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,
Energy and Buildings 40 (2008) 394398
[3] Nurdil Eskin, Hamdi Turkmen, Analysis of annual heating and cooling energy
requirements for office buildings in different climates in Turkey, Energy and Buildings
40 (2008) 763773
[4] http://www.designingbuildings.co.uk/wiki/Thermal_comfort_in_buildings
[5] Yang Wang, Classroom energy efficiency and air environment with displacement
natural ventilation in a passive public school building, Energy and Buildings 70 (2014)
258270
[6] Ghjuvan Antone Faggianelli, Natural cross ventilation in buildings on Mediterranean
coastal zones, Energy and Buildings 77 (2014) 206218
[7] Faye C. McQuiston, Heating, ventilating and air conditioning, analysis and design,
Wiley student edition, 2011
[8] http://apps1.eere.energy.gov/buildings/energyplus/energyplus_documentation.cfm
[9] R. Becker, Inter-related effects of cooling strategies and building features on energy
performance of office buildings, Energy and Buildings 34 (2002) 25-31
[10] Steinar Grynning, Solar shading control strategies in cold climates Heating,
cooling demand and daylight availability in office spaces, Solar Energy 107 (2014) 182
194
[11] Saeed, A Khan, Arif, Musthaque , Electricity consumption for energy conservation
in office building in Lahore Pakistan architectural engineering and design, Pakistan
Journal of Science (Vol. 65 No. 2 June, 2013)
46
[12] E. Dascalaki, M. Santamouris, On the potential of retrofitting scenarios for offices,
Building and Environment 37 (6) (2002) 557567.
[13] Joseph C. Lam et al, Impacts of lighting density on heating and cooling loads in
different climates in China, Energy Conversion and Management 47 (2006) 19421953
[14] Ivan Oropeza-Perez, Energy saving potential of utilizing natural ventilation under
warm conditions A case study of Mexico, Applied Energy 130 (2014) 2032