Solution Space

Contents 1.0 Solution space ......................................................................................................................................... 2 1.2 Thermal bridges .................................................................................................................................. 2 1.2.1 Original building ........................................................................................................................... 4 1.2.2 Original building ‐ Results .......................................................................................................... 15 1.2.3 Improved building ...................................................................................................................... 15 1.2.4 Improved building ‐ Results ....................................................................................................... 21 1.2.5 Improved thermal bridging ........................................................................................................ 22 1.2.6 Improved thermal bridging ‐ Results ......................................................................................... 24 1.2.7 Improved wall construction using self supporting insulation batts ........................................... 25 1.2.8 Improved wall construction using self supporting insulation batts ‐ Results ............................ 26 1.2.9 Thermal bridges ‐ Overall findings ............................................................................................. 26 1.3 Energy usage regarding heating ........................................................................................................ 27 1.3.1 Worst case scenario ................................................................................................................... 27 1.3.2 Worst case scenario ‐ inputs ...................................................................................................... 27 1.3.3 Worst case scenario 10 persons – peak day .............................................................................. 28 1.3.4 Worst case scenario 10 persons ‐ peak week ............................................................................ 32 1.3.5 Worst case scenario 2 persons ‐ peak day ................................................................................. 34 1.3.6 Worst case scenario 2 persons ‐ peak week .............................................................................. 36 1.3.7 Energy usage regarding heating ‐ Overall findings .................................................................... 38 1.3.8 Energy usage regarding heating ‐ Guidelines ............................................................................ 39

PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.0 Solution space The solution space is generated by listing up a number of important subjects inferred from selected requirements, reflections, supplementary discussions, various computer simulations etc. The purpose of the solution space is to list up relevant parameters, guidelines that can be used within the design process. The solutions space features an investigation of; “thermal bridge”, “insulation usage”, “indoor temperature”. The items investigated represent selected items, more could have been included.

1.2 Thermal bridges By using the calculation tool Heat2, possible thermal bridges (resulting in heat loss) of a traditional Greenlandic building assembly have been investigated. The investigation makes it possible to determine whether improvements can be made and ultimately of what type.

The thermal bridge investigation is conducted on the basis of assembly drawings produced in 1972.

Therefore, some information regarding materials properties have not been available. In these cases assumptions has been made using properties matching typically materials that are used today.

The investigation is done as a “steady‐state” calculation with a focus on finding the heat flow though the different constructions types.

The Heat 2 models used in the investigation are constructed on the basis of cross sections of 1 meter surface area in both X and Y direction (see figure below). This is assumed to be sufficient when investigating heat flows though the sections.

Figure 1: Example of dimensions used in Heat2 (wall‐floor joint)

The investigations are conducted based on design temperatures from Sisimiut. Below various parameters used in the investigation are pointed out: • •

External design temperature: ‐30 °C Internal design temperature: 20 °C 2

PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

• • •

Internal surface residence: 0,13 m2*K/W External surface residence: 0,04 m2*K/W The calculation implements an auto generated mesh

The Heat2 material library is used to define properties of the different materials. However, the material names have been translated from German to English.

In the drawings the insulation type is described as “Handy‐Batts”, with no reference to the thermal conductivity or other properties. It is therefore assumed to be equivalent to the existing Rock Wool product “Handy 37”. [http://guiden.rockwool.dk/produkter/bygningsisolering/handy‐37] “Handy 37” has a thermal conductivity of 0,037 W/(m*k). An equivalent insulation material from the Heat 2 material library is used.

The Heat2 models are created to be as identical as possible to the original drawings. However, some simplifications have been made. These simplifications have little or no influence on the precision of the simulations.

In the Heat2 model the left side is always outdoors and the right the indoor.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.2.1 Original building Walls Table 1: Technical information ‐ Walls Element Material λ [W/(m*k)] Thickness [mm]

Exterior surface

Insulation

Insulation

Interior surface

Plywood 0,17 16

Mineral Wool 0,037 50

Mineral Wool 0,037 75

Plywood 0,17 9,8

Figure 2: Original drawing of wall

Figure 3: Heat2 model of wall

Figure 4: Heat flow though the wall

Figure 5: Directions of heat flow though the wall

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 6: Temperatures though the wall

The simulations shows an even heat flow though the section and a decrease in temperature going from the inside and out. Total heat flow through the section: 12,77 W/m.

