THERMAL CHARACTERIZATION OF GYPSUM COMPOSITES BY...

THERMAL CHARACTERIZATION OF

GYPSUM COMPOSITES BY USING

DIFFERENTIAL SCANNING CALORIMETRY

ANA M. BORREGUERO, IGNACIO GARRIDO, JOSE L. VALVERDE,

JUAN F. RODRÍGUEZ AND MANUEL CARMONA

E2KW 2013, ENERGY AND ENVIRONMENT KNOWLEDGE WEEK

20th-22nd November, Toledo, Spain

THERMAL ENERGY STORAGE MATERIALS

A PCM is a substance with a high heat of fusion which, melting

and solidifying, is able to absorb and store or release large

amounts of energy.

ABSORB

STORE

RELEASE

WORLD

ENERGY

DEMAND

Development of new systems for

saving energy

Use of renewable energy

sources

SOLAR ENERGY

IT NEEDS TO BE STORED!

Petroleum

50 years

Carbon

330 years

Uranium reactors

1000 years

Nuclear Fission

1 Million of years

Solar Energy

5000 millions of years

Energy

sources

CLEAN UNIVERSAL RENEWABLE

INTRODUCTION



EU directives 2002/91/EC and 2010/31/UE: Directives on the Energy

Performance of Buildings

- Buildings are responsible for 40% of energy consumption and 36% of CO2

emissions in the Europe Community

- Energy performance of buildings is key to achieve the EU Climate and Energy

objectives.

PCMs application in buildings:

Thermal energy storage

Money spent in energy

Reduction of

Environmental pollution

Energy consumption in heaters and air conditioners

Development of buildings with a more efficient use of energy

INTRODUCTION

WHY USE PCMS IN BUILDINGS?



HOT

OUTSIDE

Heat Released

COLD

OUTSIDE

Heat stored BUILDING

INSIDE

External T > Melting T

PCM becomes liquid

(Heat stored)

External T < Freezing T

PCM solidifies

(Heat released)

INTRODUCTION

HOW DO THE PCMS WORK?

BUILDING

INSIDE

INSIDE THE BUILDING TEMPERATURE REMAINS CLOSE TO

THE MELTING POINT



INTRODUCTION

PCMS INCORPORATION IN BUILDINGS

• Building systems to incorporate PCMs: - Wallboards, ceilings and floors

- Shutter of windows

- Cooling and heating systems

• Ways of incorporating PCMs into building

materials: - Direct incorporation

- PCMs microencapsulation and further incorporation

• Properties of proper PCMs for applications in buildings

- Melting temperature about 25ºC - High latent heat of fusion

- Low cost - Good availability

- Non-toxic - Non-corrosive



INTRODUCTION


PCMs microencapsulation and further incorporation

SHELL: POLYMERS

- To avoid PCM interaction with the rest of building materials.

- To avoid the PCM leakage when they remain liquid.

- To give a high area of heat transfer.

- Easy handling.

- Microcapsules properties modification

MAIN REASONS FOR PCMS MICROENCAPSULATION:

-Low cost

-Chemically inert respecting the building materials

-Low density



• Avaliability

• Widely used in buildings

• Low cost

• Easy incorporation of additives

• In situ or precast slabs gypsum

Gypsum

INTRODUCTION


Buildings



Thermal properties improvement

Mechanical properties preservation

Good durability

No gas emissions

PCM Gypsum Gypsum composites

WITH THERMOREGULATING

PROPERTIES

GLOBAL AIM



PARTIAL AIMS

EXPERIMENTAL

CHECKING THE TES

CAPACITY IMPROVEMENT

(sensible and latent heat)

Microscale analyses

(MDSC)

Sample size <10 mg

Thermal properties improvement

APPARENT HEAT CAPACITY (Cpap)

EVALUATION

Macroscale analyses

(Thermal Experimental set up)

Blocks 6x10x3 cm3

PREDICTION OF THE THERMAL BEHAVIOR



PROPERTIES OF THE MICROENCAPSULATED PCMS

Product dpn0.5

(mm)

dpv0.5

(mm)

Tf

(ºC)

DHf

(J/g)

Paraffin content

(wt%)

mSD-(LDPE·EVA-RT27) 3.9 10.0 28.40 98.14 49.32

mSP-(PS-RT27) 116.8 584.0 28.46 96.74 48.61

Micronal®DS 5001X 7.1 77.2 27.67 116.2 Unkown

mSD-CNFs - - 27.6 95.64 48.06

Product Shell Core Synthesis technique

mSD-(LDPE·EVA-RT27) LDPE-EVA Rubitherm®RT27 Spray drying

mSP-(PS-RT27) Polystyrene Rubitherm®RT27 Suspension polymerization

Micronal®DS 5001X PMMA Paraffin wax Spray drying (Commercial

product)

mSD-CNFs LDPE-EVA Rubitherm®RT27

and CNFs Spray drying

MATERIALS, METHODOLOGY AND SET UP




GYPSUM COMPOSITE MANUFACTURING

Microcapsules/

Hemihydrate

(wt%)

