A simulation framework for the evaluation of intelligent ...Energy performance of building envelope...

A simulation framework for the evaluation of intelligent glazing technologies

in an office building in Egypt.

Rewaa E., Mahrous, Demonstrator, Department of Architecture, Assiut University, Egypt

Rabee M., Reffat, Professor, Department of Architecture, Assiut University, Egypt

Ola, Abdalmugod, Lecturer, Department of Architecture, Assiut University, Egypt

Abstract:

There is a growing interest among architects to allow for a huge amount of daylighting inside office

buildings as a way of achieving user’s visual comfort, however, this result in high energy consumption due

to the high solar gain. Intelligent window techniques are considered a suitable solution for this issue due to

their ability to change their main functional parameters based on the changing environmental situations and

therefore contribute to reducing energy consumption. This paper reviews various types of glazing

techniques and conducts a comparative study on 12 glazing techniques by measuring their performance on

different facades of 1000 sq. m office building using Energy plus 8.6 simulation software (WWR 40%).

Thus, guiding the selection of the best glazing technique for each facade.

Studying the performance of each technique on single façade showed that the best glazing technique on the

east and west directions were “Electrochromic glazing (EC) with low SHGC” which allowed for a reduction

of 32.18% and 32.45% respectively. While the “EC glazing with medium SHGC” reached 31.91%

reduction when applied on the south facade. On the other side, by applying each technique on the four

facades together, the best cooling reduction of almost 49% was achieved by using “Triple with suspended

Low-E film” glazing technique.

Keywords: Intelligent window techniques, Electrochromic glazing (EC), Energy consumption.

Introduction

Energy performance of building envelope components is a critical aspect in measuring the amount of energy

required for cooling and lighting.(Liu, Wittchen et al. 2014) The careful design of building’s envelope can,

therefore, have a huge effect on both building energy consumption and costs in addition to contributing to

the reduction of carbon dioxide emissions. The window, with its glazing and shading parts, is an important

component of building envelopes that contribute not only to energy consumption rates but also to user’s

comfort. Traditionally, building’s envelopes have been treated with various passive design approaches (see

Fig.1). These solutions refer to a series of architectural design strategies used by the designer to develop

buildings that have the capacity to respond adequately to climatic requirements (Behbood, Taleghani et al.

2010). However such approaches can deal with the high solar gain problems and other comfortable issues

to a certain degree as it is limited to specific environmental conditions and cannot adapt to changing and

excessive situations.

Fig.1 Examples of the traditional facade treatments ‘‘passive design” which showing designing with low WWR

because of the high solar gain outside, or designing with wide shading to decrease high solar, but the problem with

limiting the daylighting.

On the other hand, intelligent window techniques offer flexibility and convenience that passive building

design may not exclusively afford. Rapid temporary changes, options to open individual widows or operate

specific blinds in response to various environmental conditions are examples of such intelligent attributes.

These techniques can modulate the optical and thermal properties of the transparent portion of the façade

in response to changing outdoor conditions as shown in Fig.2 and Fig.3 (Favoino, Cascone et al. 2015).

Fig.2. shows sequential colors switching

of a thermochroic glazing (TC)

Fig.3. shows schematic diagram of a

four-layer electrochromic glazing (EC).

With the increasing global efforts to develop reliable solutions for reducing energy consumption, intelligent

glazing techniques appears as a promising approach that has the ability to enhance energy performance

while improving indoor environmental quality (Baetens, Jelle, & Gustavsen, 2010). An approach that may

help architects in delivering zero-energy building and sustain the required flexibility to maximize occupant

visual and thermal comfort.

The study conducted a review of previous research with a focus on intelligent glazing techniques and found

a wide range of the available techniques with numbers exceeding (25). This diversity is also a product of

introducing various technical properties for each original technique which contribute to a growing number

of options. Table 1 shows an example of the main types of glazing techniques including electrochromic

(EC), thermo-chromic (TC), gas-chromic, insulating glazing and spectrally-selective glazing summarized

based on their working mechanisms, physical properties, advantages, and disadvantages. With the

abundance of the available techniques, determining which glazing technique has the best performance

becomes a huge challenge that requires intense consideration. Therefore, this study conducts a comparative

analysis between different glazing techniques with the aim of determining their performance across each

façade, thus allowing for an informed selection

Literature data on details of the working mechanisms, physical properties, advantages, and disadvantages

of the above-mentioned technologies are summarized in Table.1

Intelligent

Glazing

Techniques

Technology

Type

Material

How it works

Coloring

bleaching

Notes

Drawbacks

Details of the of the glazing Technologies

Electrochromic

glazing (EC)

(Lee,

Selkowitz et

al. 2006)

Active devices

technology (that

can be directly

controlled in

response to any

variable)

It consists of a thin,

multi-layer

assembly that

would typically be

sandwiched

between traditional

glazings. The two

outside layers of the

assembly are

transparent

electronic

conductors. Next

are a counter-

electrode layer and

an electrochromic

layer, with anions

conductor layer in

between.

A low voltage is applied

across the conductors,

moving ions from the

counter-electrode to the

electrochromic layer, tinting

the assembly. It varies their

optical and thermal properties

due to the action of an

electric field and changes

back again when the field is

reversed.

- Switching

from bleached to

full color takes

about 6–7

minutes.

-For colder

temperatures

with low solar

irradiance,

switching could

take 40–85

minutes to reach

full coloration

EC window with

daylighting controls can

reduce a typical

commercial office

building’s perimeter

zone annual primary

energy use by 15–23%

for moderate-area

windows (WWR=0.30)

and 10–24% for large-

area windows

(WWR=0.60).

