1. Munters Heat Exchangers DOAS Review: Cost to Operate & Energy Analysis
Brad Perdew
Applications Engineer
8/27/12
DOAS Review: Cost to Operate & Energy Analysis
Mike Herwald Regional Sales Manager October 7, 2015

2. DOAS Unit Comparison
Brute Force
Condenser Heat Reactivated Desiccant (HCUc)
Enthalpic Heat Recovery (Single Wheel)
Enthalpic Plus Sensible Heat Recovery (Wringer Plus)
Condenser Heat Reactivated Plus Enthalpic Recovery (ERV)

3. Assumptions
Baltimore TMY Bin Data – All Hours
10,000 CFM, 45 Dew-Point, Neutral Supply Required
$0.08/Kwh and $12/Million BTUH, COP=3, 80% Heat
75% Enthalpic Recovery
60% Sensible Reheat Effectiveness
Reheat Available from Compressor – 15 Deg. Max
Reheat Cost Assessed 72 Deg. and Cooler

4. Cost to Operate Comparison

8. HCUc vs. Single Wheel Base Line

9. HCUc vs. Single Wheel Base Line

12. Wringer Plus vs. DryCool ERV

13. Wringer Plus vs. DryCool ERV

14. Cost to Operate Comparison

15. DOAS Comparison Recap
The Most Efficient Systems Provide Reheat that is not “Hot Gas Reheat” (Heat Exchanger or Desiccant Reheat)
Dual Heat Exchanger Systems Dominate with Superior summer and winter performance characteristics
Condenser Heat Reactivated Desiccant Provides the Minimum DH Compressor Size – Lower KW/Ton and Better MRE
Efficient DOAS systems, ie Wringer Plus or ERV can payback very quickly vs. brute force options

16. DOAS Recap
45 Dew-Point Dry Air Required for “People Driven Outside Air”
Reheat systems required, and reheat systems can drastically increase recovery potential
All DOAS Systems should be viewed the same, chilled beam or not
The most efficient Systems are not Necessarily the most Expensive
Evaluate DOAS offering for meeting outdoor air needs – There are many offerings that DO NOT include required performance

17. Questions