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Table of Contents

Figure 13: Cooling energy demand in Summer ...................................................................... 6 Figure 14: Heating energy demand in Winter 6 Figure 15: Daylight illumination level in different zones for different days ................... 6 Figure 16: Modified house design and details 8 Figure 17: Modified house plan ..................... 8 Figure 18: New house perspective view ........ 8 Figure 19: Shading chart for south facing window [21] ................................................... 9 Figure 20: New zone illumination layout ........ 9 Figure 21: Passive house summer cooling load ............................................................. 10 Figure 22: Passive house winter temperature .................................................................... 10 Figure 23: Passive house summer temperature ................................................. 10 Figure 24: Passive house winter heating load .................................................................... 10 Figure 25: Illumination plan for different zones in the modified house design ....................... 10 Figure 26: New improved site plan .............. 11 Figure 27: Perspective view of the new development ................................................ 11 Figure 28: Summer heat conduction through building fabric .............................................. 12 Figure 29: Winter heat conduction through building fabric .............................................. 12 Figure 30: Average house temperature in Summer ....................................................... 12 Figure 31: Average house temperature in Winter .......................................................... 12 Figure 32: Hourly energy use comparison ... 13 Figure 33: Perspective view of original house design .......................................................... 14 Figure 34: Original Dining room ................... 14 Figure 35: Original Living room (front) and Kitchen (back) ............................................. 14 Figure 36: Original entrance to the house .... 15 Figure 38: Passive house solarium (sunspace) .................................................................... 15 Figure 37: Perspective view of improved passive house design .................................. 15 Figure 39: Passive house kitchen and dining .................................................................... 15 Figure 40: Passive house bedroom ............. 15 Table 1: Diurnal range for different times….12 Table 2: Original living room lighting level…16 Table 3: Original bedroom lighting level….16 Table 4: Original kitchen lighting level……16 Table 5: Passive living room lighting level.17 Table 6: Passive bedroom lighting level…17 Table 7: Passive dining lighting level…….18

List of Figures and Tables ........................... 1 Chapter 1: Review of relevant literature and introduction to the project and discussion of the given building and selected site. ........... 2 Section A: Project Brief............................ 2 Section B: Building and Site .................... 2 Section C: Literature Review ................... 3 Chapter 2: Development and Presentation of the Solar Village Initial Site plan using the Given House Design ................................... 3 Chapter 3: Investigating Energy Performance of the Original House Design . 5 Section A: Setup ...................................... 5 Section B: Results and Discussion .......... 5 Section C: Shortcomings of the Design ... 7 Chapter 4: Investigating Energy Performance of the Passive Solar House Design ......................................................... 7 Section A: Passive Strategies Implemented............................................ 7 Section B: Design and Setup ................... 8 Section C: Results and Discussion .......... 9 Chapter 5: Comparison of the Energy/Environmental Performance of Original and Passive Solar House Design and Presentation of the Final Site plan ..... 11 Section A: Updated Site-plan ................ 11 Section B: Energy/Environmental Performance Comparison...................... 11 Chapter 6: Conclusion Drawn from the Project and Design Recommendations ..... 12 References................................................ 13 Appendices ............................................... 14 List of Figures and Tables Figure 1:Given house plan, total dimension 14m x 10.5m (including front porch and steps) ...................................................................... 2 Figure 2: Site aerial view................................ 2 Figure 3: Monthly average temperature and radiation ......................................................... 2 Figure 4: Wind rose [8] .................................. 2 Figure 5: Milan sunpath [9] ............................ 3 Figure 6: Site plan (trees not shown here), NTS ............................................................... 4 Figure 7: Perspective view from eye level ...... 4 Figure 8: Building elevation and details ......... 4 Figure 9: EnergyPlus model and zones in the initial design ................................................... 5 Figure 10: Outdoor air temperature (DBT) ..... 5 Figure 11: Winter day zone temperatures ...... 6 Figure 12: Summer day zone temperature .... 6

[1]


Chapter 1: Review of relevant literature and introduction to the project and discussion of the given building and selected site.

Section B: Building and Site The site is in the shape of an irregular parallelogram, with a 10m wide road running along its shorter northern edge. Located in

Section A: Project Brief It is widely known and understood that buildings constitute a significant proportion of energy demand. The European EED [1] notes that ‘buildings account for 40% of final energy use and 36% of CO2 emissions.’ It further states, ‘that 50% of final energy consumption is accounted for by heating and cooling, and 80% is used in buildings with much of it wasted.’ Most of the energy consumption in buildings is related to protection from the external climate, and the need to use mechanical systems to maintain a comfortable indoor environment [2].

Figure 2: Site aerial view

the historic city of Milan (45.5°N & 9.2°E), in northern Italy, it experiences humid subtropical climate (Cfa) according to the Koppen climate classification. At a height of 100m it has a typical continental climate, with cold and foggy winters, followed by warm and humid summers [7].

The recast EPBD [3] aims to achieve nearly zero energy design for both old and new buildings by 2020. Therefore, the passive design strategies are a significant key to achieve these goals [4]. In passive solar building design, the architectural elements of a building are designed to collect, store, and distribute solar energy as light and heat [5], offering great promise to reduce energy costs and associated emissions [6]. Recognizing these potentials, the current study aims to develop a senior citizens’ housing project in the city of Milan (Italy) on a site of approximately 1.23 acres. For simplifying the study and deriving conclusions from the parametric design, a single unit is simulated, which comprises of a single storey, one-bedroom house.

