The desired performance of unpressurized integral collector storage systems hinges on the appropriate selection of storage volume and the immersed heat exchanger. This paper presents analytical results expressing the relation between storage volume, number of heat exchanger transfer units, and temperature-limited performance. For a system composed of a single storage element, the limiting behavior of a perfectly stratified storage element is shown to be superior to a fully mixed storage element, consistent with a more general analysis of thermal storage. Since, however, only the fully mixed limit is readily obtainable in a physical system, the present paper also examines a division of the storage volume into separate compartments. This multielement storage system shows significantly improved discharge characteristics as a result of improved elemental area utilization and temperature variation between elements, comparable in many cases to a single perfectly stratified storage element. In addition, the multielement system shows increased robustness with respect to variations in heat exchanger effectiveness and initial storage temperature.

1.
Duffie
,
J. A.
, and
Beckman
,
W. A.
, 1991,
Solar Engineering of Thermal Processes
, 2nd ed.,
Wiley
,
New York
.
2.
Cole
,
R. L.
, and
Bellinger
,
F. O.
, 1982, “
Natural Thermal Stratification in Tanks, Phase 1 Final Report
,”
Argonne National Laboratory
, Report No. ANL-82-5.
3.
Hollands
,
K. G. T.
, and
Lightstone
,
M. F.
, 1989, “
A Review of Low-Flow, Stratified-Tank Solar Water Heating Systems
,”
Sol. Energy
0038-092X,
43
, pp.
97
105
.
4.
Fanney
,
A. H.
, and
Klein
,
S. A.
, 1988, “
Thermal Performance Comparisons for Solar Hot Water Systems Subjected to Various Collector and Heat Exchanger Flowrates
,”
Sol. Energy
0038-092X,
40
, pp.
1
11
.
5.
Arora
,
S.
,
Davidson
,
J.
,
Burch
,
J.
, and
Mantell
,
S.
, 2001, “
The Thermal Penalty of an Immersed Heat Exchanger in Integral Collector Storage Systems
,”
Proceedings of Solar 2001
.
6.
Burch
,
J. D.
, and
Gawlik
,
K. M.
, 2001, “
Using an Ersatz Thermosiphon Loop to Model Natural Convection Flows Inside a Shallow Enclosure
,”
Proceedings of Solar 2001
.
7.
Johnson
,
G. A.
, and
Goldschmidt
,
V. W.
, 1983, “
Standby and Recovery Behavior of a Typical Residential Gas Water Heater
,”
ASHRAE Trans.
0001-2505,
89
, pp.
61
75
.
8.
Fanney
,
A. H.
, and
Dougherty
,
B. P.
, 1996, “
The Thermal Performance of Residential Electric Water Heaters Subjected to Various Off-Peak Schedules
,”
ASME J. Sol. Energy Eng.
0199-6231,
118
, pp.
73
80
.
9.
Cook
,
R. E.
, 1980, “
Effects of Stratification in Performance and Control of Residential Electric Water Heaters
,”
ASHRAE Trans.
0001-2505,
86
, pp.
927
937
.
10.
Gaggioli
,
R. A.
, 1985, “
Second Law Analysis of a Solar Domestic Hot Water Heating System
,”
Analysis of Energy Systems: Design and Operation
,
McGraw-Hill
,
New York
, Vol.
1
.
11.
Eames
,
P. C.
, and
Norton
,
B.
, 1998, “
The Effect of Tank Geometry on Thermally Stratified Sensible Heat Storage Subject to Low Reynolds Number Flows
,”
Int. J. Heat Mass Transfer
0017-9310,
41
, pp.
2131
2142
.
12.
Lightstone
,
M. F.
,
Raithby
,
G. D.
, and
Hollands
,
K. G. T.
, 1989, “
Numerical Simulation of the Charging of Liquid Storage Tanks: Comparison With Experiment
,”
ASME J. Sol. Energy Eng.
0199-6231,
111
, pp.
225
231
.
13.
Clark
,
J. A.
, 1985, “
Thermal Energy Storage
,”
Handbook of Heat Transfer Applications
,
W. M.
Rohsenow
,
J. P.
Hartnett
, and
E. N.
Ganic
, eds.,
ASME
,
New York
, pp.
