window on which the cold surface temperature sensor is located is 80˚F. At space conditions of 84˚F and 60% RH, the room dew point is 70˚F, which is lower than the cold surface temperature. At these conditions, condensate will not form on the window. In Figure 16, the outside temperature has dropped to 40˚F, causing the interior surface temperature to drop to 65˚F. When this condition occurs, the PoolPak™ controls automatically reduce the space RH to 55% and dew point to 65˚F (or less) to prevent condensate from forming on the glass. In Figure 16, the outside temperature has dropped to 20˚F, resulting in interior glass surface temperature to drop to 50˚F. Under these conditions, the PoolPak™ controls activate the all the stages of dehumidification. That dehumidification in conjunction with the dehumidifying effect from the 20˚F ventilation air will bring the space dew point down to 50˚F or less. As the outside temperature warms up, the dew point resets work in reverse the space is restored to its original conditions. Figure 15. Wall Condensate Prevention MKW07-NATCONTROL-20140721 20 PoolPak™ Technical Library TM Natatorium Control Figure 16. Cold Wall Temperature and Room Psychrometrics Humidity Reset Based on Cold Wall Temperature Dew Point 69˚F / 21˚C 60% 84˚F / 29˚C Humidity Reset Based on Cold Wall Temperature Dew Point 65˚F / 18˚C 50% 84˚F / 29˚C Humidity Reset Based on Cold Wall Temperature Dew Point 49˚F / 10˚C 30% 84˚F / 29˚C 21 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control POOL WATER HEATING To perform pool water heating, the following items are included in the PoolPak™ unit: • Cupro-Nickel Tube-in-Tube Pool Water Condenser • Aquastat • Flow Switch A secondary pool water circulation loop and pump, supplied by others, are required. The pool water circulation loop brings pool water from the filter system, past the mounted PoolPak™ aquastat into the pool water condenser where the water is heated. The heated pool water is then returned to the pool via the return leg of the secondary circulation loop. Pool water heating is controlled via a refrigerant solenoid valve that directs hot gas from the compressor(s) into the pool water condenser. Control of the main pool water heater is taken over by the PoolPak™ unit. As can be seen in the schematic, the thermostat for the auxiliary pool water heater is wired into the PoolPak™ aquastat. The dashed yellow line on the diagram below is a control wire (not a pipe)(see figure 17). The PoolPak™ unit will keep the auxiliary pool water heater “locked out” until the PoolPak™ unit cannot supply all the pool water heating requirements. Figure 18 shows the auxiliary pool water heater activated. Typically the PoolPak™ unit will provide 70% to 80% of the pool’s annual water heating needs. The PoolPak™ energy saving Smart Pump Controls will turn the auxiliary pool water pump on or off. When the PoolPak™ unit is not in a heat recovery pool water heating mode, the Smart Pump Control will turn off the auxiliary pool water pump. Figure 17. Heat Recovery Pool Water Heating and Smart Pump Control Smart Pump Control - Turns PWC Pump On When PPK in Pool-WaterHeating Mode PWC Pump On Auxiliary Pool Water Heater - Off MKW07-NATCONTROL-20140721 22 PoolPak™ Technical Library TM Natatorium Control A new feature with the MPK is improved pool water flow monitoring. Pool water pressure transducers are factoryinstalled in the PoolPak™ MPK unit. Pressure transducers measure the difference in water pressure across the pool water condenser and display this reading on the controller in feet of head. This reading is used to determine whether proper flow has been received by the PoolPak™ MPK unit. The unit can be operated with inadequate water flow; however, the MPK system will not go into a water-heating mode until the head pressure differential reaches the required value. Figure 18. Auxiliary Pool Water Heater Heating Mode Smart Pump Control - Turns PWC Pump Off When PPK NOT in PoolWater- Heating Mode 23 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control FLYWHEEL AIR CONDITIONING Flywheel air conditioning uses the enormous thermal mass of the swimming pool as a heat sink during the day. Flywheel air conditioning does not require any remote condensers and is typically used in locations that have warm days and cool nights. During the day while the natatorium is occupied and space cooling is required, the outside temperature is cooler than the inside temperature and the PoolPak™ unit will cool the space with its 100% outside-air economizer. This condition usually occurs from the time the pool opens in the morning, about 6 am, until the outside temperature rises above the inside temperature in the early afternoon, about 12:30 p.m. Figure 19 illustrates this point. When the outside temperature is higher than the inside temperature the PoolPak™ unit reduces the outside air to the minimum quantity and cools the space mechanically. The PoolPak™ unit will only activate the number of mechanical cooling stages needed to meet the cooling load. The heat removed from the air is stored in the pool water. The space is mechanically cooled for a total of about 7 hours. See Figure 20. During this air conditioning mode the water temperature can rise about one degree above the set-point. The PoolPak™ controls limit this rise to a maximum of two Fahrenheit degrees. This pool water temperature rise is offset by the evaporative cooling effect occurring throughout the entire occupied period. Water agitation by the swimmers will accelerate this evaporative cooling effect. When the outside air temperature drops back below the inside temperature in the early evening, about 7:30 p.m., the PoolPak™ unit resumes space cooling with its economizer. The economizer cooling continues until the pool closes, about 11:00 p.m. If the pool temperature is below set-point at closing, the PoolPak™ controls close the outside air dampers until the pool opens the next morning. See Figure 21. Should the water temperature exceed the set-point at closing time and additional pool water evaporative cooling is required to return the water temperature