ENERGY AUDIT OF GEFLE VAPEN Slottstorget 1, Gävle

DEPARTMENT OF TECHNOLOGY AND BUILT ENVIRONMENT

ENERGY AUDIT OF GEFLE VAPEN

Slottstorget 1, Gävle

Sui Chen

February 2010

Master’s Thesis in Energy Systems

Program: Energy Systems

Examiner: Taghi Karimipanah

Supervisor: Roland Forsberg

Preface

As for the energy crisis increased, it's an extremely urgent and important issue to reduce energy

using and increase the efficiency of energy using. For this reason, the energy audit is a useful

method to preliminary estimate of savings potential. The objects of energy audit are to

quantification the energy uses and losses and improve the energy efficiency. Accurate and

complete are essential factors to determine the energy audit’s success.

It is impossible to finish this thesis project without the help of my teachers, friends and staffs in

the building Gefle Vapen, particularly grateful to Mr. Roland for his greet help. And also thanks to

those kind people who help me in the thesis process. This thesis work has been an unforgettable

experience in my life.

“We don’t inherit the earth from

our parents;

We borrow it from our children. ”

----Antoine de Saint-Exupéry

ABSTRACT

The energy audit is a very interesting and complex work. The building energy audit is defined as a

process to evaluate where the energy used in the building structure and to identify the

opportunities of reduce energy consumptions. In this paper, it is a first time detailed study of

energy audit for me. In this research, the object is to find is it necessary to improve the ventilation

systems. So the first step is to estimate how much energy consumed in the building and to find out

the saving potential.

The major mission in this thesis is that to make a basic energy audit which is include the heat

losses from the building and the heat supply in the building. The major heat losses are

transmission losses, ventilation losses, heat losses from hot tap water and infiltration losses. In this

project the first three types of heat losses could be find out by some useful methods but the

infiltration losses is hard to measure. On the other side, the heat supply are composed by district

heating , free heating from people inside, free heating from electricity applications and sun

irradiation.

To make an accurate and complete energy audit is essential for finding out where the energy

consumption could be reduced. And this is what I am going to do in this thesis work.

1. INTRODUCTION···1

1.1 Energy Problem ···1

1.2 Energy Audit···1

1.3 Building Information and Object Areas···4

2. ENERGY BALANCE of GEFLE VAPEN···5

3. CALCULATION and RESULTS···7

3.1 The Part of Transmission Losses···7

3.2 The Part of Heat Losses from Ventilation Systems···12

3.3 The Part of Infiltration Losses···15

3.4 The Part of Heat Losses from Hot Tap Water···16

3.5 The Part of Free Heating···17

3.5.1 The Free Heating from Sun Irradiation···17

3.5.2 The Free Heating from People Inside···26

3.5.3The Free Heating from Electricity Applications···27

3.6 District Heating···29

4. ENERGY SAVING···31

4.1 Indoor Temperature Standard···31

4.2 The Improvement of Windows···33

4.3 The Improvement of Ventilation Systems···34

4.4 Saving Energy with Saving Water···36

5. CONCLUSION···38

REFERENCE···39

APPENDIX CONTENTS···40

APPENDIX···40

1. INTRODUCTION

1.1 Energy Problem

The energy is an essential part when the social improved, but also the world energy sources is

rapid decrease after the human society stepped into the industrial age. And a bigger and bigger

demand of energy comes with the development of human society. So that, the human being has to

face to an unavoidable problem that what is the next energy sources for world. But before this, to

save energy is a feasible plan to slow the process of energy source reached the point of exhaustion.

1.2 Energy Audit

To save energy, the first step is to do an energy audit which can be used to determine the saving

potential and whether it is worthy to improve the energy systems with the preliminary estimate of

energy audit. To make an audit, the most essential rule is keeping accurate and complete of energy

audit. And the first step is to make a thorough evaluation for the object building with low cost,

then the second step is standard audit include site visit, quantification the energy uses and

efficiency of energy systems, and estimate the economic result of improvement. The last step is

computer simulation for optimization.

In an energy audit, there are three sections of parameters which needed be measured in the

following list:

1. Heat exchange through the building structure.

- Heat losses through floor, wall, ceiling, windows and doors.

- Heat losses due to infiltrations, such as wind through a gap between windows and wall.

- Sunshine radiation through windows.

2. Internal heat from people activities and equipments inside building.

- Heat generated by people inside building.

- Heat generated by equipments such as lighting and computer cooling.

3. Energy supply for thermal comfort in the units.

- Heating and cooling during different seasons.

- For ventilation systems to keep save indoor environment.

- Domestic hot water.

All of these three sections have to be considered as a complete energy audit, and it is better to have

a more accurate data from the measurement than those not. The energy balance decided by both

heating and cooling, as to the situation of Gavle ( Average temperature is 5.0℃) [Appendix

1.Location and Out Door Temperature], the heating takes a major influence. For this project, the

three sections can be divided into another group, see Fig 1.2.1.

Fig 1.2.1 The Components of Building Energy Systems.

Except these factors, the schedule is one of the important factors for complete the energy audit

since the energy usage changed with the operation time change. From site visit, the periods of the

activities of the office building is 8:00 to 17:00 and the office building is always closed during

holidays and weekends. However, some systems are always running during holidays and nights. It

is an opportunity to reduce energy usage.

As well as the value of schedule, the sunshine is another major factor which influences the heat

inside building. And it always varies with sun rise and down and the seasons’ change, especially

for high latitudes (Gefle Vapen’s Latitude and Longitude: 60°41′N, 017°10′E). [Appendix 1.

Location and Out Door Temperature]

From these above, it is important that the final result changed by the change of the factors.

Building Envelope

Internal Heat

Building services

Floor Wall Ceiling

Windows and Doors Lighting

People activities Appliances HVAC systems

Hot water

1.3 Building Information and Object Areas

Gefle Vapen is located in the central of Gavle city faced to South west. It is a 6 floors building

(Include basement). From the map, it can be found that the building was surrounded by the roads

and a river flows by the root to the building on North west side [Appendix 2.Pictures of Gafle

Vapen]. Obviously, there are nothing blocked off the strong wind and sunshine.

The building is using for office working. There working hour of this building is 2450 hours

according to Official public holidays in Sweden [Appendix 3.Official public holidays in Sweden].

And there is 103 people working inside every working day, see Table 3.5.9.

In this audit, the object area is not the whole building. The object is to make an energy audit for

the office parts of Gefle Vapen. The areas from floor 2 to floor 6 are the mission areas which are

the areas under the blue lines in Fig 1.3.1, and it does not include the first floor and basement.

Fig 1.3.1 The Object Areas of Energy Audit

2. ENERGY BALANCE of GEFLE VAPEN

The building of Gefle Vapen was built as an office building with the first floor as a part of Gavle

library. As an office building, it is included 4 floors from floor 2 to floor 6. The major energy

consumption of Gefle Vapen is taken by area heating, hot water and ventilation systems. The

graph Fig 2.1 below shows the energy consumption from January, 2008 to December, 2008.

