Munters Heat Exchangers Brad Perdew Applications Engineer 8/27/12 DOAS Configurations Cheryl Hughes Regional Sales Manager October 11, 2016 cheryl.hughes@munters.com
Munters DOAS Configurations Presentation Purpose of Dedicated Outside Air Systems Review Building Loads Talking Dew Point is Critical How DOAS is Applied Munters Core Components Munters DOAS Configurations Munters Cost to Operate Spreadsheet
Purpose of DOAS ASHRAE recommends decoupling sensible and latent loads ASHRAE recommends lower delivered dew points Lower than the original Neutral Air Unit Lower than standard packaged DX or chilled water can deliver Outside air is good, but consumes a lot of energy to treat 90.1 wants to reduce energy LEED makes you prove you have reduced energy
Sensible Loads Have Reduced Less Cooling Required, Less Reheat Available = Reduced Lighting Load = Reduced Solar Load = Improved Envelope
Outdoor Air People Infiltration Operations No Reduction in Moisture Load Requires Active Dehumidification
Typical Buildings Design Dew Points Building Space Served Dew Point Control Meeting Space Single 51-55 F Loose Grocery Store Single 48-52 F Medium Pharmaceuticals Single 49-56 F Tight Hotel/Condo Multiple 54-56 F Loose Office Multiple 52-55 F Loose Classrooms Multiple 52-55 F Loose Healthcare Depends 42-52 F Depends
Supply Air at the Correct Dew Point SPACE DEW POINT VS. OUTDOOR AIR CFM DELIVERED PER PERSON SPACE DEW POINT 80.0 75.0 70.0 65.0 60.0 55.0 50.0 45.0 0 10 20 30 40 O/A CFM DELIVERED PER PERSON 40 DP 45 DP 50 DP 55 DP 60 DP Chart accounts for internal latent load of occupants at 200 Btu/hr/person
Multiple DOAS Options Different DOAS technologies Different system combos and methods of laying out DOAS Standard or custom solutions for every application EVAPORATIVE COOLING SENSIBLE ENERGY RECOVERY EVAPORATIVE COOLING & SENSIBLE ENERGY RECOVERY DEHUMIDIFICATION & TOTAL ENERGY RECOVERY
Munters Products Core Components Focus on Humidity Control Over-Cool & Reheat Wringer Cycle Cooling Coil Surrounded by Single Heat Exchanger Active Desiccant Reactivated by external source of heat Reactivated using site recovered energy Focus on Energy Recovery Wheels Enthalpy or Sensible Heat pipes Plates Counter-flow or Crossflow EPX Polymer Tubes
Munters DOAS Products Without Exhaust Air Energy Recovery Cool-Reheat Wringer DryCool / HCU DDS (Config 1,2 & 5) HCD ICA With Exhaust Air Energy Recovery Sensible Heat Recovery Total Heat Recovery Sensible Wringer Plus Total Wringer Plus DryCool ERV DDS (Config 3 & 4)
Old Version of Neutral air to space 75 F at 55 F dewpoint = 50% rh 55 F 75 F DX Cooling Coil Hot Gas Reheat Compressors Supply Fan OA S/A
Now DOAS Should Deliver Over Dried Air to Space 75 F at 45 F dewpoint = 35% rh 45 F 75 F DX Cooling Coil Hot Gas Reheat Compressors Supply Fan OA S/A
Cool-Reheat (Brute Force) Cool air to desired leaving dew point and then reheat it to Space Neutral temperature Reheat must not be a "new" energy source per 90.1 Packaged DX unit (with Hot Gas Reheat) Highly competitive, Munters rarely sells Outside Air SA Cool Reheat
Over-Cool & Reheat (Common Selection) 60 ton CU 47.5F dp
