Investigation of alternative energy and renovation opportunities for villa

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FACULTY OF ENGINEERING AND SUSTAINABLE DEVELOPMENT

Department of Building, Energy and Environmental Engineering

Investigation of alternative energy and

renovation opportunities for villa

Zhongtao Wang

2015

Student thesis, Master degree (two years), 30 HE Energy Systems

Master Programme in Energy Systems

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Summary

Calculate energy consumption; investigate

alternative energy and renovation opportunities for a villa is the main purpose of this thesis.

The calculation processes contains both hand calculation and IDA-ICE building energy modelling simulation. After validation for both hand-calculation and modelling simulation results, several energy investigations are done in the villa: introducing of heat pump, sol energy, district heating etc. for energy opportunities. Meanwhile, some building renovation suggestions for

construction improvement are also introduced to reduce the energy consumption. At the end of the result part, the author combines different energy and renovation methods to improve the energy performance of villa. The result shows that, the villa has good energy potential to meet the BBR standard. And the investment for renovation is acceptable.

LCC analysis is also considered during the

investigation and renovation processes. That makes the results of investigation and renovation become more convincible and more economically.

The discussion and conclusion part, the author make a conclusion about different renovation method, meanwhile the author also discuss about the advantage and disadvantage of the thesis, which will make the author improve in the future project.

Nomenclatures

Acronyms

BBR-Swedish building regulation LCC-Life cycle cost analysis

EPBD-Energy performance of building IDA-ICE- Software of indoor climate and energy

SAHs-solar air heating system SWHs-solar water heating system COP-coefficient of performance Symbols

Qt-Transmission losses Qv-Ventilation losses Qi-infiltration losses

Qtvv-Energy for hot tap water

Wfel-Operational electricity = electricity for pumps, fans, ext. lighting etc Whel-Household electricity Qvå-Heat that can be recovered

Qtillskott-Heat contribution from people, household electricity, hot tap water etc Qsol-Heat contribution from sun radiation through windows

Qenergy=total energy consumption/year Qvärm=energy consumption for heating Um-average heat transfer coefficient Aom-Total surface area of the enclosing parts of the building in contact with heated indoor air

Atemp-The area enclosed by the inside of the building envelope of all storeys including cellars and attics for

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Acknowledgements

At first, I want to thank Per Roland Forsberg which give me this exciting project and help me to solve the problems in my thesis. He is a nice old man, en trevlig gubbe. Thank you Roland!

Ulla and Leif, they are the owner of the little nice villa, thank you for supplying the information of the building even at night. And also Tack för kaffe! 

Taghi Karimipanah, who is one of the best teachers during my bachelor and master studying time, from him I got the knowledge from ventilation, building technology, fluid mechanics etc. which are the best tools for my future studying or working. Thank you sir!

Björn Karlsson, he as my supervisor, gives me a lot of information about solar energy. Thank you! Björn!

Mathias Cehlin, he is one of our best teachers, thank you for giving my knowledge about IDA-ICE, it is the most powerful and useful software which I know in energy system! Tack så mycket!

Perter Hansson who working on SWECO, he give me the knowledge about energy balance calculation. Thank you!

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1. Introduction and background

1.1 Energy policy and development in EU

The energetic strategy of the European Union aims to reduce the domestic greenhouse gas emission up to 80% by 2050, which compared with the 1990 levels. 1

The greenhouse gas emissions to the environment and the energy consumption which attributed to building are significant contributors to this environmental impact. Buildings operational energy consumption has the single largest impact on the

environment. In Great Britain, about 27% of the emissions are attributed to the building In the U.S. the building sector accounts for about 40% of total energy consumption and 38% of the CO2 emissions. In Sweden, the energy consumption of building and service etc. is about 40% (166TWh, 2011) of the inland total energy usage. 60% of the final energy was used for space heating and DHW production (domestic hot water), which is the largest delivered energy end user of all the civil energy users. 2 The average final energy usage in existing single (semi-detached) houses and multifamily houses was 117 kWh/m2 and 140 kWh/m2. 3

The greenhouse gas emission from building sector is the major part of EU total

greenhouse gas emissions (35%). It is followed by transport (32%) and industry (25%) sectors. The building stock in EU is estimated that will increase with 25% by 2050, therefore it is important to reduce the energy dependency and implicitly the greenhouse gas emissions from buildings.

1

Hållbar, säker och prisvärd energi för EU. www.europa.eu

2_{B. Atanasiu, A. Arcipowkska. Synergies between Energy Efficiency and Renewable Energy in EU Built} Environment. Further Need of Data Collection for Implementing EU Buildings Policies.

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8 Table 1: History of energy using in Sweden TWh.

Source: Swedish Energy Agency, the energy situation in 2012. * Foreign transport and use for non-energy purposes

** Conversion and distribution losses of energy other than nuclear power

*** According to the methodology used by the UN / ECE for calculate supply from nuclear power.4

In this respect, in 2002, the Directive 2002/91/CE has been issued on Energy

Performances of Buildings (EPBD), the Directive which required all EU members to develop and improve their energetic strategy by introducing energy consumption certification schemes for buildings.5

In Sweden, the Swedish government unveiled The 2009 Vision “in 2050, Sweden has a sustainable and resource-efficient energy supply and no net emissions of greenhouse gases into the atmosphere”. The vision has no demarcation between the trading and non-trading sector. To reach this vision, the Swedish government has identified a number of long-term priorities. The emissions from the activities included in the EU:s system should have been reduced considerably by 2050.6

In building sector, the goals of energy consumption reducing are divided into two levels:

By 2020, decrease 20 percent of energy for heating (kWh per kvm), which compared with 1995 level.

By 2050, decrease 50 percent of energy for heating (kWh per kvm), which compared with 1995 level. 7

4_{Energianvändning i Sverige, energibalans i Sverige, www.ekonomifakta.se} 5_{Klimat- och energimål till år 2020, Regeringskansliet, www.regeringen.se} 6

Prop. 2009/10:155 Svenska miljömål - för ett effektivare miljöarbete. Regeringskansliet, www.regeringen.se

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1.2 Building energy system

The building energy system is the system which to analyze and calculate building construction, properties of building materials etc. and to improve the energy performance and indoor climate of building.

It start from the assessment of building energy consumption per square meter; it contains analyzing of building materials, constructions, thermal bridge, ventilation systems, windows areas, building direction, room units and also outside environment etc. In Sweden, all new buildings should be designed follows by BBR which is Swedish building code.

The building energy systems is a very important part for building construction process, at the beginning of building plan, the building energy systems can guide the architect to design a building which can follow the BBR code (t.ex building energy modelling). Meanwhile, it can also give some suggestions about reducing energy consumption to architect.

For building renovation, the building energy system is the key role to make the old building become more energy efficiency and better thermal comfort.

