ANALYSIS OF ANNUAL HEATING AND COOLING ENERGY

REQUIREMENTS OF A NATURALLY VENTILATED OFFICE

BUILDING USING ENERGYPLUS

By

Supervised by

Zain-ul-Abdin Qureshi

Lecturer

Department Of Mechanical Engineering

Mehran University of Engineering & Technology, Jamshoro

Submitted as a partial fulfillment of the requirement for the Degree

Of Bachelor of Mechanical Engineering

January 2015

Abdul Manan Abro (G.L) 11ME51

Bilal Shaikh (A.G.L) 11ME161

Ali Raza 11ME153

Waleed Ahmed Khan 11ME101

Ahmed Kamaleldin Abdelgadir Babikir 11-10ME136

ii

DEDICATION

Whatsoever is in the heavens and the earth glorifies Allah, and He is the All-Mighty, All-

Wise. This is the kingdom of the heavens and the earth, It is He Who gives life and

causes death; and He is Able to do all things. He is the first (nothing is before Him) and

the Last (nothing is after Him), the Most High (nothing is above Him) and the Most Near

(nothing is nearer than Him). And He is the All-Knower of everything. (Surah Al Hadid).

All Thanks and gratitude is due only to ALLAH, the most gracious, the most merciful

and the most beneficent, who bestowed upon us enlightenment, courage and strength to

undertake and complete this work.

This humble effort is dedicated to our BELOVED PARENTS & KIND SUPERVISOR

SIR ZAIN-UL-ABDIN QURESHI. We thank our parents, pray for and promise to do

whatever is possible in our powers to comfort them and promote their good mission for

the noble cause of spread of education and development of human beings. They served us

their best efforts and brought us up to level what we are now, May ALMIGHTY ALLAH

blesses them.

We would also like to thank our kind supervisor Sir Zain-ul-Abdin Qureshi who devoted

his energy and time for us and provided us the complete guidance throughout process.

May ALLAH ALMIGHTY always shower his blessings upon him.

iii

CERTIFICATE

This is certified that the work presented in the thesis entitled Analysis of Annual

Heating and Cooling energy requirements of a Naturally Ventilated Office Building using

EnergyPlus is entirely simulated by following students under the supervision of MR.

ZAIN-UL-ABDIN QURESHI, Lecturer Mechanical Engineering Department, Mehran

UET, Jamshoro.

Name of Students

Roll Nos.

1. Abdul Manan Abro (G.L) 11ME51

2. Bilal Shaikh (A.G.L)

11ME161

3. Ali Raza

11ME153

4. Waleed Ahmed Khan

11ME101

5. Ahmed Kamaleldin Abdelgadir Babikir

11-10ME136

Project Supervisor External Examiner

Chairman

Department of Mechanical Engineering

Dated: ..

iv

ACKNOWLEDGMENT

We are thankful to Almighty Allah, for giving us the strength and courage to

complete our project.

We would like to express the deepest appreciation to our project

supervisor Mr. Zain-ul-Abdin Qureshi, who has shown the attitude and the

substance of a genius. He continually and persuasively conveyed a spirit of

adventure in regard to our project, and an excitement in regard to teaching.

Without his supervision and constant help this dissertation would not have been

possible.

In the end, we would again like to forward all words of thanks &

gratitude to the entire Faculty members who helped us in any capacity and made

this project possible.

v

ABSTRACT

Buildings all around the world consume a significant amount of energy, which is more or

less one-third of the total primary energy resources. Energy simulation programs have

now become a useful tool for predicting cooling, heating, and electricity loads for

facilities. Here heating and cooling energy requirements in office buildings have been

calculated considering the effect of parameters like shading, window system including

window area and glazing system, fins, people and light load and wind capture. The model

was used as a means to examine some energy conservation opportunities on annual

cooling and heating energy requirements, keeping in view the thermal comfort criteria of

the building occupants using EnergyPlus software.