Energy Balance(Mwh)

58.6 71.6 197

177.7

16.97

18.3

284.6

38.77

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Energy supply Energy demand

District Heating / Others heat losses

Free heating from people / Heat losses from hot tap water Free heating from sun / Heat losses of ventilation systems Free heating from electricity / Heat losses of transmission

Fig 2.1 Energy Balance of Building Gefle Vapen

As the Fig 2.1 shown, the energy balance consists of the heat losses of the building and energy

supply. Firstly, the heat losses are including heat losses from transmission, heat losses ventilation

systems, heat losses from infiltration and heat losses from hot water. Secondly, the energy is

supplied by district heating, sun irradiation, internal heating generated (Free heating) which is

from the staff and electricity applications inside the building.

From all talked above, the energy balance could be expressed as:

sun d

atgenerate Internalhe

DH Hotwater

iltration n

ventilatio on

transmissi

Q Q Q Q Q Q

Q + +

_inf

+ = + +

One hand, as it can be seen from the energy balance, the heat losses from transmission takes

197Mwh (45.6%) of the total loss in a nature year, which is the major part of energy losses. The

second heating loss of Gefle Vapen is heat losses through the ventilation systems of the building,

which takes 177.7Mwh 41.2%) of the amount of total energy loss. Considered about the structure

of the heating loss in this building, the section of transmission losses and ventilation losses should

be focused for reducing the energy supply.

On the other hand, the positive energy supply is dominated by district heating which takes more

than 284.6Mwh (65.9%) of energy supply in the building for a year from January 2008 to

December 2008. And the free heating from electricity and sun take 130.2Mwh (30.2%) is the

secondary part of heat supply in the building.

3. CALCULATION and RESULTS

To complete an energy audit of the building energy systems, the most important thing is to find out

how much is energy consumption during a natural year and whether the energy consumption is

fulfill the energy demands.

The major consumptions of Gefle Vapen are electricity consumption and district heating

consumption. The electricity consumed 1429.5Mwh from January 1, 2008 to July 1, 2009, which

was mostly sued by ventilation systems and electricity applications inside building. And the

heating consumed 645.6Mwh from January 1, 2008 to July 1, 2009.

3.1 The Part of Transmission Losses

To calculate the transmission losses, the following equation has been used in this part.

∑

=

_ree

on

transmissi

U A q

Q * *

_deg

So, 3 types of data are needed to calculate the transmission loss, they are U-value, Areas of the

envelope and

q

_degree.

The U-value and Areas of the envelope can be found below:

Table 3.1.1 The U-value for Each Building Components

Envelope U-value Areas(m²)^**(2)

Wall 0.2 1907

Ceiling 1.15*0.15^*(1) 697

Windows(type a size 1.15 m² ) 1.95 316

Windows(type b size 0.49 m²) 2.95 4

Base floor 0.6 697

*(1)Due to the heat radiation reflective the U-value of ceiling times 0.15. Usually, the U-value of ceiling is

between 0.11 (winter) to 0.16 (summer). [Appendix 4. U-values of Building Envelop].

**(2) The areas of the building components are calculated from the “blue print of Gefle Vapen” [1] by the scale,

and they are calculated only for the object areas (Not include the basement and the first floor).

The value could be found in the Table 3.1.2 Degree-hours below, and it is also used in

the part of heating loss of ventilation systems.

q

_degree

Table 3.1.2 Degree-hours as a Function of Balance Temperature and Annual Mean Outdoor

Temperature for Gavle City [Appendix 5. The Q_degree of Gavle]

Temperature

-2 -1 0 1 2 3 4 5 6 7 8

5 80750 73500 66500 59700 53200 47000 41000 35200 29700 24500 19500 6 87000 79500 72300 65300 58500 52000 45800 39700 33900 28400 23000 7 93500 85800 78300 71100 64100 57400 50800 44500 38400 32600 26900 8 100200 92200 84600 77200 69900 62900 56200 49600 43200 37100 31100 9 107200 99000 91200 83500 76000 68800 61800 54900 48200 42000 35500

10 114500 106000 98000 90100 82400 74900 67700 60600 53600 47100 40300 11 121900 113300 105100 97000 89000 81400 73900 66500 59300 52500 45400 12 129500 120700 112300 104000 95800 88000 80200 72600 65100 58100 50700 13 137000 128100 119500 111000 102500 94500 86500 78700 70900 63600 55900 14 144600 135400 126700 118000 109300 101100 92900 84700 76700 69200 61200 15 152100 142800 133900 125000 116100 107600 99200 90800 82500 74800 66500 16 159700 150200 141100 132100 122900 114200 105500 96900 88300 80400 71800 17 167200 157600 148300 139100 129600 120700 111800 103000 94100 85900 77000 18 174800 155000 155500 146100 136400 127300 118100 109100 99900 91500 82300 19 182300 172300 162700 153100 143200 133800 124500 115200 105700 97100 87600 20 189900 179700 169900 160100 149900 140400 130800 121300 111500 102600 92800 21 197400 187100 177100 167100 156700 146900 137100 127300 117300 108200 98100 22 205000 194500 184300 174100 163500 153500 143400 133400 123100 113800 103400 23 212500 201900 191500 181100 170200 160000 149700 139500 128900 119300 108600 24 220100 209200 198700 188100 177000 166600 156100 145600 134700 124900 113900 25 227600 216600 205900 195100 183800 173100 16400 151700 140500 130500 119200

The value 127300 is the value when the outdoor temperature is 5 Celsius degree and

the indoor temperature is 21 Celsius degree. It can be considered that the is constant

during a year. From the view of building energy systems, the duration diagram express why the

could be used in the transmission loss calculation. The graphic Fig 3.1.1 below shows

the temperature duration diagram for a normal year.

q

_degree

q

_degree

q

_degree

Fig 3.1.1 Temperature Duration Diagram for Gavle in a Normal Year

Table 3.1.3 The Heating Losses of Different Components of Building

Part U- value Area (m²) q _degree

Heating

losses(Mwh)

Wall 0.2 1907 127300 48.5

Ceiling 1.15*0.15 697 127300 15.3

Windows(type a

size 1.15 m² )

1.95 316 127300 78.4

Windows(type b

size 0.49 m²)

2.95 4 127300 1.5

Floor 0.6 697 127300 53.2

Total 197Mwh

The Heat Losses from Heat Transmission(Mwh)

25%

8%

39%

1%

27% Wall

Ceiling

Windows(size 1.15

m2 )

Windows(size 0.49

m2)

Floor

Fig 3.1.2 Graph of the Heat Losses from Heat Transmission

The graph Fig 3.1.2 shows that the heat loss from windows is the major parts of the total heat

transmission losses, which takes 40% of the total. It also takes big share of total transmission

losses that the heat losses from floor and wall, which take 27% and 25% individually of the total

heat losses of the building. To reduce the transmission losses, the first thing is to improve the

U-value of each building components.