- Expensive

- Limited

modulation

levels

-Long response

time relative to

other active

systems

- Needs

electrical

energy for

transparency

modulation

(very low)

Suspended

Particle Device

(SPD)

(Gavrilović and

Stojić 2011)

(Favoino 2016)

(Kamalisarvesta

ni, Saidur et al.

2013)

http://www.smar

tglassinternation

al.com/downloa

ds/SPD_SmartG

lass_Data.pdf

Active devices

technology (that

can be directly

controlled in

response to any

variable)

IT consist of two

glass or transparent

plastic surfaces

with special

conductivity

coatings on the

panel interior. The

coating film

consists of tiny

"suspended"

particles specially

designed by the

chemical

composition

sandwiched

between two glass

covered surfaces.

When an electrical voltage is

applied, the suspended

particles are forced to align

and the light cannot pass

through the window.

- Switching

times (less than

one second)

between (100 -

200 ms)

- The ability to control

light levels also removes

the need to have blinds

and therefore decrease the

use of artificial lighting

throughout the day

- Curved or flat glass is

available

- the large size of any

shape can be produced at

least 2m*1m

- The reduced

glare in working

environments

that will cause

uncomfortable

conditions,

disruption to

computer

operation, and

possible eye

strain.

Insulating

Glass Unit

(IGU) data

sheet

Insulating glass

with Gas Fills

GU – Double pane

(a 1" (25mm) IGU

with two 1/4"

(6mm) and 1/2"

(12.7mm) argon

airspace; EC

coating on surface

#2)

Maximum 60" x

120" (1,524mm

x 3,048mm)

Minimum 14" x

14" (356mm x

356mm)

Maximum

overall thickness

2” (52mm) All

angles must be

≥30° with at

least one 90°

angle

>90%Argon,<10

%air

Contributes to

LEED and other

green building

rating systems

Several studies focused mainly on studing the impacts of each glazing technique on energy consumption

rates, while little attention has been established to compare the existing various products in order to select

the best performance. (Sbar, Podbelski et al. 2012) simulated applying electro-chromic EC windows in

three different climate zones and reported substantial energy savings in all cases. Energy savings for

dynamic EC double pane glazing compared to static condition were around 45% in every case. With respect

to CO2, EC glass reduced peak load carbon emissions by an average of 35% in new construction and 50%

in renovation projects. In another study (Feng, Zou et al. 2016) evaluated the application GC smart window

Liquid Crystal

Windows

(PDLC)

Active devices

technology (that

can be directly

controlled in

response to any

variable).

A very thin layer of

liquid crystal is

covered by

transparent

conductive metal,

which is wired to

the power supply

and laminated

between two layers

of glass.

When the power is off liquid

crystals are in a random, out

of position, and they scatter

the light. In this phase we

have an opaque glass with a

high privacy. When the

power is on the liquid

crystals are became align by

electricity, the light can pass

through the window.

Switching times

(less than one

second) between

(20 - 200 ms).

_It has a good Control

privacy,

Glare control

And Transmit incident

light.

_Large-area windows are

available in sizes up to

1.0*2.8 m2.

_ requires

constant energy

to maintain its

clear state, this

product has no

energy saving

benefits

_High Voltage

operates (24 -

100 VAC).

_ using interior

for privacy

Thermochroic

glazing (TC)

Passive device

( technology)

that respond

directly to a

single

environmental

variable(temp-

erature)

The thermochromic

coating is on the

glass.

It automatically reducing

solar load when it's hot

outside by changing color in

response to temperature

variations Because this,

glazing loses its transparency

when it switches

-Reduce glare

_ reduce SHGC

_Reflecting infrared light

(visual comfort)

_Reflecting heat gain

(thermal comfort)

- The switching

temperature of the glass

was between 89 and-91°F

(31-33°C), or nominally

90°F (32°C).

- units as large as 64" x

144" have been produced

with the thermochromic

interlayer and installed

throughout the world

-Difficult

manufacturing

for large pieces

_ Low visibility

Gas chromic

Windows

Active devices

technology (that

can be directly

controlled in

response to any

variable).

A hydrogen gas

(H2) is applied to

switch between

colored and

bleached states.

Gas chromic windows

produce a similar effect to

electrochromic windows, but

in order to color the window,

diluted hydrogen (below the

combustion limit of 3%) is

introduced into the cavity in

an insulated glass unit.

Exposure to oxygen returns

the window to its original

transparent state.

Switching

speeds are 20

seconds to color

and less than a

minute to

bleach.

Gas chromic windows

with an area of 2-by-3.5

feet are now undergoing

accelerated durability tests

and full-scale field tests

and are expected to reach

the

The market in the near

future.

_Gas supply

units are

required

the low -E

coating

(Rezaei,

Shannigrahi et

al. 2017)

Coating with

Gas Fills

A typical coating

(of thickness

around 0.1μm) has

three layers, i.e. a

thin metal layer

sandwiched

between two

dielectric layers

Change the original long

wave (>3μm) emissivity of

around 0.9 to less than 0.1.

There are two basic coating

techniques: pyrolytic and

sputtered, which can be

categorized into hard and soft

coatings.A substantial

amount of the long-wave

radiation could be reflected

by employing a Low-E

coating either on one glass

surface or both surfaces

bounding the air gap of

window units.

_Good performance

especially in summer, and

meet certain energy

performance criteria for

an ENERGY STAR.