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Wall/Floors Table 2: Technical information ‐ Wall/Floors Element

Floor

Construction beams

Cavity

Insulation

Insulation

Ceiling surface

Material

Beech wood

Construction wood

Air

Mineral Wool

Mineral Wool

Plywood

0,13

0,18

0,037

0,037

0,17

22

50x150

50

75

9,8

λ [W/(m*k)] Thickness [mm]

50

Figure 7: Original drawing of wall/floor

Figure 8: Heat2 model of wall/floor

Figure 9: Heat Flow though the wall/floor

Figure 10: Directions of heat flow though the wall/floor

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Figure 11: Temperature spread though the wall/wall

The simulations shows a relatively even heat flow though the section and a decrease in temperature going from the inside and out. There is an increase in heat flow at the two pieces of wood just above and below where the floor hits the wall (see Figure 10). This indicates that these areas have an increased thermal conductivity. Total heat flow through section: 12,82 W/m.

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Ground floor 1 Table 3: Technical information ‐ Ground floor 1 Element

Floor

Construction beams

Insulation

Insulation

Sub floor surface

Cavity

Wood lists

Exterior surface

Sub floor beams

Material

Beech wood 0,13

Construction wood 0,18

Mineral Wool 0,037

Mineral Wool 0,037

Eternit

Air

Plywood

0,17

1

Construction wood 0,13

0,17

Construction wood 0,18

22

50x150

50

75

9,8

50

45x50

16

45x50

λ [W/(m*k)] Thickness [mm]

Figure 12: Original drawing of ground floor 1

Figure 13: Heat 2 model of ground floor 1

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 14: Heat Flow through ground floor 1

Figure 15: Direction of heat flow through ground floor 1

Figure 16: Temperature spread through ground floor 1

The simulations show that the constructions beams in the floor are clear thermal bridges. Total heat flow through section: 19,58 W/m.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Ground Floor 2 Table 4: Technical information ‐ Ground floor 2 Element

Floor

Construction beams

Insulation

Insulation

Sub floor surface

Cavity

Wood lists

Exterior surface

Sub floor beams

Material

Beech wood 0,13

Construction wood 0,18

Mineral Wool 0,037

Mineral Wool 0,037

Eternit

Air

Plywood

0,17

1

Construction wood 0,13

0,17

Construction wood 0,18

22

50x150

50

75

9,8

50

45x50

16

45x50

λ [W/(m*k)] Thickness [mm]

Figure 17: Original drawing of ground floor 2

Figure 18: Heat2 model of ground floor 2

Figure 19: Heat flow through ground floor 2

Figure 20: Direction of the heat flow through ground floor 2

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Figure 21: Temperature spread through ground floor 2

The wooden beams in the bottom of the floor construction show thermal weakness. The floor performs slightly better than “ground floor 1” because there is no direct thermal bridge from the outside and in.

Total heat flow through section: 17,42 W/m.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Roof Table 5: Technical information ‐ Roof Element

Roof sheet

Construction beams

Cavity

Insulation

Insulation

Ceiling surface

Material

Plywood

Construction wood

Air

Mineral Wool

Mineral Wool

Plywood

0,17

0,18

1

0,037

0,037

0,17

22

50x150

50

75

9,8

λ [W/(m*k)] Thickness [mm]

Variable

Figure 22: Original drawing of roof

Figure 23: Heat2 model of roof

Figure 24: Heat flow through the roof

Figure 25: Direction of the heat flow through the roof

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 26: Temperature spread through the roof

The simulation shows that the corner construction allows more heat to pass through than the rest of the construction. Total heat flow through section: 14,11 W/m.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Corner Table 6: Technical information ‐ Corner Element

Exterior surface

Construction beams

Insulation

Insulation

Insulation

Interior surface

Material

Plywood

Construction wood

Mineral Wool

Mineral Wool

Mineral Wool

Plywood

0,17

0,18

0,037

0,037

0,037

0,17

22

50x150

50

75

13

9,8

λ [W/(m*k)] Thickness [mm]

Figure 27: Original drawing of corner ‐ horizontal section

Figure 28: Heat2 model of corner ‐ horizontal section

Figure 29: Heat flow through corner

Figure 30: Direction of the heat flow through corner

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 31: Temperature spread through corner

The construction beams show massive thermal bridges that significantly decrease the thermal performance of the corner. Total Heat Flow through section: 31,6 W/m.