3.2 The Part of Heat Losses from Ventilation Systems

The ventilation systems are a most important for keeping safe indoor climate of a building. It is

usually running all day. For this reason, it is the major energy consumer among the building

energy systems. Meanwhile, the amount of heat loss through air exchange takes a big share of

total heat loss of a building, because of the basic job of ventilation systems. In the building Gefle

Vapen, the heat loss of ventilation is compensated by district heating.

The heat demand, which is necessary to keep indoor climate comfortable, is decided by the outside

temperature, inside temperature and the heat exchange efficiency of ventilation host. It could be

expressed by the following equation:

)

1

(

*

8760

/

*

*

*

*

}

,

max{

_{sup deg}

.

= V V ρ C q H − η

Q

_{lossbyv s exhaust ply air p ree}

The data of V_exhaust and V_supply are the volume of exhaust airflow and supply airflow. They are

measured by me. The data

ρ

_air is the density of air (1.237 kg/m³) with the temperature 20 ℃ and standard air pressure. The data is the heat capacity of air (1.012 kJ / (kg K)) with the

temperature 20 ℃ and standard air pressure. The data of is 127300℃

h

which has been used in the part of transmission losses. And the efficiency of heat exchange

C

p

q

_degree

η

is 55% for rotary heat exchanger, suggested by Mr. Roland. The H is 5832hours which is calculated in this

way, 243 heating days per year and 24 running hours each working day.

Table 3.2.1 The Information of the Ventilation Systems Hosts

Area of central A/C host Supply air (l/s) Exhaust air (l/s)

Room 322 448 460

Room 352 3110 3160

Room 611 83 103

Total^*(1) 3638 3723

*(1) Usually, the total volume of supply air is more than or equal to the total volume of exhaust air. In this case,

the results are measured by hands with the equipments, so there is an inaccuracy due to low precision. However, it

is in an acceptable level with 2.3% inaccuracy.[Appendix 6. The Section of Ventilation Systems]

From all the data above, the heat losses through ventilation systems could be calculated by the

equation below.

)

1

(

*

8760

/

*

*

*

*

}

,

max{

_{sup deg}

.

= V V ρ C q H − η

Q

_{lossbyvs exhaust ply air p ree}

The result are calculated and shown in the table below.

Table 3.2.2 The Calculation of Ventilation Systems’ Heat Losses.

Room of

central

A/C host

Air flow

difference

(m³/s)

Air density

(kg/m³)

C_p

(J/kg ℃)

q_degree

(℃h)

Hours

per year

(%)

1-

η

Heat losses (kwh)

Room

322

460*0.001 1.237 1.012 127300

8760

5832

0.45 21961.5

Room

3160*0.001 1.237 1.012 127300

352

8760 5832

0.45 150866.1

Room

103*0.001 1.237 1.012 127300

611

8760 5832

0.45 4917.5

Total 177.7Mwh

Table 3.2.3 The Heat Losses from Ventilation Systems

Area of central A/C host Heat Losses (Mwh)

Room 322

21.9 Room 352

150.9 Room 611

4.9

Total 177.7

The Heat Losses of Ventilation

Systems(Mwh)

21.9, 12%

150.9, 85%

4.9, 3%

Host in Room 322 Host in Room 352 Host in Room 611

Fig 3.2.2 The Heat Losses from Ventilation Systems’ Hosts

The graph shows that the major heat loss comes from the host in room 352 (85%), which is also

the main ventilation host supplied air for more than 76 persons in this building.

3.3 The Part of Infiltration Losses

From the view of building energy systems, the infiltration loss is composed by three parts:

z The first part is that the heat loss from the difference of air flow volume between the

exhaust air and supply air.

z The second part is that the heat loss from the connection of building envelope with

windows and doors.

z The last part is that the heat loss from the envelope air gap, which is not easy to find out.

This part has to be neglected in this case, because the air flow of infiltration is nearly impossible to

measure.

3.4 The Part of Heat Losses from Tap Water

To fulfill daily activity inside building, hot tap water is necessary, which is supplied by district

heating. The demand volume of hot tap water is decided by the number of people inside building

when they use the hot water in the kitchens or toilets.

The volume of hot water consumption could be calculated by a constant percent of cold water

consumption by the following equation in this case. The percentage of 30% is estimated by

experience which is recommended by Mr. Roland.

The V_coldwater is 1047 m³ during year 2008 given by Camilla Larsson from Gästrike Vatten AB.

The temperature is 50 ℃ and the C_water is 4190 J/kg*℃. So the result of heat losses from tap

water is 18.3 Mwh.

The heat loss from tap water is 18.3Mwh for a year. From this situation, the heat losses from hot

tap water are decided by the cold water consumption. So the best way to reduce heat loss is save

cold water consumption. However, it is not easy to improve.

3.5 The Part of Free Heating

In this section, the free heating is divided into three parts:

z The Free Heating from Sun Irradiation.

z The Free Heating from People Inside.

z The Free Heating from Electricity Application.

3.5.1 The Free Heating from Sun Irradiation.

The sun irradiation is a big energy supply source during cold days which is also free to use. From

the location of the Gefle Vapen, the sun irradiation is rich during a year. There are 4 sides which

could receive sun irradiation. They are facing to South west (60°) , North west (150°), North

east (-120°) and South east (-30°). The main side for receiving sun irradiation is facing to South

west (60°). [Appendix 2. Pictures of Gefle Vapen]

The equation for calculation the heat from sun irradiation is below:

Days

S

S

S

W

Q

_{sunirradiation}

= *

_area

*

_sunfactor

*

_shadowfactor

*

The W is found in the table following. It is days sums that the sun irradiation at 15th of each

month of radiation on vertical surfaces, Wh/m²day. (Latitude 60°N, Radiation type 0)

.

Table 3.5.1 The Sun Irradiation on Vertical Surface Orientation [Appendix 7. Windows and Sun

Irradiation Section]

Vertical Surface Orientation Month

-120 N -30 E 60 S 150 W

January 160 2360 1440 130

February 640 4280 2900 370

March 1720 5740 4520 900

April 3320 6370 5850 1990

May 4460 5980 6150 3050

June 5230 5820 6350 3870

July 4910 5820 6280 3510

August 3720 6070 5850 2380

September 2200 5760 4820 1230

October 1010 4960 3570 530

November 270 3040 1910 200

December 90 1770 1060 80

Then, the area of windows has already been calculated in the following table. There are two basic

types of windows: size 1.15 m² (sun radiation factor 0.72) and 0.49 m² (sun radiation factor 0.8).