vi

TABLE OF CONTENTS

Page No

CHAPTER 1 INTRODUCTION 1-8

1.1 Building energy scenario

1

1.2 Indoor Building Comfort

3

1.2.1 Environmental factors

3

1.2.2 Personal factors

4

1.3 Natural Ventilation

4

1.4 Building Description

5

1.5 Heating Load

5

1.6 Cooling Load

6

1.7 Zone

7

1.8 Objectives of the study

8

1.9 Methodology

8

CHAPTER 2 LITERATURE REVIEW

9-13

CHAPTER 3 BUILDING ENVELOPE

14-22

3.1 Site location

14

3.2 Schedule

14

3.3 Material

15

3.4 Window Material: Glazing

16

3.5 Window Material: Gas

17

3.6 Construction 17

3.7 Zone 18

vii

3.8 Building Surface: Detailed

19

3.9 Fenestration Surface: Detailed

20

3.10 Internal Gains

21

3.10.1 People

21

3.10.2 Lights

22

CHAPTER 4 ENERGYPLUS

23-28

4.1 What is EnergyPlus?

23

4.2 Why does EnergyPlus exist?

23

4.3 EnergyPlus Environment

24

4.4 EP-Launch

24

4.5 Selecting Input and Weather Files

25

4.6 Running a Single Input File

25

4.7 Completing Simulation

26

4.8 Looking at the Results

26

4.9 IDF Editor

27

CHAPTER 5 RESULTS AND CONCLUSIONS

29-44

5.1 Effect of shading

30

5.2 Effect of Glazing Area

33

5.3 Effect of Fin

35

5.4 Effect of people gain load and wind capture

38

5.5 Effect of Glazing Material Thickness 41

viii

LIST OF TABLES

Page No

Table 1 Site Location Details

14

Table 2 Various Construction Material Properties

15

Table 3 Various Glazing Material Properties

16

Table 4 Construction of Building

17

Table 5 Single Zone Detail

18

Table 6 Building Surfaces Detail

19

Table 7 Fenestration Surfaces Detail

20

Table 8 People Load Details

21

Table 9 Light Load Details

22

ix

LIST OF FIGURES

Page No

Fig. 1.1 Building Energy Consumption for Various Countries

1

Fig. 1.2 Buildings Energy Consumption Outlook

2

Fig. 1.3 EnergyPlus Building Model

5

Fig. 4.1 EP-Launch

24

Fig. 4.2 DOS Window

25

Fig. 4.3 End of Program

26

Fig. 5.1 Shading over Door only

30

Fig. 5.2 Shading over Door and Windows

30

Fig. 5.3 External Shading also considered

30

Fig. 5.4 Effect of Shading Techniques on MRT for coolest day

30

Fig. 5.5 Effect of Shading Technique on MRT for hottest day

31

Fig. 5.6 Effect of Shading Technique on Heating Energy

32

Fig. 5.7 Effect of Shading Technique on Cooling Energy

32

Fig. 5.8 Building with increased Glazed Area

33

Fig. 5.9 Effect of Increased Glaze Area on MRT for Coolest Day

33

Fig. 5.10 Effect of Increased Glaze Area on MRT for Hottest Day

34

Fig. 5.11 Effect of Increased Glaze Area on Heating Energy required 34

x

Fig. 5.12 Effect of Increased Glaze Area on Cooling Energy

35

Fig. 5.13 Building with Fins attached

35

Fig. 5.14 Effect of Fins on MRT for Coolest Day

36

Fig. 5.15 Effect of Fins on MRT for Hottest Day

36

Fig. 5.16 Effect of Fins on Heating Energy

37

Fig. 5.17 Effect of Fins on Cooling Energy

37

Fig. 5.18 Building Without Wind Capture

38

Fig. 5.19 Building with Wind Capture

38

Fig. 5.20 Effect of People/Light Load and Wind Capture on MRT for Coolest Day

39

Fig. 5.21 Effect of People/Light Load and Wind Capture on MRT for Hottest Day

39

Fig. 5.22 Effect of People/Light Load and Wind Capture on Heating Energy

40

Fig. 5.23 Effect of People/Light Load and Wind Capture on Cooling Energy

41

Fig. 5.24 Effect of Glazing Material Thickness on MRT for Coolest Day

42

Fig. 5.25 Effect of Glazing Material Thickness on MRT for Hottest Day

42

Fig. 5.26 Effect of Glazing Material Thickness on Heating Energy

43

Fig. 5.27 Effect of Glazing Material Thickness on Cooling Energy 43

1

CHAPTER 1

INTRODUCTION

1.1 Building Energy Scenario

With the enormous consumption of energy in the world since last two decades, the

predominant energy resources i.e. fossil resources are decreasing day by day and they are

at the verge of depletion. This being a matter of great concern the government,

researchers, policy makers and scientist have great attention towards energy security,

changing climatic conditions (i.e. global warming, depletion of ozone layer, etc. ) and

adverse environmental effects. Keeping in view the current energy scenario, the

International Energy Agency (IEA) has raised the concerns for environment, energy

security and the economic prosperity generally known as (3Es).

In this regard the energy consumption in building projects is a great concern. Buildings

all around the world consume more than one third of the total primary energy supply. The

energy consumption in various countries in buildings is shown in Fig.1.1. Since 40% of

the worlds energy is being consumed in the buildings, ultimately, it accounts for 30% of

the CO2 emissions. [1]

Fig. 1.1 Building Energy Consumption for Various Countries

2

The EIA, in its International Energy Outlook, analyses and forecasts future trends in

building energy consumption (Fig. 1.2). Energy use in the built environment will grow by

34% in the next 20 years, at an average rate of 1.5%. In 2030, consumption attributed to

dwellings and the non-domestic sectors will be 67% and 33% respectively

(approximately). Spread in Southeast Asian, and therefore, the growth of construction

will boost energy demand on the residential sector. Forecasts predict that both developed

and non-developed economies will be balanced in the use of energy in dwellings by

2010. Economic, trading and population growth in emerging economies will intensify

needs for education, health and other services, together with the consequential energy

consumption. It is expected that energy consumption in the service sector in non-

developed countries will be doubled in the next 25 years, with an annual average growth

rate of 2.8%. [2]

Fig 1.2 Buildings Energy Consumption Outlook. Source: EIA.

3

In building energy consumption space heating and cooling is major concern as it is

needed throughout the year. Reducing energy consumption for this is the key measure for

energy conservation and environmental protection. Therefore study of the factors

affecting energy conservation in buildings is essential and their designing is major

concern. With the help of computer simulation program it is now possible to study these

factors extensively and systematically. [3]

Here in our study we have studied various passive techniques affecting the energy

demand in office buildings for space heating and cooling, how changing in these factors

affect the energy conservation. EnergyPlus software is used for the annual energy

simulations of the building considered as single zone of area 48m2 and height 2.7m.

1.2 Indoor Building Comfort

Indoor building comfort is the most important criteria to be considered while designing a

building because approximately 90% people spend most of their time in buildings. So

inhabitants health, morale, working efficiency, productivity and satisfaction are greatly

affected by buildings performance. So building should be designed which is thermally

comfortable. [1]

Thermal comfort is that condition of mind that expresses satisfaction with the thermal

environment. It results from a combination of environmental and personal factors:

1.2.1 Environmental factors

Air temperature: The temperature of the air that a person is in contact with,

measured by the dry bulb temperature (DBT).

Air velocity: The velocity of the air that a person is in contact with (measured in

m/s). The faster the air is moving, the greater the exchange of heat between the

person and the air.

Radiant temperature: All bodies exchange thermal radiation with their

surroundings, depending on the difference in their surface temperatures and

their emissivity. This radiant exchange is an important component of the thermal

comfort that will be experienced by a person. Mean radiant temperature (MRT) is

4

a measure of the average temperature of the surfaces that surrounds a particular

point, with which it will exchange thermal radiation.

Relative humidity: The ratio between the actual amount of water vapor in the air

and the maximum amount of water vapor that the air can hold at that air

temperature, expressed as a percentage. The higher the relative humidity, the

more difficult it is to lose heat through the evaporation of sweat.

1.2.2 Personal factors

Clothing: Clothes insulate a person from exchanging heat with the surrounding air

and surfaces as well as affecting the loss of heat through the evaporation of sweat.

Clothing can be directly controlled by a person (i.e. they can take off or put on a

jacket) whereas environmental factors may be beyond their control.

Metabolic heat: The heat we produce through physical activity. A stationary

person will tend to feel cooler than a person that is exercising.[4]

.