Component

Water

(g)

Hemihydrate

(g)

Microcapsules

(g)

0.0 110 231 0

7.5 110 231 17.3

15.0 115 231 34.7

Block dimensions: 3x6x10 cm3 Powder material




MODULATED DIFFERNCIAL SCANING COLORIMETRY (MDSC)

Inert reference Sample

Basis of operation: Measurement of the difference in heat flow

between both of them as a function of time and temperature




Conventional DSC

MDSC

A sinusoidal modulation is overlaid on the conventional

linear heating ramp

Linear heating rate for scanning





Applied method

- heating rate of 0.5ºC/min

- amplitude of ±0.5 ºC

- period of 100 seconds

- temperature change from 10 to 40 ºC

Conventional DSC or macroscale

equipment

APPARENT HEAT CAPACITY EVALUATION

MDSC

Direct

apparent heat capacity-temperature

curve





THERMAL BEHAVIOR EXPEROMENTAL SET UP

1.Rotameter

2.Signal transmitter

and converter

3.Computer

4.Peristaltic pump

5. Thermostatic bath

6.Thermocouples

7.Isothermal chamber

8.Insulating structure

1. CHECK THE FEASIBILITY OF USING THE MDSC FOR TES CAPACITY

EVALUATION OF THE COMPOSITE MATERIALS

2. EXPERIMENTAL DATA REQUIRED, IN ADDITION TO THE APPARENT HEAT

CAPACITY, TO PREDICT THE THERMAL BEHAVIOR



q outgoing

Surface (1)

Plate (1) Plate (2)

Middle (1) Middle (2)

Liquid

flow

direction

Liquid

flow

direction

q outgoing q outgoing


THERMAL BEHAVIOR EXPERIMENTAL SET UP

Thermal treatment:

Cell temperature change from 18 to 40ºC

Measurements:

- gypsum blocks temperatures in six

positions

- incoming and outgoing heat fluxes

q incoming

Surface (2)

Hollow cell

Composite block



MICROSCALE

RESULTS



0 10 20 30 401000

1200

1400

1600

1800

2000

2200

Cpap

(J/

kgºC

)

Temperature (ºC)

mSD-(LDPE·EVA-RT27)/Hemihydrate (wt%)

0.0

7.5

15.0

7.5 mSD-CNFs

RESULTS

APPARENT HEAT CAPACITIES BY MDSC (<10 mg)

Microcapsules

/ hemihydrate Heat capacity

Narrower peak when CNFs addition

0 10 20 30 401000

1200

1400

1600

1800

2000

2200

Cpap

(J/

kgºC

)

Temperature (ºC)

Micronal®DS 5001X/Hemihydrate (wt%)

0.0

7.5

15.0

0 10 20 30 401000

1200

1400

1600

1800

2000

2200

Cpap

(J/

kgºC

)

Temperature (ºC)

mSP-(PS-RT27)/Hemihydrate (wt%)

0.0

7.5

15.0



RESULTS

APPARENT HEAT CAPACITIES BY MDSC

0 10 20 30 40800

1000

1200

1400

1600

1800

2000

2200

2400

Cpap

(J/

kgºC

)

Temperature (ºC)

Gypsum

mSD-(LDPE·EVA-RT27)

mSP-(PS-RT27)

Micronal®DS 5001X

ap

pc mSD-(LDPE-EVA-RT27)> ap

pc Micronal®DS 5001X > ap

pc mSP-(PS-RT27) > ap

pc gypsum

Material Cp

LDPE 1800

PMMA 1466

PS 1300

Gypsum 1090

Cpap depends on the shell material and on the DHf of PCM



0 4 8 12 16

22000

24000

26000

28000

30000

32000

34000

DH

(J/

kg)

Microcapsules/Hemihydrate (wt%)

Microcapsules type

mSD-(LDPE·EVA-RT27)

mSP-(PS-RT27)

Micronal®DS 5001X

RESULTS

TES CAPACITIES BY MDSC

∆𝐻 = 𝑞𝑎𝑐𝑐 = 𝐶𝑝𝑎𝑝𝑇𝑒

𝑇𝑖

· 𝑑𝑇

For a temperature change from 18 to 36 ºC

DH = 47%



MACROSCALE

RESULTS



0 5000 10000 15000 20000

-0.3

0.0

0.3

0.6

0.9

1.2

1.5

1.8q

acc (

W)