25

400

20

300

15

200

10

100

5

0

0

Dry bulb temperature °C

Radiation Wh/m²

Daily average monthly climate data 500

Daily average Horizontal Radiation Daily average Temperature

Figure 3: Monthly average temperature and radiation

Figure 4: Wind rose [8] Figure 1:Given house plan, total dimension 14m x 10.5m (including front porch and steps)

The average temperature in summer is 23°C, with maximum reaching above 30°C. The winters are quite cold with average [2]


temperature of 2°C and recorded minimum of -10°C. As is evident from figure 4 that winds are predominantly from north and annual average wind speeds between 2 to 3 m/s.

length(l) [11]. In this light many authors and designers have studied and implemented the use of solar conservatories (sunspaces) to collect and store heat. Energy savings from sunspaces are threefold: the ‘buffer’ or insulation effect, the supply of preheated ventilation air throughout the year and the supply of sun warmed air to the house when the sun is shining via open windows, doors are ventilators [10, 14]. Some designers have in fact retrofitted an entire balcony to act as a sunspace. Another important attribute of a passive house is the presence of thermally heavy material which ‘acts as a heat reservoir, with the capacity to absorb considerable heat gains without raising the temperature of the air space’ [15]. Thermally heavy space is better able to make use of solar and other passive heat gains than the thermally light space [16], by storing the heat during heating period and releasing it when temperature drops below that of the building fabric. Simulations done by various researchers suggest that not only must the thermal mass be located within the insulated building envelope, but it must also be exposed to sunlight and coupled with indoor space.

Figure 5: Milan sunpath [9]

The sunpath diagram is shown in Figure 5, and we observe that days in summer are long (~17 hrs) with sun altitude of 70° at noon time, while in winter the days are significantly short (~9 hrs) with low altitude sun (20°). The given design is a detached one-bedroom house, with a kitchen and a living room. There are steps in front leading to the porch, and the interior is connected to the porch through a transition space acting like a buffer zone. Occupants are directly led into the dining through this entrance. The sleeping quarters and bath are on the right, while kitchen and living on the right (see Figure 1).

Overheating is another concern which must be avoided in the design. Fixed external shading, blinds and ventilation openings to name a few. Gupta et.al [17] presented a new methodology for design of external static sunshades. Kumar et al. [18] introduced some of the passive cooling techniques like application of insulating material and proper surface treatments.

Section C: Literature Review Passive solar buildings are designed to collect energy from the sun to provide heating and lighting within the building, and to reject solar energy when it can lead to overheating [10]. Appropriate passive solar design should consider key building parameters such as building orientation, plan proportion and shape, facade glazing design and obstruction by surrounding buildings [11].

Chapter 2: Development and Presentation of the Solar Village Initial Site plan using the Given House Design The concept of the design is to ensure that each house has maximum access to the sun. This is done by orienting the porch due south with maximum solar gains through the large fenestrations. The houses are spaced out so that even on winter evenings their shadows are not casted on one another (see appendices). All houses face south, with slight deviations to adjust the shading coefficient on other houses. These houses form a ring, with the central open court acting

For best orientation, referring to the axis along which the house is elongated, should be equator facing with solar glazing installed on the façade [6, 12], Ralegaonkar et al. [13] have suggested that heat gain is also a function of the surface area of building envelope exposed to sunlight, which depends on aspect ratio. The aspect ratio (w/l) is the relation between the equatorialfacing facade width (w) and the lateral facade [3]


like a community space. It has a fountain and a pergola where the community can meet and hold discussions or events.

Figure 7: Perspective view from eye level

A periphery ring of trees acts like an acoustic insulator, protecting the interior site. There are also pockets of vegetations included in the site. These deciduous trees shed their leaves in winter allowing greater penetration of sunlight into the living zones.

Figure 6: Site plan (trees not shown here), NTS

The design of the house follows the traditional approach of the location. The main element is wood, which is used in this case to make the roof, floor, interior walls, doors and windows. Exterior walls are made of bricks and the whole building is raised on a 600mm concrete plinth as a protection from water. A 45° pitched timber gable roof, with eaves projection of 500mm protects the house from sun, wind and rain. A smaller roof is placed over the porch to prevent high solar gains during summer. (See details in Figure 8)

Since the development is communal in nature, hard tarmac roads have been replaced with paver-block paths which make the site very informal in character. Moreover, the albedo of brick blocks is 0.2~0.4 while that of tarmac is in range 0.05~0.2. This means that bricks will help in reducing the UHI by reflecting more radiation. Presence of shrubs and trees along the path provide shading as well as add biodiversity in the site.

Figure 8: Building elevation and details

[4]


Chapter 3: Investigating Energy Performance of the Original House Design

It is first, important to ascertain the energy demand of the base case (initial given design) so that key features can be identified, and improvements can be made. For this purpose, this section deals with evaluating the energy and lighting characteristics of the original house.