to set-point, the economizer operation continues circulating the cooler and dryer night air over the water until the pool water reaches set-point. In this night mode the pool water evaporation rate increases dramatically because the pool water is warmer than the air above it. Figure 19. Northern Climate Summer Design Data - Flywheel Air Conditioning Mode MKW07-NATCONTROL-20140721 24 PoolPak™ Technical Library TM Natatorium Control Figure 20. Flywheel Air Conditioning - Occupied Mode Figure 21. Flywheel Air Conditioning - Unoccupied Mode 25 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control REMOTE OR INTEGRAL AIR-COOLED CONDENSER AIR CONDITIONING For this cooling mode, the refrigerant is connected to a remote or integral air-cooled condenser. When remote, addtional field-supplied, field-installed piping and refrigerant is required. When cooling is called for in the space, the PoolPak™ controls open the solenoid valve sending hot gas to the air cooled condenser. The PoolPak™ refrigeration system removes heat from the natatorium and rejects the heat to the outside air through the external air-cooled condenser. The evaporator coil cools and dries the air which is delivered to the natatorium. If there is a simultaneous call for space cooling and pool water heating, the PoolPak™ controls will close the refrigerant solenoid valve sending hot gas to the air cooled condenser and open the valve to the pool water condenser. The heat recovered from the evaporator coil is used to heat the pool water (see Figure 22). Figure 22. integral Air-Cooled Condenser Air Conditioning MKW07-NATCONTROL-20140721 26 PoolPak™ Technical Library TM Natatorium Control REMOTE WATER-COOLED CONDENSER AIR CONDITIONING In this mode a cleanable cooling tower water-cooled condenser module or non-cleanable chilled water condenser module is provided. The refrigerant side of this water condenser is attached to the discharge side of the compressor circuit. When cooling is called for in the space, the PoolPak™ controls open the valve directing hot gas into the cooling tower or chilled water condenser. The PoolPak™ refrigeration system removes heat from the natatorium and rejects the heat through the cooling tower water condenser or chilled water condenser. The evaporator coil cools and dries the air which is delivered to the natatorium. If there is a simultaneous call for space cooling and pool water heating, the PoolPak™ controls will close the valve sending the heat to the cooling tower or chilled water condenser and directs the heat to the pool water condenser. The heat recovered from the evaporator coil is used to heat the pool water (see Figure 23). Figure 23. Remote Cooling Tower Condenser or Chilled Water Condenser Air Conditioning 27 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control INTEGRAL CHILLED WATER COIL AIR CONDITIONING If chilled water is available at the natatorium, then a chilled water coil and three-way control valve can be installed in the PoolPak™ unit down-stream of the auxiliary air heating coil. When cooling is needed for a space, the PoolPak™ controls open the chilled water valve. The coil cools and dries the air which is delivered to the natatorium. If there is a simultaneous call for space cooling and pool water heating, the PoolPak™ controls will shut the chilled water valve and activate the refrigeration system. Heat recovered from the evaporator coil is used to heat the pool water see (Figure 24). Figure 24. Chilled Water Coil Air Conditioning MKW07-NATCONTROL-20140721 28 PoolPak™ Technical Library TM Natatorium Control SELECTION AND SPECIFICATIONS ENGINEERED FOR RELIABILITY Designed for continuous exposure to corrosive pool moisture and outdoor weather, PoolPak™ units eliminate the high maintenance and service requirements typical of conventional pool environmental control equipment. All-copper coil construction and multi-stage, special-duty compressors add to the long-term durability built into every PoolPak™ system. INSTALLATION FLEXIBILITY The PoolPak™ system easily adapts to new construction, retrofit or replacement applications. It can be roofmounted, installed at ground level outdoors or installed indoors, providing flexibility to meet virtually any architectural requirement. SELECTION ASSISTANCE Swimming pools and their enclosures vary greatly in size, design and use. As a result, selecting the right size for your application depends on a range of factors, and should not be based solely on moisture evaporation rates. A local PoolPak™ representative can select the right system for all your needs. • Building size and construction • Typical design conditions (water temp. range: 78˚F - 82˚F, air temperature, 2˚F above water temperature, relative humidity, 50% - 60%) • Total pool surface area • Building design heat loss • Moisture evaporation rates (max/min) • Average hours of pool area use • Air flow volume rate • Method of air distribution • Additional areas served by system (changing rooms, halls, etc.) • Ventilation for odor control 29 MKW07-NATCONTROL-20140721 PoolPak™ Technical Library TM Natatorium Control The following chart is provided for general reference only. A PoolPak™ International, LLC. representative will gladly help you determine the optimum PoolPak™ system for your specific requirements. MPK Unit Performance (at 82˚F and 60% RH) MPK Model# 0060 0070 0080 0090S 1 Evap Coil Type 1 Std (HiS) Std (HiS) Std (HiS) Std (HiS) Moisture Removal Rate (Lb/Hr) 329 (350) 377 (412) 437 (455) 472 Evaporator Total Capacity (MBtu/H) Evaporator Sensible Capacity (Mbtu/H) D - cabinet (30-40kCFM) 743 (813) 401 (449) 852 (946) 460 (518) 977 (1056) 523 (583) 1061 570 Compressor Input Power (KW) Total Heat Rejection (Mbtu/H) Reheat Capacity (MBtu/H) 56.9 (55.5) 63 (63.5) 74.6 (74.8) 80.1 927 (993) 1056 (1152) 1219 (1299) 1321 927 (993) 1056 (1152) 1219 (1299) 1321 HiS = High Sensible Cooling Capacity option performance in parentheses TM PoolPak™: The Leader in Indoor Pool Dehumidification 3491 Industrial Drive . York, PA 17402 . USA . 800-959-7725 . Fax 717-757-5085 for more information: www.poolpak.com MKW07-NATCONTROL-20140721