1.2.2 Original building ‐ Results The original drawings and matching Heat2 simulations show that there are significant thermal bridges in many of the investigated sections. In many cases there has been made no attempt to break the thermal bridges. The amount of insulations used, typically 125 mm, seems to be too little.

A way of improving the existing buildings principles could be to increase the insulation thickness, which thereby would break the thermal bridges.

1.2.3 Improved building The first improvement implements an insulation thickness of 250 mm (an increase of 100 mm when comparing to the originally 150 mm). No attempts have been made in order to improve the thermal bridges. The investigation uses same materials as in the original constructions.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved wall [W­250I]

Total heat flow through section: 6,99 W/m

Heat flow 5,79 W/m less than original construction

Improvement: 45 %

Figure 32: Heat2 model of improved Wall

Figure 33: Heat flow through improved wall

Figure 34: Direction of Heat flow through improved wall

Figure 35: Temperature spread through improved wall

Improved wall/floor [WF­250I]

Total heat flow through section: 7,00 W/m

Heat flow 5,82 W/m less than original construction

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improvement: 45 %

Figure 36: Heat2 model of improved wall/floor

Figure 37: Heat flow through improved wall/floor

Figure 38: Direction of heat flow through improved wall/floor

Figure 39:Temperature spread through wall/floor

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved ground floor 1 [GF1­250I]

Total heat flow through section: 12,95 W/m

Heat flow 6,63 W/m less than original construction

Improvement: 34 % Figure 40: Heat2 model of improved Ground Floor 1

Figure 41: Heat flow through improved Ground Floor 1

Figure 42: Direction of heat flow through improved Ground Floor 1

Figure 43: Temperature spread through improved Ground Floor 1

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved ground floor 2 [GF2­250I]

Total heat flow through section: 9,61 W/m

Heat flow 7,81 W/m less than original construction

Improvement: 45 % Figure 44: Heat2 model of improved ground floor 2

Figure 45 Heat flow through improved ground floor 2

Figure 46: Direction of heat flow through improved ground floor 2

Figure 47: Temperature spread through ground floor 2

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved roof [­250I]

Total heat flow through section: 8,38 W/m

Heat flow 5,74 W/m less than original construction

Improvement: 41 % Figure 48: Heat2 model of improved Roof

Figure 49: Heat flow through improved Roof

Figure 50: Direction of Heat flow through improved Roof

Figure 51: Temperature spread through improved Roof

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved corner [ C­250I]

Total heat flow through section: 17,96 W/m

Heat flow 13,61 W/m less than original construction

Improvement: 43 %

Figure 52: Heat2 model of improved corner

Figure 53: Heat flow through improved corner

Figure 54: Direction of heat flow through improved corner

Figure 55: Temperature spread through improved corner

1.2.4 Improved building ‐ Results The increase of the insulation thickness results in improvements regarding thermal performance in a range of 34% to 45%. Therefore, a significant amount of energy and heat can be saved by increasing the insulation thickness. The simulations show that the thermal bridges still are significant.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.2.5 Improved thermal bridging The objective of this improvement is to break or minimise the thermal bridges in the constructions. This is done by adding extra construction layers and offsetting the carrying components. 250 mm of insulation is used.