And the radiation type is only “0” for these two types of windows. [ Appendix 7. Windows and

Sun Irradiation Section]

Table 3.5.2 The Windows Areas of Building Gefle Vapen

Windows Area(m2) U-value

(W/m² K)

Sun radiation

factor

Radiation

-type

Face to South west (60°) 155.25 = 135*1.15 m² 1.9 – 2.0 0.72 0

Face to North west (150

°)

5.75 = 5*1.15 m² 1.9 – 2.0 0.72 0

157.21 = 135*1.15m² 1.9 – 2.0 0.72 0 Face to North east (-120

°) + 4*0.49 m² 2.9 – 3.0 0.80 0

Face to South east (-30°) 1.96 = 4*0.49m² 2.9 – 3.0 0.80 0

(Two types of windows: type a size 1.15 m² and type b size 0.49 m²)

The third, to decide the shadow factor, the cloudy days of Gavle in a year needed to be considered.

Table 3.5.3 The Cloudy Days of Gavle for a Year (The data is given by Mr. Roland.)

Month Calculation Factor

January 0.45

February 0.49

March 0.58

April 0.58

May 0.63

June 0 (No heating need)

July 0 (No heating need)

August 0 (No heating need)

September 0.58

October 0.51

November 0.42

December 0.43

The free heating of sun irradiation is calculated in the following table.

Tables 3.5.4 The Heat Supply from Sun Irradiation of Windows of -120N (type a windows size

1.15m²)

Month -120N

Cloudy

Factor

Windows’

Aeras(m²)

Sun

Factor

Days

Free Heating of Sun

Irradiation(wh)

January 160 0.45 155.25 0.72 31

249493 February 640 0.49 155.25 0.72 28

981517.8 March 1720 0.58 155.25 0.72 31

3456864 April 3320 0.58 155.25 0.72 30

6457307

May 4460 0.63 155.25 0.72 16

5025271

June 5230 0 155.25 0.72 30

0

July 4910 0 155.25 0.72 31

0

August 3720 0 155.25 0.72 31

0 September 2200 0.58 155.25 0.72 15

2139469 October 1010 0.51 155.25 0.72 31

1784914 November 270 0.42 155.25 0.72 30

380275.6 December 90 0.43 155.25 0.72 31

134102.5

Total 20.6Mwh

Tables 3.5.5 The Heat Supply from Sun Irradiation of Windows of -30E (type b)

Month -30E

Cloudy

Factor

Windows’

Aeras(m²)

Sun

Factor

Days

Free Heating of Sun

Irradiation(wh)

January 2360 0.45 1.96 0.8 31

51621.7 February 4280 0.49 1.96 0.8 28

92075.47

March 5740 0.58 1.96 0.8 31

161825.8

April 6370 0.58 1.96 0.8 30

173794 May 5980 0.63 1.96 0.8 16

94516.53

June 5820 0 1.96 0.8 30

0

July 5820 0 1.96 0.8 31

0

August 6070 0 1.96 0.8 31

0 September 5760 0.58 1.96 0.8 15

78575.62 October 4960 0.51 1.96 0.8 31

122958.8 November 3040 0.42 1.96 0.8 30

60060.67 December 1770 0.43 1.96 0.8 31

36995.55

Total 0.87Mwh

Tables 3.5.6 The Heat Supply from Sun Irradiation of Windows -120N (type b windows size

0.49m² )

Month -120N

Cloudy

Factor

Windows’

Aeras(m²)

Sun

Factor

Days

Free Heating of Sun

Irradiation(wh)

January 160 0.45 1.96 0.8 31

3499.776 February 640 0.49 1.96 0.8 28

13768.29

March 1720 0.58 1.96 0.8 31

48491.34

April 3320 0.58 1.96 0.8 30

90580.22 May 4460 0.63 1.96 0.8 16

70492.26

June 5230 0 1.96 0.8 30

0

July 4910 0 1.96 0.8 31

0

August 3720 0 1.96 0.8 31

0 September 2200 0.58 1.96 0.8 15

30011.52 October 1010 0.51 1.96 0.8 31

25037.98 November 270 0.42 1.96 0.8 30

5334.336

December 90 0.43 1.96 0.8 31

1881.13

Total 0.29Mwh

Tables 3.5.7 The Heat Supply from Sun Irradiation of Windows of 60S (type a)

Month 60S

Cloudy

Factor

Windows’

Aeras(m²)

Sun

Factor

Days

Free Heating of Sun

Irradiation(wh)

January 1440 0.45 155.25 0.72 31

2245437 February 2900 0.49 155.25 0.72 28

4447503 March 4520 0.58 155.25 0.72 31

9084316 April 5850 0.58 155.25 0.72 30

11378086

May 6150 0.63 155.25 0.72 16

6929466

June 6350 0 155.25 0.72 30

0

July 6280 0 155.25 0.72 31

0

August 5850 0 155.25 0.72 31

0 September 4820 0.58 155.25 0.72 15

4687383 October 3570 0.51 155.25 0.72 31

6309053 November 1910 0.42 155.25 0.72 30

2690097 December 1060 0.43 155.25 0.72 31

1579429

Total 49.4Mwh

Tables 3.5.8 The Heat Supply from Sun Irradiation of Windows of 150W (type a)

Month 150 W

Cloudy

Factor

Windows’

Aeras(m²)

Sun

Factor

Days

Free Heating of Sun

Irradiation(wh)

January 130 0.45 5.75 0.72 31

7507.89 February 370 0.49 5.75 0.72 28

21016.3

March 900 0.58 5.75 0.72 31

66993.48

April 1990 0.58 5.75 0.72 30

143351.6

May 3050 0.63 5.75 0.72 16

127280.2

June 3870 0 5.75 0.72 30

0

July 3510 0 5.75 0.72 31

0

August 2380 0 5.75 0.72 31

0 September 1230 0.58 5.75 0.72 15

44302.14

October 530 0.51 5.75 0.72 31

34690.3

November 200 0.42 5.75 0.72 30

10432.8

December 80 0.43 5.75 0.72 31

4414.896

Total 0.46Mwh

The Free Heating of Sun Irradiation of Each

Side of Windows(Mwh)

0.46, 1%

49.4, 69% 0.87, 1%

0.29, 0%

20.6, 29% ^{120N a}

120N b 30E b 60S a 150W a

Fig 3.5.1 Graph of Free Heating from Sun Irradiation of Each Side of Windows

The graph Fig 3.5.1 above shows that the major sources of sun irradiation are windows facing to

-120 North and 60 South. The amount of free heating from these two sides takes 99% of the total.

The total free heating from sun irradiation is 71.62Mwh for a year. It is a big part of energy supply

in this building.

3.5.2 The Free Heating from People Inside.

The free heating from people inside is a small part of energy supply compare with the heat comes

from sun irradiation. The heat from people is decided by the number of people and the activities of

the people inside. By asking the staff working in the building, the number of people and the

activities hours are in the following table calculated by the following equation.

type

Activities

rs

workinghou

people

No

g

Freeheatin N H W

Q = _. * *

The power of activities of office working could be considered as 100W/h. So the result of the free

heating is calculated.