• •

Section A: Setup

An energy model has been prepared in ‘Sketchup Make 2017’ using the EnergyPlus 8.7 plugin (see figure 9). Weather file of Milan from EP website [19] has been used to simulate outdoor environmental condition. For simplicity the following assumptions have been made:

• • • • •

Only one representative day of summer and winter has been used to run the simulation (see Figure 10). Internal gains have not been considered, so that only the building’s performance, without the occupant’s activities, can be assessed. The architectural spaces ‘living room’ and ‘kitchen’ has been clubbed into a single zone – ‘ZONE_LIVING_ROOM’ The architectural spaces ‘toilet’ and ‘change/store’ has been clubbed into a single zone – ‘ZONE_TOILET’ Since the zones are situated on plinth, ground coupling is assumed zero. ZONE_PORCH is outdoors but covered zone and hence its temperature (dry-bulb) is same as outdoor environment. Lighting analysis is done only for primary occupied spaces, namely ZONE_LIVING_ROOM, ZONE_DINING and ZONE_BEDROOM (see Figure 9). The coordinate system for illumination map (at height of 800mm) is as follows: o East-west direction – X axis o North-south direction – Y axis For comparison purposes, the average illuminance level (in lux) of the following times have been analysed 9AM, 12PM and 3PM.

Figure 9: EnergyPlus model and zones in the initial design

Site outdoor air dry bulb temperature

Temperature °C

ventilated, for the first simulation. For the second simulation HVAC is introduced. In case of natural ventilation, all the zones except ‘ZONE_TOILET’ is set at 4 air changes/hr, throughout the day. No heating/cooling is provided for ‘ZONE_THRESHOLD’ and ‘ZONE_PORCH’. For primary occupancy zone, the heating setpoint is set at 18°C and cooling setpoint is set at 25°C, following the adaptive thermal comfort model [20]. For secondary occupancy zone (ZONE_TOILET) the setpoints are set at 15°C and 27°C respectively. ZONE_LIVING_ROOM and ZONE_DINING is occupied only during the day. While ZONE_BEDROOM only during night time. ZONE_TOILET is scheduled to be used for the whole simulation period. (The scheduled occupancy checks that the energy demand is not unrealistic).

35 30 25 20 15 10 5 0 -5 1

3

5

7

9 11 13 15 17 19 21 23 Time of the day

Summer 21st July

Winter 17th December

Figure 10: Outdoor air temperature (DBT)

Section B: Results and Discussion After running the simulation with 4 transient timestep per hour, the resultant temperature profile of the free-running naturally ventilated building is plotted in Excel (shown in figure 11 and 12 here). Energy demand for the four zones is shown in Figure 11,Figure 12 and sunlight illuminance is shown in figure 15.

HVAC assumptions: • The building is assumed to be free running- with no HVAC, and is naturally [5]


Summer temperature profile

Winter temperature profile

14

36

12

34

10

Temperature 째C

Temperature 째C

38

32 30 28 26 24 22

8 6 4 2 0 -2

20 1

3

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7

-4

9 11 13 15 17 19 21 23

1

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7

9 11 13 15 17 19 21 23

Hour of the day

Hour of the day Figure 12: Summer day zone temperature 7

9 11 13 15 17 19 21 23 40 38 36 34 32 30 28 26 24 22 20

1

3

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7

1

9 11 13 15 17 19 21 23

Outdoor DBT

16 14 12 10 8 6 4 2 0 -2 -4

3

5

7

9 11 13 15 17 19 21 23

Figure 14: Heating energy demand in Winter

Figure 13: Cooling energy demand in Summer Legends:

Winter time heating energy demand

48 44 40 36 32 28 24 20 16 12 8 4 0

Temperature 째C

5

Energy (MJ)

3

20 18 16 14 12 10 8 6 4 2 0

Temperature 째C

Energy (MJ)

1

Figure 11: Winter day zone temperatures

Z_Living_Room

Z_Bedroom

Z_Toilet

Z_Dining

Z_Threshold

8.51 7.62

4.3

8.5

5.84

3.35

7.7

4.95

2.4

6.9

1.45

6.1

0.5

5.3

8.82

8.41

8

7.59

C-2

250-500

500-750

Figure 15: Daylight illumination level in different zones for different days

[6]

750-1000

Above 1000 lux

8.82

8.41

5.3

8

0.5

7.59

6.1

7.18

1.45

6.77

6.9

6.36

2.4

5.95

7.7

5.54

3.35

5.13

8.5

13.43

13.03

12.63

4.3

B-2 0-250

7.18

6.77

6.36

13.43

13.03

12.63

12.23

12.23

C-1

11.83

11.43

11.03

A-2

Key: 1-Summer, 2- Winter

11.83

11.43

11.03

10.63

10.63

10.23

8.51 7.62 6.73 5.84 4.95 4.06 3.17 2.28 1.39 0.5

0.5 0.9 1.3 1.7 2.1 2.5 2.9 3.3 3.7 4.1

B-1

A-1

9.83

4.1

3.7

3.3

2.9

2.5

2.1

1.7

1.3

0.9

0.5

0.5

10.23

1.39

9.83

2.28

5.95

3.17

5.54

4.06

5.13

6.73


From figures 11 and 12 it is quite apparent that the zone temperatures follow that of the outside condition, and more closely during winters. Spaces are generally always warmer than the outside air during summer, which can be attributed to the fact that the ventilation rate is not enough to dissipate the radiation absorbed by the building fabric. In winter, although the average temperatures are quite less, the spaces exhibit a reduced diurnal fluctuation than outside air temperature. It is interesting to observe that the toilet remains at a constant temperature throughout the day, during both summers and winters. The absence of ventilation in this zone keeps the air temperature constant.

round. Except for the area close to the south window which receives diffused light from the adjacent zone (see appendix for absolute daylighting levels). The fall-off in bedroom (B1, B2) is most significant, with high illumination near the west facing window which drastically decreases away from it. The zone mostly receives light from the afternoon sun rather than the morning. Section C: Shortcomings of the Design The design significantly fails in many aspects of passive house. In general, the temperature during summers are too high, while in winter it is too cold. There are untimely heat gains/losses from ventilation, fabric and solar geometry. The temperature curves being closely like outdoor conditions indicate the absence of thermal lag in the house.

