Low Cost Desiccant Wheels
AND
Heat Pump
Liquid Desiccant Regeneration
Presented at
Integrated Energy Systems
Peer Review Meeting
April 30, 2002
Presented by
Douglas Kosar, Principal Research Engineer
Energy Resources Center, University of Illinois at Chicago
E-mail: dkosar@uic.edu Web Site: www.erc.uic.edu
Sponsored by

Heat Pump
Liquid DesiccantRegeneration••••

NREL 3/01 RFP
7/02 – 12/02 schedule$34,780 funding
Project goal:– prototype designs via CFD– Primary COP > 1.0– RSHI < 1000 Btu/lb• TAT & IES impact:– higher efficiency TAT– more cost effective IES• Project team:– UIC/ERC– DryKor

Low Cost
Desiccant Wheels••••

NREL 4/01 RFP
7/02 – 4/03 schedule$115,220 funding
Project goal:– prototype rotor(s)– ∆ gr/lb > 50 (@600 fpm)
– 50% $/cfm reduction• TAT & IES impact:– lower cost TAT– more cost effective IES• Project team:– UIC/ERC– RotorSource– ProFlute– IRE & NRG

Liquid Desiccant Heat Pump (LDHP)
NREL testing– COPs up to 3.0 (0.84 PCOPs)– Energy efficiency promising/potential for high COP

Advanced LDHP
Theoretical COPs up to 7.0– 1 unit of energy into compressor– 3 units of heat into evaporator– 4 units of heat out of condenser (into regenerator)

Fluid Equalizer

Advanced LDHP “Fluid Equalizer”
Double Diffusion (DD)– Solute (LiCl) diffusion and solvent (water) osmosis– Reductions in thermal mass of liquid desiccantsolution cycled between collector and regenerator
Thermal Mass
Reductions(%)

Equipment
COP

Primary
COP

Equipment
RSHI (Btu/lb)

Comments03.40

0.95

1413

103.67

1.03

1271

20

3.94

1.10113030

4.22

1.18

989

40

4.49

1.26

848

50

4.76

1.33

707

60

5.03

1.41565

DryKor catalog datafor Model DL 4.0.
Power plant to site
efficiency = 28%.
Prototype targets:Primary COP = 1.0
RSHI = 1000 Btu/lb
NREL targets:Primary COP = 1.4
RSHI = 700 Btu/lb

Advanced LDHP Project Team• ERC at UIC– 40 years desiccant experience– Fluent CFD modeling– www.erc.uic.edu• DryKor– Israeli based– Atlanta distribution– 500 systems installed– schools, hotels, QSRs
supermarkets, hospitals,industries, etc.
– www.drykor.com

Advanced LDHP Tasks & Milestones• 7-12/02: Task 1 High Efficiency System Design– Modeling Algorithms (including but not limited to DD)– Fluent CFD Simulations and Evaluations– DryKor Feedback• 12/02: Deliverable from Single Task Phase 1– High Efficiency LDHP Design Report– 0.5 inch ∆P, 1.0 ARI PCOP, & 1000 Btu/lb ARI RSHI

• 1/03: Phase 2 Go/No-Go Decision– Task 2 Advanced Regeneration Bench-ScaleExperiments– Task 3 Manufacturing Cost Analysis– Task 4 High Efficiency Full Scale Prototype

Advanced LDHP Summary
noting Technical Approach & Barriers/Risks• Potential advancement in LDHP
energy efficiency using double
diffusion (DD) reductions inamount of solution regenerated• Much scientific debate withmultiple DD theories in playthat presents barriers/risks• UIC Chemistry Department
faculty expertise in diffusion andosmosis theory will overcomebarriers and minimize risk
during CFD modeling project

SOA Desiccant Wheel Media$/cfm
SOA Rotor Costs• Formed Matrix @ $18/lb$.06($.50 to $14/lb materials)• Desiccant in Matrix@ $9/lb $.12($.50 to $10/lb materials)• Hub/Spoke/Rim/Face$.06• Total Cost of Rotor$.24
Specification: 8 inches deep
@15 lb/ft3 density 600
80% desiccant fpm

Low Cost Desiccant Wheels (LCDW)
Design Parameters• Flute size
– NTUs– Pressure drop
• Media Depth• Media density– Matrix wall thickness– Desiccant type
– Desiccant loading– Binder level• Media strength/stability– Manufacturing stress– Thermal cycling

LCDW with High Performance
0.7

180.6

160.5

140.4
120.30.2

100.18354045505560
Grain Depression, gr/lb ARI 1

65

From 40 to 45 gr/lb: 23% increase in cost
From 45 to 50 gr/lb: 26% increase in cost
From 50 to 55 gr/lb: 30% increase in cost

C o s t, $ /lb W a te r R e m o v e d

C o s t, $ /c fm

Cost vs. Performance Tradeoffs• NREL Goals– ∆ gr/lb > 50(@600 fpm)
– 50% $/cfm
reduction fromSOA wheels• Incremental
improvements ingrain depression
are costly in the50 gr/lb range

LCDW Project Team• ERC at UIC– 40 years desiccantexperience (14 testing)– Sorption Test Facility– www.erc.uic.edu• Rotor Source– US cassette &unit manufacturer– www.rotorsource.com• ProFlute– Swedish supplier to RS– www.proflute.se• Consultants– NRG/Dr. Collier– IRE/Dr. Belding

LCDW Tasks & Milestones• 7-9/02: Task 1 SOA Review/Advanced Modeling• 9-12/02: Task 2 Media/Rotor Experiments• 1/03: Task 3 Manufacturing Cost Analysis• 2/03: Task 4 Low Cost/High Performance Design• 3-4/03: Task 5 Rotor Prototype– NREL test of prototype in 4/03
– Summary report/presentation deliverable in 4/03

• 4/03: Phase 2 Go/No-Go Decision– Cassette cost reduction tasks– Seals, drives, frames, etc.

LCDW Summary
noting Technical Approach & Barriers/Risks• Potential low cost/high performance rotor with– Shorter depth wheel– Smaller height flute– Thinner paper matrix– Higher performance desiccant/binder• 50% SOA cost reduction very challenging at– Grain depression of 50 gr/lb– Face velocity of 600 fpm– ARI 940 Rating #1 of 95Fdb/75Fwb (99 gr/lb)• Possible, but at what
– Pressure drop?
– Regeneration Sensible Heat Input (RSHI)?