Fraunhofer Center for Sustainable Energy Systems
Energy Performance Analysis of Building
Envelopes Utilizing Blown Fiber Insulation
with Microencapsulated Phase Change
Material (PCM).
Elizabeth Kossecka Ph.D.
Polish Academy of Sciences –
Warsaw, Poland
Jan Kosny Ph.D.
Fraunhofer CSE, Cambridge, MA
David Yarbrough Ph.D.
P.E.
R&D Services, Cookeville TN
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Agenda
Application of PCMs in residential buildings




Available PCM performance data – testing, validated simulations
Theoretical analysis of performance limits for basic PCM applications
Cost competitiveness of PCMs comparing to conventional insulations
Progress on development of the PCM database for U.S. building
applications
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Existing Performance Data on PCM Applications
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Available PCM performance data – testing, validated simulations
Authors - reference
PCM location
PCM enthalpy
PCM loading
Stovall, Tomlinson –
1997
Wall – gypsum board
140 kJ/kg (64 Btu/lb),
Zhang, Medina - 2005
Wall core containers
123.7 kJ/kg (52 Btu/lb)
Zhang, Medina - 2005
Wall core - pipes
123.7 kJ/kg (52 Btu/lb)
30% 32-Btu/ft2 0.5 lb/ft2
10% ~10 - Btu/ft2 0.2 lb/ft2
20% ~21 - Btu/ft2 0.4 lb/ft2
Kissock, Limas - 2006
Wall – gypsum board
143 kJ/kg (65 Btu/lb)
30% ~32 - Btu/ft2 0.5 lb/ft2
16% - Dayton, OH
Willson - 2010
Wall – gypsum board
110 kJ/kg (48 Btu/lb)
Murugananthama et al.
– 2010
Wall, Celilng, Floor –
PCM containers
178 kJ.Kg (81 Btu/lb)
Wall Cavity – PCM
enhanced cellulose
120 kJ/kg (50 Btu/lb)
Metal roof–
polyisocyanurate
board
Roof deck – PCM
containers
143 kJ/kg (65 Btu/lb)
22-Btu/ft2
~ 0.4 lb/ft2
Walls; 45Btu/ft2
~ 0.56 lb/ft2
22% ~10 - Btu/ft2 0.2 lb/ft2
30 - Btu/ft2 0.5 lb/ft2
13.5% - Dynamic
HFMA testing
16% - whole
building – Tempe,
AZ
7% - Charleston, SC
40% - Oak Ridge,
TN
14% - Dayton, OH
27-Btu/ft2
~ 0.3 lb/ft2
25% - PCM - Oak
Ridge, TN
Kosny - 2007
Kissock - 2007
Kosny et al. - 2011
178 kJ.Kg (81 Btu/lb)
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Appr. cooling load
savings
7% - Miami, FL
15% - Nashville, TN
9% Lawrence, KS
11% Lawrence, KS
4
Two tests; ~ 60% with days with PCM melting-freezing
100.00%
90.00%
78.00%
75.00%
80.00%
60.00%
57.00%
50.00%
46.00%
50.00%
40.00%
30.00%
20.00%
8
10.00%
7
0.00%
May
June
July
2009
August September
6
5 2008
4
3
ORNL – metal roof
Kosny et al. -2012
2
1
0
04.02.10
04.09.10
04.16.10
04.23.10
04.30.10
05.07.10
05.14.10
05.21.10
05.28.10
06.04.10
06.11.10
06.18.10
06.25.10
07.02.10
07.09.10
07.16.10
07.23.10
07.30.10
08.06.10
08.13.10
08.20.10
08.27.10
09.03.10
09.10.10
09.17.10
09.24.10
10.01.10
10.08.10
% of days
70.00%
ORNL – cellulose
Kosny - 2008
top melting/bottom frozen
© Fraunhofer USA 2009
all layers cycling
top freezing/bottom melted
Theoretical Analysis of Performance Limits for Basic PCM
Applications
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Theoretical analysis of performance limits for basic PCM
applications
 Two thicknesses representing wall and attic applications were used in
modeling;
• 14 cm (5.5 in) representing walls and vaulted ceiling applications, and
• 30 cm. (11.8 in.) representing attic floor insulations.
 Numerical program developed for this purpose used the control volume
heat balance method, explicit scheme, with temperature dependent
effective heat capacity and experimentally determined thermal
conductivity.
 Distance between nodes within insulation was 0.01 – 0.02 m (0.39 and
0.79-in.), and time step was 30 s.