The investigation has only been performed on the “corner” and on one of the ground floors. This is done because these sections are the only ones that can be improved using these methods.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved thermal bridging ­ Corner [C­250I­TB]

Total heat flow through section: 14,99 W/m

Heat flow 16,62 W/m less than original construction

Improvement: 53 %

Figure 56: Heat2 model improve thermal bridge ‐ corner

Figure 57: Heat flow through improved thermal bridge ‐ corner

Figure 58: Direction of heat flow through improved thermal bridge ‐ corner

Figure 59: Temperature spread through improved thermal bridge ‐ corner

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Improved thermal bridging ­ Ground floor [GF­250I­TB]

Total heat flow through section: 10,25 W/m

Heat flow 9,34 W/m less than original construction

Improvement: 48 %

Figure 60: Heat2 model of improved thermal bridge ‐ ground floor

Figure 61: Heat flow through improved thermal bridge ‐ ground floor

Figure 62: Direction of heat flow through improved thermal bridge ‐ ground floor

Figure 63: Temperature spread through improved thermal bridge ‐ ground floor

1.2.6 Improved thermal bridging ‐ Results By breaking or reducing the thermal bridges the heat flow through the corner and floor is reduced with 53% and 48% (when comparing with the original construction). Compared with the simulations where only the insulation thickness was increased, the corner is 10% better and the ground Floor 14%.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.2.7 Improved wall construction using self supporting insulation batts In order to reduce the thermal bridges even more, a simulation with an extra insulation layer is placed on the outside of the building is preformed. This type of construction is possible if self supporting insulation batts are used (Rock Wool). The total insulation thickness is still 250 mm.

Improved corner – Self supporting insulation batts [C­250I­SSI]

Total heat flow through section: 15,27 W/m

Heat flow 16,34 W/m less than original construction

Improvement: 52 % Figure 64: Heat2 model of corner improved with self supporting insulation batts

Figure 65: Heat flow through corner improved with self supporting insulation batts

Figure 66: Direction of heat flow through corner improved with self supporting insulation batts

Figure 67: Temperature spread through corner improved with self supporting insulation batts

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.2.8 Improved wall construction using self supporting insulation batts ‐ Results Using external self supporting insulation batts proves to be another way of significantly improving the thermal performance of the building constructions. The investigated corner is 52% better than the original and 9% better than the one with increased insulation. However, it is 1% poorer than improvement “C‐250I‐TB” where the thermal bridges have been reduced. The difference could be caused by the fact that “C‐25I‐TB” implements an extra layer of plywood. Still, self supporting insulation, which could be added on the exterior of a building, could be useful when renovating buildings, as they do not take up any indoor area.

1.2.9 Thermal bridges ‐ Overall findings The investigation shows that great amounts of heat and energy can be saved by improving the constructions. An increase of the insulation thickness appears beneficial, whereas the 125 mm of mineral wool clearly is insufficient in arctic areas. Furthermore, more effort should be made in order to reduce or break thermal bridges. When constructing new buildings (or renovating old buidlings), these subjects should be taken in to account.

In this investigation improvements are only made by using extra insulation and rearranging the construction in order to break the thermal bridges. Using other types of insulation materials such as polystyrene or vacuum insulation is not investigated. However, these materials could improve the overall thermal performance even more.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.3 Energy usage regarding heating The investigations regarding energy usage are based on the information gathered within the design manual. The objective is an idealized energy scenario simulation conducted in the program iDbuild using the parameter variation methods. The program is meant to give a quick overview of the different thermal envelope designs influencing the energy consumption and energy performance. Normally this gives an output in kWh/m² pr year. As this project deals with tourist huts, which for long periods are unused, this solution space simulation is a worst case scenario, consisting of a “worst day” and a “worst week” scenario. The scenario is conducted in mid winter when the given hut has been unused for the longest period of time and outside temperature is at its lowest.

That is, the parameter variations design goals are to investigate the energy usage in a worst case scenario, in order to make a comparison of the amount of energy used for providing acceptable indoor temperatures and the amount of insulation. This gives an idea of the energy supply system demands.

1.3.1 Worst case scenario The worst case scenario is oriented towards south (it could have been oriented toward any other direction). By selecting mid winter time the passive solar gain is at a minimum and has a little influence on the energy needed to heat up the building to acceptable temperature. Based on the design manual and the building use the decision is made; all solutions require shutters or other wall parts that outside time of use are put in front of the windows. This is done in order minimize the heat loss through the window area.