1.3 Natural Ventilation

Natural ventilation is the ventilation of a building with outside air without using fans or

other mechanical systems. With the global energy and environment issues, natural

ventilation, very old and traditional technology for enhancing building environment, has

attracted great attentions. It is an effective way to simultaneously enhance indoor air

quality and reduce energy consumption of buildings. The aim of the ventilation is not

only to provide hygienic ventilation but also ventilation for cooling. [5]

It has the advantage of exploiting a free and abundant resource and remains easy to use. It

improves occupant comfort by creating air movement in the building and by cooling the

building structure at night with lowest outdoor temperatures. Neglected since the 50s for

mechanical systems of ventilation and air conditioning they tend to disappear from

constructive methods. However, natural ventilation fits perfectly with the current issue

which is to design low-energy buildings with low emissions of greenhouse gases. [6]

5

1.4 Building Description

The building selected here is situated in Karachi region having latitude 24.860 and

longitude 67.010. It has a floor area of 48m

2 and ceiling height of 2.7m. It is an office

building whose surfaces are made up of different materials like fiberglass, plasterboard

etc. having different thermal properties. In fenestration door is made up of plasterboard

while double pan window having air gap and glazed material. In internal gains two

people are considered having light load of 1000 watt. For different simulations fins are

also considered and somewhere shading material is also considered.

Fig. 1.3 EnergyPlus Building Model

1.5 Heating Load

It is the rate at which energy must be supplied to a space to maintain the temperature and

humidity at the design values.

Prior to the design of the heating system, an estimate must be made of the maximum

probable heat loss of each room or space to be heated. There are two kinds of heat losses

(1) The heat transmitted through the walls, ceiling, floor, glass, or other surfaces

(2) The heat required to warm outdoor air entering the space.

6

The sum of heat losses is referred to as the heating load.

The actual heat loss problem is transient because the outdoor temperature, wind velocity,

and sunlight are constantly changing. For this purpose 24 hour dynamic load calculation

has been carried out using EnergyPlus software which takes weather file having 24 hour

weather data.

The ideal heating system would provide just enough heat to match the heat loss from the

structure.

1.6 Cooling Load

The cooling load is the rate at which energy must be removed from a space to maintain

the temperature and humidity at the design values. Transient analysis is used in design for

cooling. EnergyPlus calculates the cooling load using Heat Balance Method.

The heat balance method ensures that all energy flows in each zone are balanced and

involves the solution of a set of energy balance equations for the zone air and the interior

and exterior surfaces of each wall, roof, and floor. These energy balance equations are

combined with equations for transient conduction heat transfer through walls and roofs

and algorithms or data for weather conditions including outdoor air dry bulb temperature,

wet bulb temperature, solar radiation, and so on.

Heat gain is the rate at which energy is transferred to or generated within a space. It has

two components, sensible heat and latent heat, which must be computed and tabulated

separately. Heat gains usually occur in the following forms:

(1) Solar radiation through openings.

(2) Heat conduction through boundaries with convection and radiation from the inner

surfaces into the space.

(3) Sensible heat convection and radiation from internal objects.

(4) Ventilation (outside air) and infiltration air.

(5) Latent heat gains generated within the space.

Cooling load will generally differ from the heat gain because the radiation from the inside

surface of walls and interior objects as well as the solar radiation coming directly into the

7

space through openings does not heat the air within the space directly. This radiant

energy is mostly absorbed by floors, interior walls, and furniture, which are then cooled

primarily by convection as they attain temperatures higher than that of the room air. Only

when the room air receives the energy by convection does this energy become part of the

cooling load.

Heat extraction rate is the rate at which energy is removed from the space by the cooling

and dehumidifying equipment. This rate is equal to the cooling load when the space

conditions are constant and the equipment is operating. [7]

1.7 Zone

A zone is an air volume at a uniform temperature plus all the heat transfer and heat

storage surfaces bounding or inside of that air volume. It is the thermal not the geometric

concept. EnergyPlus calculates the energy required to maintain each zone at a specified

temperature for each hour of the day. In order to correctly carry out the zoning of the

building it is necessary to distinguish between both heat transfer and heat storage

surfaces.

1. Heat transfer surface: Any surface, which is expected to separate surfaces of

significantly different temperatures, is defined as heat transfer surface. Outside

walls such as walls, roofs, floors come into this category.

2. Heat storage surfaces: Any surfaces, which is expected to separate spaces

maintained at the same temperature. Interior surfaces (partitions) come into this

category.[8]

8

1.8 OBJECTIVES OF THE STUDY

1. Analysis of annual heating and cooling energy requirements of a naturally

ventilated office building.

1.9 METHODOLOGY

1. Collecting weather data / weather file in EPW format and enter in EnergyPlus

Software.

2. Provide details of the building envelope to EnergyPlus.

3. Provide building construction, material, building surface detail and fenestration

detail to EnergyPlus.

4. To model/ simulate the building using EnergyPlus.

5. Results / Conclusions.

9

CHAPTER 2

LITERATURE REVIEW

Pervez Hameed Shaikn, Nursyarizal Bin Mohd Nor, Perumal Nallagownden, Irraivan

Elamvazuthi,Taib Ibrahim presented a review paper which presents a comprehensive and

significant research conducted on state-of-the art intelligent control systems for energy

and comfort management in smart energy buildings (SEBs). It also aimed at providing a

building research community for better understanding and up-to-date knowledge for

energy and comfort related trends and future directions. This paper presented works

closely related to the mentioned issue. Key areas focused on include comfort parameters,

control systems, intelligent computational methods, simulation tools, occupants behavior

and preferences, building types, supply source considerations and countries research

interest in this sector. Trends for future developments and existing research in this area

have been broadly studied and depicted in a graphical layout. In addition, prospective

future advancements and gaps have also been discussed comprehensively. [1]

Luis Perez-Lombard presented a study in which he analyzed energy consumption in

detail and presented some future predictions. The rapidly growing world energy use has

already raised concerns over supply difficulties, exhaustion of energy resources and

heavy environmental impacts (ozone layer depletion, global warming, climate change,

etc.). The global contribution from buildings towards energy consumption, both

residential and commercial, has steadily increased reaching figures between 20% and

40% in developed countries, and has exceeded the other major sectors: industrial and

transportation. Growth in population, increasing demand for building services and

comfort levels, together with the rise in time spent inside buildings, assure the upward

trend in energy demand will continue in the future. For this reason, energy efficiency in

buildings is today a prime objective for energy policy at regional, national and

international levels. Among building services, the growth in HVAC systems energy use is

particularly significant (50% of building consumption and 20% of total consumption in

the USA). This paper analyses available information concerning energy consumption in

buildings, and particularly related to HVAC systems. Comparisons between different

10

countries are presented specially for commercial buildings. The case of offices is

analyzed in deeper detail. [2]