Table 3.5.9 The Free Heating from the People Inside Building [The number of people is the

number of registered staff]

Floor No. No. of People Working hours Activities type Free Heating

3 30 1650 Office working 4.95Mwh/year

4 18 1650 Office working 2.97Mwh/year

5 43 1650 Office working 7.07Mwh/year

6 12 1650 Office working 1.98Mwh/year

Total 16.97Mwh/year

It is good with more free heating for cold season, which could save a little bit of energy supply.

However, it is not suit for hot season, which will consume more energy for cooling process than it

without the free heating in the building.

3.5.3 The Free Heating from Electricity Applications

The heating from electricity applications is a passive energy supply in the building. So it is hard to

measure the quantity of heat supply from them. In this energy audit, there are two major heat

sources from electricity, which are the lighting and the computers inside building.

The heat from lighting could be estimated as 10W/m². So it is known that the building areas are in

the following table. The usable areas are estimated by 75% to 85% of the building areas.

Table 3.5.10 The Building Areas for Lighting

Floor No. Usable areas(m²) Using hours Power type

Free

heating(Mwh)

Floor 3 697*0.8 1650 10 w/m² 9.2

Floor 4 697*0.8 1650 10 w/m² 9.2

Floor 5 697*0.8 1650 10 w/m² 9.2

Floor 6 390*0.85 1650 10 w/m² 5.47

Total 33.07Mwh

The free heating from computers is estimated as 150w/person. So it is known that the numbers of

people in each floor in the following table.

Table 3.5.11 The Free Heating from the Computer Inside Building (One Computer per Person)

Floor No.

Numbers of

Person

Working hours Power type

Free

Heating( Mwh)

Floor 3 30 1650 150w/person 7.425

Floor 4 18 1650 150w/person 4.455

Floor 5 43 1650 150w/person 10.6425

Floor 6 12 1650 150w/person 2.97

Total 25.5Mwh/year

The free heating from electricity is 58.6Mwh form those two calculations.

3.6 District Heating

District heating is the major part of energy supply in the building energy systems. In this case, the

district heating is the only positive energy supply process. The data of heating consumption is

given by company Gavle Energi. [Appendix 8. Electricity and Heating Consumption]

Table 3.6.1 The District Heating Consumption

Type of reading Reading period from Reading consumption (Mwh).

Reading 07‐12‐31 to 08‐01‐29  68.6

Reading 08‐01‐29 to 08‐02‐25  50.34

Reading 08‐02‐25 to 08‐03‐25  55.49

Reading 08‐03‐25 to 08‐05‐01  46.81

Reading 08‐05‐01 to 08‐06‐01  16.59

Reading 08‐06‐01 to 08‐07‐01  3.48

Reading 08‐07‐01 to 08‐08‐01  2.8

Reading 08‐08‐01 to 08‐09‐01  7.19

Reading 08‐09‐01 to 08‐10‐01  19.81

Reading 08‐10‐01 to 08‐11‐01  30.07

Reading 08‐11‐01 to 08‐12‐01  47.79

Reading 08‐12‐01 to 09‐01‐01  57.56

Total  406.53Mwh

The district heating in year 2008

68.6 50.34

55.49 46.81 16.59

3.48 2.8

7.19

19.81

30.07

47.79

57.56

0 10 20 30 40 50 60 70 80

07-12-31 to 08-01-29 08-01-29 to 08-02-25 08-02-25 to 08-03-25 08-03-25 to 08-05-01 08-05-01 to 08-06-01 08-06-01 to 08-07-01 08-07-01 to 08-08-01 08-08-01 to 08-09-01 08-09-01 to 08-10-01 08-10-01 to 08-11-01 08-11-01 to 08-12-01 08-12-01 to 09-01-01

Kwh

Fig 3.6.2 The district heating of Gefle Vapen in year 2008

Due to the object areas are the part of building, the heating of office floors are estimate as 70 % of

total district heating supply. So, the heating supply of office floor is estimate as 284.6 Mwh.

[Appendix 9. The Estimate of Heating Supply of Building Gefle Vapen]

4. ENERGY SAVING

4.1 Indoor Temperature Standard

As usually, the normal indoor temperature is set as 20 degree Celsius all over the world. And the

building operator will make the indoor temperature a little higher, 21 degree, than 20 degree

Celsius. However, there is a strange phenomenon sometimes that the people enjoy the beautiful

snow scene eating ice cream behind the windows in summer clothes. This means the energy is not

used effectively. So, why not low down the indoor temperature a little bit than 20 degree Celsius

and put one more cloth on.

In the following table, the q_degree shows the energy need for a year decided by the outdoor and

indoor temperature.

Table 4.1.1 Degree-hours as a Function of Balance Temperature and Annual Mean Outdoor

Temperature for Gavle City.

Temperature

-2 -1 0 1 2 3 4 5 6 7 8

5 80750 73500 66500 59700 53200 47000 41000 35200 29700 24500 19500 6 87000 79500 72300 65300 58500 52000 45800 39700 33900 28400 23000 7 93500 85800 78300 71100 64100 57400 50800 44500 38400 32600 26900 8 100200 92200 84600 77200 69900 62900 56200 49600 43200 37100 31100 9 107200 99000 91200 83500 76000 68800 61800 54900 48200 42000 35500 10 114500 106000 98000 90100 82400 74900 67700 60600 53600 47100 40300 11 121900 113300 105100 97000 89000 81400 73900 66500 59300 52500 45400 12 129500 120700 112300 104000 95800 88000 80200 72600 65100 58100 50700 13 137000 128100 119500 111000 102500 94500 86500 78700 70900 63600 55900 14 144600 135400 126700 118000 109300 101100 92900 84700 76700 69200 61200 15 152100 142800 133900 125000 116100 107600 99200 90800 82500 74800 66500 16 159700 150200 141100 132100 122900 114200 105500 96900 88300 80400 71800 17 167200 157600 148300 139100 129600 120700 111800 103000 94100 85900 77000 18 174800 155000 155500 146100 136400 127300 118100 109100 99900 91500 82300 19 182300 172300 162700 153100 143200 133800 124500 115200 105700 97100 87600 20 189900 179700 169900 160100 149900 140400 130800 121300 111500 102600 92800 21 197400 187100 177100 167100 156700 146900 137100 127300 117300 108200 98100 22 205000 194500 184300 174100 163500 153500 143400 133400 123100 113800 103400 23 212500 201900 191500 181100 170200 160000 149700 139500 128900 119300 108600 24 220100 209200 198700 188100 177000 166600 156100 145600 134700 124900 113900 25 227600 216600 205900 195100 183800 173100 16400 151700 140500 130500 119200

Accroding to the location of Gavle, the annual mean temperature is 5 degree Celsius and the

former indoor temperature is 21 degree Celsius, sometimes the indoor temperature is more than

that. The q_{degree 21} is 127300. And the q_{degree 18} is 109100 when the indoor temperature is 18 degree

Celsius. The decrease of the qdegree shows 14.3% energy saving potential by set indoor temperature

at 18 degree Celsius.