 To visualize dynamic effects, heat fluxes for steady state, which
represent the “zero mass” wall, were calculated, taking into account
dependence of insulation conductivity on temperature.
 An accurate elementary solution of the non-linear steady state heat
transfer problem, in the case of linear dependence of conductivity on
temperature, may be obtained using the Kirchoff transform method; see
Kossecka (1999).
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Thermal Excitations Used in Analysis
100
85 oC (185 oF)
TEMPERATURE [ oC]
80
65 oC (149 oF)
60
45 oC (113 oF)
PCM melting point
27 oC (81 oF)
40
20
20
oC
(68
oF)
25 oC (77 oF)
0
0
2
4
6
8
10
12
14
16
18
20
TIME [h]
Ti
Tes a)
Tes b)
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Tes c)
22
24
PCM Enthalpy Profile Used in Analysis
30
29
28
27
26
Temp.
oC
J/g
25
Freezing
24
Melting
23
22
21
20
0
10
20
30
40
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50
oC
Temp.
kJ/kg
a
b
2x6 wall
c
© Fraunhofer USA 2009
Ti = 20ºC (68 oF)
TPCM = 27ºC (81 oF)
a
b
2x6 wall
c
© Fraunhofer USA 2009
Ti = 25ºC (77 oF)
TPCM = 27ºC (81 oF)
a
b
Attic
c
© Fraunhofer USA 2009
Ti = 20ºC (68 oF)
TPCM = 27ºC (81 oF)
a
b
Attic
c
© Fraunhofer USA 2009
Ti = 25ºC (77 oF)
TPCM = 27ºC (81 oF)
80
Cooling load % reduction
60
0.14-m Ti=25C
0.20-m Ti=25C
40
0.30-m Ti=25C
20
0.14-m Ti=20C
0.20-m Ti=20C
0
-20
schedule (a)
schedule (b)
schedule (c)
0.30-m Ti=20C
TPCM = 27ºC (81 oF)
100
Peak-hour % load reduction
80
0.14-m Ti=25C
0.20-m Ti=25C
60
0.30-m Ti=25C
40
0.14-m Ti=20C
20
0.20-m Ti=20C
0
schedule (a)
schedule (b)
schedule (c)
© Fraunhofer USA 2009
0.30-m Ti=20C
12
Peak load time shifting [h]
10
8
0.14-m Ti=25C
6
0.30-m Ti=25C
4
0.14-m Ti=20C
2
0.30-m Ti=20C
0
schedule (a)
2
schedule (b)
schedule (c)
Reverse heat flow during the day
HEAT FLUX [W/m2]
1
0
0
4
8
12
16
20
24
28
32
36
-1
-2
Reverse heat flow during the night
-3
TIME [h]
no-PCM
30% PCM
© Fraunhofer USA 2009
40
44
48
Effect of PCM Temp. Range on % Cooling Load Reductions
Attics
80
70
60
50
40
30
20
10
0
0.30-m (11.8-in.) Ti=25C
(77F)
0.30-m (11.8-in.) Ti=20C
(68F)
schedule (a)
schedule (b)
schedule (c)
TPCM = 27ºC (81 oF)
25
20
Walls
Vaulted ceilings
0.14-m (5.5-in.) Ti=25C
(77F)
15
10
0.14-m (5.5-in.) Ti=20C
(68F)
5
0
schedule (a)
schedule (b)
schedule (c)
© Fraunhofer USA 2009
Example of Payback Time Analysis for PCM Cellulose Blend
Phoenix, attic schedule "a"
Payback time [years]
35.0
30.0
PCM enthalpy
[kJ/kg]
(Btu/lb)
25.0
20.0
15.0
10.0
5.0
0.0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
120
(52)
150
(65)
190
(82)
220
(95)
7.5
PCM price [$/lb]
Phoenix off peak attic schedule "a"
Payback time [years]
30.0
PCM enthalpy
[kJ/kg]
(Btu/lb)
25.0
20.0
15.0
10.0
5.0
0.0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
120
(52)
150
(65)
190
(82)
220
(95)
7.5
PCM price [$/lb]
© Fraunhofer USA 2009
17
Cost comparisons with conventional insulations:
1. Microencapsulated PCMs 110 J/g - $7.00/lb
2. Macroencapsulated PCMs 110 J/g - $2.50/lb
3. Microencapsulated PCMs 170 J/g - $3.50/lb
4. Packaged bio PCM – 188 J/g - $3.50/lb
5. Packaged inorganic PCM – 134 J/g - $1.50/lb
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Potential savings in annual costs of cooling electric energy
generated by the attic calculated for a single-story ranch
house and for five southern U.S. climates.