In 2007 Nurdil Eskin and Hamdi Turkmen presented a paper, in which the interactions

between different conditions, control strategies and heating/cooling loads in office

buildings in the four major climatic zones in Turkey hot summer and cold winter, mild,

hot summer and warm winter, hot and humid summer and warm winter through

building energy simulation program has been evaluated. The simulation results were

compared with the values obtained from site measurements done in an office building

located in Istanbul. The site-recorded data and simulation results were compared and

analyzed. This verified model was used as a means to examine some energy conservation

opportunities on annual cooling, heating and total building load at four major cities which

were selected as a representative of the four climatic regions in Turkey. The effect of the

parameters like the climatic conditions (location), insulation and thermal mass, aspect

ratio, color of external surfaces, shading, window systems including window area and

glazing system, ventilation rates and different outdoor air control strategies on annual

building energy requirements is examined and the results are presented for each city.[3]

Yang Wang, Fu-Yun Zhaoc, Jens Kuckelkorna, Di Liud, Jun Liue, Jun-Liang Zhang t

presented a paper which stated that the natural ventilation is an effective method to

simultaneously improve indoor air quality and reduce energy consumption in buildings,

especially when indoor temperature is close to ambient temperature e.g. the transitional

seasons in Germany. Heat loss due to opened window and ventilation effectiveness ratio

were analytically modeled. Following that, the effects of thermal buoyancy on the steady

classroom air-flow and thermal stratification comfort as well as the contaminant

dispersion were discussed. Class room displacement ventilation and its thermal

stratification as well as indoor air quality indicated by the CO2 concentration have been

investigated concerning the effects of supplying air temperature and delivering

ventilation flow velocity. Representative thermal comfort parameters, percentage

dissatisfied and temperature difference between ankle and head have been evaluated.

Subsequent energy consumption efficiency analysis illuminates that classroom energy

demands for natural ventilation not only in transitional seasons but also in winter could

be decreased with the promotion of the ventilation effectiveness ratio for heat distribution

11

when the natural ventilation rate maintains a constant, and with the shrinking of the

ventilation effectiveness ratio for heat distribution when the supplying air temperature is

not variable. Detailed fitting correlations of heat loss resulted from opened window and

ventilation effectiveness of natural ventilation inside the classroom have been

presented.[5]

Ghjuvan Antone Faggianelli presented a study in which he investigated the use of

thermal breezes. Natural ventilation of buildings is a common way to improve indoor air

quality, thermal comfort in summer and reduce energy consumption due to air

conditioning. However, efficiency of such a system is highly dependent on climatic

conditions. This paper investigates the use of thermal breezes, characterized by moderate

speeds and well defined direction, to improve natural cross ventilation technique on

Mediterranean coastal zones. The interest of this phenomenon is highlighted by the

development of climate indicators with meteorological data from various places in

Corsica (France). A statistical wind rose is used to give more information on main wind

sectors and speed fluctuations. The natural ventilation potential is assessed by a radar plot

which groups the main climate indicators for comfort ventilation and passive cooling.

Tracer gas measurements on a seaside building in Corsica show that high air change rates

are reached by cross ventilation during day (higher than 25 ACH). Night ventilation gives

more moderate results for passive cooling with air change rates close to 10 ACH. As the

comfort in building is related to the airflow, it is necessary to be able to control it. The

issue of controlling openings to maintain a satisfying airflow is treated with the help of an

empirical model. Due to the regularity of thermal breezes, it shows that even if the

airflow varies greatly during the day, a minimal control on opening surface is sufficient

to maintain the airflow rate on a comfortable range. [6]

Becker and Paciuk reported a study in 2002, which investigated the impact of various

night ventilation and pre-cooling strategies on peak cooling demand for an office building

located in moderately warm climatic regions of Israel. For this study 25m 40m space in

a typical office building was considered. Simulations were performed by means of the

public demand computer program TARP. The building had 40 m south and north facing

facades, with 0.90 m high windows along their entire length. A 0.5 m horizontal

overhang was assumed to run on top of the southern windows. The internal floors

12

consisted of 130 mm reinforced concrete, with a 7.5 mm carpet on top and a suspended

12.5 mm gypsum wallboard ceiling underneath, with 50 mm acoustic mineral-wool mats

in the gap. Internal mass included 150 m2

of 200 mm concrete walls, and 375 m2

of 12.5

mm wallboard partitions with 50 mm acoustic mineral-wool mats in the gap. Results

indicated significant reductions of required daytime peak power loads may be obtained

by cooling strategies that contribute to lowering internal mass temperatures. For buildings

with large internal heat loads, intensive night pre-cooling is the most effective strategy

for smoothing required power loads. However, for non-loaded buildings, it largely

increases total energy loads, and night-time peak power loads. Intensive night ventilation

reduces required peak power loads as well as total cooling energy loads for both building

types. For non-loaded buildings, it is an extremely efficient strategy, whereas the efficacy

of other pre-cooling strategies is highly questionable. [9]

Steinar Grynning , Berit Time, Barbara Matusiak studied various strategies of shading

and no of panes in windows and there effect on the building heating, cooling, lighting and

ventilation demands. For their research they considered two office south- and north-

facing cubicles, one with single person and other with two persons. The simulations show

that the choice of shading strategy can have an impact on the energy demand of the

offices. Depending on strategy, the energy demand can either increase or decrease

compared to an unshaded one- or two-person office cubicle. For thermal comfort

Fangers model was considered. The simulations were carried out using EnergyPlus

software. [10]

Saeed, A. Khan , S. Arif , M. Mushtaq studied the effect of glaze area on the energy

requirement of an office building. This paper presents analysis of electricity

consumption for typical highly glazed office building in Lahore through simulations

process. The parameters selected for simulation were the orientation, shape of building,

elements of faade such as windows, their size and the type of glazing. The paper

concludes that highly glazed buildings require huge electricity than the buildings

designed with climatic considerations. [11]

Dascalaki and Santamouris, reported another study in 2002, which investigated the

energy conservation potential of office buildings in five climatic zones in Europe for

13

different passive retrofitting scenarios. This study showed that shading reduced both the

cooling load and yearly energy consumption of buildings. However, this study did not

incorporate any occupancy schedule or internal loads for the buildings. [12]

Joseph C. Lam presented a study in which effect of light load on cooling and heating

energy requirement have been analyzed. Changes in lighting load density affect not only

energy use for electric lighting but also energy requirements for space heating and

cooling. In general, a reduction in electric energy use would tend to increase space

heating during the winter months and lower the cooling requirement in the summer. The

implications for total building energy use, however, would vary, depending on the

building and building services designs, its operation and the prevailing climates. This

paper presents an analysis of the interactions between lighting and space heating/cooling

loads in office buildings in the five major climatic zonessevere cold, cold, hot summer

and cold winter, mild, and hot summer and warm winterin China through building

energy simulation using DOE-2.1E. [13]