Wringer Introduced by Des Champs in 1980 as a patented process surrounding a dehumidification coil with a single energy recovery device First pass across energy recovery device pre-cools humid air before coil... Reducing refrigeration requirements Second pass across energy recovery device reheats leaving air, reducing or eliminating the need for supplemental reheat Achievable dew point limited by coil temperature Sensible Heat Exchanger Outside Air SA Cool Reheat
Wringer 50 ton CU 46.4F dp
Exhaust Air Energy Recovery Pre-conditions OA with energy recovery device before cooling to desired dew point and then reheat it to space neutral temperature EA Return/Exhaust Air Reheat Outside Air SA Energy Recovery Device CW Coil DX (AC/WC/WSHP)
Special WARNING About Energy Recovery System Performance! TAG MODEL NUMBER AIR CAPACITY RETURN AIR TEMP CFM SUMMER WINTER SUPPLY AIR FAN EXHAUST AIR FAN SUPPLY EXHAUST (db/rh, F) (db/rh, F) ESP TSP HP ESP TSP HP RTU-1 PVR-12 11,600 11,600 75/50% 72/- 1.0 4.2 15.0 1.0 2.7 10.0 RTU-2 PVR-6 6,100 6,100 75/50% 72/- 1.0 4.0 7.5 1.0 2.9 5.0 RTU-3 PVR-4 4,450 4,450 75/50% 72/- 1.0 4.3 5.0 1.0 2.9 5.0 SUPPLY AIR, SUMMER SUPPLY AIR, WINTER ROTARY HXR DX COIL HEAT EXCHANGER Ind. Gas Supply E.A.T. L.A.T. E.A.T L.A.T. TOTAL E.A.T L.A.T. Heat MBH Air (db/w b, F) (db/w b, F) (db/w b, F) (db/w b, F) MBH (db/w b, F) (db, F) (Output) (db, F) Accessories 90/73 77.6/66.8 80.6/67.7 58/58 462.1 0/- 38.0 640.0 88.9 90/73 77.8/66.8 80.8/67.7 59/59 243.0 0/- 38.0 160.0 62.2 90/73 78.1/67 81.1/67.9 61/61 180.4 0/- 38.0 120.0 62.9 Critical Relationship
Exhaust Air Energy Recovery 50 ton CU 46.5F dp
Wringer Plus Adds exhaust air energy recovery, sensible or total, to a Wringer Enthalpy Wheel Heat Pipe, Plate or EPX Sensible Wheel Heat Pipe or Plate EA Return/Exhaust Air Outside Air SA Cool Reheat
Wringer Plus 30 ton CU 46.2F dp
DryCool Hybrid Cooling plus Active Desiccant DH Outside air first passes the pre-cool coil to < 60 F saturated The pre-cooled air then passes thru the desiccant wheel to continue drying the air to ~45 Fdp, the dehumidification process simultaneously raises the dry bulb temperature to ~75 F Combining pre-cooling with active desiccant dehumidification reduces refrigeration requirements by ~40% Outside air for reactivation is heated by a condenser coil, the rest of the condenser heat is rejected to atmosphere EA EA Outside Air Outside Air SA Cool Desiccant DH Wheel
DryCool Standard / HCU 40 tons precooling 43.6 F dp
no. 24
DryCool Chilled Water One 10 ton DX ckt 45.3 F dp
DryCool ERV Adds exhaust air energy recovery to DryCool unit Suitable for indoor installations Condenser Coil B Return/ Exhaust Air React Condenser Coil A Outside Air Outside Air SA Energy Recovery Wheel Cool Desiccant DH Wheel
DryCool ERV 26 ton CU 43.7 F dp
Enthalpy Wheel + Desiccant
Cost to Operate Comparison
Munters DOAS Presentation Recap Dedicated Outside Air Systems should be considered for all occupied spaces to provide adequate ventilation and meet codes Properly conditioning outside air takes a lot of energy, it makes sense to consider all ways to reduce operating costs Sizing and operating DOAS to maintain proper humidity control is crucial to occupant comfort and integrity of the building envelope Munters experience in humidity control plus Des Champs experience in energy recovery provide customers with a wide range of product options and expertise Each Munters system design has advantages and limitations to consider and can be compared side by side to aid in the decision making process
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