_Reflects NIR or IR

radiation

_ Reduces heat radiation

by the window

_Decreases SHGC

_Slight decrease

in the light

transmittance

that makes

darker inside

building and

higher

reflectance when

viewed from the

outside.

and EC windows using e-QUEST 3.64 program, typical climate zones in China were selected for the

building energy simulation including Harbin (a coldest in winter A region), Changchun (a coldest in winter

B region), Beijing (a cold in winter region), and Compared with the single clear float glass. EC and GC

smart windows appeared to decrease the annual consumption of HVAC loads by 27–31% and 25–35%,

respectively. For thermochromic glazing (Saeli, Piccirillo et al. 2013) studied the impact of using it on the

energy demand and reported reduction in energy demand by 51.6% compared to a standard double glazed

system. Energy simulation also used by (Hoffmann, Lee et al. 2014) to assess the potential energy efficiency

benefits of thermos-chromic windows within simple room models with a low critical switching temperature

range (14–20 1C) achieved reductions in total site annual energy use of 14.0–21.1 kW h/m2 -floor-yr or

12–14% for moderate- to large-area windows (WWRZ0.30) in Chicago area and 9.8–18.6 kW h/m2 -floor-

yr or 10–17% for WWRZ0.45 in Houston.

On the other hand by studying the glazing techniques with their thermal, visual and technical specification

as (U-value and solar heat gain coefficient (SHGC), and daylighting indices, visible transmittance (Tv)),

and comparing them with the glazing performance. The study found that these specifications give Indicators

about the expected performance, however there are another factors which affect on the exact performance

such as the relationships between window heat gain, perimeter zone loads, and heating, cooling, and lighting

energy. Also performance is dependent on climate, building type (as defined by construction and internal

load profile), window orientation, window size, and the efficiencies of the space conditioning and lighting

equipment. Therefore, it is important to indicate the exact performance for each glazing type and choosing

the best, have to simulate them on the same base-case and on the same climate.

Selecting the Glazing Techniques to apply in the research

In each glazing technique there are variation which difference in thermal properties such as U-value, SHGC,

and Tvis. To choose between the variations and remodeling the window structure in WINDOW LBNL here

are some guide recommendations:

▪ Façade design tool in commercial window website: (This site originally developed by

the University of Minnesota and Lawrence Berkeley National Laboratory with support from

the U.S. Department of Energy's Emerging Technologies Program), after choosing the location,

building type, WWR, and facade orientation, the website will choose the window properties which

achieve the best performance in reduction in energy consumption. The website select the glazing

system with high VT, low SHGC, argon gas fill, second choose with high VT, moderate SHGC,

argon will achieve the best performance. http://www.commercialwindows.org/

▪ Previous studies.

▪ EWC’s Window Selection in Efficient Windows Collaborative: Window Design Guidance for

New in a Hot Climate, 2016 the best glazing system.

http://www.efficientwindows.org/

From are all variations of EC available from SAGE and other techniques, according to DOE report (Belzer

2010) Select high SHGC, low SHGC, medium SHGC, and techniques which mentioned in previous studies.

Here is the description in details of the glazing techniques Center of glass solar-optical and thermal

properties of systems that were simulated in Table.2.

http://www.csbr.umn.edu/

http://windows.lbl.gov/

http://energy.gov/eere/buildings/windows-skylights-and-doors-research

http://www.commercialwindows.org/

http://www.efficientwindows.org/

Code no. Description of Glazing Techniques U-value SHGC T vis

T 1 Electrochromic GLZ-with very low SHGC. The glazing is a25-mm-thickdouble-glazing unit

(SageElectronicsInc2013). With mix (10% air, 90% Argon) between two layers.

1.56 0.205 0.185

T 2 Triple with suspended low-e film (90% argon 10% air) with 6.0 mm low-e, spectrally selective

coating on iron glass, second layer is suspended film e=0.711, and the inside layer is 6.0 mm clear

0.994 0.101 0.171

T 3 Electrochromic GLZ SAGE Glazing is a 23-mm-thick double-glazing unit, with 12.7 mm Argon-

filled cavity. The outside layer is 8.0 mm with low-e coating and the inside layer is 3.0 mm clear.

The glazing switches to its fully tinted state if the solar radiation on the façade.

1.34 0.247 0.441

T 4 The glazing is 42 mm thick triple glazing. The outer and inner layer is low-e bronze, and the layer

in between is clear 6mm. The gap is mixed (12% air / 22% argon / 66% krypton). The glazing

switches to its fully tinted state according to the solar radiation on the window.

0.68 0.122 0.161

T 5

Double Glazing (Xenon) the outside layer is VIEW glass-tint ,the inside is NS20_3.bsf (WINDOW

lbnl library), in between is 12.5mm Xenon

2.33 0.603 0.63

T 6 Electrochromic GLZ with a 25-mm-thick double-glazing unit, with 12.7 mm mixed (12%air, 22%

Argon, 66% Krypton)-filled cavity. The outside layer is 8.7 mm Sage glazing and the inside layer

is 3.0 mm Bronze.

1.82 0.18 0.24

T 7 Thermo-chromic glazing ,Thermo-chromic example file in Energy Plus

2.289

0.279

0.237

T 8 Double high solar gain low-e with 16 mm argon between two glass layers. The external glass pane

is 5.9 mm thick with solar coat and the internal glass is 4.7mm low-e pane.