Ivan Oropeza-Perez presented a study in which the energy conservation opportunities

were found for naturally ventilated buildings. For this purpose he compared the naturally

ventilated building with non-naturally ventilated buildings. The objective of the article

was to show the potential of natural ventilation as a passive cooling method within the

residential sector of countries which are located in warm conditions using Mexico as a

case study. The method is proposed as performing, with a simplified ventilation model,

thermal airflow simulations of 27 common cases of dwellings (considered as one thermal

zone) based on the combination of specific features of the building design, occupancy

and climate conditions. The energy saving potential was assessed then by the use of a

new assessment method suitable for large-scale scenarios using the actual number of air-

conditioned dwellings distributed among the 27 cases. Thereby, the energy saving was

presented as the difference in the cooling demand of the dwelling during one year without

and with natural ventilation, respectively. Results indicate that for hot-dry conditions,

buildings with high heat capacity combined with natural ventilation achieve the lowest

indoor temperature, whereas under hot-humid conditions, night ventilation combined

with low heat capacity buildings present the best results. [14]

14

CHAPTER 3

BUILDING ENVELOPE

3.1 Site location

The building considered here is located in Karachi having latitude 24.860

and longitude

67.010 as shown in Table 1.

Table 1 Site Location Details

Field

Units Object

Name

Karachi

Latitude

Degree 24.86

Longitude

Degree 67.01

Time zone

Hour 4

Elevation

M 190

3.2 Schedule

Schedule specifies the utilization of an equipment or lighting or activity level of people.

This varies according to the type of building used i.e. residential, office or hospital

building. Since in our work we are simulating for an office building so office occupancy

and office lighting schedule have been used.

15

3.3 Material

The materials used in the building and their respective properties, as given by

EnergyPlus, are given in Table 3.

Table 2 Various Construction Material Properties

Field Units Obj1 Obj2 Obj3 Obj4 Obj5

Name Plasterboard Fiberglass

Quilt

Wood

Siding

Roof

Deck

HF-C5

Roughness Medium smooth Rough Rough Rough Rough

Thickness m 0.012

0.066 0.09 0.019 0.1015

Conductivity w/m-k 0.16

0.04 0.14 0.14 1.7296

Density kg/m3 950

15 530 530 2243

Specific heat j/kg-k 840

840 900 900 837

Thermal

Absorptance

0.9 0.9 0.9 0.9 0.9

Solar

Absorptance

0.6 0.6 0.6 0.6 0.65

Visible

Absorptance

0.6 0.6 0.6 0.6 0.65

16

3.4 Window Material: Glazing

The glazing material for windows used is having properties as shown in Table 3. Clear

3MM, Clear 6MM shows the thickness of material as 3mm, 6mm.

Table 3 Various Glazing Material Properties

Field

Units Object

Name

CLEAR 6MM

Thickness

m 0.006

Solar Transmittance at Normal Incidence

0.775

Front Side Solar Reflectance at Normal Incidence

0.071

Back Side Solar Reflectance at Normal Incidence

0.071

Visible Transmittance at Normal Incidence

0.881

Front Side Visible Transmittance at Normal Incidence

0.08

Back Side Visible Transmittance at Normal Incidence

0.08

Infrared Transmittance at Normal Incidence

0

17

3.5 Window Material: Gas

Since the windows used here are double pan windows so the gas material used in the gap

is air having varied thickness.

3.6 Construction

The construction of walls, roof, floor, door, window etc is given as under. The materials

are specified from outside layer and worked towards inside. This is given in Table 4.

Table 4 Construction of Building

Field

Obj1 Obj2 Obj3 Obj4 Obj5

Name North Door Double Pane

Window

Wall Floor Roof

Outside

Layer

Plasterboard-1 Clear 6mm Wood Siding-1 HF-C5 Roof Deck

Layer 2 Air 3MM Fiberglass Quilt-1 Fiberglass Quilt-

2

Layer 3 Clear 6MM Plasterboard-1 Plasterboard-2

18

3.7 Zone

The building considered here is single zone building. The coordinates and other various

properties are given in Table 6.

Table 5 Single Zone Detail

Field

Units Object

Name

Zone One

Direction of Relative North

degree 0

X Origin

m 0

Y Origin

m 0

Z Origin

m 0

Type

1

Ceiling Height

m 2.7

Volume

m3 129.6

19

3.8 Building Surface: Detailed

The description of all surfaces like wall, roof, ceiling etc. of building is given here. In

which zone they are located are also specified here. Their exposure to sun and wind is

also specified here. Their relative coordinates are also specified here according to global

geometry rules.

Table 6 Building Surfaces Detail

Field Units Obj1 Obj2 Obj3 Obj4 Obj5 Obj6

Name Surface

North

Zone

Surface

East

Zone

Surface

South

Zone

Surface

West

Zone

Surface

Floor

Zone

Surface

Roof

Surface

Type

Wall Wall Wall Wall Floor Roof

Zone Name Zone One Zone One Zone One Zone One Zone One Zone

One

Outside

Boundary

Condition

Outdoors

Outdoors Outdoors Outdoors Ground Outdoors

Sun

Exposure

Sun

Exposure

Sun

Exposure

Sun

Exposure

Sun

Exposure

No

Sun

Sun

Exposure

Wind

Exposure

Sun

Exposure

Sun

Exposure

Sun

Exposure

Sun

Exposure

No

Wind

Sun

Exposure

Vertices(No) 4 4 4

4 4 4

Vertex 1 X-

coordinate

m 8 8 0 0 8 0

Vertex 1 y-

coordinate

m 6 0 0 6 6 6

Vertex 1 z-

coordinate

m 2.7 2.7 2.7 2.7 0 2.7

20

3.9 Fenestration Surface: Detailed

The detail of all fenestration surfaces are given in Table 7.

Table 7 Fenestration Surfaces Detail

Field Units Obj1 Obj2 Obj3 Obj4 Obj5

Name East Window 1

West Window 2

North Door East Window 2

West Window 2

Surface Type Window Window Door Window Window

Construction Type

Double Pane Window

Double Pane Window

North Door Double Pane Window

Double Pane Window

Building Surface Name

Zone Surface East

Zone Surface West

Zone Surface South

Zone Surface East

Zone Surface West

Number of Vertices

4 4 4 4 4

Vertex 1 X-coordinate

m 8 0 2.5 8 0

Vertex 1 y-coordinate

m 3.5 2.5 0 1.5 4.5

Vertex 1 z-coordinate

m 2.35 2.35 2 2.35 2.35

21

3.10 Internal Gains

Internal heat gains i.e. peoples, lights, and equipment are often a significant component

of the heating/cooling load of office buildings. Therefore care should be taken to

carefully observe the peoples activity and equipments usage in the buildings. This

depends upon the type of building we are simulating for. For this purpose EnergyPlus

provides the scheduling object. Where according to type of office; peoples occupancy,

lights and equipments usage is specified.