Cities:
Atticgenerated cooling
energy consumption
[kWh]
Annual cost
of electricity
used for
cooling
(atticgenerated)
[$]
Installation R-19
insulation over
existing R-30 (level
of savings for each
location)
Addition of
microencapsulated
PCM to the existing
R-30 (savings level
for schedule “a”)
Atlanta
269.3
30.43
2.74 (9%)
21.91
10.65
Bakersfield
456.4
155.18
15.52 (10%)
111.73
54.31
Fort Worth
458.0
43.05
3.87 (9%)
31.00
15.07
Miami
911.4
105.72
9.52 (9%)
76.12
37.00
Phoenix
870.8
188.09
16.93 (9%)
135.43
65.83
Annual cost savings of electricity used for cooling
(attic-generated) [$]
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Addition of
microencapsulate
d PCM to the
existing R-30
(savings level for
schedule “b”)
19
Comparisons of energy cost savings and material costs
calculated for a single-story ranch house for five southern
U.S. climates
Cities
Annual cost savings of electricity used for
cooling
(attic-generated) [$]
Installation R-19
insulation over
existing R-30 (level
of savings for each
location)
Atlanta
2.74 (9%)
Adding 30% by weight
of PCM to the existing
R-30, savings levels
for schedules “a” and
“(b)”
21.91
Approximate cost of materials
Assuming net attic floor area of 1108 ft2
[$]
R-19 insulations –
based on US RS
Means
Fiberglass - $0.77/ft2
(Cellulose - $0.55/ft2)
Addition of
microencapsulated
PCM at
$3.50/lb
Assuming enthalpy of
190 kJ/kg (82 Btu/lb)
(10.65)
853.16
(609.40)
1151
111.73 (54.31)
853.16
(609.40)
1151
Bakersfield
15.52 (10%)
Fort Worth
3.87 (9%)
31.00
(15.07)
853.16
(609.40)
1151
Miami
9.52 (9%)
76.12
(37.00)
853.16
(609.40)
1151
Phoenix
16.93 (9%)
135.43 (65.83)
853.16
(609.40)
1151
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PCM database update:
Review process and approvals by individual PCM
companies
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PCM Cost Components:
THERMAL PEROFRMANCE
Maximum Enthalpy
•Uniform performance labels for PCMs
•Dependable Test Data for PCMs and PCM products
•Durability standards
Company
Location
Product
amount
Temp.
Range (°C)
Raw
Data
Downloaded
Flyers
Testing
Method
Micro. Labs
USA
17
-30~52
Yes (5)
16
DSC
PCES
USA
4
23~29
Yes (4)
No
DSC
BASF
Germany/
USA
9
21~26
Yes (1)
6
DSC
PCM
UK
127
-114~885
No
5 tables
-
RGEES
USA
16
-27~88
Yes (16)
16
T-history
PLUSS
As of March. 2012
305 PCM products
with detailed energy ESI
performance data
Climator
India
18
-37~89
No
1 table
T-history (In)
USA
32
-37~151
Yes (8)
1 table
DSC
Sweden
11
-21~70
No
11
-
JCXT
China
18
5~110
No
No
-
SGL
Germany/
USA
4
22~58°C
Rubitherm
Germany
49
-10~86°C
Fraunhofer CSE
PCM Database
~ 200 with no test
data
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DSC
No
3-layer
Calorimeter
22
Fraunhofer CSE PCM Database – Example Input
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Conclusions
 Comparison of calculated daily heat flow values indicates that for cyclic
processes the effect of PCM in an insulation layer results in time shifting
of the heat flux maxima and in reduction of the peak-hour heat flow.
 For insulation thickness of 0.14 m reduction of the heat gains maxima,
compared to plain cellulose fiber insulation, is significant only when the
external sol-air temperature amplitude if not too high (up to 25ºC); for
very high external temperature peaks its rather small.
 The situation is much better for very thick PCM enhanced insulation
layer. In this case, reduction of the heat gains maxima, compared to
plain cellulose fiber insulation, may reach 80% with 11 hours long peakhour load shift.
 The presented above results indicate that a thick layer of the attic floor
insulation may be one of the best-performing immediate applications of
the PCM-enhanced insulation, today.
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