1.437

0.25

0.303

T 9 Electrochromic GLZ. The glazing is a 25-mm-thick double-glazing unit (SageElectronicsInc2013)

with 12.7 mm argon between two glass layers. The glazing switches to its fully tinted state

according to the solar radiation on the window.

1.578 0.441 0.497

T 10 The glazing is a 25-mm-thick double-glazing unit (SageElectronicsInc2013), with 12.7 mm air

between two glass layers. The external glass pane is 7 mm thick and the inner is clear 6 mm. The

glazing switches to its fully tinted state if the solar radiation on the façade.

1.833 0.43 0.601

T 11 The glazing is a 21-mm-thick double-glazing unit (View Glass) with 12.7 mm air-filled cavity .The

outside layer is tint layer (view) with thickness 5.6 mm. The glazing switches to its fully tinted

state if the solar radiation on the façade.

1.45 0.4 0.13

T 12 Double glazed with a low-e aluminum louvers integrated between the two pans 2.068 0.293 0.161

Simulation methodology

From the previous studies, computer-based simulation is accepted by many researchers as a tool to

evaluate the building energy consumption with alternatives in envelope treatments. Energy Plus is the most

widely-used simulation tool in the scientific researchers since it is the oldest among other software, and

EnergyPlus has had the largest growth in adaptive facade techniques modeling capabilities since it was

developed.

The simulation is performed in two stages. Firstly, the Lawrence Berkeley national laboratory (LBNL)

window software, WINDOW 7 is adopted to analyze the major optical and thermal parameters of different

glazing types, which include the U-value, solar heat gain coefficient (SHGC), and visible transmittance

(Tvis). In particular, Tvis is a factor for visibility of glazing material and is the portion of visible light that

passes through the window. SHGC referred to as Shading Coefficient (SC) to Solar Heat Gain Coefficient

(SHGC), which is defined as that fraction of incident solar radiation that actually enters a building through

the entire window assembly as heat gain and ranges from 0 to 1 for which higher value means higher solar

heat transmitted, and U-Factor expresses the total heat transfer coefficient of the system (in W/m2 °C), and

). http://www.commercialwindows.org/includes conductive, convective, and radiative heat transfer. (

In the second stage, with exporting from WINDOW 7, is calculating the dynamic properties for different

states from light to dark, by exporting these dynamic properties for each to EnergyPlus 8.6 and as shown

in Fig.4 with using energy management systems (EMS) of various kinds by linking sensors, control logic

and actuators Among the possible EMS actuators are various thermo-physical building envelope material

properties these actuators can be controlled with user-defined IF-ELSE statements during simulation run-

time. (Ellis, Torcellini, & Crawley, 2007)

Fig.4.Schematic that presents the main components

of an Energy Management System (EMS) and

displays the way of functioning in order to control a

dynamic window construction.

Fig.5 showing the sequence of simulation framework to reach to the best scenarios in applying glazing techniques

To have scenarios of combination between different types of glazing techniques as a second direction in

optimization to reach to the best performance which mentioned in Fig.5:

1- From simulate the individual technique in each façade and define the high performance in facades

in the range on 10% cut off from the best façade performance as in Table.3

2- Set scenarios of accumulation glazing techniques to reach to high reduction in energy

consumption.

Description of the commercial office building base-case

The office building base-case for simulation was defined as a 1-story from multi story building, with a

rectangular floor plate that is 40m (north–south) by 25 m (east–west) as 1000 sq.m area. Perimeter zones

Simulation inputs in Energy plus Modeling the base-case

Modeling the building base-case in Design Builder

software

▪ Weather file

▪ Location and climate

▪ Construction elements

▪ Occupancy schedule

▪ Lighting schedule

Exporting it

as .idf file

To Energy

plus

Running

simulation to have

base-case results

Running simulation to

have the individual

performance in each

facade

Calculate the dynamic optical and thermal

parameters of each glazing technique

Modeling the window structure

Exporting

To Energy

plus

By window construction state actuator and

sensors in EMS, offers the possibility to

change the window construction according

to the environmental changing

Control a dynamic window construction

Optimization to reach to the best performance in designing the four facades

Generating accumulation scenarios between

glazing techniques

Simulate solo-type of glazing technique in all

facades Comparing the

combination scenarios with

the solo-type in all facades

to reach to the best

performance.


were 7.5 m deep, with a 3.5m ceiling height, and core with area percentage 25% from total area. The

perimeter zones were oriented in the four cardinal directions: due north, east, south, and west. The window-

to-exterior-wall ratio was 0.40 as the common ratio in Egypt. (The modelling details is in Appendix A).

Simulation results

The results for applying the 12 glazing techniques and indenting their individual performance in each façade

are compared in terms of annual energy use, cooling electricity use, and lighting electricity use, and all

cases are using dimming lighting control to control artificial lighting to in case the internal environment

hasn’t the visual comfort by illuminance level 500 lux and glare index 22.

By comparing the energy savings achieved by each glazing technique in each façade individual, found that

EC (T3) has the best performance in north, east and west with reduction 28.66%, 32.18%, 32.45%

respectively and consumption 161.75, 153.77, 153.16 MJ/m2 comparing with the base case 226.72 MJ/m2.

For south façade the best performance is T9 with reduction 31.91% in total energy consumption.

Table.3. showing results of applying single treatment on each façade on energy consumption and

percentage of reduction compared to the base-case.