3.10.1 People

The heat gain from people has two components: sensible and latent. The total and the

proportions of sensible and latent heat vary depending upon the level of activity.

EnergyPlus requires that number of people should be specified while their activity level

and their presence in building can be obtained from the occupancy schedule. Detail to be

inserted is given in Table 8.

Table 8 People Load Details

Field

Unit Object

Name

People

Zone or Zone List Name

Zone One

Number of People Schedule Name

Office Occupancy

Number of People Calculation Method

People

Number of People

2

Carbon Dioxide Generation Rate

m3/s-W 0.0000000382

22

3.10.2 Lights

Since lighting is often the major internal load component, an accurate estimate of the

space heat gain it imposes is needed. Some of the energy emitted by the lights is in the

form of radiation that is absorbed by the building and contents. The absorbed energy is

later transmitted to the air by convection. The manner in which lights are installed, the

type of air distribution system, and the mass of the structure are important. The primary

source of heat from lighting comes from light emitting elements or lamps, although

significant additional heat may be generated from associated components in the light

fixtures housing such lights. The total light wattage is obtained from the ratings of all

lamps installed, both for general illumination and display purpose.

The use factor is the ratio of the wattage in use, for the conditions under which load

estimate is being made, to the total installed wattage. For heating/cooling load design

calculation program, this number is usually taken from a schedule with 24 values, one for

each hour of the day. The data to be inserted is given in Table 10.

Table 9 Light Load Details

Field

Unit Object

Name

Zone one lights

Zone or Zone List Name

Zone one

Schedule Name

Office lighting

Design Level Calculation Method

Lighting level

Lighting level

W 1000

Return Air Fraction

0

Fraction Radiant

0.72

Fraction Visible

0.18

Fraction Replaceable

1

23

CHAPTER 4

ENERGYPLUS

4.1 What is EnergyPlus?

Energy plus is a building energy simulation program for modeling building heating,

cooling, lighting, ventilating, and other energy flows. Developed by U.S Department of

Energy it has its roots in both the BLAST and DOE-2 programs. BLAST and DOE-2

were both developed and released in the late 1970s and early 1980s as energy and load

simulation tools. Their intended audience is a design engineer or architect that wishes to

size appropriate HVAC equipment, develop retrofit studies for life cycling cost analyses,

optimize energy performance, etc. Born out of concerns driven by the energy crisis of the

early 1970s and recognition that building energy consumption is a major component of

the American energy usage statistics.

Like its parent programs, EnergyPlus is an energy analysis and thermal load simulation

program. Based on a users description of a building from the perspective of the

buildings physical make-up, associated mechanical systems, etc., EnergyPlus will

calculate the heating and cooling loads necessary to maintain thermal control set points,

conditions throughout an secondary HVAC system and coil loads, and the energy

consumption of primary plant equipment as well as many other simulation details that are

necessary to verify that the simulation is performing as the actual building would. It

comprises completely new code written in Fortran 90.

4.2 Why does EnergyPlus exist?

The existence of EnergyPlus is directly related to some of the increasingly obvious

shortcomings of its predecessor programsBLAST and DOE2. Both programs, though

still valid tools that will continue to have utility in various environments, have begun to

show their age in a variety of ways. Both BLAST and DOE2 were written in older

version of FORTRAN and used features that will eventually be obsolete in new

compilers. Secondly, the speed with which new technology in the HVAC field is

24

developed has far outpaced the ability of the support and development groups of both

programs to keep the programs current and viable. This is really the key issue in the

existence of EnergyPlus: there simply are not enough researchers worldwide who have

enough experience with the complex code of the programs to keep pace with new

technology. In addition, due to the years of experience necessary to make modifications

to either BLAST or DOE2, it is extremely expensive and time consuming to produce

models or train someone to become proficient in either programs code.

4.3 EnergyPlus Environment

4.3.1 EP-Launch

EP-Launch is located in the main directory/folder for EnergyPlus. In addition, it is

available on the shortcut menu for EnergyPlus. By double clicking on the EP-Launch

icon the following screen appears for running a single input file. The EP-Launch program

simply starts the programs.

Fig. 4.1 EP-Launch

25

4.3.2 Selecting Input and Weather Files

The input file and weather files can be selected on the Single Input File tab from the two

pull down lists which show recently used files or can be browsed by pressing the

"Browse" buttons to locate an input or weather file.

4.3.3 Running a Single Input File

After selecting the weather and input files simply pushing the "Simulate" button starts

the EnergyPlus building energy simulation engine. At this point a black DOS window

pops up on the screen and shows the progress of simulation. The simulation is complete

when the black OS box closes. The EnergyPlus program black DOS window will show

scrolling text as the simulation procedure progresses.

Fig. 4.2 DOS Window

26

4.3.4 Completing Simulation

After running simulation the black DOS window closes, which shows EnergyPlus has

completed simulation, and a status message is displayed as shown in figure below. This

status gives a quick overview of whether there were warning (should look at), severe

(should probably fix) or fatal (must fix) errors in the run as well as the time it took for the

simulation to complete. After pressing OK from this box, selecting ERR/EIO/BND

Output Files Only from the View menu will display the ERR, EIO, and BND files

useful when errors may have occurred.

Fig. 4.3 End of Program

4.3.5 Looking at the Results

In the EP-Launch main screen below is the section named View Results where results

can be viewed in various formats.

By clicking on the "Drawing File" button EP will open the generated DXF file if

an appropriate viewer has been configured. The DXF file is a CAD format that

displays the physical shape of the building being modeled in three dimensions.

The Drawing File button also opens the HVAC diagram generated with the

HVAC-Diagram utility

We can also visualize the physical shape of the building being modeled is Google

SketchUp by using Open Studio Plug-in

By Clicking on the "Spreadsheets" buttons will open any generated CSV files in

Microsoft Excel

27

The HTML file opens just the tabular results file if that file was produced

By pressing the "Text Output Files button, a text editor will open each of the text

output files.

