1. Achieving Dry Outside Air in an Energy-Efficient Manner PSU Building Thermal and Mechanical Systems Laboratory Environment A/E Stanley A. Mumma, Ph.D., P.E., Professor, and Kurt M. Shank, M.S. Graduate Department of Architectural Engineering College of Engineering Penn State University @ University Park, PA

2. Presentation Outline l Introduction and Objectives l Potential Dedicated OA System Configurations l Psychrometric Analysis of the DOAS l Load and Hourly Energy Analysis of the Configurations l Conclusions and Recommendations

3. Objective l Develop a fundamental understanding of OA preconditioning equipment for dedicated OA systems composed of: Passive desiccant wheels, Sensible heat exchangers, Deep dehumidification cooling coils. l Present the design load and energy performance perspective.

4. Potential Configurations l #1, Conventional Cooling Coil, Heating Coil, and Humidifier; HC CC Humidifier OA

5. l #2, A Run around heat recovery system added to configuration #1. HC CC OA Humidifier

6. l #3, Passive Desiccant (Enthalpy) wheel added to the heating and cooling coils HCCC OA RA EW

7. l #4, Enthalpy wheel, Cooling Coil and run around Heat Recovery HC CC OA EW RA

8. l #5, Dual Wheel DOAS Unit CC OA EW RA SW 01 2 3 4 5 6 55F DBT, 45F DPT 80F DBT, 55F DPT 45F PH State Point #, typ

9. l #6, Conventional All Air VAV System with air side Economizer. –Illustration unnecessary

10. Design energy demand to treat 10,000 scfm of OA in Atlanta Conf. # CC load Tons Humid- ification k-Btu/hr Heating k-Btu/hr 194238465 285238465 3510108 4430108 54300 6852380

11. Energy consumed to treat 10,000 scfm of OA in Atlanta (3744 hr) Conf. # CC TH Reheat k-Btu Heating k-Btu Humid ification k-Btu 1113,000255,000110,000155,000 2103,00014,800110,000155,000 3103,000255,0007,0000 483,00014,8007,0000 589,000000 692,00000155,000

12. Four Regions on the Psych. Chart, w/ Atlanta Data 45 55 70 80 Region A, 1,635 hours Region B, 784 hours Region C, 1,111 hours Wet regions Dry regions Region D, 214 hrs 6 5 3 4

13. l #5, Dual Wheel DOAS Unit CC OA EW RA SW 01 2 3 4 5 6 55F DBT, 45F DPT 80F DBT, 55F DPT 45F PH State Point #, typ

14. Region A, enthalpy wheel, cooling coil, and sen. wheel 45 55 70 80F 1 6 2 5 3 4 Key: 1-2-6, enthalpy wheel 2-3, cooling coil 5-6, 3-4, sen. wheel

15. Region B, cooling coil, and sen. wheel 45 55 70 80F 1,2 6 5 3 4 Key: 1/2-3, cooling coil 5-6, 3-4, sen. wheel

16. Region C, enthalpy wheel and cooling coil 45 55 70 80F 1 2 5, 6 3, 4 Key: 1-2-5/6, enthalpy wheel 2-3/4, cooling coil

17. Region D, enthalpy wheel, and sen. wheel 45 55 70 80F 1 6 2 5 3 4 Key: 1-2-6, enthalpy wheel 5-6, 3-4, sen. wheel

18. Control Status of DOAS Equipment (See Tech Paper 4428) RegionEnthalpy Wheel, CTL CC, CTLSensible Wheel, CTL A Max speed and effectiveness Modulate to hold 45F Modulate to hold 55F BOff Modulate to hold 45F Modulate to hold 55F C Mod. Speed to req’d DPT Modulate to hold 55F Off D Mod. Speed to req’d DPT Off Modulate to hold 55F

19. Conclusions: l The DOAS, configuration 5, exhibits superior demand and energy performance when compared to the other configurations analyzed. l The DOAS assures verifiable ventilation delivery. l Decoupled sensible and latent cooling contributes to improved comfort, health and productivity

20. Recommendation: l Make the transition to dedicated OA designs. l Use configuration 5 to decouple the space sensible and latent loads. l Save energy, improve quality of the spaces, and minimize litigation potential.