Furthermore, the window size can be adjusted on behave of the user. This means that there is no optimal solution of window size compared to floor area. This gives the client and user a flexible building, which can be adjusted to different times of the year. E.g. periods of use with clear sky, it is possible to adjust the solar gain easily, achieving higher inside temperatures improving the thermal comfort. The principle functions like applying the building an extra “overcoat” in winter time. The “overcoat” is removed in summertime.

As pointed out, the worst case scenario investigation gives an idea of the relationship between the thermal envelope properties (expressed as an U‐value [W/mK]) and the energy demanded acceptable room temperatures (expressed as kWh and liters of petro‐diesel, ethanol and biodiesel).

1.3.2 Worst case scenario ‐ inputs The parameter variation is based on a module of 5 x 5 x 3 metres with respectively 10 persons inside and 2 persons. The construction and design parameters of the building are pointed out in the tables below: Table 7: Building dimensions

Building dimentions

Hight Length Deepth Window (Hight, Lenght)

3 m 5 m 5 m 1 m x 2 m

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Table 8: Constructions and internal loads

Constructions Type U‐Value walls, roof, floor/foundtion Window Internal people load

Variation 1, 2, 3, 5 and 6 Light weight constructions 0.1, 0.2, 0.5, 1.0, 2.0 and 3.0 [W/m²K] 1.1 W/m²K 10 persons [900 Watt], 2 persons [180 Watt]

Table 9: Indoor environment

Indoor enviorment Temperatur setpoints Ventilation rates (Class III prEN15251)

Heating: 18°C, Cooling setpoint: 30°C 4 l/s pr person 0,3 l/s pr m² for building emissions pollutions

1.3.3 Worst case scenario 10 persons – peak day The following figures show the energy use during one day with 10 people using the building from 17:00 to 08:00. The figure illustrates the energy used to maintain 18°C in the room (energy demand expressed in Watt).

30

Temperature

20 10

Outdoor

0

0.1

‐10

0.2

‐20

0.5 1.0

‐30

2.0 ‐40

3.0

Hours

Figure 68: Peak day temperature plot of different u‐values

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

16000,0 14000,0

Watt

12000,0 10000,0

0.1

8000,0

0.2

6000,0

0.5

4000,0

1.0

2000,0

2.0

0,0

3.0

Hours

Figure 69: Peak heating power in peak day

As seen in the figure above the energy demand regarding acceptable indoor temperatures is high. Even with a well insulated building there is a “peak‐need” during the first hour of approx 8000 Watts. All three U‐values below 1.0 [W/mK] reaches a point where no energy for heating is needed (the graphs reaches 0 Watts around 23:00 to 01:00). That is, at this time of hour no further heating is needed. The building has reached a point where both room and constructions have a temperature of 18°C, and the heat generated by the internal load (people and equipment) is able to sustain the heat loss. The illustration outlines that constructions with u‐values above 1.0 [W/mK] requires heating throughout all time of use. This means that the requested temperature is not reached; the temperature of the room and construction is too low.

Below the output from iDbuild is illustrated:

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 70: Peak heating power U‐value of 0.1

Figure 71: Peak heating power U‐value of 0.2

Figure 72: Peak heating power U‐value of 0.5

Figure 73: Peak heating power U‐value of 1.0

Figure 74: Peak heating power U‐value of 2.0

Figure 75: Peak heating power U‐value of 3.0

The figure below shows the specific relation between total energy demand during occupancy and various U‐values. That is, as mentioned above, the energy needed in order to achieve a temperature of 18°C. Obvious, the well insulated building variation performs best (U‐value of 0.1 [W/mK]). However, U‐ values of 0.2 [W/mK] and 0.5 [W/mK] are relatively close.

60 50 0.1

kWh pr day

40

0.2 30

0.5 1.0

20

2.0 3.0

10 0 U‐value

Figure 76: Peak heating demand compared to different U‐values

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The figure below points out the relation between the amount of insulation and the amount of liquid energy needed. This is of course theoretical values, as an oven or a generator has a given efficiency. This is not taken in to account. The figure illustrates the lowest possible energy supply demand with an efficiency of 100%.