With the indoor temperature reduction, the energy losses decrease at the same time. The table

below shows the reduction of energy.

Table 4.1.2 Energy Saving by Reduction Indoor Temperature

Process  Energy saving

percentage 

Former energy

losses(Mwh) 

Energy

saving(Mwh) 

Cost(Kr) 

Ventilation

systems 

14.3%  177.7  25.4  0 

Transmission  14.3%  197  28.2  0 

Others  >14.3%  38.77  5.5  0 

Total  >14.3%  413.47  59.1  0 

 

From the calculation, it is obviously that the heat losses reduced 59.1Mwh which means

23640kr/year and cost nothing. No doubt it is an effective way to saving energy.

4.2 The Improvement of Windows

With the improvement of windows, the low U-value gives the benefit to save energy. The heat

losses of transmission will reduce a lot every year. With the U-value reduced from 1.9 to 1.3 for all

the windows in this building, the heat losses from transmission would reduce from 77.7Mwh

(U-value 1.9) to 43.2Mwh (U-value 1.3), 1.7Mwh (U-value 2.95) to 0.7Mwh (U-value 1.3).

The results of the heat losses reduction due to windows’ U-value improvement are in the following

table.

Table 4.2.1 The Heat Reduction due to U-value Improvement

Heat Reduction from  Former

U-value 

New U-value Former heat

losses(Mwh) 

Energy saving

(Mwh )  

Transmission of

windows 

1.95  1.3  78.4  26.1 

Transmission of

windows 

2.95  1.3  1.5  0.84 

Total  27 

 

Set the price of 1Mwh is 400kr, the result of improvement save money 10800kr each year.

However, with the investment of replace the old windows to new windows with U-value 1.3, there

is a more than 30 years’ payback time. And the cost for first purchase is a big money.

4.3 The Improvement of Ventilation Systems

There are several methods for improve ventilation systems. In this case, I suggest the methods that

using a new operation schedule instead the old schedule.

In present ventilation systems, the operation time of ventilation hosts are 24 hours for each

working day. That is 5832 hours for a year of 243 working days. To save energy, a new schedule is

necessary.

Table 4.3.1 New schedule for operation ventilation systems hosts

Office time  Ventilation hosts operation air flow percentage 

0:00 to 5:00  0% 

5:00 to 8:00  60% 

8:00 to 18:00  100% 

18:00 to 22:00  60% 

22:00 to 0:00  0% 

 

The method to reduce the power ventilation systems is area supply ventilation systems. The

method comes out with the situation that is only a part of building was used when the stuffs have

to work overtime.

For example, there is only one level used after 18:00 but the ventilation systems still works for the

whole building of each level. It supposed that the ventilation systems should supply air for the

needed area. In this way, the energy could be saved by low down the volume of supply air and

exhaust air and stop to air exchange in the no people area, which could be done by install several

switches to control the air in and out in each levels.

In the new schedule, the running hour is 17 hours each working day with different air flow

percentage. By the change of operation hours and power, the heat losses will reduce to 59%

(104.8Mwh), saving 41% (72.9Mwh), which means save money 29142kr as 400kr/Mwh. It will

cost a little for install a time operator for the ventilation hosts. So it is a possible method to save

money and save energy.

4.4 Saving Energy with Saving Water

In the office building, most of water is used in toilet, and the toilet has a flush toilet which

consumes 9 liter of water for each using. So if the flush toilet could be replaced by 6 / 3 liters two

buttons flush toilet, the minimum used water could be 38% of the form water consumption. The

calculation is following.

The times of using toilet for a health adult are 7 times every day. There are 6 times for somebody

passes water according to statistics of researchers. So that is 6 times 3 liters and 1 times 6 liters

and divided by 7 times 9 liters. The result is 38%. In this case, the building consumed 1047 m³

during 2008, which means the average water consumption is 61.6 liter for one person (103 persons

totally) one day (165 days totally). However, not everyone will use toilet in the working place. So

the 38% is the minimum percentage of using water in toilet.

If 80% of water were used in toilet, the saving potential is 30.4% (18.7 liter per person). That is

mean 30.4% of heat losses from tap water could be saved which is 5.6Mwh compare with total tap

water losses 18.3Mwh. And it also saves the cost of water consumption, which is a good choice

for saving energy.

5. Conclusion

The aim of this thesis is to make an energy audit and give some suggestions for improvement. The

total energy supply in Gefle Vapen is 431.77 Mwh during 2008, and the energy demand is equal to

energy supply. The major parts of heat losses is the heat losses from transmission and ventilation

systems, those two parts take 88% of the total. One the other hand, the energy supply is dominated

by district heating, which take 65.9% of the total.

In the chapter 4, the suggestions are given. The best suggestion is to low down the indoor

temperature, which could reduce 59.1 Mwh compared with total heat losses 431.77 Mwh. The

new schedule for ventilation systems is another effective way for saving energy, which could save

72.9 Mwh. However, it is not recommended, because it will cause problems when the ventilation

systems shut down. Saving water is a good method, 5.6Mwh could be saved. The last method is to

replace the present windows with the low U-value windows (1.3), it would save 27Mwh per year,

but the pay back time will last approximate 30 years.

The total saving potential is 38.1% (164.6Mwh) of the present energy consumption (431.77 Mwh).

REFERENCE

:

[1]. “Blueprint of Gefle Vapen”, GAVLE FASTIGHETER OCH LOKALER.

[2]. “2009 ASHRAE Handbook - Fundamentals (I-P Edition)”, American Society of Heating,

Refrigerating and Air-Conditioning Engineers, Inc. 2009. ISBN 978-1-933742-54-0.

[3]. Thumann Albert. “Handbook of energy audits -- 7th ed”. The Fairmont Press, Inc. ISBN:

0-88173-577-9.

[4]. “ACHIEVING THE DESIRED INDOOR CLIMATE, Energy Efficiency Aspects of

Systems Design”. The commtech group. ISBN: 91-44-03235-8.

[5]. Roberto Gonzalo and Karl J. Habermann. “Energy-efficient architecture: basics for planning

and construction”. 2006.

[6]. M. Santamouris. “Energy performance of residential buildings: a practical guide for energy

rating and efficiency”. Earthscan, 2005.

[7]. Richard E. Putman. “Industrial energy systems: analysis, optimization, and control”, New

York: ASME Press, 2004.

[8]. Pan Yunying and Enric Pica Gonzalez, “ENERGY AUDIT OF A BUILDING, Vinddraget 28,

Andersberg, in Gavle”, July 2007.