In Sweden, between 1965 and 1974, about 1 million dwellings were built under these ten years; it is called the Million Program. At that time, the Million Program was the most ambitious building program in the world—to build one million new homes in a country with a population of eight million. 8

Picture 1, old pictures taken from Sätra

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Under the time of million-program, the energy was not a problem which needs to be considered. But right now, the energy shortage has become a world problem. At the same time, the price of energy is raising, building with big energy demand is not fit for the modern world. Which is not good for the energy saving and thermal comfort. The Swedish housing stock comprise approximately 2.5 million dwellings (including apartment units and multifamily houses), and approximately 2 million detached or semi-detached single-family houses or villas. The total heated floor areas of single family houses and apartment units are around 301 million m2 and 237 million m2. 9

Energy utilization and the mitigation of environmental impacts are increasingly

important in building stock. Meanwhile the building energy system becomes more and more important.10

9_{EU:s och Sveriges klimat- och energimål, boverket}

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1.3 BBR- building code in Sweden

Swedish government attached particular importance to building.

BBR is the Swedish building code which is a collection of rules and guidelines established by the Boverket. BBR contains requirements and guidelines regarding, among other things, designing, carrying capacity, fire, hygiene, noise, safety and energy conservation.

The rules for energy conservation of building are not the same in Sweden; it depends on which kind of building it is: premises or dwelling and also the location of building. Sweden is a long, narrow country from south to north, due to latitude changes; the climate of Sweden is variable. From 2015, in BBR, Sweden is divided into 4 parts from north to south: climate zoon1, climate zoon 2, climate zoon 3, and climate zone 4. Gävle is located in the climate zoon 2.11

Picture 2, new climate zones in Sweden.12

Table 2,Buildings that have other heating means than electric heating

Climate zone Zone-one Zone-two Zone-Three Zone-four

specific energy

consumption(kWh/m2/year)

130 110 90 80

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Table 3, Buildings that have heating with electric heating

Climate zone Zone-one Zone-two Zone-Three Zone-four

specific energy

consumption(kWh/m2/year)

95 75 55 50

average heat transfer coefficient (u-value)

0.4 0.4 0.4 0.4

-Specific energy consumption (kWh / m²)

-Average heat transfer coefficient (Um) (W / m²K) for building parts that surrounds the building (Aom)

Generally, the requirements for energy contained in BBR are for all buildings (both new and old buildings after innovation), but there are some exceptions.

Exceptions apply for example to:

• Greenhouses or similar buildings which could be used for its intended purpose of the requirements needed to be met.

• Buildings used for shorter periods.

• Buildings with no need for heating or space cooling are for the most part of the year.13

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1.4 Thermal comfort

Thermal comfort is an emotional and affective experience in building or room which the main factor that influence it are those determine heat gain and loss, namely metabolic rate, clothing insulation, air temperature, mean radiant temperature, air speed and relative humidity, psychological parameters such as an individual’s history and expectation also affect thermal comfort.14

There are two models which are normally used in thermal comfort which are PMV (The Predicted Mean Vote) and PPD (Predicted percentage dissatisfied).

Picture 3, thermal comfort PMV.

Picture 4, graph of PMV/PPD.

The PMV/PPD model was developed by P. O. Fanger. He proposed that the condition for thermal comfort is that the skin temperature and sweat secretion lies within narrow limits. Fanger obtained data from climate chamber experiments, in which sweat rate and skin temperature were measured on people who considered themselves comfortable at

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various metabolic rates. Fanger proposed that optimal conditions for thermal comfort were expressed by the regression line of skin temperature and sweat rate on metabolic rate in data from these experiments. In this way an expression for optimal thermal comfort can be deduced from the metabolic rate, clothing insulation and environmental conditions.15

Fanger’s equations are used to calculate the PMV of a large group of subjects for a particular combination of air temperature, mean radiant temperature, relative humidity, air speed, metabolic rate, and clothing insulation. Zero is the ideal value, representing thermal neutrality, and the comfort zone is defined by the combinations of the six parameters for which the PMV is within the recommended limits (-0.5<PMV<+0.5). Fanger also developed another equation to relate the PMV to the Predicted Percentage of Dissatisfied (PPD). 16

1.5 LCC analysis

LCC analysis, also known as Life Cycle Cost analysis is defined as “the total discounted dollar cost of owning, operating, maintaining, and disposing of a building or a building system”.

Several authors report that LCC is used to inform designers and clients about different investment scenarios. The LCC can also be used to assess financial benefits of building energy efficiency measures etc.

Initial and future expenses can be combined into LCC analysis by taking into account the time value of money. The time value of money can reflect future inflation and interest rates. Inflation is the general increase of prices over time, without corresponding increase in value. In the LCC approach, future costs are discounted to “present value” (PV) using a suitable discount rate over their lifetime.

As the price of energy and materials on market are fluctuating all the time, it is actually hard to derive the result accurately, so in terms of accuracy, the LCC analysis of

buildings contains several uncertainties. Building has long lifetime, the longer the time be considered, the less accuracy can get from LCC result. But this exactly become the reason to run LCC analysis before project taking action. The evaluation of LCC analysis is best to be performed in designing stage, in debating stage, where it can give minimize most mistakes as the later to make changes.17

To improve the accuracy of LCC results, the choice of appropriate discount and inflation rate are critical.

15_{Parsons, K C. Introduction to thermal comfort standards.} 16

Ursa Ciuhab, Ola Eikend, Igor B. Mekjavica. Effects of normobaric hypoxic bed rest on the thermal comfort zone.

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1.6 Lunda Byväg 10

Lunda Byväg 10 is the project which the author investigates.

Picture 5. The villa of Lunda Byväg 10

The villa is located at ca 30km north of Gävle. The main building was built at 1934 and two big renovations have been done at 1979 and 2002.

It is a common villa in Sweden which with two floors and a basement. The main construction material of this building is wood and insulation materials; concrete is the main material for the basement. And there is no insulation under the ground or outside the basement wall.

Wood is the main heating resource for this villa, the wood stove connected with 5 water heating radiators supply main heating energy and the wood consumption is about 10-13 m3 per year.

3 electronic radiators are also used to keep the villa warm when the owners are not at home.

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1.7 Purpose

Calculate energy consumption and Investigate alternative energy opportunities for villa are the main purpose of this thesis.

The author will calculate the energy consumption of the villa for the whole year, the calculation processes will contains both hand calculation and IDA-ICE building energy modelling simulation. After validation for both hand-calculation and modelling

simulation results, several energy investigations should be done in the villa: such as introducing of heat pump, sol energy etc. for energy opportunities. Meanwhile, some building suggestions of construction improvement should also be introduced to make the villa meet the BBR code and guide the owners renovate the villa in the future. LCC analysis should be also considered during the investigation and renovation

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2. Method

In this part, the author will introduce the software, mothed and equations which were used during thesis work.