Clicking All button will open all results individually. The list of all text output

files is listed below

ERR list of errors and warnings

MTR raw report meter output

TABLE tabulated report of bin and monthly data in comma, tab or space

delimited or HTML format

DXF drawing file in AutoCAD DXF format

4.4 IDF Editor

Input data file can be edited in the IDF editor. Brief description regarding some

parameters is given below.

Version: The version allows you to enter the proper version or criteria in which

the input data file (IDF) is created for.

Simulation control: Here we can select either we run simulation for our design

day or weather data provided by EnergyPlus.

Building: The Building object describes parameters that are used during the

simulation of the building.

Location and climate: Describes the location of the building we are simulating

and the climatic conditions of that particular region.

Run period: It describes the time, simulation should be carried for.

Schedules: This describes the type of building we are simulating for i.e either that

is an office building, residential building, hotel building etc and according

occupancy schedule, lighting schedule etc would be used.

Material: Here all the materials used in the building are specified.

Construction: This describes the construction type of building i.e. how material

layers are constructed for walls, windows, doors etc.

28

Thermal Zones and Surfaces: Here the number of thermal zones is specified and

also the wall surfaces and fenestration surfaces specified. The surfaces are

specified in terms of co-ordinates.

Internal Gains: This specifies the internal load of building like people, light,

miscellaneous equipment etc.

Output Reporting: This command gives us the various outputs according to our

desire. [6]

29

CHAPTER 5

RESULTS AND CONCLUSIONS

Here in our research we have considered different passive techniques and their effect on

temperature and on the energy requirements for heating and cooling. In every technique

firstly their respective temperature have been compared and then their effect on energy

requirement.

Weather data file shows that maximum dry bulb temperature occurs on 28th

of May and

minimum temperature occurs on 15th

of January. So for simplicity of representing the

result we have shown compared mean radiant temperature for those two days only and

then the energy requirement have been compared for whole year taking energy

requirements monthly.

Five parameters considered here are

1) Effect of shading

2) Effect of glazing area

3) Effect of fins

4) People and light load and wind capture

5) Effect of glazing material

30

5.1 Effect of shading

Here the shading technique has been considered in steps and their results have been

compared. First shading over door only has been considered as shown in Fig. 5.1. Then it

has been extended to windows also (Fig. 5.2) and finally some external shading has also

been considered (Fig. 5.3).

The effect of these techniques on mean radiant temperature of coolest and hottest day is

shown in Fig. 5.4 and Fig. 5.5 respectively.

Fig. 5.4 Effect of Shading Techniques on MRT for coolest day

0

5

10

15

20

25

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

January 15th

Shading over Door only

Shading all windows anddoor

Shading all

Fig. 5.1 Shading over

Door only

Fig. 5.2 Shading over

Door and Windows

Fig. 5.3 External

Shading also considered

31

Fig. 5.5 Effect of Shading Technique on MRT for hottest day

By comparing temperatures of coolest day and hottest day we see the highest temperature

occurs for shading over door only as compared to other shading techniques and is least

for shading all technique.

The effect of these techniques on heating and cooling energy is shown Fig. 5.6 and Fig.

5.7

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

May 28th

Shading over Door only

Shading all windows anddoor

Shading all

32

Fig. 5.6 Effect of Shading Technique on Heating Energy

Fig. 5.7 Effect of Shading Technique on Cooling Energy

Fig. 5.6 shows the heating energy required is high for shading over door technique by an

amount of almost 0.02GJ for the peak heating time period. Otherwise energy requirement

is almost equal. While Fig. 5.7 shows that the cooling energy requirement has

considerable difference. Shading over windows almost saves 0.2GJ of energy for cooling.

And if there is some external energy also, amount decreases by almost 0.1GJ more.

0100000000200000000300000000400000000500000000600000000700000000

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

He

atin

g En

erg

y R

eq

uir

ed

(J)

Heating Energy Compare for Different Shading Techniques

shading over door only

shading all windows anddoor

shading all

0

200000000

400000000

600000000

800000000

1E+09

1.2E+09

1.4E+09

1.6E+09

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

erCo

olin

g En

erg

y R

eq

uir

ed

(J)

Cooling Energy Compare for Different Shading Technique

Shading over Door only

Shading all Windows andDoor

Shading All

33

5.2 Effect of Glazing Area

Here the effect of increased glazing area has been considered.

Glazed area has been increased by an amount of 2m2 on both

East and West sides and their effect on heating and cooling

energy have been analyzed. Building with increased glaze area

is shown if Fig. 5.8.

The effect of increasing glaze area on mean radiant temperature for hottest and coolest

day is shown in Fig. 5.9 and Fig. 5.10.

Fig. 5.9 Effect of Increased Glaze Area on MRT for Coolest Day

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

January 15th

Simple building

Increase Glazed Area

Fig. 5.8 Building with

increased Glazed Area.

34

Fig. 5.10 Effect of Increased Glaze Area on MRT for Hottest Day

The effect of this technique on heating and cooling energy demand is shown in Fig 5.11

and Fig. 5.12.

Fig. 5.11 Effect of Increased Glaze Area on Heating Energy required

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

May 28th

Simple building

Increase Glazed Area

0100000000200000000300000000400000000500000000600000000700000000800000000

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

He

atin

g En

erg

y (J

)

Heating Energy Required for Increased Glaze Area

Simple Room

Increased Glazed Area

35

Fig. 5.12 Effect of Increased Glaze Area on Cooling Energy

Fig. 5.11 shows during peak heating times the energy requirement for heating almost

increases by 0.05GJ for increased glazed area. The effect is more considerable for

cooling energy as shown in Fig. 5.12 increasing glazing area increases cooling energy by

almost 0.3GJ.

5.3 Effect of Fin

Here the fins having depth of 0.25m have been attached

to both sides of windows. The fins are at 900 to walls.

The building with fin over its windows and door is

shown in Fig. 5.13.

The effect of this technique on mean radiant

temperature for coolest and hottest day is shown in Fig.

5.14 and Fig. 5.15 below.

0200000000400000000600000000800000000

1E+091.2E+091.4E+091.6E+091.8E+09

2E+09

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

Co

olin

g En

erg

y (J

) Cooling Energy Required for increase Glaze

Area

Simple Room

Increased Glaze Area

Fig. 5.13 Building with Fins

attached

36

Fig. 5.14 Effect of Fins on MRT for Coolest Day

Fig. 5.15 Effect of Fins on MRT for Hottest Day

During coolest day the temperature has considerable difference during noon while during

other hours the difference is negligible, while during hottest day the temperature

difference is negligible as shown in above figures.