[9]. Liu Yuanyuan and Shen Yang. “ENERGY AUDIT AND ACCOUNTING FOR

RIKSBYGGEN FASTIGHETSSERVICE, Gavle”, July 2008.

[10]. Zhongli Chen. “Optimize energy use of industrial buildings at Myrhagen, Skutskär”,2006.

APPENDIX CONTENTS:

Appendix 1. Location and Out Door Temperature···41

Appendix 2. Pictures of Gefle Vapen···43

Appendix 3. Official Public Holidays in Sweden···45

Appendix 4. U-values of Building Envelop···51

Appendix 5. The Q_degree of Gavle ···49

Appendix 6. The Section of Ventilation Systems···50

Appendix 7. Windows and Sun Irradiation Section···55

Appendix 8. Electricity and Heating Consumption···59

Appendix 9. The Estimate of Heating Supply of Building Gefle Vapen···63

APPENDIX:

Appendix 1. Location and Out Door Temperature

Gefle Vapen’s address is Slottstorget 1, Gävle, Sweden. Latitude and Longitude: 60°41′N,

017°10′E.

Building location in map: Gefle Vapen is in the blue square. (Source: http://kartor.eniro.se/)

View of building location: Gefle Vapen is in the red circle. (Source: http://maps.google.se/)

The following table is the normal out door temperature in Celsius Degree of Gavle for the months

and year, 1931-1960. (Source: Climate Data for Sweden, the State Institute for Building Research)

Station Average Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Gavle 5.0 -5.1 -4.9 -2.2 3.3 8.7 13.8 16.6 15.3 10.7 5.3 0.9 -2.1

Appendix 2. Pictures of Gefle Vapen

The following picture is taken from the South west side of the building Gefle Vapen.

The following picture is taken from the North west side and North east side of the building.

The following picture is taken from the North east side and South east side.

From the pictures, it is easily found that there is nothing to keep off the sun irradiation and wind.

And it should notice that the building is connecting with the library behind the building.

Appendix 3. Official Public Holidays in Sweden

The total holiday is approximately 120 days in Sweden in 2008, according to the holiday’s list

below and the normal weekends. So, the total working hours T _total = (365-120) * 10 = 2450 hours.

The reason of number 10 hours replaced 8 hours for a working day is due to the worker have rest

during lunch time (1 hour), and the building is still in operation in this 1 hours.

It also needs to be considered that the working days from 16, May to 15, September is no heating.

For this reason, they are 80 days in 2008, which means 10 days from May, 15 days from June, 23

days from July, 21 days from August and 11 days from September. So the heating hours are 1650

for year 2008.

Except every weekend, the public holidays in Sweden as defined by law are:

Public holiday Date of observation

New Year's Day (nyårsdagen) 1 January

Epiphany (trettondedag jul) 6 January

Good Friday (långfredagen) The Friday closest before Easter Sunday.

Easter Sunday (påskdagen)

The Sunday closest after the full moon that occurs on or

closest after 21 March.

Easter Monday (annandag påsk) The day after Easter Sunday.

International Workers' Day (första

maj)

1 May

Ascension Day (Kristi

himmelsfärdsdag)

Sixth Thursday after Easter Sunday.

Whitsunday (pingstdagen) Seventh Sunday after Easter Sunday.

National Day of Sweden (Sveriges

nationaldag)

6 June

Midsummer's Day (midsommardagen) The Saturday during the period 20–26 June.

All Saints' Day (alla helgons dag) The Saturday during the period 31 October–6 November.

Christmas Day (juldagen) 25 December

Boxing Day (annandag jul) 26 December

De facto holidays: The day before an official holiday is in most cases treated as a de facto holiday

in two variants, full day and half day.De facto full holidays ("Helgdag"): The de facto full holidays

are treated as official holidays.

De facto full holiday Date of observation

Midsummer's Eve (midsommarafton) The day before Midsummer's Day

Christmas Eve (julafton) 24 December

New Year's Eve (nyårsafton) 31 December

De facto half holidays ("Helgdagsafton"): The de facto half holidays are in many cases treated

with the afternoon off.

De facto half holiday Date of observation

Twelfth Night (trettondagsafton) 5 January

Maundy Thursday (skärtorsdagen) The day before Good Friday

Holy Saturday (påskafton) The day before Easter

Valborg (valborgsmässoafton) 30 April

Ascension Eve (Kristi himmelsfärdsdag) The day before Ascension Day.

All Saints' Eve (allhelgonaafton) The day before All Saint's Day

(Source: http://en.wikipedia.org/wiki/Public_holidays_in_Sweden)

Appendix 4. U-values of Building Envelop

When calculating the transmission heat losses, the U-value is different and making an essential

effect in the result of heat losses. The following data shows the normal thermal resistance of a

building assembly, such as a wall or roof, the insulating effect of the surface air film is added to

the thermal resistance of the other materials.

Surface position Direction of heat flow R_US

(h·ft²·°F/Btu) R_SI

(K·m²/W)

Horizontal (eg: a flat ceiling) Upward (eg: winter) 0.61 0.11

Horizontal (eg: a flat ceiling) Downward (eg: summer) 0.92 0.16

(Source: 2009 ASHRAE Handbook - Fundamentals (I-P Edition & SI Edition). (pp: 26.1).

American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc)

Appendix 5. The Q

_degree

of Gavle

Source: “Meteorologi och klimatologi – Varaktighet för uteluftens temperature och

värmeinnehåll”, page 7:28.

Appendix 6. The Section of Ventilation Systems

The ventilation systems of Gefle Vapen are operated by 3 central air conditional hosts. They are in

the room 322, room 352 and room 611 separately. The host in room 322 is used for floor 3 only,

and the host in room 611 is used for top floor only. The host which is in room 352 is the main host

of the ventilation systems in the building. It controls the whole ventilation systems from floor 3 to

top floor.

Area of central A/C host Supply air (l/s) Exhaust air (l/s)

Room 322 448 460

Room 352 3110 3160

Room 611 83 103

Total 3638 3723

The table below is the volume of supply air and exhaust air in each floor. The total air volume is

approximate equal to the volume of the three hosts.

Floor Total supply air (l/s) Total exhaust air (l/s)

3 960 910

4 970 1035

5 955 915

6 525 684

Total 3410 3544

The table below shows the measurement of each room, and then compared them with the data in

the plan. It shows that the real data is approximate equal to the data in the plan of ventilation

systems.