2.1 Software and simulation part

2.1.1 Auto-CAD: for building drawing

The building was built over 80 years ago; it has not information from Gävle Kommun’s drawing system. Building measuring becomes the first step of author’s thesis work. Auto-CAD is the best way to processing the building data from figure to drawing. At the same time, the CAD file is the basic input data which can be used into IDA-ICE under the building energy modelling process.

2.1.2 IDA-ICE: Building energy modelling

IDA-ICE (IDA Indoor Climate and Energy) is one of the 20 major building energy simulation software in the world and it is also one of the four main energy simulation tools in building field. The software likes other building energy simulation tools which are based on the building geometrical description and which can provide the basic information of building’s location for solar radiation from outside to inside of buildings and more detail between each room.

IDA-ICE is one kind of user friendly software; follow the software input data construction, after simulation the user can get the energy result such like: energy consumption, energy balance, temperature table, thermal comfort etc. from the output results file.18

IDA-ICE simulation starts at construct the building body and zones; the software supplies a 2-D interface-floor plan which can draw in building’s 2-D drawing by user themselves or can just import file from another kind of software such like Auto-CAD. P.S. the IDA-ICE just accepts CAD files which before 2004 version.

The 3-D interface gives user a direct view of building and its surrounding, meanwhile, some data input can be done under 3-D interface, such like add balcony etc.

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2.1.3 Comsol

The thermal bridge is also called Heat bridge or cold bridge; it is an area of an object (such like a building) which has a significantly higher heat transfer than the surrounding area (cause higher heat transfer than the materials heat transfer properties, u-value). The thermal bridge occurs in three ways:

-Through materials with higher thermal conductivity than the surrounding materials. -Through penetrations of the thermal envelope.

-Through discontinuities or gaps in the insulation material.19

Thermal bridge is one of the most heat loss parts in building, to calculate thermal bridge in building, software which named Comsol was introduced.

2-D and 3-D model can be built in Comsol which depends on which kind of thermal bridge will be simulated.

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2.2 Hand calculation part

2.2.1 Transmission losses, Qt

Transmission loss is calculated according to:

Ch A U Q o om m t    [1]

Where Um = average heat transfer coefficient, Aom = Total surface area of the enclosing

parts of the building in contact with heated indoor air (m2). °Ch = degree hours (see table).20 om j k k i i m A x l A U U 



 



 



[2] golv golv tak tak dörr dörr fönster fönster vägg vägg i i A U A U A U A U A U A U           



[Equation 3]

U for walls multiplied with area for walls etc. for windows Ais calculated using the external frame dimensions.



l_k_k= sum of linear thermal bridges. A thermal bridge exists between floor and outside wall, outside wall and roof, outside wall and outside wall, around windows and doors. l = length of thermal bridge [m] (always measured inside of building),  = heat transfer coefficient of thermal bridge [W/m K].



xj = sum of heat transfer coefficient for the thermal bridge j acting at one point

(W/K)

2.2.2 Energy balance equations

sol tillskott vå hel fel tvv i v t värme energi Q W Q Q Q Q W W Q Q Q Q            [4] Qperson + 20%Qtvv + 50%Wfel + 70%Whel water hot tap sun, people, y, electricit hold house from heat   tillskott Q [5]

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2.2.3 Validation

Validation process is one of the most important parts in this thesis, it plays a big roll on how much can author trust the result of simulation and hand calculation.

Validation process is the process to compare and validate result from both simulation and hand calculation with the truly energy consumption of the villa: about 8000 kWh electricity and 10 m3 wood.

2.2.4 Investigate alternative energy and renovation opportunities

Try to find out energy investigation opportunities and energy renovation opportunities are the two main aim of this thesis.

On energy investigation part, several new energy resources are introduced such like heat pump, sol-energy, district heating etc.

On energy renovation part, to reduce the energy consumption and increase thermal comfort of villa, several renovation plans are introduced.

Most of the energy investigation and renovation parts are done by IDA-ICE.

2.2.5 LCC analysis calculation

Picture 6, LCC calculation file.

The LCC (Life Cycle Cost) analysis uses different materials or appliance to balance the value of energy saving investment and the need of performance efficient improvement. To calculate the LCC analysis, a special excel file is used. The input data contains Atemp,

energy price, interest rate, energy price increase electricity, investigation cost etc. After calculation, this file can show if it is a good investment.

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3. Result

3.1 Energy performance of villa

3.1.1 Average energy consumption in real life:

Electricity consumption=8000 kWh/year Wood consumption=12 m3=27000kWh/year Efficiency of wood stove=70%

Total energy using for villa= 8000kWh/year+70%*27000kWh/year=26900kWh/year

3.1.2 Energy consumption from IDA-ICE result:

Simulation time range: 2014-01-01 to 2014-12-31

Table 4, energy result from IDA-ICE.*

delivered energy kWh

Lighting, facility 184

Electric cooling 0

HVAC aux 0

Electric heating 5627

Total, Facility electric 5811

Fuel heating 19980

Total, Facility fuel* * 19980

Total 25791

Equipment, tenant 914

Total, Tenant electric 914

Grand total 26705

*The result from IDA-ICE, the input data shows at Appendix D.

**set the efficiency of fuel at 70% to simulate the wood. From the result table:

Wood consumption=19980kWh/year

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3.1.3 Energy consumption from hand calculation:

Total energy consumption=26800 kWh/year Net energy input for heating=23759,27kWh/year

Electricity using for household electricity and hot tap water=2534,025+3040,83 5574,855=kWh

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3.2 Validation of energy performance

Table 5, energy result from different methods.

Energy consumption kWh/year

Average energy consumption in real life 26900

Energy consumption from IDA-ICE 26705

Energy consumption from hand calculation

26800

Compare energy consumption from different methods, the difference of them is less than 1%.

Average heat transfer coefficient of the villa: IDA-ICE Um=0.53 W/m2*K

Hand calculation Um=0.54 W/m2*K

Thermal bridge from IDA-ICE=17.135 W/K Thermal bridge from hand calculation=17.47 W/K

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3.3 More energy performance about the villa

3.3.1 Specific energy consumption:

The yearly energy consumption of villa is around 26900 kWh. Atemp*=101.361m2

*the Atemp in this villa is the total floor area but without basement, storeroom etc. those don’t need to be heated up over 10 Degree-C.

Specific energy consumption=Qenergy/Atemp=265.4 kWh/Atemp(m2)

Compared with BBR, the specific energy consumption in this villa should not over 110 kWh/Atemp, if it was a new building or new renovated.

3.3.2 Average heat transfer coefficient:

According to IDA-ICE and hand calculation, the average heat transfer coefficient is 0.5363W/m2*K. Which is also higher than the BBR (0.4W/m2*K) for new building or new renovated building.

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Graph 2, transmission loss structure through different parts of building envelope.

The highest transmission loss part is windows, about 29% of heat transmission loss via windows. Transmission loss through roof and walls ranked second and third places.