Treatment No. North South East West

Solo-Type in all facades

MJ/m2 % MJ/m2 % MJ/m2 % MJ/m2 % MJ/m2 %

Single Treatment on Base Case

T 1

Cooling Load 132.48 -12.13 126.05 -16.40 123.77 -17.91 123.38 -18.17 87.31 -42.09

lighting Load 36.29 -52.22 33.52 -55.87 31.79 -58.14 32.35 -57.41 44.93 -40.84

Total Load 169.06 -25.43 159.82 -29.51 155.85 -31.26 156.02 -31.18 132.42 -41.59

T 2

Cooling Load 131.69 -12.66 124.40 -17.49 121.41 -19.47 126.26 -16.26 76.95 -48.96

lighting Load 40.48 -46.70 40.06 -47.25 34.12 -55.08 35.50 -53.26 61.15 -19.49

Total Load 172.46 -23.93 164.70 -27.36 155.82 -31.27 156.06 -31.17 138.25 -39.02

T 3

Cooling Load 131.09 -13.05 124.66 -17.32 123.48 -18.10 122.83 -18.53 83.93 -44.33

lighting Load 30.36 -60.03 30.15 -60.30 29.99 -60.51 30.04 -60.45 31.53 -58.49

Total Load 161.75 -28.66 155.06 -31.61 153.77 -32.18 153.16 -32.45 115.63 -49.00

T 4

Cooling Load 132.36 -12.21 125.23 -16.94 121.94 -19.12 121.13 -19.66 81.71 -45.80

lighting Load 42.08 -44.60 40.59 -46.56 35.02 -53.89 23.54 -69.01 64.22 -15.44

Total Load 174.74 -22.93 166.07 -26.75 157.26 -30.64 156.96 -30.77 146.09 -35.56

T 5

Cooling Load 133.24 -11.63 128.58 -14.72 129.25 -14.27 127.22 -15.62 112.25 -25.55

lighting Load 27.99 -63.15 30.20 -60.24 29.95 -60.57 30.00 -60.50 31.09 -59.07

Total Load 163.75 -27.77 159.02 -29.86 159.49 -29.65 157.52 -30.52 143.53 -36.69

T 6

Cooling Load 132.02 -12.44 127.75 -15.27 123.83 -17.87 123.39 -18.16 86.65 -42.53

lighting Load 33.52 -55.87 31.78 -58.16 30.94 -59.26 31.40 -58.66 38.63 -49.14

Total Load 165.84 -26.85 157.77 -30.41 155.06 -31.61 155.08 -31.60 125.36 -44.71

T 7

Cooling Load 134.00 -11.12 129.54 -14.08 128.84 -14.55 127.48 -15.45 102.31 -32.14

lighting Load 34.09 -55.12 32.18 -57.63 31.10 -59.05 31.57 -58.43 39.94 -47.41

Total Load 168.41 -25.72 161.99 -28.55 160.24 -29.32 159.35 -29.72 142.46 -37.16

T 8 Cooling Load 131.80 -12.58 125.83 -16.54 122.78 -18.56 122.38 -18.83

88.91 -41.03

lighting Load 53.68 -29.32 50.37 -33.68 46.98 -38.14 47.65 -37.26 67.67 -10.90

Total Load 185.80 -18.05 176.47 -22.16 170.08 -24.98 170.34 -24.87 156.77 -30.85

T 9

Cooling Load 132.65 -12.02 123.33 -18.20 126.51 -16.09 128.71 -14.63 99.83 -33.79

lighting Load 30.37 -60.01 30.78 -59.47 29.98 -60.53 30.02 -60.47 31.74 -58.21

Total Load 163.33 -27.96 154.37 -31.91 156.79 -30.84 159.03 -29.86 131.80 -41.87

T 10

Cooling Load 133.78 -11.27 129.08 -14.39 128.43 -14.82 128.36 -14.86 104.09 -30.96

lighting Load 29.96 -60.55 29.89 -60.65 29.82 -60.74 29.82 -60.74 30.04 -60.45

Total Load 164.04 -27.65 159.24 -29.76 158.55 -30.07 158.47 -30.10 134.81 -40.54

T 11

Cooling Load 134.82 -10.58 131.39 -12.85 128.18 -14.98 129.89 -13.85 107.91 -28.43

lighting Load 39.37 -48.16 36.45 -52.01 33.07 -56.46 33.70 -55.63 53.58 -29.45

Total Load 174.50 -23.03 168.12 -25.85 161.56 -28.74 163.86 -27.73 161.73 -28.67

T 12

Cooling Load 134.78 -10.61 131.70 -12.65 129.81 -13.90 129.09 -14.38 109.76 -27.20

lighting Load 31.40 -58.66 31.33 -58.75 30.41 -59.96 31.29 -58.80 35.41 -53.38

Total Load 166.48 -26.57 163.29 -27.98 160.53 -29.19 160.69 -29.12 145.40 -35.87

Fig.6.showing the reduction in Total Energy Consumption for 12 glazing technique in N/S/E/W facades.

Total reduction Lighting reduction Cooling reduction

The best three glazing techniques in each façade are electrochromic EC in different technical specifications

(T3, T6, and T9) as shown in Fig.4. that in west façade have T3 and T6 the best performance by reduction

32.45% and 31.60% respectively, in south T9 and T3 have the best performance with reduction 31.91%

and 31.61% respectively, in east façade the best are T3 and T6 with reduction 32.18% and 31.61%

respectively and in north façade T3 and T9 have the best performance with reduction 28.66% and 27.96%

respectively. Reference to the description of the glazing techniques in Table.2. showing the thermal and

visual specifications, found that T3, T6, T9 are electrochromic glazing with the lowest SHGC and the

highest Tvis from the different techniques.