8.1
8.40
.
14.
Homan
,
K. O.
,
Sohn
,
C. W.
, and
Soo
,
S. L.
, 1996, “
Thermal Performance of Stratified Chilled Water Storage Tanks
,”
HVAC&R Res.
1078-9669,
2
, pp.
158
170
.
15.
Musser
,
A.
, and
Bahnfleth
,
W. P.
, 1998, “
Evolution of Temperature Distributions in a Full-Scale Stratified Chilled Water Storage Tank With Radial Diffusers
,”
ASHRAE Trans.
0001-2505,
104
, pp.
55
67
.
16.
Wildin
,
M. W.
, 1984, “
Use of Thermally Stratified Water Tanks to Store Cooling Capacity
,”
Solar Engineering 1984, Proceedings of ASME Solar Energy Division Conference
.
17.
Schmidt
,
F. W.
, and
Willmott
,
A. J.
, 1981,
Thermal Energy Storage and Regeneration
,
Hemisphere
,
Washington
.
18.
Beckmann
,
G.
, and
Gilli
,
P. V.
, 1984,
Thermal Energy Storage
,
Springer-Verlag
,
New York
.
19.
Liu
,
W.
,
Davidson
,
J. H.
, and
Mantell
,
S. C.
, 2000, “
Thermal Analysis for Polymer Heat Exchanger for Solar Water Heating: A Case Study
,”
ASME J. Sol. Energy Eng.
0199-6231,
122
, pp.
84
91
.
20.
Zollner
,
A.
,
Klein
,
S. A.
, and
Beckman
,
W. A.
, 1985, “
A Performance Prediction Methodology for Integral Collection-Storage Solar Domestic Hot Water Systems
,”
ASME J. Sol. Energy Eng.
0199-6231,
107
, pp.
265
272
.
21.
Dorgan
,
C. E.
, and
Elleson
,
J. E.
, 1994,
Design Guide for Cool Thermal Storage
,
American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc.
,
Atlanta
.
22.
Krane
,
R. J.
, 1987, “
A Second Law Analysis of the Optimum Design and Operation of Thermal Energy Storage Systems
,”
Int. J. Heat Mass Transfer
0017-9310,
30
, pp.
43
57
.
23.
Krane
,
R. J.
, and
Krane
,
M. J. M.
, 1992, “
The Optimum Design of Stratified Thermal Energy Storage Systems. Part I: Development of the Basic Analytical Model
,”
ASME J. Energy Resour. Technol.
0195-0738,
114
, pp.
197
203
.
24.
Krane
,
R. J.
, and
Krane
,
M. J. M.
, 1992, “
The Optimum Design of Stratified Thermal Energy Storage Systems. Part II: Completion of the Analytical Model, Presentation and Interpretation of the Results
,”
ASME J. Energy Resour. Technol.
0195-0738,
114
, pp.
204
208
.
25.
Homan
,
K. O.
, 2003, “
Internal Entropy Generation Limits for Direct Sensible Thermal Storage
,”
ASME J. Energy Resour. Technol.
0195-0738,
125
, pp.
85
93
.
26.
Mather
,
D. W.
,
Hollands
,
K. G. T.
, and
Wright
,
J. L.
, 2002, “
Single- and Multi-Tank Energy Storage for Solar Heating Systems: Fundamentals
,”
Sol. Energy
0038-092X,
73
, pp.
3
13
.
27.
Bejan
,
A.
, 1996,
Entropy Generation Minimization
,
CRC
,
Boca Raton, FL
.
28.
Fanney
,
A. H.
, 1990, “
The Measured Performance of Residential Water Heaters Using Existing and Proposed Department of Energy Test Procedures
,”
ASHRAE Trans.
0001-2505,
96
, pp.
288
295
.
29.
1998, “
Energy Conservation Program for Consumer Products: Test Procedures for Water Heaters; Final Rule
,”
Fed. Regist.
0097-6326,
90
, pp.
25995
26016
.
30.