3.3.3 Energy using of the villa

Graph 3, energy using structure in the building 23%

24% 7%

29%

4% 13%

Transmission loss through envelope

kWh/year

walls 3802,8 roof 3938,7 floor 1192,9 windows 4771,5 doors 582,4 thermal bridges 2160,8 7% 9% 77% 7%

energy using kWh/year

electricity water heating 2534,0kWh/year electricity for household 3040,8/year

wood consumption 27000kWh/year

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The wood energy is the main energy which input in this villa (about 77% of total energy input), 12m3 of wood contains 27000kWh energy, but for old wood stove, just about 70% of wood energy (18900kWh) can regard as energy benefit for water heating and house heating. So 30% of wood energy regards as heat loss through smoke.

Graph 4, transmission loss from different zones.

The graph shows the transmission loss (kWh/year) from different zones-rooms of the villa. The zone2-kitchen gets the highest transmission loss value which to reach 3757.8kWh/year. 973,4 1805,1 3757,8 1055,3 1064,3 48,1 1605,5 1509,9 1650,2 2368,3 28,8

transmission loss from different

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Graph 5, transmission loss from different zones per square meter.

The graph shows the transmission loss from different zones-rooms per square meter (area of each zone). The transmission loss from kitchen gets the highest total value (from last graph), but when considers transmission loss under per square meter, bathroom gets much higher value than others which reaches 251,6kWh/m2. The zone3-corridor (205,9kWh) gets the second place on transmission loss per square meter.

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3.4 Building thermal comfort

At the IDA-ICE, two thermal comfort checking points are added into the villa, one is in the living room and the other is in the bedroom. These two rooms are where the owners of villa spend most of their time when they at home.

Building comfort reference for two checking points Table 7, thermal comfort result.

Percentage of hours when operative temperature is above 27°C in worst zone _{5 %} Percentage of hours when operative temperature is above 27°C in average zone _{3 %} Percentage of total occupant hours with thermal dissatisfaction _{9 %}

The PPD of living room and bedroom is 9%

Graph 6, Temperature graph of living room.

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29 Graph 7, Temperature graph of bedroom

The mean air temperature of bedroom is just like that at living room; it is controlled around 22 Degree-C during the heating season and then increase from April to September. The highest mean air temperature reaches to over 30 Degree-C.

The PPD and mean temperature graphs are just reference for thermal comfort. The results of thermal comfort which the author get are based on: The villa has no

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3.5 Investigate alternative energy opportunities

3.5.1 Solar energy

Solar energy systems can be classified as two main parts: solar PV systems and solar thermal systems. In solar PV system, it converts solar energy into direct current

electricity. Lower conversion efficiency (market average of 12%-18%) and higher price are two of the biggest problem to restrict its progress. In solar thermal systems, the function of a solar collector is to convert solar radiation on its surface into thermal energy. The solar water heater system (SWHs) is the most common device and it can convert solar radiation into thermal energy to heat the water.

As one of the main system in solar thermal system, the solar air heater system (SAHs) will be introduced by author at this thesis.

Compared with PV-system and SWHs, the SAHs get lower price, higher solar energy conversion efficiency, easy to install etc.

The price of SAHs in Swedish market is around 2000kr-5000kr, which depends on the size of the collector.

The efficiency of SAHs is around 60% of solar radiation.

Picture 7, working process of SAHs.

One SAHs contains four main parts: solar collector, ventilation fan, solar cell for supporting electricity to fan, temperature controller.

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The volume of the first floor is about 143 m3, the author choose one SAHs production from BAUHAUS.COM which with heating volume up to 150m3.21

Table 8, production information of SAHs production information

Power of fan 11W

Room volume (up to) 150m3

Efficiency 60%

Weight (kg) 15.2

size 0.6m2

Price 2495kr

To get the highest solar radiation, the SAHs can be installed outside the south wall of first floor, which direction is south 30o.

From the table of solar energy through windows at the appendix: Table 9, solar radiation with south 30o.

S 30o Wh/m2*day calculatio n factor Total days Collector area efficienc y Jan 2360 0,45 31 0.6 60% Feb 4280 0,49 28 0.6 60% Mar 5740 0,58 31 0.6 60% Apr 6370 0,58 30 0.6 60% Maj 5980 0,63 15 0.6 60% Sep 5760 0,58 15 0.6 60% Okt 4960 0,51 31 0.6 60% Nov 3040 0,42 30 0.6 60% Dec 1770 0,43 31 0.6 60%

Total solar energy 199kWh Saving energy price 169kr Reduction energy 1%

Result of LCC-analysis Table 10, LCC result table.

The LCC result shows, this is a good investment.

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Information and price about Solar air heater system at Bauhaus. www.bauhaus.se. energy savings (kWh/year) Reduction energy usage

(% /year) saved energy form Investment costs (kr)

annual savings (kr/year), today´s energy price pay-off (years) life length (years) Life cycle savings (kr) Is this a good investment?

solar air heating

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3.5.2 Heat pump

A heat pump is a device that works as a reversed heat engine operating between the two heat reservoirs. The heat pump systems can be used as cooler/or heater by changing the direction of current flow through the thermoelectric couples. In Sweden, the heat pump system is popular and widely used as heater.

The common heat sources for smaller heat pump are energy from bedrock, lake water or air. The heat pump system can get higher coefficient of performance (COP), the

common COP for a heat pump system is around 3-4, but the value is totally depends on the temperature difference between two thermal reservoirs or outside temperature. T.ex. for an air heat pump heating system, when the outside temperature is lower than -20oC, the COP is around 1, which all heat is produced from input electricity energy.22

Picture 8, sample heat pump cycle

According to different heat resources and different thermal destination, the heat pump systems are divided into several types:23

Exhaust air heat pump (frånluftsvärmepump): this is the most sample and cheap kind of heat pump, which is to recover the heat loss from exhaust air from the ventilation system.

Air heat pump system has two types: air-air heat pump and air-water heat pump. An air-air heat pump is an air conditioning system for heating; it has good effect in order to heat up a house of about 100-150m2. But this requires the house has an open floor plan (öppen planlösning) and the outdoor temperature does not fall below minus 20 degrees.

An air-water heat pump transfer the heat from outside air to the water heating system in the house (element, radiator), it also gets the same problem of air-air heat pump which the outside temperature does not fall below minus 20 degrees, and the installation works compared with air-air heat pump is more complicated.

Ground source heat pump uses the heat from the water underground; the temperature of water is around 4 degrees. The effect of a ground source heat pump is not as good as air heat pump system, but it can get a stable effect year round. The water pipe is installed about 80-200m underground, which is not cheap to drill a deep hole.

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S.C. Kaushik, S. Manikandan, Ranjana Hans. Energy and exergy analysis of thermoelectric heat pump system.