-33.00

-28.00

-23.00

-18.00

T 1 + DL T 2 + DL T 3 + DL T 4 + DL T 5 + DL T 6 + DL T 7 + DL T 8 + DL T 9 + DL T 10 + DL T 11 + DL T 12 + DL

N -25.43 -23.93 -28.66 -22.93 -27.77 -26.85 -25.72 -18.05 -27.96 -27.65 -23.03 -26.57

E -31.26 -31.27 -32.18 -30.64 -29.65 -31.61 -29.32 -24.98 -30.84 -30.07 -28.74 -29.19

S -29.51 -27.36 -31.61 -26.75 -29.86 -30.41 -28.55 -22.16 -31.91 -29.76 -25.85 -27.98

W -31.18 -31.17 -32.45 -30.77 -30.52 -31.60 -29.72 -24.87 -29.86 -30.10 -27.73 -29.12

TO

TA

L E

NE

RG

Y R

ED

UC

TIO

N

GLAZING TECHNIQUE

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

Tota

l re

duct

ion

Lig

hti

ng r

educt

ion

Cooli

ng r

educt

ion

T12 T11 T10 T9 T8 T7 T6 T5 T4 T3 T2 T1

Percentage of reduction in Cooling, Lighting and Total Energy Consumption for applying each Glazing technique in all facades

-35

.87

-53

.38

-27

.20

-28

.67

-29

.45

-28

.43

-40

.54

-60

.45

-30

.96

-41

.87

-58

.21

-33

.79

-30

.85

-10

.90

-41

.03

-37

.16

-47

.41

-32

.14

-44

.71

-49

.14

-42

.53

-36

.69

-59

.07

-25

.55

-35

.56

-15

.44

-45

.80

-49

.0

-58

.49

-44

.33

-39

.02

-19

.49

-48

.96

-41

.59

-40

.84

-42

.09

Fig.7. Percentage of reduction in Cooling, Lighting and Total Energy Consumption for applying solo-glazing

technique in all facades

By applying each glazing techniques in all facades found that the best performance is T3 with

reduction 49.0% in annual total energy, 44.33% reduction in cooling energy, and 58.49%

reduction in lighting energy. The second best performance is T6 with 44.71%, 42.53% and

49.14% reduction in total, cooling and lighting energy respectively.

Another direction for more optimization and having a wide range of alternatives for designing

facades glazing, have a combination between different glazing techniques in all facades. This

direction by generating scenarios of combination according to the individual performance for

each glazing technique as shown in Table.4 the combination scenarios between different glazing

techniques in all facades which is the second direction for optimization as mentioned previously

in Fig.5

-60.00

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

EN

ER

GY

RE

DU

CT

ION

GLAZING TECHNIQUES

T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12T1

Solo-type in all facades Performance In comparison to Base Case

Scenarios of accumulate different

types of Glazing Techniques

Per

centa

ge

of

reduct

ion i

n t

ota

l lo

ad

Solo

-gla

zing t

ype

Per

centa

ge

of

reduct

ion i

n t

ota

l lo

ad

Solo

-gla

zing t

ype

Total Lighting load Cooling load Glazing type in each facade

Per

centa

ge

of

reduct

ion i

n t

ota

l

load

Solo

-gla

zing t

ype

Percentage

of

reduction

%

MJ/m2

Percentage

of

reduction

%

MJ/m2

Percentage

of

reduction

%

MJ/m2

West

East

South

North

Scenario

no

- 226.72 -

75.95 -

150.77

Clear Clear Clear Clear Base-

Case

-49.00 T3 41.59- T1 -46.85 120.50

-54.40 34.63

-43.83 84.69 T1 T1 T3 T3 Scenario

1.

49.00- T3 -39.02 T2 -47.04 120.07

-45.87 41.11

-47.75 78.78 T2 T2 T3 T3 Scenario

2.

-39.02 T2 -44.71

T6 -44.09

126.75 -39.55

45.91 -46.49

80.68 T2 T2 T6 T6 Scenario

3.

-36.69 T5 41.59- T1 -39.02 T2 -38.94 138.44

-27.29 55.22

-44.92 83.04 T2 T2 T1 T5 Scenario

4.

-36.69 T5 -39.02 T2 -37.16 T7 -36.98 142.89

-29.05 53.89

-41.09 88.82 T2 T2 T7 T5 Scenario

5.

49.00- T3 -40.54

T10 -48.16

117.54 -59.05

31.1 -42.67


6.

49.00- T3 -35.87

T12 -47.04

120.07 -57.13

32.56 -41.96


7.

-41.87

T9 -35.56 T4 -46.52 121.26

-58.18 31.76

-40.78 89.29 T9 T9 T4 T4 Scenario

8.

-36.69 T5 -35.56 T4 -34.06 149.5

-18.78 61.69

-41.76 87.81 T4 T4 T5 T5 Scenario

9.

-35.56 T4 -44.71

T6 -42.90

129.46 -38.31

46.85 -45.21


10.

49.00- T3 -35.56 T4 -37.16 T7 -41.85 131.83

-41.95 44.09

-41.81 87.74 T4 T3 T7 T3 Scenario

11.

-35.56 T4 -40.54

T10 -42.44

130.5 -45.54

41.36 -40.88


12.

-36.69 T5 -39.02 T2 -37.81 140.99

-16.67 63.29

-48.57 77.54 T5 T2 T5 T2 Scenario

13.