The effect of fins on heating and cooling energy demand is shown in Fig. 5.16 and Fig.

5.17 respectively.

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 101112131415161718192021222324

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

January 15th

Room Without Fins

Room with Fins

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 101112131415161718192021222324

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

May 28th

Room Without Fins

Room with Fins

37

Fig. 5.16 Effect of Fins on Heating Energy

Fig. 5.17 Effect of Fins on Cooling Energy

0

100000000

200000000

300000000

400000000

500000000

600000000

700000000

He

atin

g En

erg

y R

eq

uir

ed

(J)

Heating Energy Required with and without

Fins

Room Without Fins

Room With Fins

0

200000000

400000000

600000000

800000000

1E+09

1.2E+09

1.4E+09

1.6E+09

Co

olin

g En

erg

y (J

)

Cooling Energy Required for with and without Fins

Room without Fins

Room with Fins

38

Above figures (Fig. 5.16 and Fig. 5.17) show that during peak heating period the heating

energy needed is almost 0.1GJ less than the building without fins. Hence this amount of

energy can be saved by attaching the fins of 0.25 depth on both sides of window. The

effect is quite visible for cooling energy as shown in Fig. 5.17. The figure shows that

attaching fins saves considerable amount of energy throughout the year.

5.4 Effect of People Gain Load and Wind Capture

First we have considered a simple building without any load. Then people gain load and

light load have been added. Here two people have been considered having office

occupancy schedule while the light load of 1000 watt light again having office lighting

schedule. Then a wind capture has been added at roof of 1 m2. Here wind capture is

simply considered as no mass area.

Fig. 5.18 Simple building Fig. 5.19 Building with Wind

Capture

39

The mean radiant temperature for the coolest day and hottest day is shown in Fig. 5.20

and Fig. 5.21 respectively.

Fig. 5.20 Effect of People/Light Load and Wind Capture on MRT for Coolest Day

Fig. 5.21 Effect of People/Light Load and Wind Capture on MRT for Hottest Day

0

5

10

15

20

25

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

January 15th

Room Without any Load

Room With People andLight Load

With Wind Capture

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

May 28th

Room Without any Load

Room With People andLight Load

With Wind Capture

40

The Fig. 5.20 shows that the temperature has not much effect due the people or light load

but the effect is quite visible for wind capture. The temperature is much less for the night

or early morning hours with wind capture and on the opposite for the hottest day

temperature is higher during hot hours i.e. noon time.

The effect of this technique on heating and cooling energy demand is shown in Fig 5. 22

and Fig. 5.23 respectively.

Fig. 5.22 Effect of People/Light Load and Wind Capture on Heating Energy

0

100000000

200000000

300000000

400000000

500000000

600000000

700000000

800000000

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

He

atin

g En

erg

y (

J )

Heating Energy Required considering Load and Wind Capture

Room Without any Load

Room with People andLight Load

Room with Wind Capture

41

Fig. 5.23 Effect of People/Light Load and Wind Capture on Cooling Energy

The effect on the heating energy (as shown in Fig. 5.22) shows that the heat energy

required is least for the building having light load as well as people gain load. During

peak heating hours the energy decreases by an amount of almost 0.1GJ due to load.

Whereas the wind capture decreases heating energy required, by an amount of almost

0.05GJ. The effect on the cooling energy required is shown in Fig. 5.23. The figure

shows that the energy required for cooling increases by an amount of almost 0.4GJ as an

activity of two people included and light load of 1000watt inserted.

5.5 Effect of Glazing Material Thickness

Finally the effect of changing glazing material has been considered. Here the glazing

material of two different thicknesses have been considered, one having 3mm thickness

while other having 12mm thickness.

0

200000000

400000000

600000000

800000000

1E+09

1.2E+09

1.4E+09

1.6E+09

1.8E+09

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

Co

olin

g En

erg

y (

J )

Cooling Energy Required for Load and Wind Capture

Room Without any Load

Room with People andLight Load

Room with Wind Capture

42

The effect of this technique on MRT for coolest and hottest day is shown below.

Fig. 5.24 Effect of Glazing Material Thickness on MRT for Coolest Day

Fig. 5.25 Effect of Glazing Material Thickness on MRT for Hottest Day

This shows the temperature for less thickness is more as compared to increased thickness

during peak heat hours of the day.

0

5

10

15

20

25

1 3 5 7 9 11 13 15 17 19 21 23Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

January 15th

3MM Glaze Material

12MM Glaze Material

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Me

an R

adia

nt

Tem

pe

ratu

re (

C )

Time (hours)

May 28th

3MM Glaze Material

12MM Glaze Material

43

The effect of this technique on heating and cooling energy demand is shown in following

figures.

Fig. 5.26 Effect of Glazing Material Thickness on Heating Energy

Fig. 5.27 Effect of Glazing Material Thickness on Cooling Energy

0

100000000

200000000

300000000

400000000

500000000

600000000

700000000

800000000

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

er

He

atin

g En

erg

y (

J )

Heating Energy Required for different Glazing Material

3MM Glaze Material

12MM Glaze Material

0

200000000

400000000

600000000

800000000

1E+09

1.2E+09

1.4E+09

1.6E+09

Jan

uar

y

Feb

ruar

y

Mar

ch

Ap

ril

May

Jun

e

July

Au

gust

Sep

tem

ber

Oct

ob

er

No

vem

ber

Dec

emb

erCo

olin

g En

erg

y R

eq

uir

ed

( J

)

Cooling Energy Required for different Glazing Material

3MM Glaze Material

12MM Glaze Material

44

This shows that during peak heating hours the energy almost increases by almost 0.7GJ

for 12mm thick glaze material. The effect on the cooling energy required is shown in Fig.

5.27. The figure shows that during peak cooling time the energy required decreases as

thickness increases, but by a negligible effect as compared to heating.

45

References

[1] Pervez Hameed Shaikh et al, A review on optimized control systems for building

energy and comfort management of smart sustainable buildings, Renewable and

Sustainable Energy Reviews, Renewable and Sustainable Energy Reviews 34 (2014)

409429

[2] Luis Perez-Lombard, A review on buildings energy consumption information,

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[3] Nurdil Eskin, Hamdi Turkmen, Analysis of annual heating and cooling energy

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[4] http://www.designingbuildings.co.uk/wiki/Thermal_comfort_in_buildings

[5] Yang Wang, Classroom energy efficiency and air environment with displacement

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[6] Ghjuvan Antone Faggianelli, Natural cross ventilation in buildings on Mediterranean

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