Time (s)

mSD- (LDPE·EVA-RT27)/Hemihydrate

(wt%)

0.0

7.5

15.0

RESULTS

TES CAPACITIES BY THE THERMAL BEHAVIOR SET UP

Accumulated heat when the

composite materials are

subjected to a temperature

change from 18 to 36 ºC

mSD-(LDPE·EVA-RT27) mSP-(PS-RT27) Micronal®DS 5001X Gypsum

7.5 15 7.5 15 7.5 15

qacc MDSC

(J/kg) 27351 32657 26361 27711 27818 31034 22021

qacc

Macroescale

set up

(J/Kg)

26488 34084 26459 32181 27004 34447 19776

Deviation

(%) 3.26 4.19 0.37 13.89 3.02 9.91 11.35

THE MDSC SEEMS TO BE SUITABLE

FOR HEAT CAPACITY EVALUATION OF

COMPOSITE MATERIALS WITH PCMS



RESULTS

TES CAPACITIES IMPROVEMENT

BUILDING APPLICATION

𝑇𝐸𝑆 =𝑞𝑎𝑐𝑐 · 𝜌𝑏3.6 · 106

1m3 of gypsum boards with a

15% of mSD-(LDPE·EVA-RT27)

Due to the microcapsules:

Savings of 4.5 kWh/operating cycle

0.35 kg CO2/ kWh

(CNE, 2010)

Reduction of 1.6kg CO2

emissions/operating cycle

http://www.google.es/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=oKURKUCEFnDmeM&tbnid=XF-oB-91_iTkCM:&ved=0CAUQjRw&url=http://steelchannel.en.made-in-china.com/product/dqpmgYoMhGDe/China-Gypsum-Board.html&ei=vg6KUrTyJca_0QWW9YHYAw&bvm=bv.56643336,d.d2k&psig=AFQjCNH18pROj-YR4be_ihT5wdpwFTH4ug&ust=1384865568222248



THERMAL BEHAVIOR PREDICTION

RESULTS

https://www.google.es/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=71b82r3_xsVptM&tbnid=3JxcqIinLbQkJM:&ved=0CAUQjRw&url=https://www.educate-sustainability.eu/kb/sitemap&ei=zUqKUryxI6Ot0QWis4CYAg&bvm=bv.56643336,d.d2k&psig=AFQjCNGXYjElIgL4iA2ZENOqZmF620ZSKw&ust=1384881226253632



RESULTS


PROBLEM:

Boundary conditions movement with the solid-liquid interface

SOLUTION:

Apparent heat-capacity as a temperature function

https://www.google.es/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=71b82r3_xsVptM&tbnid=3JxcqIinLbQkJM:&ved=0CAUQjRw&url=https://www.educate-sustainability.eu/kb/sitemap&ei=zUqKUryxI6Ot0QWis4CYAg&bvm=bv.56643336,d.d2k&psig=AFQjCNGXYjElIgL4iA2ZENOqZmF620ZSKw&ust=1384881226253632



RESULTS


0 3000 6000 9000 12000 15000 18000 21000 2400016

20

24

28

32

Tem

per

ature

(ºC

)

Time (s)

mSP-(PS-RT27) (wt% )

Experimental Theoretical

0.0 0.0

7.5 7.5

15.0 15.0

0 5000 10000 15000 20000

16

20

24

28

32

Tem

per

ature

(ºC

)

Time (s)

Micronal®DS 5001X (wt%)


0.0 0.0

7.5 7.5

15.0 15.0

0 5000 10000 15000 20000 2500016

20

24

28

32T

emper

ature

(ºC

)

Time (s)

mSD-(LDPE·EVA-RT27) (wt%)


0.0 0.0

7.5 7.5

15.0 15.0

Good agreement

between experimental

and predicted data

THE MDSC HEAT CAPACITY-TEMPERATURE

CURVES ARE SUITABLE FOR THERMAL

BEHAVIOR PREDICTION



CONCLUSIONS

The higher the microcapsules content, the higher the heat

capacity

The addition of CNFs promotes faster heat absorption

the Cpap depends on the shell type and the PCM latent heat of

fusion

The addition of PCMs allows to obtain composite materials

with improved TES capacity which allow to save 4.5 kWh and

reduce the CO2 emissions in 1.6kg per operating cycle

THE MDSC SEEMS TO BE SUITABLE FOR HEAT CAPACITY

EVALUATION OF COMPOSITE MATERIALS WITH PCMS

THE MDSC HEAT CAPACITY-TEMPERATURE CURVES ARE

SUITABLE FOR THERMAL BEHAVIOR PREDICTION

Thank you for your attention

Acknowledgments Acciona Infraestructuras S.A.