The Result of Measurement of Floor 3 Area No. of

Floor 3

Supply air flow (l/s)

Exhaust air flow (l/s)

Supply in plan Exhaust in plan

303 17 15

304 26 30 305 20 30

306 70 67 No data No data

311 23 20 312 25 20 314 34 17 30 15 318 22.38 11 20 10

320 12 No data

323 32 30 324 34 30

330 32 15 30 No data

333 33 30 335 24 20 336 22 20

337 23 20 342 23 20 343 15 20 344 23 20 346 46 40 347 32 30 348 33 30

350 290 No data

352 32 30

354 33 22 30 No data

355 17 15

356 16 15

360 16 No data

The Result of Measurement of Floor 4 Area No. of

Floor 4

Supply air flow (l/s)

Exhaust air flow (l/s)

Supply in plan Exhaust in plan

410 202 No data

411 23 20

413 23 20 414 22 20 416 23 20 418 26 20 420 22 20

421 64

424 35 30 425 77 75 75 75

426 32 30

427 33 30

429 27 28 25 25 431 33 20 433 32 20 436 25 20

The Result of Measurement of Floor 5 Area No. of

Floor 5

Supply air flow (l/s)

Exhaust air flow (l/s)

Supply in plan Exhaust in plan

502 231 No data

504 35 20 505 27 20 506 28 20 509 61 50 510 73 60 512 72 60

514a 68 60

515 22 20 516 23 20

518 24 30

519 28 30

521 33 30

523 24 20 524 23 20 525 30 20 526 29 20

527 28 20 529 28 20 530 33 20

535 18 15

537 32 25

539 18 15

541 30 20

543 25 59 60 No data

544 73 30 No data 30

The Result of Measurement of Floor 6 Area No. of

Floor 6

Supply air flow (l/s)

Exhaust air flow (l/s)

Supply in plan Exhaust in plan

603 17 15

605 120 105 60 120

606 29 60 30

608 26 No data

609 35 30

612 17 15

613 17 15

614 40 30

615 17 15

617 143 110 160 120 618 32 30

619 36 30

622 17 15

Appendix 7. Windows and Sun Irradiation Section

The windows are a major medium of heat loss, and the amount of heat loss is decided by the

windows area, the type of windows and shadow factor.

Windows area of building Gefle Vapen:

Windows Area(m²) U-value

(W/m²K)

Sun radiation

factor

Radiation

-type

Face to South west

(60°)

155.25 = 135*1.15 m² 1.9 – 2.0 0.72 0

Face to North west

(150°)

5.75 = 5*1.15 m² 1.9 – 2.0 0.72 0

157.21 = 135*1.15m² 1.9 – 2.0 0.72 0 Face to North east

(-120°) + 4*0.49 m² 2.9 – 3.0 0.80 0

Face to South east

(-30°)

1.96 = 4*0.49m² 2.9 – 3.0 0.80 0

There are two basic types of windows: size a 1.15 m² and size b 0.49 m².

Days sums the 15th of each month of radiation on vertical surfaces, Wh/m²day (Latitude 60°N,

Radiation type 0).

Vertical Surface Orientation Month

-120 N -30 E 60 S 150 W

January 160 2360 1440 130

February 640 4280 2900 370

March 1720 5740 4520 900

April 3320 6370 5850 1990

May 4460 5980 6150 3050

June 5230 5820 6350 3870

July 4910 5820 6280 3510

August 3720 6070 5850 2380

September 2200 5760 4820 1230

October 1010 4960 3570 530

November 270 3040 1910 200

December 90 1770 1060 80

Source: Given by Mr. Roland.

To decide the shadow factor, the cloudy days of Gavle in a year needed to be considered.

Month Calculation Factor

January 0.45

February 0.49

March 0.58

April 0.58

May 0.63

June 0 (No heating need)

July 0 (No heating need)

August 0 (No heating need)

September 0.58

October 0.51

November 0.42

December 0.43

Source: The data is given by Mr. Roland.

Calculation factors for windows according to sun radiation

Windows type U-value Calculation factor

1- glass, normally 5.4 0.90

2- glass, normally 2.9 - 3.0 0.80

3- glass, normally 1.9 - 2.0 0.72

Special glass 1.0 - 1.5 0.69

2- glass, energy glass 1.0 - 1.5 0.70

Source: The data is given by Mr. Roland.

There are two kinds of windows Radiation types. The left side type’s radiation factor is 0, and the

right side type’s radiation factor is 10.

The following graph is using for measure the vertical surface orientation for calculated sun

irradiation.

Appendix 8. Electricity and Heating Consumption

Table A8.1 Electricity Consumption during Period from 08-01-01 to 09-07-01. (Source: Gordana

Hagelin ,Gävle Energi AB).

Type of reading Reading period from Reading period to Reading consumption (kWh).

Readings 09-06-01 09-07-01 93543

Readings 09-05-01 09-06-01 88741

Readings 09-04-01 09-05-01 72215

Readings 09-03-01 09-04-01 77988

Readings 09-02-01 09-03-01 73683

Readings 09-01-01 09-02-01 76434

Readings 08-12-01 09-01-01 72886

Readings 08-11-01 08-12-01 71376

Readings 08-10-01 08-11-01 81803

Readings 08-09-01 08-10-01 83032

Readings 08-08-01 08-09-01 86969

Readings 08-07-01 08-08-01 93094

Readings 08-06-01 08-07-01 84882

Readings 08-05-01 08-06-01 81693

Readings 08-04-01 08-05-01 75117

Readings 08-03-01 08-04-01 72925

Readings 08-02-01 08-03-01 70092

Readings 08-01-01 08-02-01 73026

Reading consumption of Electricity(kWh)

73026 70092

72925 75117

81693 84882

93094 86969 83032 81803 71376

72886 76434 73683

77988 72215

88741 93543

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000 08-01

08-02 08-03 08-04 08-05 08-06 08-07 08-08 08-09 08-10 08-11 08-12 09-01 09-02 09-03 09-04 09-05 09-06

Fig. A8.1 Electricity Consumption during Period from 08-01-01 to 09-07-01.

It shows the electricity consumption of the building in Fig A8.1. It implies that it consumed more

electricity in summer than that in winter. The reason for this phenomenon is that the fans in each

room consume electricity during summer.

Table A8.2 Heating Demand from Period 08-03-25 to 09-07-01. (Source: Gordana Hagelin ,Gävle

Energi AB)

District Heating

Type of reading Reading period from Reading period to Reading consumption (MWh).

Readings 09-06-01 09-07-01 5.43

Readings 09-05-01 09-06-01 5.5

Readings 09-04-01 09-05-01 16.07

Readings 09-03-01 09-04-01 48.56

Readings 09-02-01 09-03-01 73.09

Readings 09-01-01 09-02-01 71.36

Readings 08-12-01 09-01-01 57.56

Readings 08-11-01 08-12-01 47.79

Readings 08-10-01 08-11-01 30.07

Readings 08-09-01 08-10-01 19.81

Readings 08-08-01 08-09-01 7.19

Readings 08-07-01 08-08-01 2.8

Readings 08-06-01 08-07-01 3.48

Readings 08-05-01 08-06-01 16.59

Readings 08-03-25 08-05-01 46.81

Readings 08-02-25 08-03-25 55.49

Readings 08-01-29 08-02-25 50.34