The figure shows that for well insulated buildings it will be possible for the users to transport the energy along (this account for all energy types). The demand of around 2 litres of petro or bio diesel is, in order to reach the temperature of 18°C, not that high considering that the outside temperature is around minus 30°C. 9 8

Litres pr day

7 6 5 Biodiesel

4

Ethanol

3

Petro‐diesel

2 1 0 0,1

0,2

0,5

1,0

2,0

3,0

U‐value

Figure 77: Litres of petro‐diesel, biodiesel and ethanol needed compared to U‐value

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.3.4 Worst case scenario 10 persons ‐ peak week The figures below illustrate the temperature and peak energy demand during one week of usage. The heating demand during one week, in order to achieve temperatures of 18°C, is achieved relative quick (as seen in the one day scenario). Below the figures show that well insulated buildings reaches the point where no further need of heating power is required. The best insulated scenarios achieve this situation during the first day of use. Here the internal load during use appears to be enough; the temperature comply with the requirements put up (the building withstand the heat loss).

40 30 Temperature

20 Outdoor

10

0.1

0

0.2

‐10

0.5

‐20

1

‐30

2

‐40

3

Hours

Figure 78: Plot of temperature during one week

14000,0 12000,0

Watt

10000,0 0.1

8000,0

0.2 6000,0

0.5

4000,0

1.0

2000,0

2.0

0,0

3.0

Hours

Figure 79: Peak heating power peak week

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

Figure 80: 5 Peak heating power U‐value of 0.1

Figure 83: Peak heating power U‐value of 1.0

Figure 81: Peak heating power U‐value of 0.2

Figure 82: Peak heating power U‐value of 0.5

Figure 84: Peak heating power U‐value of 2.0

Figure 85: Peak heating power U‐value of 3.0

The figure below shows that the 4 lowest U‐values perform almost alike. Furthermore, comparing the results for one day and one week, again regarding the 4 lowest U‐values, shows almost the same demands. The energy demand is around 20 kWh during the worst week.

200 180

kWh pr week

160 140

0.1

120

0.2

100

0.5

80

1.0

60

2.0

40

3.0

20 0 U‐value

Figure 86: Peak heating demand compared to different U‐values

The following figure shows the same pattern as described above. The best insulation types have almost the same energy demand. This means that the heating power supplied the first day is enough to reach a 33

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temperature of 18°C. In other words, one can bring along the same amount of fuel whether it is for one day or one week.

30

Litres pr week

25 20 15

Biodiesel Ethanol

10

Petroilum 5 0 0,1

0,2

0,5

1,0

2,0

3,0

U‐value

Figure 87: Liters of Petro‐diesel, biodiesel and ethanol needed compared to U‐value

1.3.5 Worst case scenario 2 persons ‐ peak day The following section describes the same scenarios as above, this time with only 2 persons using the building. Looking at the figure below, it is shown that the peak heating demand during the worst day with 2 persons is higher compared to the scenario with 10 persons. Furthermore, the figure illustrates that it takes more time to heat up the building. This is due to a lower internal gain of only 2 persons.

30

Temperature

20 Outdoor

10

0.1

0

0.2

‐10

0.5

‐20

1.0 2.0

‐30

3.0

Hours

Figure 88: Peak day temperature plot of u‐values

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

16000,0 14000,0

Watt

12000,0 10000,0

0.1

8000,0

0.2

6000,0

0.5

4000,0

1.0

2000,0

2.0

0,0

3.0

Hours

Figure 89: Peak heating power peak day

Below The figures show the total peak heating demand and temperature, from the figure above can be seen that the two lowest u‐values lie close, less than 30 kWh pr peak day.

The figure above shows the amount of fuel needed in order to reach and keep a temperature of 18°C, when occupied by two persons.