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The villa with closed-plan (sluten planlösning), has a wood water boiler which connect with elements for heating and no ventilation system, so consider about investment and COP, the author decide to use air-water heat pump for replacing the old wood boiler.

Picture 9, Cycle heating heat pump installation diagram

Graph 8, COP curve for KF400 heat pump.

The COP of heat pump depends on the outside temperature, which the average temperature in Gävle is 5 degrees, from the curve the COP is around 3.

The investment for a house hold heat pump contains two main parts: heat pump and installation. Several company in Sweden offer the package price (parket-pris) which is around 100,000SEK.

Energy usage of villa

Table 11, Electricity usage of villa

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34 Table 12, energy usage of villa

Energy use of villa

Electricity of hot tap water 2534.0 kWh

Electricity for el-heater 2426 kWh

Average electricity price 0.85kr/kWh

Electricity cost for heating 4216kr Wood energy consumption=70% of 12m3 18900kWh

Wood price for 12m3 3600 SEK

Energy price of wood 0.19kr/kWh

Total heating energy cost for villa 7816 SEK

The total energy for heating (space heating and water heating) is 23860kWh.

For using heat pump with average COP=3, the average yearly electricity consumption for heat pump

=23860/COP=7953.3kWh.

Table 13, energy usage after install heat pump Energy use after heat pump

Electricity for heat pump 7953.3 kWh

Electricity cost for heat pump 6760 SEK

The calculation result shows, it is not cheap to use heat pump for replacing the traditional wood stove and electricity water heater.

Table 14, energy result after install heat pump

Total energy consumption of villa 26900kWh Total energy input for heating without heat

pump

23860kWh Energy input with heat pump 7953.3kWh

Energy saving 15907kWh

Reduction energy usage 59%

LCC analysis

Table 15, LCC result of heat pump

LCC shows, this is a good investment. energy savings (kWh/year) Reduction energy usage

(%/year) saved energy form Investment costs (kr)

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3.5.3 District heating system

The district heating is a system to distribute the heat from heating plant for residential and commercial heating requirements such like space heating and water heating. Compared with house boiler, the combustion efficiency for a combined heat and power plant (CHP) is much higher; the output energy (heat and electricity) can reach 90% of the energy supplied. This can make good contribution for reducing greenhouse emission.

Sweden has a long tradition for using district heating in urban areas and 47% of the heat resources which supplied in Swedish district heating plant are renewable bioenergy sources.

Table 16, Installation price for connect with district heating Price information

District heating package price 87200kr

What is included in the price 15 meter digging works Price for digging after 15 meter 3000kr/meter

The total investment cost depends on the location of the building, the basic investment is 87200kr.

After contacted with Kicki Wannberg who working at Gävle Energi, she said right now, it is impossible to connect the Lunda Byväg 10 to their district heating system. There is no district heating pipe at that area.

Table 17, Energy price of district heating from Gälve Energi.24

The total yearly heating demand for the villa is around 20000 kWh, which means the total cost for using district heating is 15038kr. That price is much higher than the cost of using electricity and wood.

24

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36

3.6 Investigate renovation opportunities

3.6.1 Windows

The energy loss from windows is about 30% of the total energy loss in the whole building.

To improve or replace the old wood windows becomes the first step of renovation. Table 18, Windows information of villa

Glass construction 2 pane glazing, clear.

U-value 2.9 W/(m2*K)

g-value, solar heat gain Coef (SHGC) 0.8

Windows area 11.93m2

A new window with 3-galzing and 1.2 U-value is not cheap. For example, one 1.2m*1.2m energy window cost about 6000kr in Sweden.

The price for changing of the windows in this villa is about 50000kr. (price from bygglagret.se)

The installation cost is about 20000kr.

Table 19, energy result after install new windows.

Heat loss from old windows 4771.5kWh/year Heat loss from new windows 1909.8kWh/year

Energy saving 2861.7kWh/year

Energy saving percentage for windows 60% Reduction energy usage for whole

building

10.64%

Renovation cost 70000kr

Table 20, LCC result of new windows

After check the LCC, it shows it is a good investment.

The payback time is about 28 years, which the author thinks it is a little bit longer, even it is a good investment.

energy savings (kWh/year) Reduction energy usage

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There are some Swedish companies supply the extra glass pane for old windows, which is cheaper compared with change windows.25

Picture 10, extra windows pane

Table 21, Information list for extra glass pane price incl. glass and installation for 11m2 windows area

11310kr Energy saving through windows 30%

Table 22, energy result of extra glass pane.

Energy loss for old windows 4771.5kWh/year Energy loss with extra glass pane 3340kWh/year

Energy saving 1431.45kWh/year

Reduction energy usage for whole building

5.3%

Table 23, LCC result of extra glass pane.

25

Nordic Rutan extra windows pane, Boklimat. www.boklimat.se energy savings (kWh/year) Reduction energy usage

extra glass pane 1431,45 5% transmission

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38

3.6.2 Close door

Picture 11, 3-D graph of building, the rooms with red marks are bathroom and corridor (from left to right).

Compared with other zones/rooms, the bathroom and corridor get the highest

transmission loss per square meter. Each of these rooms has 4 sides which face to the outdoor air or ground.

For corridor, the best way to reduce transmission loss is reduce the heat demand which means regard the corridor is an unheated unit. So close the door between corridor and main building is the easiest way (corridor does not have heating unit, it is heated by heat transfer from other units through the door or walls).

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Table 24, transmission loss comparison between before and after close door. Energy

loss kWh

Walls Roof Floor Windows Doors Thermal bridges

total energy transmission loss Before 332,8 283,9 181,5 0 0 257,1 1055,3 after 190,5 158,9 84 0 0 154,9 588,3 Energy saving 467

The result shows, 467kWh energy can be saved every year to just keep the door closed. For electricity price at 0.85kr/kWh, it means the “closing door” method can save about 400kr without any investment input.

3.6.3 Extra roof insulation

The area of roof is 74.15m2 which covers 24.6% of the total envelope area of the villa. The transmission loss through roof is 3938.7 kWh, which is 25% of the total

transmission loss in the whole building.

The U-value of roof is 0.41 W/(k*m2), which compared with BBR u-value for roof (u-value=0.08 W/(k*m2)), the value for the villa is much higher.

So add extra insulation material is necessary.