-41.87

T9 -44.71

T6 -42.71

129.88 -52.24

36.27 -38.06


14.

-44.71

T6 49.00- T3 -46.46

121.38 -53.31

35.46 -43.01


15.

49.00- T3 -30.85

T8 -36.69 T5 -31.33

155.69 -11.27

67.39 -41.43


16.

-30.85

T8 -41.87

T9 -43.20

128.77 -47.24

40.07 -41.17


17.

-30.85

T8 -44.71

T6 -36.69 T5 -29.72

159.35 -7.87

69.97 -40.72


18.

-41.87

T9 49.00- T3 -42.53

130.3 -58.22

31.73 -34.62


19.

-41.87

T9 49.00- T3 -44.04

126.88

-58.21

31.74

-36.90

95.14

T9 T3 T9 T3 Scenario

20.

-28.67

T11 49.00- T3 -39.99

136.06 -50.35

37.71 -34.77


21.

-28.67

T11 -36.69 T5 -28.63

161.81 -24.50

57.34 -30.71


22.

-28.67

T11 -44.71

T6 -36.69 T5 -32.71

152.56 -34.06

50.08 -32.02


23.

-28.67

T11 -41.87

T9 -37.44

141.83 -50.03

37.95 -31.10


24.

-28.67

T11 -40.54

T10 -37.17

142.45 -51.27

37.01 -30.07

105.44 T11 T11 T10 T10 Scenario

25.

-49.00 T3 -35.87

T12 -44.71

T6 -39.56

137.02 -52.22

36.29 -33.19


26.

-35.87

T12 -41.87

T9 49.00- T3 -40.41

135.11 -56.66

32.92 -32.22


27.

Combination with percentage reduction in total energy between 40-50%

( the range of 20% from the highest performance)

Combination scenarios with reduction in energy higher than reduction with applying the solo-glazing

in all facades

Table.4 showing the combination scenarios between different glazing techniques in all facades

which is the second direction for optimization

Fig.8. Percentage of reduction in Total Energy Consumption for applying combination scenarios and solo-glazing

technique in all facades, and selecting which exceeding than 40% (in the range of 20% than the highest

performance).

From Table.4 and Fig.8., there are 14 scenarios from combination between different glazing

techniques with reduction in total consumption between 42% and 49%, however using solo-

glazing technique in all facades generate 3 scenarios only with range of reduction in total

consumption between 42% and 49%.

Conclusions

This paper presented a frame work for applying the high performance glazing by comparing and

evaluating 12 types of glazing techniques, firstly by the individual performance in each facades

and then by the solo-type in all facades. The simulation results using Energy plus software showed

the EC (SHGC 0.247, Tvis 0.441) achieved the best performance as solo-type in all facades with

49% reduction in total energy consumption. The second performance was 44.71% reduction in

total energy by applying EC (SHGC 0.18, Tvis 0.24) in all facades. For optimization, the research

proposed combination scenarios between different types of glazing techniques that can increase

the reduction of total energy consumption than applying solo-glazing technique in all facades.

Another advantage in using combination scenarios, giving a wide range of scenarios with high

performance to select between them. This wide range increase flexibility to select the most suitable

economically, the more available, the easily in maintenance …etc.

Minimizing the whole building energy consumption can be by applying intelligent glazing

techniques which have advantage more the traditional façade treatments in responding to various

environmental conditions. This advantage give the balance between lowing the solar gain indoors

and don’t minimizing the daylighting.

-46

.85

-47

.04

-44

.09 -3

8.9

4

-36

.98

-48

.16

-47

.04

-46

.52

-34

.06

-42

.9

-41

.85

-42

.44 -3

7.8

1

-42

.71

-46

.46

-31

.33

-43

.2

-29

.72

-42

.53

-44

.04 -3

9.9

9

-28

.63

-32

.71

-37

.44

-37

.17

-39

.56

-40

.41

-41

.59

-39

.02

-49

-35

.56

-36

.69

-44

.71

-37

.16

-30

.85

-41

.87

-40

.54

-28

.67

-35

.87

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

Sce

nar

io 1

.

Sce

nar

io 2

.

Sce

nar

io 3

.

Sce

nar

io4

Sce

nar

io 5

.

Sce

nar

io 6

.

Sce

nar

io 7

.

Sce

nar

io 8

.

Sce

nar

io 9

.

Sce

nar

io 1

0.

Sce

nar

io 1

1.

Sce

nar

io 1

2.

Sce

nar

io 1

3.

Sce

nar

io 1

4.

Sce

nar

io 1

5.

Sce

nar

io 1

6.

Sce

nar

io 1

7.

Sce

nar

io 1

8.

Sce

nar

io 1

9.

Sce

nar

io 2

0.

Sce

nar

io 2

1.

Sce

nar

io 2

2.

Sce

nar

io 2

3.

Sce

nar

io 2

4.

Sce

nar

io 2

5.

Sce

nar

io 2

6.

Sce

nar

io 2

7.

T1

T2

T3

T4

T5

T6

T7

T8

T9

T1

0

T1

1

T1

2

PE

RC

EN

TA

GE

OF

RE

DU

CT

ION

IN

TO

TA

L L

OA

D

ACCUMLATION SCEANRIOS & SOLO-TYPE GLAZING TECHNIQUE

Performance of accumlation scenarios& solo-type reduction in total load accumlation scenarios between glazying techniques Solo-type glazing in

all facades

References:

Belzer, D. B. (2010). An Exploratory Energy Analysis of Electrochromic Windows in Small and Medium

Office Buildings–Simulated Results Using EnergyPlus. Seattle: PNNL .

