Sustainable Design Report for Small Residential Building in Annecy

House in Annecy Sustainable Design Strategies for Small Residential Building in Annecy, Mont Blanc, France Bengi Bayar, 2020

In this report, the climate of Annecy has been evaluated through Climate Consultant software and some design strategies have been proposed by the software. These strategies have been evaluated and implemented and the building performance and maintenance cost has been reviewed. Below, the building performance will be discussed in terms of passive performance, maintenance cost and environmental impact.

Climate in Annecy The climate in Annecy is warm in summers and cold and wet in winters with temperatures varying from 0°C in winter to about 25°C in summer and the wetter season being approximately 8 months. The temperature is below comfort zone for almost all year round. Sky cover range is around 65% and wind speed is as low as 2 m/s. Relative humidity changes between 45% and 94%.

In the temperature range above, it is clear that the temperature in Annecy is below comfort zone almost year round. This is the fundamental concern in design, as there will always be need for heating.

Above are the wind velocity (left) and sky cover range (right) charts for Annecy. Low wind speed decreases the air flow and makes air sealing more sensible.

High sky cover range that is more than 65% on average eliminates the need for thorough shading.

Design Strategies Some of the design strategies that are useful to increase building performance in cold and wet climates can be listed as; -Providing well insulated exterior surfaces -Using low heat transmission glasses -Facing most of glass are on the southern faรงade -Using high mass interior surfaces -Minimizing area exposed to the exterior -Air sealing the building

Glazing area to be maximized on the southern faรงade.

Low-E double pane glass to be used in glazings.

Extra insulation to keep indoor temperatures more uniform.

Surface area to be kept small in order to minimize heat loss.

These design strategies were suggested by Climate Consultant software to be used in cold and wet climates, and they constitute the basis for sustainable design.

HEED HEED software has been utilized for the estimation of building performance and maintenance costs. Given the floor area and purpose of the building, the software creates two schemes automatically. The first of these two schemes, Scheme 1, is a building that just meets the 2013 California Energy Code. Scheme 2, is a building that uses 70% of the energy Scheme 1 uses.

Using the design strategies mentioned above, changes have been made to these two schemes, making one change at a time to see how each modification changes the energy cost of the building. These schemes can be described as: Scheme 1: California Energy Code Minimum This scheme consists of a building that is designed to fit the 2013 California Energy Code. The yearly maintenance cost is approximately 1440$ for this scheme.

Scheme 2: 30% less than California Energy Code This scheme consumes 30% less energy than Scheme 1.

Scheme 3: Glazing Windows are changed to cover maximum area on the southern faรงade to improve visual and thermal comfort.

Scheme 4: Insulation Insulation has been improved upto 1.5x the basic insulation in Energy Code Minimum scheme.

Scheme 5: Ground slab Ground slab has been raised to create a crawl space to minimize contact with ground and heat loss as a result.

Scheme 6: Air sealing Passive house standard air sealing (0.3 SLA=Specific Leakage Area) has been added.

Scheme 7: Heating and cooling systems Heating and cooling equipment have been changed to best available efficiency equipment and solar water heating has been added. The yearly maintenance cost of this scheme is as low as 912$.

Scheme 8: Solar panels (5kW) Solar panels of 5 kW capacity have been added to balance some of the energy needs. The yearly maintenance cost of this building is 230$, meaning it produces 1100$ worth energy on site. (see next page)

Scheme 9: Solar panels (8kW) Solar panels have been increased to 8 kW capacity to make the building energy producing. The yearly maintenance cost of this building is approximately -920$, meaning it produces 920$ worth energy per year, in addition to compensating its consumption.

By applying these strategies, it is aimed to decrease building maintenance cost and increase passive performance.

Building Design

Image of the house designed according to Scheme 2.

Image of the house designed according to Scheme 3 with environment elements added.

Image of the house designed according to Scheme 9 with environmental elements and solar panels added.

Building Performance Building performance can be assessed through different charts and graphs calculated by HEED.

1. Home Energy Rating

Home energy rating of schemes 1-9 can be seen in this screen. Energy performance of the building increases from Scheme 1 to Scheme 9 with design changes made step by step to achieve a less energy consuming house. Scheme 8 consumes 20% of the energy a building that barely meets the California 2013 Energy Code while Scheme 9 produces 10% more of this energy in addition to the energy to balance its consumption.

2. Home Energy Costs

Energy costs of the building can be seen in this figure where schemes are ordered from Scheme 1 to 9. Although electricity needs fluctuate, we can see a certain decrease in fuel consumption. The electricity consumed can be balanced by photovoltaic panels on site. Therefore the building can be net zero or even producing more energy than it consumes.

3. CO2 Production

Carbondioxide produced on site compared for Scheme 9 and Scheme 1.

Scheme 9 is more environmentally sustainable as it depends less on fossil fuels compared to Scheme 1.

4. Energy Efficient Design

Passive performance of the building decreases drastically in Scheme 2 with most of the sustainable design strategies being employed. After this point, it fluctuates at a low level. Changing the glazing and floor exposure decrease the passive performance slightly. However it is visible that all the changes decrease heating consumptions as they are made towards a better isolation from exterior conditions.

5. Shadows and Sunlight

In these figures we can see how the building receives daylight in (clockwise) June, September and December. Sloar panels should be placed in accordance to the site shading conditions to maximize energy production.

6. Bar Chart Hourly

In hourly bar chart it is possible to see which building components heat is lost and gained through. It is visible that southern windows are a big contribution to the heat gain of the building.

7. Energy Performance Comparison

Energy performance comparison for Schemes 1-9. It is seen that after Scheme 2, where glazing area is reduced, an increase in total lighting electricity occurs. It is also visible that after the heating and cooling system improvement, cost in cooling electricity decreases drastically.

8. Peak Loads Comparison

Peak loads comparison for Schemes 1-9. It can be seen in the second column that the net fueal consumed on site decreases from Scheme 1 to 9 in coordinance with changing design strategies. