December 12, 2018 Advanced Desiccant Dehumidification Technologies Keep it Dr Dry, wi with CDI CDI
DESI DESICC CCANT NT FUNDAM UNDAMENT NTALS PS PSYCHRO CHROMETRI RICS CS REVI REVIEW Mark Welker
Psychrometric Chart: 3 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Relative Humidity: Relative Humidity (%) is the ratio of: Actual water vp in the air vs. o The water vp if the air were saturated at that same dry bulb temperature. o Not an absolute value - dependant upon the db at which it was measured. 4 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Humidity Ratio (Specific Humidity): Humidity Ratio (lb/lb or gr/lb) is the absolute amount of moisture in the air. This is like counting the water molecules and adding their weight together. o There are 7000 grains in one pound of water. 5 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Vapor Pressure: Vapor Pressure (in. Hg) is the pressure exerted by water molecules on their surrounding environment. This is an absolute measurement. Unit of measure is inches of mercury, which tells us how high the vapor pressure can lift o a column of mercury due to its own pressure. This is the driving force behind how the desiccant dehumidifiers attract water molecules out of the air and into their surface. 6 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Dew Point: Dew Point (°F) is the temperature where moisture will condense out of the air onto nearby surfaces forming “dew”. This is an absolute measurement. The higher amount of moisture in the air, the higher the dew point. 7 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
GE GENERAL L OV OVERVIEW W OF OF DEHUM DEHUMIDI DIFICAT CATION N SY SYSTEMS
Common Mechanical Based Systems: Direct Expansion System Chilled Water, Glycol or Brine System Cool-Reheat System Ammonia Systems 9 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Mechanical vs Desiccant Application: Air is circulated over a cold coil and cooled to saturation. Relatively “Lower First Cost” type systems. However… Dewpoint reduction is physically limited. Min CC LAT’s: 43°F db/42.9°F wb (99.2% RH & 32°F SST). Running these systems at or below 32°F SST will: Cause coils to frost up - requires HGRH Cycles to defrost o Defrosting is not Dehumidifying o If NOT Dehumidifying – what happens to your Control Levels? o Likely add reheat to meet required LAT conditions o Added Energy + Downtime = $$$ o 10 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Refrig frigera ratio tion v vs Desi sicca ccant Mechani hanical al System em: Desi esiccant Syst ystem: Deposition (Vapor to Solid): Sublimation (Solid to Vapor): Ice crystals form on surfaces w/o going through Ice crystals are removed from surfaces w/o going through liquid phase liquid phase. 11 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
What at D Desic iccant nt Dehum humidif idific icat ation i ion is N NOT: NOT a Substitute for Cool/Reheat in Comfort Applications • NOT an Energy Saving Scheme • NOT a Cost Saving Scheme • NOT a Heat Wheel • 12 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Dry Desiccant Systems: How They Work Desiccants ad(b)sorb and release moisture based upon ∆ vapor pressure. 3 3 – Ph Phase ase Pr Proce ocess: ss: 1. Sorpt rption on Ph Phase ase: Desiccant ant ab(d) d)sor orbs bs moistur ure. o VP of desiccant is lower than that of the conditioned air stream. o Rotor surface attracts moisture out of the process air. o Pr Proce ocess ss Air is Warm rm & & Dry y Becau cause se: o 1. 1. Heat at of Conve nversi sion on. 2. 2. So Some e React activa vation on H Heat at Carr rry y Over er. 13 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Dry Desiccant Systems: How They Work 2. DESOR ORPTI TION ON (REAC EACTIVAT VATION) PHASE ASE: o Desiccant cant r releases w eases water. o VP of desiccant is higher than that of reactivation air stream. o Moisture is passed into the reactivation air stream. o Act ctivated by by v ver ery hot y hot ai air s strea eam of m of 250 250+°F (high temp & high moisture = high vapor pressure). 14 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Dry Desiccant Systems: How They Work 3. COOLI LING NG PHASE ASE: o Desi esicc ccant c coo ools t s to o or original s stat ate. o VP of desiccant is lower than the conditioned air stream. o Wheel’s surface is warm and dry (~110 to 135°F). o Need eeds s to o be be coo ooled bef befor ore ad( ad(b) b)so sorbtion oc occu curs (low temp & low moisture = low VP). o Opt ptima mal R Rang ange: 50 50 to o 90 90°F. 15 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Dry Desiccant Systems: How They Work 2 3 1 VP differential dictates where moisture migrates Even against air flow direction o Efficient year round: Colder air actually increases the wheel’s o efficiency. Desiccant is at optimum performance at 50F to 55F Will not “over cool” space or require defrosting cycles. This means consistent controllable humidity and temperature independent of one another
APPLIC LICATION TIONS
Welker’s Rules of Engagement First Rule: Do as much moisture removal as possible with refrigeration. Second Rule: See First Rule. 18 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Applications That BENEFIT from DESICCANT DEHUMIDIFICATION • Very Dry Air Required • Independent Control of Temperature/ Humidity • Fog or Condensation Control • Control of Dripping (Excessive Condensation) • Enhanced Indoor Air Quality • Improved Safety & Comfort • Structural Decay (Corrosion) Prevention • Mold or Bacteria Control • Improved Process Operation 19 Crea eating ng the he climat ate you n ou nee eed d to achi chiev eve your our cri ritica cal missi sion on
Unders nderstandi anding ng the he Appl pplicati ation on Requi equirem rements ents Ins nside de Condi onditions ons - Ho How w Dr Dry? Dry enoug ough h to achiev eve e the e maximum um econom onomic benef nefit—and no no dri drier. o Humidity control projects are often the result of summer problems o So ... What is the moisture condition during the winter when no problem occurs? o Wide range of parameters / requirements – “No Silver Bullet” o Pharmaceutical Applications: Food Plant Applications: Temperature: 55 - 200F o Temperature: -40 – 80+F o Humidity: 10 - 70% RH o Humidity: 1 - 50% RH o Pressurization: Negative to o Pressurization: Negative to Positive Positive o Ventilation: 0 - 100% OA Ventilation: 0 - 100% OA o o Filtration: 30% - HEPA Filtration: 30% - HEPA o o Dry Storage Applications: Manufacturing Process Temperature: 30+F Applications: o Humidity: 0 - 50% RH Temperature: 55 - 200F o o Pressurization: Negative to Positive Humidity: 0.1 - 70% RH o o Ventilation: 0-100% OA Pressurization: Negative to o o Positive Filtration: 30% - HEPA o Ventilation: 0 - 100% OA o Filtration: 30% - HEPA o 20 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
Gener neral A al Applic icat ation C ion Categ egor ories ies Corrosion Prevention • Condensation Prevention • Mold & Fungus Prevention • Moisture Regain Prevention • Product Drying • 21 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
12,950 CFM SA = 15.15+18.49=33.64 TR 20 TR +209,790 BTUH for 15 deg heat rise Total BTUH = approx. 840,000 BTUH 22 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
= 45.5TR 23 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
24 CDI is s the Prem remier Pro rovider of of Desi esiccant an and Air r Han andling S Syst ystems
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