During summers, the temperatures of all zones increases in the morning until sunset when the temperatures are highest. After that it shows a decreasing trend. Kitchen being bordered by other zone from East, South and West does not receive any direct radiation and its temperatures are lower than other zones. Likewise living room is usually always higher than bedroom as the afternoon hot sun beats down upon the living room from west more than the bedroom located in the east. Except for the early hours in the morning, temperatures in the spaces are always above the comfort zone.

When it comes to daylight performance, the house has unequal distribution of light. For instance, the front of the living area has good illumination (above 500 lux) while in the rear parts, where the kitchen is located and requires minimum 500 lux for any activity, the zone fails to provide sufficient natural lighting. Passive strategies when implemented in the design will lead to better indoor environmental quality and reduced energy demand.

Sunshine during winter is not enough to heat the spaces and much is lost due to ventilation in the evenings. Again, the temperatures in the mornings are lowest leading to peak heating demand when occupants begin their activities. By afternoon, the demand (figure 14) is reduced due to heat gain from sun. a steady heating load exists during the night to heat the bedroom. Contrastingly, in summer the peak cooling load is in the afternoon when the gains from sun is maximum. In fact, the demand is continuously rising from sun rise to compensate for the steady gain.

Chapter 4: Investigating Energy Performance of the Passive Solar House Design Section A: Passive Strategies Implemented Simulations from previous design, and analysis have shown that performance can be improved in different areas, a modified house design is thus proposed with the following passive characteristics: •

In terms of daylight availability (Figure 15), position of windows plays a significant role in determining the light intensity. Living room (A1, A2), having large south facing glazed units, generally has sufficient light (greater than 500 lux) throughout the year. In winters however, the rear part of the zone has on average less than 500 lux. Dining zone (C1, C2) is partially always in shadows, with illumination levels less than 250 lux, all year

•

[7]

Improved building fabric: Having a lower U-value and higher thermal mass to introduce thermal buffering. Outside insulation to prevent heat gain/loss from the building fabric. In essence the indoor conditions will be thermally coupled to the mass and this mass will act like a thermal battery storing heat when in excess and releasing heat when temperatures fall below a certain value.


Figure 16: Modified house design and details

• • • • •

Earth sheltering to introduce a stable outdoor condition which can reduce the diurnal swings in the indoor condition. Triple glazed (low-e) external windows and double glazed internal windows. Sunspace to allow heat collection during winters. Scheduled window blinds to prevent overheating of space, along with window overhangs. Skylight for better thermal collection as well as illumination. Also, more windows in bedroom and kitchen along with a new glass wall is introduced to have better illumination levels within the house. Controlled ventilation to prevent overheating or overcooling. This is done by introducing night flushing as well as temperature-based air change rate.

Figure 17: Modified house plan

Section B: Design and Setup A change in the building zoning can also lead to better indoor conditions. This has been brought about by clubbing the architectural spaces ‘living room’, ‘threshold’ and ‘porch’ into a single zone – ‘ZONE_LIVING_ROOM’. Which also acts like a sunspace, with glazing on south and west walls as well as skylight on roof. The ‘kitchen’ and ‘dining’ is now clubbed into ‘ZONE_KITCHEN’. Other zones remain the same (see figures 17, 21). Ventilation and HVAC settings are as follows:

Figure 18: New house perspective view

[8]

Sunspace is ventilated with 4 air changes/hour only during times when outside temperature is more than 2°C than indoor temperature. Bedroom and kitchen have two ventilation strategies, during summer by outside air at 4 ac/hr, while during winter


by air in sunspace (interzone ventilation) at 3 ac/hr. This is equivalent to opening the middle partition in the house to letting the warm sunspace air flow into the interiors. Auxiliary cooling/heating in living room (sunspace) and kitchen is only during day time, while for bedroom only during night time. Toilets are maintained by steady heating/cooling.

range, and hence sunspace design was optimized as an alternative. Section C: Results and Discussion Figures 20 to 23 show the temperature and energy demand in the zones, while figure 24 is the illuminance map. B1, B2 is the bedroom summer and winter time illumination respectively. A similar notation is used for kitchen (C). In case of living room, only the summer time illumination is shown (A1) while during winters since the levels are above 1000lux, a chart of time vs %of area above this value is plotted instead. (see A2).

Other settings •

Depth corresponding to half the glazing height is used on south façade to block high altitude sun. This is in fact the eaves projection from the roof.

The foremost and a striking thing to observe is the drastic reduction in energy consumption for both summer and winter days. From 9.72 kWh (35 MJ hourly) to 2.7 kWh (10 MJ hourly) on average. During summer days cooling is needed in the living room (sunspace) due to heat gains from glazing. This demand steadily increases as day progresses, but after midday it shows a decreasing trend even when the outside temperature rises. This is because the blinds roll down and cover the windows preventing further solar gain, and the increased ventilation rate dissipates the internal heat.