Spanish Ministry of Science and Innovation

THERMAL CHARACTERIZATION OF

GYPSUM COMPOSITES BY USING

DIFFERENTIAL SCANNING CALORIMETRY



l l l l l l l

l

l l

uu u u

uu u

u

u

u

u

u u

¬

¬ ¬ ¬

¬

¬

¬¬

¬

¬

¬

¬

¬

¬

¬

¬

¬

27.40°C

26.25°C93.96J/g

27.97°C

26.14°C94.93J/g

29.06°C

26.15°C94.90J/g

-7

-5

-3

-1

He

at

Flo

w (

W/g

)

-40 -20 0 20 40 60

Temperature (°C)

l heating rate 0.5ºC/min–––––––u hetaing rate 5ºC/min–––––––¬ heating rate 10ºC/min–––––––

Exo Up Universal V4.2E TA Instruments

RESULTS

INFLUENCE OF THE HEATING RATE



Ciclo durante el día Ciclo durante la noche

Aislante PCM

Pared



0 10 20 30 401000

1200

1400

1600

1800

2000

2200

2400

Cpap

(J/

kgºC

)

Temperature (ºC)

Gypsum

7.5 mSD-(LDPE·EVA-RT27)

15.0 mSD-(LDPE·EVA-RT27)

7.5 mSP-(PS-RT27)

15.0 mSP-(PS-RT27)

7.5 Micronal®DS 5001X

15.0 Micronal®DS 5001X

7.5 mSD-CNFs



-10 0 10 20 30 40-3

-2

-1

0

DHf=96,2 J/g

DHf=96,7 J/g

Inte

nsi

dad

(u.a

.)

Temperature (ºC)

Material

Original

After thermal treatment

Low Angle Laser Light Scattering (LALLS) Scanning Electron Microscopy (SEM)

-10 0 10 20 30 40-4

-3

-2

-1

0

DHfJ/g

DHfJ/g

Inte

nsi

ty (

u.a

.)

Temperatura (ºC)

Microcapsule

Pure paraffin

Differential Scanning Calorimetry (DSC)

PROPERTIES OF THE MICROENCAPSULATED PCMS




Spray drying technique

Suspension polymerization

Gas for solvent evaporation

Feed

Gas + solvent Product

MICROENCAPSULATION OF PCMS




0

10

20

30

40

50

60

70

0 10000 20000 30000 40000 50000 60000 70000

Tem

pera

ture

(ºC

)

Time (s)

Cpaverage=f(T)

http://www.google.es/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=ApJyCvQilWQQ3M&tbnid=nBcYwMkNzcuBEM:&ved=0CAUQjRw&url=http://cherylchattelier.blogspot.com/2009/08/soymilk-pudding-when-chinese-dessert-is.html&ei=2zOLUurXGvLZ0QXA6IGADQ&bvm=bv.56643336,d.d2k&psig=AFQjCNGEcp30g-6m3O7jGPSZV-jPkFsUHg&ust=1384940653557540

Mathematical Model

x

Tk

xt

h· [1]

R

ap

p TTch - Enthalpy dependence with temperature [2]

- and k dependence with temperature sol

PCMf

liq

PCMfPCMi

c

i

i llww ·0.1···1

sol

PCMf

liq

PCMfPCMi

c

i

i llww ·0.1···1

[3]

[4]

- Lf is the melted PCM fraction

T ≤ T0 ; lf = 0

Tf

T

app

T

T

app

f

dTc

dTcl

0

0T0 < T ≤ Tf ;

Taking into account the temperature dependences, equation 1 becomes:

R

ap

pap

p

ap

p TTT

c

Tcc

x

Tk

x

t

T

····

T >Tf ; lf = 1

[5]

[6]

[7]

[8]

THERMAL BEHAVIOUR OF BUILDING MATERIALS

CONTAINING MICROCAPSULES

Fourier heat conduction equation for one dimension

Mathematical Model

Boundary conditions:

.

0

· ;0 Qdx

dTkx

x

iniTTt ;0

x

corcho

x dx

dTk

dx

dTkx ·· ;

For the insulating material zone:

x

T

xx

T

c

k

xt

Tcorcho

corchopcorcho

corcho

·

corchoiniTTt ;0

TThdx

dTkx c

x

corcho

corcho

·· ; corcho

[9]

[10]

[11]

[12]

[13]

[14]

Boundary conditions

Model

Solution

By finite differences

Rosenbrock method for numerically integration

Unknown k and hc as fitting parameters minimizing the sum of the square of

offsets by a nonlinear least square fitting

Visual Basic application

THERMAL BEHAVIOUR OF BUILDING MATERIALS

CONTAINING MICROCAPSULES

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