The author chooses glass wool with 195 mm thickness from byggmax. 26 Table 25, Technology information from byggmax.se

Värmeledningsförmåga (Lambdavärde) Lambda 37 Typ Isolerskiva Paketvikt (kg) 12.37 Tjocklek thickness (mm) 195 mm Price per Square meter 74.8kr

The unit of lambda value is W/mk and lambda 37 =0.037W/mk Calculation equation:

U-value=_{𝑡𝑜𝑡𝑎𝑙 𝑠𝑢𝑚 𝑜𝑓 𝑅−𝑣𝑎𝑙𝑢𝑒𝑠}1

R-value=_{𝑙𝑎𝑚𝑏𝑑𝑎 𝑣𝑎𝑙𝑢𝑒}𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠

The new U-value of roof is 0.13W/(k*m2)

26

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40 Table 26, transmission result after calculation:

Old transmission loss from roof 3938.7kWh Transmission loss after new insulation 1308.2kWh Investment cost+100kr/m2 installation

works

13000kr

Energy saving per year 2630.5kWh

Reduction energy usage for whole energy 9.7%

Table 27, LCC result of insulate roof

The LCC result shows, it is a good investment to insulate the roof.

energy savings (kWh/year) Reducti on energy usage (%/year) saved energy form Investment costs (kr) annual savings (kr/year), today´s energy price pay-off

(years) life length (years)

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3.7 Combine different energy and renovation methods

3.7.1 Method 1

To help the villa reach the BBR energy goal, several energy and renovation methods can be combined.

After the renovation, heat pump becomes the main heat resource which means the villa’s specific energy consumption should be lower than 75kWh/Atemp(m2

) and Um should be lower than 0.4W/m2K.

Graph 9, energy usage structure before renovation

From the graph we can see, the total energy consumption is 26900kWh, total energy for heating is 23860kWh, the house hold electricity= 3040kWh which is fixed value and cannot be decreased.

Table 28, Energy limit for villa after renovation

Specific energy consumption from BBR 75kWh/Atemp(m2)

Atemp in the villa 101m2

Total energy consumption which meets BBR

75kWh/Atemp(m2)* 101m2 - - = 7575kWh

Fixed value household electricity 3040kWh

Energy limit for heat pump 4535kWh

So to meet the BBR, the total energy consumption of the villa with Atemp 101m2 cannot over 7575kWh. The 7575 kWh total energy consumption which includes

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Total energy limit with BBR 75kWh/Atemp for Atemp=101m2 and household electricity 3040kWh.

Table 29, information of renovation precess.

name Energy saving

Add extra windows pane 1431.45kWh

Close corridor’s door 467kWh

Insulate roof 2630kWh

Solar air heater system 357kWh

Total energy saving 4885.45kWh

Heat generation from heat pump 13605kWh Total heating supplying after renovation

with BBR

18490.45kWh

Energy limit for BBR with heat pump=18490.45˂energy demand for heating=23860kWh

That means, the villa with Atemp 101m2, household electricity 3040kWh cannot meet the BBR’s specific energy consumption even after renovation.

3.7.2 Method 2

-increase Atemp area.

From BBR, the Atemp is the area which be heated over 10 degrees, in this villa, the basement is not included. The method 2 is that try to use solar air heating system to heat up the basement over 10 degrees which increase the Atemp area from 101m2 to 131m2. Step 1. IDA-ICE simulation

Set the lowest temperature in basement is 10 degrees. Step 2. Simulation result analysis

Use the heat from solar air heating system to cover the heating demand in basement. Table 30, comparison of transmission loss between before and after heating

Heat transmission from basement before renovation

973.4kWh Heat transmission from basement after

renovation

1506.5kWh Transmission loss difference 533.1kWh

So if use two solar air heating system, the transmission loss difference can be covered.

Table 31, renovation list

Renovation name Energy

Add extra windows pane 1431.45kWh

Close corridor’s door 467kWh

Insulate roof 2630kWh

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43 Calculation of heat pump electricity input: Total energy for heating =23860kWh+533.1kWh

=energy saving from add extra window pane + energy saving from close door + energy saving from insulate roof + solar energy input from 4 pieces SAHs + (heat pump electricity input*COP)

COP=3

So the heat pump electricity input=6356kWh/year The fixed household electricity=3040kWh/year Total electricity input=6356+3040=9396kWh/year New Atemp=131m2

Specific energy consumption=9396/131=71.7kWh/Atemp(m2)˂75kWh/Atemp(m2) After calculation, average u-value=Um=0.4W/m2*k=BBR Um=0.4W/m2*K* *the calculation process of new u-value shows at Appendix C.

So the villa can meet the standard of BBR for electricity heating. Table 32, Total investment for meeting the BBR standard:

Investment name SEK

Solar air heating system 2495*4

Insulate roof 13000

Extra windows pane 11310

Heat pump 100000

total 134290

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4. Discussion and conclusion

Lunda byväg 10 is one of the common villas in Sweden: two floors with one basement, wood is the main construction material and also main heating energy resource. The villa does not have very good insulation, with about 26900kWh energy consumption and the specific energy consumption for 265.4 kWh/Atemp(m2). From energy side, the energy consumption is higher than the demand from BBR. But from economy side, it costs about 10000kr to run the villa with 101 m2 Atemp, which is cheap in Sweden.

4.1 Discussion about different energy opportunities

4.1.1 Solar air heater system

Due to the high latitude and long winter period, the solar radiation in Sweden is low, which is around 100kWh/m2 (glass area) per year. Compared with solar air heater system, the disadvantage of solar PV system and solar water heater system are obvious: The high investment, low energy output rate and long payback time are the three biggest problems which Solar PV system is facing.

Solar water system with lower investment and easy installation is not fit for Swedish winter either, during the winter period to prevent freezing, the water in the solar collector need to be emptied or heated.

It cannot be denied that, both solar PV system and solar water system are the direction of energy in the future. Meanwhile, the Swedish government is supporting the customer of new energy devices continually (ROT-avdraget from Swedish government, which customer can get 35% economy help).

Solar air heating system has low investment, easy installation process and good energy result. Combined SAHs with basement ventilation fan can decrease the moisture level at basement.

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Picture 12, homemade SAHs.

4.1.2 Heat pump

From the energy saving and LCC analysis result, the heat pump is the most effective way to reduce energy consumption in this villa, which can reduce over 59% of energy usage for whole villa with about 1000kr increasing for running cost (compared with wood). But lots of time and money can be saved from wood transportation, wood cutting, wood drying period etc. The advantage of heat pump is obvious.

Meanwhile, without insulate the villa, heat pump can reduce the Specific energy consumption from 265.4 kWh/Atemp(m2) to 108.8kWh/Atemp(m2).

Total 33, energy usage with heat pump

Electricity usage for house hold 3040 kWh/year Electricity usage for heat pump 7953.3 kWh/year Total energy consumption 10993.3 kWh/year

Atemp 101m2

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4.1.3 District heating

District heating has become one of the most visible phenomena of urbanization. It becomes a reason make more and more people move to urban area. The investment of district heating is big, for both district heating company and customers. Meanwhile, the limited covered area can restrict the development of district heating.

4.2 Discussion about renovation opportunities

4.2.1 Windows

It will be nice to change all the windows to energy saving windows. To add extra panes for windows is also a good way, compared with new windows; it gets lower investment, shorter payback time and a little bit higher heat transmission loss.

For the author, I think to add an extra pane is the best way to insulate windows from both economic and environmental sides. To make a new window, energy and material need to be inputted, the few energy and materials we use the better environment we can get.