Figure 19: Shading chart for south facing window [21]

• •

Apart from that all windows have scheduled blinds which cover the window when zone temperature rises above 20°C (blinds schedule). West and east windows have overhangs equal to a third of window height. Illumination layout follows the new zone configuration (see figure 20).

Similarly, the kitchen also requires cooling during summers – which increases as the day progresses. It is maximum during evenings when the outside temperature is highest. Absence of scheduled blinds in this zone leads to this gain. Bedroom requires a constant low cooling energy to keep it within the comfort zone. On close inspection we however observe that even without cooling, no zone temperature rises above 30°C, in fact except for the sunspace all zones’ temperature are less than 27°C. Toilet is at 23°C throughout the day. This means that the occupants can choose to not have cooling at any time as the temperature range is fairly around the summer comfort zone.

Figure 20: New zone illumination layout

Again, during winter time, the temperature in all zones, except sunspace is constant at around 16°C, which although decreases slightly due to increased ventilation but rises soon as solar radiation is absorbed by the building. By midday, however, the gains have sufficiently warmed the spaces- reducing de

Ground temperature at depth of half a meter is used for surfaces coupled with earth (kitchen, dining and toilet).

In preliminary studies it was found that the use of trombe wall and solar chimney significantly increased the temperatures during summer days beyond the comfort [9]


40

24

Temperature 째C

Temperature 째C

38 36 34 32 30 28 26

20 16 12 8 4

24 0

22 20

-4 3

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7

9 11 13 15 17 19 21 23

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9 11 13 15 17 19 21 23

Figure 22: Passive house winter temperature

Figure 23: Passive house summer temperature 5.0

3

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36

14 12

30

3.0

28 2.0

26 24

1.0

16

Heating Energy (MJ)

32

Temperature 째C

Cooling Energy (MJ)

34 4.0

10 8

12

6 4

8

2 0

4

22 0.0

-2 0

20

Figure 21: Passive house summer cooling load Outdoor DBT

7

9 11 13 15 17 19 21 23

Z_Toilet

Z_Kitchen

8.5 8.1 7.6 7.1 6.7 6.3 5.8 5.4 4.9 4.5

A1

B1 4.3 3.9 3.4 3.0 2.6 2.2 1.8 1.3 0.9 0.5

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0.5

0-250

250-500

13.5

12.6

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11.7

9.9

10 11 12 13 14 15 16

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Key: 1-Summer, 2- Winter

8.0

4.3 3.9 3.4 3.0 2.6 2.2 1.8 1.3 0.9 0.5

9.9 10.8 11.7 12.6 13.5

0.5 1.4 2.4 3.3 4.2 5.2 6.1 7.0 8.0 8.9

Z_Bedroom

A2

Summer

5

Figure 24: Passive house winter heating load

Z_Living_Room

3.5 3.1 2.8 2.5 2.2 1.8 1.5 1.2 0.8 0.5

9

3

6.1

Legends:

-4 1

9 11 13 15 17 19 21 23

4.2

7

2.4

5

0.5

3

500-750

Figure 25: Illumination plan for different zones in the modified house design load

[10]

B2

C1 8.5 8.1 7.6 7.1 6.7 6.3 5.8 5.4 4.9 4.5

0.5 1.4 2.4 3.3 4.2 5.2 6.1 7.0 8.0 8.9

1

Temperature 째C

1

750-1000

Above 1000

C2


-mand for auxiliary heating. Interior zones take advantage of warm air from sunspace. The large glazing units in the sunspace lead to high night time losses, but the decoupling of interior zones (kitchen and bedroom) prevent their temperatures from falling so significantly. At any hour the heating demand is less than 0.55 kWh (2 MJ) for any zone, except during early morning when the space is cool and awaiting absorption from solar radiation.

Three levels, at three-meter height difference have been developed on the site, beginning at the road level and moving down. The idea behind this is twofold, 1- All time solar access without mutual shading, 2-Earth shelter behind each house. Sloped pathways and ramps take care of accessibility allowing even wheelchaired person to use entire site.

As with regards to illumination, all zones have significantly increased lighting levels. During summers all zones have sufficient lighting (greater than 500lux) levels across the whole region, in general. Sunspace is usually above 500lux at all times, bedroom is lit from east facing windows from the morning sun, while the kitchen is lit by both west sun and southern sunspace. Although, a major contribution comes from the external windows, as the high summer sun does not penerate too deep into the kitchen (see appendix for lux levels).

Figure 26: New improved site plan

As mentioned earlier, deciduous trees in winters allow sunlight to reach houses, while in summer they provide shading. For visualization purpose winter scenario is shown in Figure 27. Houses receive uninterrupted sunlight during winter days. (see appendix for more images).

In winters, however, the lighting intensity in sunspace is beyond 1000lux. From Figure 24(A2) it can be established that during winters the zone is illuminated above 1000lux for almost whole part of the day. This is due to the low altitude of the sun allowing greater penetration into the house. The effect is also advantageous for the kitchen, which also receives light from south facing surfaces. The bedroom, however, facing east, gets very little daylight and most of its region is below 250lux. Chapter 5: Comparison of the Energy/Environmental Performance of Original and Passive Solar House Design and Presentation of the Final Site plan

Figure 27: Perspective view of the new development

Section B: Energy/Environmental Performance Comparison

Section A: Updated Site-plan The new design boasts of better envelope and lower energy demand, as well as improved internal environmental condition. To implement the earth sheltered dwellings on the whole site, a series of steps have been proposed. This creates a gradual slope on the site and houses can be accommodated with sunspace exposed while the kitchen being sheltered.