Garg
,
H. P.
, 1975, “
Year Round Performance Studies on a Built-In Storage Type Solar Water Heater at Jodhpur, India
,”
Sol. Energy
0038-092X,
17
, pp.
167
172
.
31.
Chauhan
,
R. S.
, 1976, “
Performance of a Collector-Cum-Storage Type of Solar Water Heater
,”
Sol. Energy
0038-092X,
18
, pp.
327
335
.
32.
Chaurasia
,
P. B. L.
, and
Twidell
,
J.
, 2001, “
Collector Cum Storage Solar Water Heaters With and Without Transparent Insulation Material
,”
Sol. Energy
0038-092X,
70
, pp.
403
416
.
33.
Smyth
,
M.
,
Eames
,
P. C.
, and
Norton
,
B.
, 2001, “
Annual Performance of Heat Retaining Integrated Collector∕Storage Solar Water Heaters in a Northern Maritime Climate
,”
Sol. Energy
0038-092X,
70
, pp.
391
401
.
34.
Garg
,
H. P.
, and
Rani
,
U.
, 1982, “
Theoretical and Experimental Studies on Collector∕Storage Type Solar Water Heater
,”
Sol. Energy
0038-092X,
29
, pp.
467
478
.
35.
Newton
,
B. J.
,
Schmid
,
M.
,
Mitchell
,
J. W.
, and
Beckman
,
W. A.
, 1995, “
Storage Tank Models
,”
Proceedings of ASME∕JSME International Solar Energy Conference
,
ASME
.
36.
Vaxman
,
B.
, and
Sokolov
,
M.
, 1985, “
Experiments With an Integral Compact Solar Water Heater
,”
Sol. Energy
0038-092X,
34
, pp.
447
454
.
37.
Bar-Cohen
,
A.
, 1978, “
Thermal Optimization of Compact Solar Water Heaters
,”
Sol. Energy
0038-092X,
20
, pp.
193
196
.
38.
Farrington
,
R. B.
, 1986, “
Test Results of Immersed-Coil Heat Exchangers and Liquid Storage Tanks Used in the Packaged Systems Program
,”
Solar Energy Research Institute
, Technical Report No. SERI∕TR-254-2841.
39.
Farrington
,
R. B.
, and
Bingham
,
C. E.
, 1986, “
Testing and Analysis of Immersed Heat Exchangers
,”
Solar Energy Research Institute
, Technical Report No. SERI∕TR-253-2866.
40.
Farrington
,
R. B.
, and
Bingham
,
C. E.
, 1987, “
Testing and Analysis of Load-Side Immersed Heat Exchangers for Solar Domestic Hot Water Systems
,”
Solar Energy Research Institute
, Technical Report No. SERI∕TR-254-3094.
41.
Liu
,
W.
,
Davidson
,
J. H.
,
Kulacki
,
F. A.
, and
Mantell
,
S. C.
, 2003, “
Natural Convection From a Horizontal Tube Heat Exchanger Immersed in a Tilted Enclosure
,”
ASME J. Sol. Energy Eng.
0199-6231,
125
, pp.
67
75
.
42.
Liu
,
W.
, 2003, “
Natural Convection Heat Transfer From Horizontal Tube Bundles Immersed in Tilted Thin Enclosures: Application of Polymer Heat Exchangers in Integral Solar Collectors
,” Ph.D. thesis, University of Minnesota.
43.
Liu
,
W.
,
Davidson
,
J. H.
, and
Kulacki
,
F. A.
, 2004, “
Natural Convection From a Tube Bundle in a Thin Inclined Enclosure
,”
ASME J. Sol. Energy Eng.
0199-6231,
126
, pp.
702
709
.
44.
Liu
,
W.
,
Davidson
,
J. H.
,
Kulacki
,
F. A.
, and
Mantell
,
S. C.
, 2002, “
Natural Convection of a Horizontal Tube Heat Exchanger Immersed in a Tilted Enclosure
,”
Proceedings of Solar 2002
.
45.
Holman
,
J. P.
, 1986,
Heat Transfer
, 6th ed.,
McGraw-Hill
,
New York
.
You do not currently have access to this content.