70

kWh pr day

60 50

0.1

40

0.2 0.5

30

1.0 2.0

20

3.0

10 0 U‐value

Figure 90: Peak heating demand compared to different U‐values

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

12

Litres pr day

10 8 6

Biodiesel Ethanol

4

Petro‐diesel 2 0 0,1

0,2

0,5

1,0

2,0

3,0

U‐value

Figure 91: Liters of Petro‐diesel, biodiesel and ethanol needed compared to U‐value

1.3.6 Worst case scenario 2 persons ‐ peak week By looking at the two figures below, it can be seen that low U‐values makes it possible to heat up the building quickly, and when returning to the building in the afternoon the heating demand is low (when looking at the constructions with the three lowest U‐values). This means, the temperature of the constructions have not been cooled that much, why demands regarding reheating of the constructions is minimised.

30

Temperature

20 Outdoor

10

0.1

0

0.2

‐10

0.5

‐20

1.0 2.0

‐30

3.0

Hours

Figure 92: Temperature plot of peak week

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

14000,0 12000,0

0.1

8000,0

0.2 6000,0

0.5

4000,0

1.0

2000,0

2.0

0,0

3.0 00:00 07:00 14:00 21:00 04:00 11:00 18:00 01:00 08:00 15:00 22:00 05:00 12:00 19:00 02:00 09:00 16:00 23:00 06:00 13:00 20:00 03:00 10:00 17:00 00:00

Watt

10000,0

Hours

Figure 93: Peak heating power peak week

The figure below shows the total energy use when using the hut for a week (only heating when the hut is occupied).

300

kWh pr week

250 0.1

200

0.2 150

0.5 1.0

100

2.0 3.0

50 0 U‐value

Figure 94: Peak heating demand compared to different U‐values

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

45 40

Litres pr week

35 30 25 Biodiesel

20

Ethanol

15

Petro‐diesel

10 5 0 0,1

0,2

0,5

1,0

2,0

3,0

U‐value

Figure 95: Liters of Petro‐diesel, biodiesel and ethanol needed compared to U‐value

The figure above shows the amount of fuel needed during one week of occupancy. It can be seen that a building with a U‐value above 0.5 [W/mK] appears problematic regarding heat supply (the amount of fuel needed reaches 10 liters, when looking at diesel).

When taking the efficiency in to consideration this is properly about 3 times higher in reality. That is, in order to keep a temperature of 18°C, using a construction type with an u‐value of around 1.0 [W/mK], about 30 liters of fuel has to be transported to the site.

1.3.7 Energy usage regarding heating ‐ Overall findings Based on the parameter variation scenarios there are certain tendencies that stand out: The more superior the insulation u‐value is, the faster an acceptable temperature is reached. Furthermore, the heating power demand decreases as the constructions becomes warm. In scenarios treating the best insulated buildings with 10 persons, the people load alone is enough to keep temperatures at an acceptable level (there are temperatures that reaches levels of overheating). The U‐values above 1.0 [W/mK] are not acceptable, as they induce a high heating demand. This means, the amount of fuel or energy needed, in order to reach the temperature required, becomes difficult. In scenarios with 2 persons, the effect of the U‐values becomes even more visible. The higher U‐values, the higher energy demand.

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PROBLEM SPACE DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.3.8 Energy usage regarding heating ‐ Guidelines On the basis of the energy usage investigations selected guidelines are pointed out: •

• • •

•

•

Flexible facade with movable inner parts, making it possible to change the window size (in regards of preference and thermal comfort as well). Additionally, a flexible facade makes it possible to close off the building outside time of use (giving the building an overcoat on).

The better the U‐value of the thermal envelope, the easier it is to control the indoor environment (as regards to reaching the comfort temperature and keeping it).

Superior U‐values makes it possible to warm up the construction faster (compared with less superior U‐values).

High‐quality insulation makes it possible to reduce the energy demand, because the people load is itself sustains acceptable temperatures during occupancy (after heating the building, reaching a preferred room temperature).

High‐quality insulation makes it possible to use alternative heating sources. With alternative heating source it could be possible to keep a more constant temperature all year. Furthermore, it allows a reduction of fossil fuel needs during peak winter situations.

When increasing the building size the same principles of more superior insulation giving a smaller peak heating load applies. However, being able to close unused spaces and thereby heating smaller areas could be a solution as well (making the building more compact).

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