The single most important criteria for a zeroenergy building is choosing proper materials and its positioning in the building envelope [14, 16, 15]. The design of the house was upgraded with materials of lower conductivity and higher capacitance leading to significant decrease in energy consumption as well as better thermal storage. A comparison is drawn between the two envelope designs by plotting the hourly heat transfer rate through [11]


implemented in the design (Figure 30Figure 31).

The heat transmitted through the fabric is much reduced in the case of new envelope, as can be seen by a flattened curve for the new envelope. In summers around midday, the new envelope conducts almost 3 times less than the original design. This means that the space inside will be protected from overheating. Equivalently, during winters, the new fabric conducts away significantly less heat at night than the previous design. In both cases, the diurnal variation of original design is much reduced in the new construction. This is indicative of the reduced transmittance of the fabric, helping in maintaining a stable indoor ambience.

Temperature °C

Cnduction rate (kW)

the fabric. For this purpose, ‘Surface average face conduction heat transfer rate’ is exported from EP 8.7 and presented in Figure 28,29.

1

5

7

9 11 13 15 17 19 21 23 Original House

Figure 30: Average house temperature in Summer

Winter Average Temperatures 20 16 12 8 4 0 -4 1

20

3

5

7

9

11 13 15 17 19 21 23

Outdoor DBT Modified House

10

Original House

Figure 31: Average house temperature in Winter

0

Temp. Range Outdoor DBT Original House Passive House

-10 -20 1 3 5 7 9 11 13 15 17 19 21 23 Original Envelope Improved Envelope

10 5 0 -5 -10 1

3

5

7

9 11 13 15 17 19 21 23

Original Envelope

Winter 15.6 7.6 6.6

For both, summer and winter, the new design achieves a more comfortable indoor condition with reduced diurnal variation. During summers it is stable around 25°C, while in winters the average is below 15°C for most part of the day. The performance is winter, although being better than original design, is less than comfort since increased glazing in the living room causes higher heat losses. In fact, the range is just a degree less than that of original design (Table 1).

Winter performance

15

Summer 9.5 4.6 1.9

Table 1: Diurnal range for different times

Figure 28: Summer heat conduction through building fabric

Conduction rate (kW)

3

Outdoor DBT Modified House

Summer performance

30

Summer Average Temperatures

34 32 30 28 26 24 22 20

Improved Envelope

Figure 29: Winter heat conduction through building fabric

Chapter 6: Conclusion Drawn from the Project and Design Recommendations

An exception is seen during winter afternoons, when the new design is losing heat to the outside. This is due to the increased temperature in the sunspace, leading to heat propagating outside.

Energy use intensity for the house was reduced from 20.34 MJ/m² to 2.48 MJ/m². The massive 10-fold reduction is evidence of the combined performance of passive strategies, namely solarium, improved skin, earth sheltering, thermal mass, controlled ventilation to name a few. The idea behind a passive house is to reduce the energy

Further, zone-volume weighted, average building temperature can also be calculated to give an estimate of the combined performance of different strategies

[12]


consumption as much as possible by intelligent planning, and should there be further demand, then auxiliary systems can step in (see figure 32).

References

[1]

European Parliament, “Implementation report on the Energy Efficiency Directive,” 2016.

[2]

International Energy Agency (IEA), “Oil Crises and Climate Challenges: 30 Yearsof Energy Use in IEA Countries,” Paris, 2004.

[3]

European Parliament, “European Commission, Energy Performance of Buildings Directive 2002/91/EC(EPBD),” 2002.

Figure 32: Hourly energy use comparison

[4]

The site demanded special attention to both summer and winter conditions, as the seasonal variation was great. In fact, even the diurnal variation being significant demanded an approach to modulate these fluctuations. Thermal mass and sheltering were main approaches to stabilizing the condition. Thermal chimney and trombe-wall over-performed leading to dismissal of use. Design recommendations include:

E. Rodriguez-Ubinas, C. Montero, M. Porteros, S. Vegaa, I. Navarro, M. CastilloCagigal, E. Matallanas and A. Gutiérrezc, “Passive design strategies and performance of Net Energy Plus Houses,” Energy and Buildings, 2014.

[5]

B. Anderson and C. Michal, “Passivesolardesign,” Annual Review of Energy 3, 1978.

[6]

K. Kelly, C. Kristin, M. Brian and K. Leidy, “Trends in observable passive solar design strategies for existing homes,” Energy Policy, 2013.

[7]

The ENVIBASE-Project, “The ENVIBASEProject,” [Online]. Available: http://www.stadtentwicklung.berlin.de/arc hiv_sensut/umwelt/uisonline/envibase/ha ndbook/climate3.htm.

[8]

Climate Consultant.

[9]

“Gaisma,” [Online]. Available: https://www.gaisma.com/en/location/milan .html.