4.2.3 Close corridor’s door

This is the easiest way to reduce energy consumption in this project. With zero

investment to get about 400kr saving from close one door. Sometime, saving energy is sample to do; a little thing can make a big difference (en liten grej kan gör stor

skillnade).

4.2.4 Insulate roof

Roof, which is the second biggest of transmission loss parts in this villa. After

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4.3 About this thesis

For an old building without construction drawing, the most difficult thing for the author is try to find out the construction information such like: building materials, insulation, ventilation etc. Most of construction information which the author used is from a building construction guide; it shows different common constriction for different

buildings by years. But the common constriction information will decrease the accuracy of results.

The equation of calculate infiltration loss:

𝑄 = 𝑁 ∗ 𝑉 ∗ 𝑆𝑝 ∗ ℎ𝑡 ∗ 𝑑𝑡 [Equation 6]

Where;

N = Number of air changes per hour. An air change is one room volume. In this thesis, the author assume the N=0.45 for calculation. For increasing the accuracy of result, a blower door test should be done.

Picture 13, blower door test.

[Equation 7]

= Natural Air Changes per Hour [1/h]

= Air Changes per Hour at 50 Pascal [1/h]

The process is use blower door to test the Air changes per hour at 50 Pascal, the real air changes per hour is one twentieth of that at 50 Pascal.27

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The advantage of this thesis is to use different calculation methods for calculation of energy consumption and energy structure. Combine the IDA-ICE simulation and hand calculation will increase the accuracy of the results and get more data information to analysis.

The introduction of LCC is also an advantage of this thesis, from the economy side to consider about the investment of renovation can make the result be more convincing. At the end of the result part, the author combine different renovation methods and try to make the villa meet the BBR standard, that shows the energy and renovation potential of the villa, with about 135000 SEK investment input, this building can become a low energy demand and comfortable building.

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5. References

[1] B. Atanasiu, A. Arcipowkska (2014) Synergies between Energy Efficiency and Renewable Energy in EU Built Environment. Further Need of Data Collection for Implementing EU Buildings Policies [Accessed 1 Apr. 2015].

[2] B. Lapillonne, K. Pollier (2013) Energy Efficiency Trends in Buildings in EU, January [Accessed 12 Apr. 2015].

[3] Commission of the European Communities

Proposal for a Recast of the Energy Performance of Buildings Directive (2002–91-EC), SEC(2008) 2865 [Accessed 11 Apr. 2015].

[4] EU:s och Sveriges klimat- och energimål, boverket [Accessed 19 Apr. 2015]. [5] Björk, C., Kallstenius, P., & Reppen, L. (2002).

(As built houses 1880–2000) Så byggdeshusen 1880–2000. Forskningsrådet Formas. [Accessed 1 Apr. 2015].

[6] Energimyndigheten (Energy Agency). (2012). Energy in Sweden. Eskilstuna Sweden:Swedish Energy Agency. http://www.termokontroll.se/fonsterisolering.html

[Accessed 9 Apr. 2015].

[7] Farshid Bonakdar,Ambrose Dodoo, Leif Gustavsson

Cost-optimum analysis of building fabric renovation in a Swedish multi-story residential building [Accessed 9 Apr. 2015].

[8] Ursa Ciuhab, Ola Eikend, Igor B. Mekjavica

Effects of normobaric hypoxic bed rest on the thermal comfort zone [Accessed 19 Apr. 2015].

[9] Tayfun Uygunoğlua, Ali Keçebaş

LCC analysis for energy-saving in residential buildings with different types of construction masonry blocks [Accessed 16 Apr. 2015].

[10] Kimmo Hilliaho, Jukka Lahdensivu, Juha Vinha

Glazed space thermal simulation with IDA-ICE 4.61 software—Suitability analysis with case study [Accessed 13 Apr. 2015].

[11] Energianvändning i Sverige, energibalans i Sverige, www.ekonomifakta.se

[12] Klimat- och energimål till år 2020, Regeringskansliet, www.regeringen.se

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[14] Mohammad Taleghania, Martin Tenpierika, Andy van den Dobbelsteena. Indoor thermal comfort in urban courtyard block dwellings in the Netherlands [Accessed 18 Apr. 2015].

[15] Parsons, K C. Introduction to thermal comfort standards [Accessed 1 Apr. 2015].

[16] F. Aguilara, J.P. Solanob, P.G. Vicente. Transient modeling of high-inertial

thermal bridges in buildings using the equivalent thermal wall method [Accessed 16 Apr. 2015].

[17] Energy performance of buildings — Calculation of energy use for space heating and cooling. ISO/FDIS 13790:2006(E). [Accessed 1 Apr. 2015].

[18] Hållbar, säker och prisvärd energi för EU. www.europa.eu [Accessed 1 Apr. 2015]. [19] Min-Hwi Kima, Jae-Hun Job, Jae-Weon Jeonga. Feasibility of building envelope air leakage measurement using combination of air-handler and blower door. [Accessed 19 Apr. 2015].

[20] S.C. Kaushik, S. Manikandan, Ranjana Hans. Energy and exergy analysis of thermoelectric heat pump system. [Accessed 18 Apr. 2015].

[21] Jung-Hoon Chaea, Jong Min Choi. Evaluation of the impacts of high stage refrigerant charge on cascade heat pump performance. [Accessed 22 Apr. 2015].

[22] Nordic Rutan extra windows pane, Boklimat. www.boklimat.se [Accessed 21 Apr. 2015].

[23] District heating installation and price, Gävle Energi. www.gavleenergi.se. [Accessed 10 Apr. 2015].

[24] Material information and price, Byggmax. www.byggmax.se. [Accessed 2 Apr. 2015].

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6. Appendix

Appendix A

-building energy consumption hand calculation

In this part, the report shows you how I calculated and how I thought.

Basic information

Appendix A table 1, Basic information of the building

build year 1934

Atemp m2 101,3

Aom m2 257,2

Vol m3 390

Yearly average wood consumption m3 12

House use electricity kWh 8000

Appendix A graph 1, picture of Aom and Atemp.

Aom=Total surface area of the building envelope facing the heated indoor air (m2). The building envelope refers to those structural elements that separate heated parts of

dwellings or non-residential premises from the outdoor, the ground or partially heated spaces.

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54 Appendix A table 2, Wood energy content

Name of wood Wood energy contains kWh/m3

Ek 2900 Björk 2650 Tall 2350 Klibbal 2350 Gran 2000 Asp 2000

The wood which the owners are using is mix with: Björk, Tall, Gran and Asp. The average energy contains is 2250kWh/m3

Volume of wood=12m3 Qwood=12*2250=27000kWh

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Degree hour

The indoor temperature is 22oC, average outdoor temperature is 5 oC.

From the degree hour table, we can get the degree hour is 133400 oC h. (red mark on the table)

Appendix A table 3: degree hour table.

