As homes move toward zero energy performance, some designers are drawn toward the solar combisystem due to its ability to increase the energy savings as compared to solar water heater (SWH) systems. However, it is not trivial as to the extent of incremental savings these systems will yield as compared to SWH systems, since the savings are highly dependent on system size and the domestic hot water (DHW) and space heating loads of the residential building. In this paper, the performance of a small combisystem and SWH, as a function of location, size, and load, is investigated using annual simulations. For benchmark thermal loads, the percent increased savings from a combisystem relative to a SWH can be as high as 8% for a 6 m2 system and 27% for a 9 m2 system in locations with a relatively high solar availability during the heating load season. These incremental savings increase significantly in scenarios with higher space heating loads and low DHW loads.

References

References
1.
Klein
,
S.
,
Beckman
,
W.
, and
Duffie
,
J.
,
1976
, “
A Design Procedure for Solar Heating Systems
,”
Sol. Energy
,
18
(
2
), pp.
113
127
.
2.
Duffie
,
J.
, and
Mitchell
,
J.
,
1983
, “
F-Chart: Predictions and Measurements
,”
ASME J. Sol. Energy Eng.
,
105
(
1
), pp.
3
12
.
3.
Weiss
,
W.
,
2003
,
Solar Heating Systems for Houses: A Design Handbook for Solar Combisystems
,
James and James Science Publishers
,
London
.
4.
Andersen
,
E.
, and
Furbo
,
S.
,
2007
, “
Theoretical Comparison of Solar Water/Space-Heating Combi Systems and Stratifications Design Options
,”
ASME J. Sol. Energy Eng.
,
129
(
4
), pp.
438
448
.
5.
Lund
,
P.
,
2005
, “
Sizing and Applicability Considerations of Solar Combisystems
,”
Sol. Energy
,
78
(
1
), pp.
59
71
.
6.
Jordan
,
U.
, and
Vajen
,
K.
,
2001
, “
Influence of the DHW Load Profile on the Fractional Energy Savings: A Case Study of a Solar Combi-System With TRNSYS Simulations
,”
Sol. Energy
,
69
(
6
), pp.
197
208
.
7.
Bales
,
C.
, and
Persson
,
T.
,
2003
, “
External DHW Units for Solar Combisystems
,”
Sol. Energy
,
74
(
3
), pp.
193
204
.
8.
TESS
,
2014
, “
TESS Component Libraries
,” Thermal Energy System Specialists, Madison, WI, accessed in March 2014, http://www.trnsys.com/tess-libraries/
9.
TESS
,
2007
,
Type 534: Cylindrical Stratified Storage Tank With Immersed Heat Exchangers
,
TESS Component Libraries, Thermal Energy System Specialists
,
Madison, WI
.
10.
TESS
,
2006
,
Type 539: Flat Plate Collector With Capacitance and Flow Modulation
,
TESS Component Libraries, Thermal Energy System Specialists
,
Madison, WI
.
11.
Hendron
,
R.
,
Hancock
,
E.
,
Barker
,
G.
, and
Reeves
,
P.
,
2006
, “
Evaluation of Affordable Prototype Houses at Two Levels of Energy Efficiency
,” Building America Field Test and Analysis Report, National Renewable Energy Laboratory, Golden, CO, Report No. NREL/CP-550-38774.
12.
Sustar
,
J.
,
2011
, “
Performance Modeling and Economic Analysis of Residential Solar Combisystems
,” M.S. thesis, University of Colorado, Boulder, CO.
13.
IECC
,
2009
, “
International Energy Conservation Code
,”
International Code Council
,
Country Club Hills, IL
.
14.
SRCC
,
2014
, “
Solar Rating and Certification Corporation for Heliodyne Flat Plate Collector
,” Solar Rating & Certification Corporation, Cocoa, FL, http://www.solar-rating.org
15.
Ramlow
,
B.
,
2009
, “
Solar Water Heating: A Comprehensive Guide to Solar Water and Space Heating Systems
,” New Society Publishers, Gabriola Island, BC, Canada.
16.
Hendron
,
R.
, and
Burch
,
J.
,
2010
, “
Tool for Generating Realistic Residential Hot Water Event Schedules
,” National Renewable Energy Laboratory, Golden, CO, Paper No. NREL/CP-550-47685.
17.
Polly
,
B.
, and
Gestwick
,
M.
,
2011
, “
A Method for Determining Optimal Residential Energy Efficiency Retrofit Packages
,” National Renewable Energy Laboratory, Golden, CO, NREL Building Technologies Report No. NREL/TP-5500-50572; DOE/GO-102011-3261.
18.
Hendron
,
R.
, and
Engebrecht
,
C.
,
2010
, “
Building America House Simulation Protocols
,” National Renewable Energy Laboratory, Golden, CO, Technical Report No. NREL/TP-550-49426.
19.
Anderson
,
R.
, and
Roberts
,
D.
,
2008
, “
Maximizing Residential Energy Savings: Net Zero Energy Home Technology Pathways
,” National Renewable Energy Laboratory, Golden, CO, Technical Report No. NREL/TP-550-44547.
20.
Weiss
,
W.
, and
Mauthner
,
F.
,
2011
,
Solar Heat Worldwide: Markets and Contributions to the Energy Supply 2009
,
IEA-SHC 2011 Edition, International Energy Agency
,
Paris
.
21.
CCSE
,
2010
, “
California Center for Sustainable Energy, Data From California Solar Initiative Residential Solar Water Heater Program. Acquired by NREL: System Advisor Model (SAM)
,” National Renewable Energy Laboratory, Golden, CO, Report No. NREL/ TP-6A20-48986.
You do not currently have access to this content.