Hourly Energy Comparison

Energy (MJ)

80 60 40 20

Original Design

• • •

W22

W19

W16

W13

W7

W10

W4

W1

S22

S19

S16

S13

S7

S10

S4

S1

0 Improved Design

Orienting the length of the building towards the equator facing direction, for maximizing gains. Installing solar reflector on ground in case the radiation is not enough, or to heat the mass. Controlling these gains in summer by appropriate mechanisms like shading, blinds etc. and the best practice is to have scheduled controls Reducing temperature fluctuations byearth sheltering, massive construction, insulation

[10] Commission of the European Communities, Solar Architecture in Europe, Prism, 1992. [11] U. Aksoy and M. Inalli, “Impacts of some building passive design parameters on heating demand for a cold region,” Building and Environment, 2006.

The benefits of designing a climatic building is the reduced energy consumption and better indoor quality. Other researchers have shown that people in a free running building are comfortable over a wider range of temperatures. They in fact, prefer the rhythmic nature of climate and seasons.

[12] J. Morrissey, T. Moore and R. Horne, “Affordable passive solar design in a temperate climate: An experiment in residential building orientation,” Renewable Energy, 2011. [13] R. Rahul V and G. Rajiv, “Review of intelligent building construction: A passive solar architecture approach,” Renewable and Sustainable Energy Reviews, 2010.

[13]


[14] L. Jankovic, Designing Zero Carbon Buildings Using DSM, 2017.

season.,” Architectural Journal Institution of Engineers India, 1999.

[15] V. Brenda and V. Robert, The New Autonomous House.

[19] “Energy Plus,” [Online]. Available: https://energyplus.net/weatherlocation/europe_wmo_region_6/ITA/ITA_ Milan.160660_IWEC.

[16] T. Simon and Mohammadi Murtaza, “Evaluation of Thermal Mass Performance (Technical Factsheet 3.2),” Hockerton Housing Project.

of

[20] ASHRAE, “Adaptive Thermal Comfort Model - ASHRAE Standard 55-2010”.

[17] R. RV and G. R., “Design development of a static sunshade using small scale modeling technique,” International Journal of Renewable Energy, 2005.

[21] Climate Consultant. [22] S. Sanja, “Optimization of passive solar design strategies: A review,” Renewable and Sustainable Energy Reviews, 2013.

[18] K. S, S. JK and B. RK, “Comfort conditioning in residential buildings through passive measures during summer

Appendices

Figure 33: Perspective view of original house design

Figure 35: Original Living room (front) and Kitchen (back)

Figure 34: Original Dining room

[14]


Figure 36: Original entrance to the house

Figure 39: Passive house kitchen and dining

Figure 38: Passive house solarium (sunspace)

Figure 40: Passive house bedroom

Figure 37: Perspective view of improved passive house design

[15]


Z_LIVING_ROOM (original design) Summer 8.51 7.62 6.73 5.84 4.95 4.06 3.17 2.28 1.39 0.5

0.5 561 1217 1676 687 733 836 1158 1875 3536 14282

0.9 694 871 937 782 774 923 1248 2133 4414 17652

1.3 494 715 656 678 824 954 1316 2328 5054 21609

1.7 507 705 629 670 799 1092 1350 2435 5393 25086

2.1 535 498 662 635 797 1138 1348 2440 5431 25126

2.5 541 594 543 765 838 1189 1444 2351 5166 24875

2.9 693 803 611 884 820 1165 1486 2168 4587 24016

3.3 675 807 818 807 796 1154 1729 1905 3743 18868

3.7 499 596 618 618 705 959 1777 1620 2794 9597

4.1 518 473 503 551 632 802 1474 1796 1968 4725

Winter 8.51 7.62 6.73 5.84 4.95 4.06 3.17 2.28 1.39 0.5

0.5 385 582 689 481 552 3468 3686 4103 4673 5195

0.9 472 460 501 570 585 3531 3781 4324 5211 7776

1.3 363 447 451 501 617 3567 3863 4445 6148 8233

1.7 366 445 444 501 667 3632 3903 5112 6953 8358

2.1 373 372 449 493 670 2644 4476 5152 6962 8378

2.5 368 398 415 534 634 3264 3476 5696 6876 8325

2.9 442 475 434 568 1177 3247 4045 4541 6600 8120

3.3 423 473 495 1155 1157 1383 2267 2522 5084 7252

3.7 348 393 421 456 1723 1888 2296 2279 2696 2670

4.1 355 345 374 419 1047 1781 2145 2193 2214 644

Table 2: Original living room absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

Z_BEDROOM (original design) Summer 4.3 3.35 2.4 1.45 0.5

9.83 311 330 600 8001 1475

10.23 375 459 1025 2234 640

10.63 461 586 1138 1488 217

11.03 566 668 1096 1077 218

11.43 1318 738 940 750 218

11.83 1524 816 817 571 216

12.23 2926 926 718 468 212

12.63 3535 1064 635 396 205

13.03 4579 1154 537 337 198

13.43 6708 1005 417 289 191

Winter 4.3 3.35 2.4 1.45 0.5

9.83 99 121 700 2137 411

10.23 130 604 1465 1355 200

10.63 168 674 1078 526 71

11.03 606 849 460 368 72

11.43 238 848 369 259 72

11.83 826 289 303 193 71

12.23 882 287 253 158 70

12.63 430 298 217 135 69

13.03 607 306 184 116 67

13.43 1015 276 148 101 65

Table 3:Original bedroom absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

Z_KITCHEN (original design) Summer 8.5 7.7 6.9 6.1 5.3

5.13 104 93 50 50 50

5.54 108 98 116 50 50

5.95 111 168 126 157 50

6.36 114 175 294 361 464

6.77 171 180 309 414 694

[16]