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region with an ability to reduce the input light and heat, and having enough visibility to outside.

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switchable glazing with energyplus: an empirical validation and calibration of a thermotropic

glazing model .

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thermal properties, energy simulation and feasibility analysis. Solar Energy Materials and Solar

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switching thermochromic windows for commercial building applications. Solar Energy Materials

and Solar Cells, 12 3 ,65-80 .

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technologies of thermochromic thin films on smart windows. Renewable and Sustainable Energy

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Federal Center, Building 41, Denver, Colorado. Retrieved from

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glazing technologies and materials for improving indoor environment. Solar Energy Materials and

Solar Cells, 159, 26-51 .

Saeli, M., Piccirillo, C., Warwick, M., & Binions, R. (2013). Thermochromic thin films: synthesis,

properties and energy consumption modelling. Formatex Res. Cent, 736-746 .

Sbar, N. L., Podbelski, L., Yang, H. M., & Pease, B. (2012). Electrochromic dynamic windows for office

buildings. International Journal of sustainable built environment, 1(1 ,)125-139 .

Windows for high performance for commercial buildings, (2014), Available from

http://www.commercialwindows.org, (accessed Aug 2014).

WINDOW 7, ⟨http://windows.lbl.gov/software/window/window.html⟩

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Office Buildings–Simulated Results Using EnergyPlus." Seattle: PNNL.

Favoino, F. (2016). Simulation-Based Evaluation of Adaptive Materials for Improved Building

Performance. Nano and Biotech Based Materials for Energy Building Efficiency, Springer: 125-166.


Favoino, F., Y. Cascone, L. Bianco, F. Goia, V. Serra, M. Perino, M. Overend and M. Zinzi (2015).

"Simulating switchable glazing with energyplus: an empirical validation and calibration of a thermotropic

glazing model."

Feng, W., L. Zou, G. Gao, G. Wu, J. Shen and W. Li (2016). "Gasochromic smart window: optical and

thermal properties, energy simulation and feasibility analysis." Solar Energy Materials and Solar Cells 144:

316-323.

Gadelhak, M. I. A. (2013). High Performance Facades: Designing Office Building Facades to Enhance

Indoor Daylighting Performance, Ain Shams University.

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buildings." Facta universitatis-series: Architecture and Civil Engineering 9(2): 261-268.

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areas."

Hoffmann, S., E. S. Lee and C. Clavero (2014). "Examination of the technical potential of near-infrared

switching thermochromic windows for commercial building applications." Solar Energy Materials and

Solar Cells 123: 65-80.

Kamalisarvestani, M., R. Saidur, S. Mekhilef and F. Javadi (2013). "Performance, materials and coating

technologies of thermochromic thin films on smart windows." Renewable and Sustainable Energy Reviews

26: 353-364.

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Yazdanian (2006). Advancement of Electrochromic Windows. California Energy Commission, PIER.

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Ventilation Centre.

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glazing technologies and materials for improving indoor environment." Solar Energy Materials and Solar

Cells 159: 26-51.

Saeli, M., C. Piccirillo, M. Warwick and R. Binions (2013). "Thermochromic thin films: synthesis,

properties and energy consumption modelling." Formatex Res. Cent: 736-746.

Appendix A. Detailed simulation input values: office building.

Variables Energy Plus Values Justification & Reference

Sch

emat

ic

Lev

el

Location Cairo

Climate EGY_Cairo.623660_IWEC

Orientation North South (BO1)

North East-South West (BO2)

Mas

s le

vel

Shape Rectangle Third Ratio of 24% after irregular and

rectilinear (51Cases)

Floor Area 1000 m2

Dominant Value ( 500<1000 m2) (51 Cases)

Dimensions 40mx25m

Golden Ratio= 24.86x 40.23

1:1.618

Core area 250 m2

25%

Plan Type Open Plan consists of five zones. Current practice in Egypt

Perimeter Zone Depth 7.5m -

Floor Height

3.5m Average Height in 51 cases

False Ceiling Height 3 m Dominant floor height: 30<50 m= 30 % (9 <

14 floors)

Number of floors 1 Maximum Allowed Height in Egypt = 36

m= 10 floors

External Wall

20mm plaster +20mm mortar+ 250 mm

brick work (outer leaf) +20mm mortar +

20 plaster

(Mostafa.M. ,2016)

External Wall Insulation None

Internal Partition

( Plaster-lightweight 2 cm+ mortar+

Brick work (inner leaf) 12 cm+ mortar+

Plaster (light weight) 2 cm)

(Mostafa.M. ,2016)

Floor

tiles 2cm+ mortar 2cm+ Sand 6cm+

reinforced Concrete + mortar+ Plaster

(light weight) 2 cm)

(Mostafa.M. ,2016)

Win

do

w Conditioned Chillers Systems With Cooling

WWR 40% Survay- (Hamza, 2004)

Glazing Single pane - Clear Float = 6mm (Gadelhak 2013)

Sill 0.95 m

Occ

up

ancy

Occupancy Pattern 8am:5pm (Hamza 2004)

Occupancy sensible gains 90 W/person (Hamza 2004)

Occupancy Density 10 m2/ person (Hamza 2004)

Lighting Power Density (LPD) 10.548 W/m2

ASHRAE/IES Standard 90.1-2010

A simulation framework for the evaluation of intelligent ...Energy performance of building envelope...

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