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17th International Passive House Conference| Rajesh | Page 0

Performance Evaluation of Solar Insulation

Materials in UAE Conditions

Authors: Rajesh Reddy and Hamid Kayal

CSEM UAE Innovation Center LLC

Date: 20th April, 2013.


Outline

•Building energy efficiency in UAE�Need for energy efficiency

�How

�Approach

•Test facility�Design

�Testing façade

�Experimentation

•Results and discussion�Summer test- steady set point

� Winter test- Free floating conditions

•Conclusions

•Reference


Building energy efficiency in UAE

Need for energy efficiency

� Buildings are one of the largest energy consumers & contributors to atmospheric CO2

� Energy efficiency in building is of prime importance for energy policy

� In UAE, residential house hold consumes 40% of total energy where 60% of it goes for

cooling due to hot and humid climate [1,4]

� The growth in electricity consumption for cooling buildings in the region has increased

ten times (from 5 to 50 Billion kWh) over the past two decades [1]

� Efficiency improvements can lead to large financial gains by eliminating large initial

investment in HVAC and by reducing energy bills on long run

How� An effective energy conservation measures in buildings is by reducing the cooling load

�Using solar insulation and reflective materials is an efficient / cost effective passive method


Building energy efficiency in UAE

Approach� Analyzed temperature and humidity (CSEMuae weather station, 5 years average)

� Designed test facility to evaluate energy savings and thermal performance of

� Solar insulating materials

� to retrofit existing buildings and for new buildings

� Solar reflective coatings

� Selected for testing

� Existing thermal insulating materials

� New building technologies

� New coating material

0

20

40

60

80

100

0 720 1440 2160 2880 3600 4320 5040 5760 6480 7200 7920 8640

Tem

pera

ture

⁰⁰ ⁰⁰C

Hu

mid

ity %

Hour of YearHimidity % Temperature ⁰⁰⁰⁰ C

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC


Test Facility-Design

Test facility before (a) and after (b) adding insulation

� Smallest size for good accuracy and flexibility to test different methods

�Four cubicles(3X3X3m3); one is reference, others for testing different measures

�Each equipped with similar air-conditioner to provide cooling

�Energy consumption of each building is measured and compared to that of reference

B1

• Reference Building: Standard local construction materials

B2

• Solar reflective coating test building : same as B1, but coating added on test façade

B3

• Retrofitting insulation test building: same as B1, but 5cm PIR board added on test facade

B4

• Innovative construction test building : same but test façade by new technology (EIFS)

a

B1 B2 B3B4

b

a


Testing surface

Reference Material (Standard local construction)

Qconductive

Tindoor

Tamb

Reference

*Same dimensions

*Same Weather

*Same Tindoor

*Different material

on testing facade

Insulation Material/

Solar Reflective Coating

Qconductive

EtEt

QirQir

Tamb

Tindoor

QconvectiveQconvective

Reference + added

Insulation/coatings

�Other façades & floor

�< 30% heat load

� Insulated to minimize heat gain

for precision measurement

� Roof & south façade [2]

�Major heat load contributors

in local buildings

�South façade(30%)

�Roof (40%)


Experimentation

� Measuring parameters� Heat flux through testing facade,

� Indoor temperature and Relative Humidity (RH)

� Energy consumption

� Facade surface temperature

� Ambient conditions (Temperature, RH, Global radiation etc.,)

� Calibration of buildings

� Testing

Calibrated for energy

consumption

At standard indoor

conditions

Insulation/coating added after calibration

• Steady indoor set point Tindoor = 24°C

• Tested for 7 days, ambient : 30°C to 44°CSummer test

• No set point is maintained; free floating

• Tested for 4 weeks, ambient :10°C to29°CWinter test


Results –Summer test- Steady set point

� Heat load reduction�23% incase of coating

�69% incase of retrofitting insulation

�76% in case of new wall

� Insulation effect�Heat flux fluctuations greatly reduced

�Thermal inertia in building increases

52.2

40.1

15.712.4

24.6 24.1 24.6 24.5

0

20

40

60

80

100

Reference(B1)

Coatings(B2)

Insulation(B3)

EIFS Wall(B4)

Heat Flux (W/m²)

Temperature (°C)

Reduction in Heat Load (%)

Variation of Heat Flux across the testing facade- Measured during steady state testing

0

5

10

15

20

25

30

35

40

45

0

10

20

30

40

50

60

70

80

90

0:00 6:00 12:00 18:00 0:00 6:00 12:00 18:00 0:00

B1 B2 B3 B4 RadiationX10 Ambient Temperature

Time (Hours)

Am

bie

nt

Te

mp

era

ture

, °C

He

at

Flu

x;

Ra

dia

tio

n,

W/m

²


Results- Winter test-Free floating conditions

� Indoor temperature fluctuations�6°C in case of reference

�Maximum of 2.5°C in other buildings

�Conditions in B2, B3, B4 are close to

thermal comfort

� Heat flux fluctuations�Minimum in case of B3 & B4 due to high

thermal mass

�Trend is same in B1 & B2, differ in magnitudeVariation of indoor temperature with ambient during free float testing

0

5

10

15

20

25

30

35

-10

0

10

20

30

40

50

0:00 6:00 12:00 18:00 0:00 6:00 12:00 18:00 0:00

B1 B2 B3 B4 Ambient Temperature

He

at F

lux

,W

/m²

Time (hours)

Variation of Heat Flux through the testing façade during free floating test

Am

bie

nt

Tem

pe

ratu

re, °

C

16

18

20

22

24

26

28

30

0:00 6:00 12:00 18:00 0:00 6:00 12:00 18:00 0:00

B1 B2 B3 B4 Ambient Temperature

Te

mp

era

ture

, °C

Time (Hours)


� The heat load was reduced up to 76% with different combinations of insulation

� Building Insulation proved to be vital in winter as well for comfort conditions

� Fluctuations in heat flux and temperature are reduced with added insulation

� Insulation has hughe impact on thermal inertia, time lag and comfort of buildings

Conclusions

Reference1. Radhi, H. Evaluating the potential impact of global warming on the UAE residential buildings – A

contribution to reduce the CO2 emissions. Building and Environment. 44: 2451- 2462 (2009).

2. Michael, B., Hoppe, K A., Rajesh, R K. et al. Design and Validation of Solar Calorimeter. Sustainability in

Energy and Buildings, Vol 1:16-23 (2012).

3. Cabeza, L.F. et al. Experimental study on the preformance of insulation materials in Mediterranean

construction. Energy and Buildings 42:630-636 (2010).

4. International Energy Agency. Electricity/Heat in United Arab Emirates in 2008. OECD/IEA (2008).

5. Al-Sanea, et al.. Effect of thermal mass on performance of insulated building walls and the concept of

energy savings potential. Applied Energy 89:430-42 (2011).


Thank you for your attention.

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