7.18 175 181 316 467 783

7.59 176 242 314 498 824

8 176 240 305 526 838

8.41 173 235 379 504 818

8.82 167 225 357 512 773


Summer 8.5 7.7 6.9 6.1 5.3

5.13 150 132 99 99 99

5.54 157 140 154 99 99

5.95 162 215 168 184 99

6.36 166 227 336 400 453

6.77 222 233 359 456 673

7.18 227 234 367 504 752

7.59 228 293 363 528 787

8 227 291 349 551 796

8.41 222 284 423 526 769

8.82 216 272 397 527 723

Table 4: Original dining absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

Z_LIVING_ROOM (passive design) Summer 3.5 3.1 2.8 2.5 2.2 1.8 1.5 1.2 0.8 0.5

0.5 795 869 915 946 962 965 957 942 913 878

1.4 860 895 928 956 973 977 971 962 950 953

2.4 897 942 976 1004 1020 1023 1014 1002 987 984

3.3 938 984 1020 1047 1062 1062 1049 1034 1013 1007

4.2 920 973 1015 1046 1064 1066 1054 1039 1018 1011

5.2 892 948 992 1026 1046 1049 1039 1026 1008 1002

6.1 851 907 950 984 1004 1009 1000 989 975 976

7.0 789 840 880 910 926 927 915 900 885 894

8.0 696 738 770 792 802 795 772 737 688 624

8.9 572 606 626 639 641 630 606 569 523 469

Winter 3.5 3.1 2.8 2.5 2.2 1.8 1.5 1.2 0.8 0.5

0.5 8309 8278 8413 8500 8662 8801 8654 8366 7901 7796

1.4 7836 7603 7741 8353 8133 8338 8695 8867 9140 9354

2.4 8424 7612 7735 8379 8653 8884 8677 8851 9128 9307

3.3 8617 8245 8346 8483 8723 8953 8721 8865 9141 9311

4.2 8530 8201 8304 8402 8668 8895 8653 8812 9087 9261

5.2 8423 8052 8155 8263 8574 8801 8576 8744 9033 9213

6.1 8211 7879 7971 8071 8337 8563 8379 8613 8939 9150

7.0 6915 6646 6712 6779 6959 7130 7904 8110 8466 8892

8.0 4759 4557 4565 4550 4584 4572 4343 4221 4068 3178

8.9 4195 4049 3517 3462 3409 3310 2570 2396 2227 2054

Table 5: Passive living room absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

Z_BEDROOM (passive design) Summer 4.3 3.9 3.4 3.0 2.6 2.2 1.8 1.3 0.9 0.5

9.9 500 529 551 565 569 564 551 529 500 467

10.8 669 736 788 818 827 818 791 744 678 604

11.7 680 793 1422 1458 917 912 1438 1379 1277 613

12.6 1007 1431 2250 2252 1537 1561 2259 2179 1821 874

13.5 991 4099 6715 5960 2013 2134 6153 6644 3466 877

Winter

9.9

10.8

11.7

12.6

13.5

[17]


4.3 3.9 3.4 3.0 2.6 2.2 1.8 1.3 0.9 0.5

146 148 150 149 147 143 138 131 124 117

242 206 210 210 206 199 188 175 159 145

213 275 286 245 241 231 216 196 172 148

390 417 445 494 468 418 406 356 278 203

921 959 1238 1433 1076 779 1178 1072 582 210

Table 6: Passive bedroom absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

Z_KITCHEN (passive design) Summer 8.5 8.1 7.6 7.1 6.7 6.3 5.8 5.4 4.9 4.5

0.5 869 7137 8445 3022 1293 1905 8247 8291 1885 738

1.43 824 1106 1228 1192 1119 1217 1305 1280 1056 842

2.37 540 611 659 684 699 734 730 794 760 724

3.3 524 567 600 622 634 666 663 750 746 737

4.23 400 422 440 455 465 503 514 626 646 663

5.17 333 346 358 368 378 419 436 556 586 613

6.1 290 302 311 320 330 370 388 507 540 570

7.03 264 270 276 282 291 324 338 444 480 525

7.97 246 251 255 260 260 279 284 330 327 303

8.9 229 231 233 235 235 242 240 260 243 220

Winter 8.5 8.1 7.6 7.1 6.7 6.3 5.8 5.4 4.9 4.5

0.5 1869 2138 1936 1594 1601 2530 2740 2420 1903 1694

1.4 1344 1131 1689 1751 1313 1542 1656 2082 2179 2308

2.4 1402 990 1062 1152 1241 1510 1638 2142 2275 2411

3.3 947 1019 1097 1182 1276 1565 1697 2236 2366 2497

4.2 906 972 1045 1127 1219 1514 1645 2201 2332 2460

5.2 866 927 996 1073 1160 1452 1579 2133 2260 2385

6.1 783 880 943 1013 1094 1370 1488 2018 2134 2250

7.0 726 767 814 866 946 1161 1253 1747 1877 2033

8.0 666 697 732 771 764 887 873 1047 1011 780

8.9 543 554 566 585 578 587 574 622 517 422

Table 7: Passive kitchen absolute lighting levels, (blue>1000, 1000>red>750, 750>yellow>500, 500>green>250, 250>grey)

.

[18]

Evaluation and comparison of performance of a Passive Solar House  
Evaluation and comparison of performance of a Passive Solar House  
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