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Calculation of UA-values

Appendix A table 4: Information of main constructions: information of main constructions U-value (W/m2*K)

main external wall(wood) 0,2

2 pane glazing windows 2,9

external door 2

roof 0,41

external floor 0,5

Appendix A table 5: U*A-value of building construction parts

name area (m2) U-value (W/m2*K) U*A (W/K)

first floor

main external wall 77 0,2 15,4

windows 6,75 2,9 19,5 door 1,6 2 3,2 external floor 51,7 0,5 25,85 roof 9,355 (0,41*115%)* 4,4 second floor

transmission loss area (m2) U-value (W/m2*K) U*A (W/K)

main external wall 32 0,20 6,4

roof wall and roof 66 (0,41*115%)* 31,1

door 0,58 2 1,16

windows 5,18 2,9 15,0

Total U*A (W/K) 122,1

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Calculate the thermal bridges

Use the COMSOL software to calculate the thermal bridges for each of them. Appendix A table 6: thermal bridges of building

thermal bridge

name joint value

(W/m*K) reference value (W/m*K) Ψ (W/m*K) length (m) Ψ *L(W/K) external floor with external wall 1,6315 1,562 0,0695 21,7 1,5 concrete wall with concrete wall 1,798 1,536 0,262 7,2 1,8 concrete wall with wood wall

1,2821 1,2783 0,0038 21,7 0,08 windows with wood wall 3,5405 3,4972 0,0433 44,2 1,9 door with wood wall 2,3535 2,301 0,0525 4,8 0,252 corner wood external wall 1,1362 1,044 0,0922 17,4 1,6 wood external wall with external floor 1,118 0,956 0,162 19,7 3,2 external wood wall with roof

0,7946 0,6616 0,133 46,9 6,2

roof with roof 0,9696 0,9219 0,0477 16,7 0,8

Total thermal bridges (W/K)

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58 Appendix A table 7, total transmission loss

total transmission loss

units

total UA-value 122,1 W/K

total thermal-bridge 17,5 W/K

total Aom 257,3 m2

Degree hour 133400 °Ch

total transmission loss 18623,9 kWh/year

So the total transmission loss of this building is

(total UA-value + total thermal-bridge)*degree hour=18623,94kWh/year Heat transfer coefficient of the whole building

om j k k i i m A x l A U U 



 



 



[2] = (122.1369+17.47284)/257.295 = 0.5426W/m2K Ventilation loss

This house does not have ventilation system. So the ventilation loss is zero. QV=0

Infiltration loss

This is the heat loss associated with air flow through a building by natural means, that is, through small openings and cracks in the structure.

The rate of natural ventilation (infiltration and exfiltration) depends on several factors such as; wind strength and direction.

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59 The formula for ventilation heat loss is:

𝑄 = 𝑁 ∗ 𝑉 ∗ 𝑆𝑝 ∗ ℎ𝑡 ∗ 𝑑𝑡 [Equation 6]

Where;

Q = heat loss (Watts) (W)

N = Number of air changes per hour. An air change is one room volume. V = Room volume (m3)

Sp.ht.= Specific heat factor for air.

dt = temperature difference between inside and outside (oC) Appendix A table 8, input data of infiltration loss

Input data

Number of air changes per hour for wood house 1/h

0.45

Room volume m3 390

Sp.ht.= Specific heat factor for air 1.01kj/(kg*K)*1,2kg/m3 Temperature difference oC (22-5)=17

One year in hours h 8760

The villa with no ventilation system and with wood construction, the author assume the air change per hour N=0.45 (For building with N lower than 0.35, must has ventilation system).

Qi=8798.85kWh

House hold electricity

House hold electricity= Whel = 30 kWh/m2 Atemp/ year.

And 70% of household electricity is a heat gain that as benefit for the building energy balance. 30% is lost.

Atemp=101,361m2

Whel1=30kWh/Atemp*year*Atemp=3040,83kWh/year

70% Whel=2128,581kWh/year

Appendix A table 9, result of household electricity, Whel

Household electricity kWh/year

Whel 3040.8

70% 2128.5

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Hot tap water

The amount of energy for hot tap water can be estimated as: Qtvv = 25  Atemp kWh/year.

Atemp=101,361m2

Qtvv=25*Atemp=25*101,361m2=2534,025kWh/year

20% Qtvv2=506,805kWh/year is regarded as heat gain can heat the house.

Appendix A table 10: total hot tap water Wtvv:

Hot tap water kWh/year

Wtvv 2534,025

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Solar energy through windows

Appendix A table 11, solar energy radiation from different direction and cloudy days calculation factor at different month.

N-150o Wh/m2*day g-value of windows calculation factor

total days windows area m2 solar energy through windows Wh Jan 130 0,8 0,45 31 1,44 2089,1 Feb 370 0,8 0,49 28 1,44 5848,0 Mar 900 0,8 0,58 31 1,44 18641,6 Apr 1990 0,8 0,58 30 1,44 39889,1 Maj 3050 0,8 0,63 15 1,44 33203,5 Sep 1230 0,8 0,58 15 1,44 12327,5 Oct 530 0,8 0,51 31 1,44 9652,9 Nov 200 0,8 0,42 30 1,44 2903,0 Dec 80 0,8 0,43 31 1,44 1228,4 total N-150o 125783,5 E-60o Wh/m2*day g-value of windows calculation factor

total days windows area m2 solar energy through windows Wh Jan 1440 0,8 0,45 31 2,88 46282,7 Feb 2900 0,8 0,49 28 2,88 91671,5 Mar 4520 0,8 0,58 31 2,88 187245,1 Apr 5850 0,8 0,58 30 2,88 234524,1 Maj 6150 0,8 0,63 15 2,88 133902,7 Sep 4820 0,8 0,58 15 2,88 96615,9 Oct 3570 0,8 0,51 31 2,88 130041,6 Nov 1910 0,8 0,42 30 2,88 55448,0 Dec 1060 0,8 0,43 31 2,88 32555,0 total E-60o 1008287,0 S-30o Wh/m2*day g-value of windows calculation factor

total days windows area m2 solar energy through windows Wh Jan 2360 0,8 0,45 31 1,5 39506,4 Feb 4280 0,8 0,49 28 1,5 70465,9 Mar 5740 0,8 0,58 31 1,5 123846,2 Apr 6370 0,8 0,58 30 1,5 133005,6 Maj 5980 0,8 0,63 15 1,5 67813,2 Sep 5760 0,8 0,58 15 1,5 60134,4 Oct 4960 0,8 0,51 31 1,5 94101,1 Nov 3040 0,8 0,42 30 1,5 45964,8 Dec 1770 0,8 0,43 31 1,5 28312,9 total S-30o 663150,6 W-120o Wh/m2*day g-value of windows calculation factor

Investigation of alternative energy and renovation opportunities for villa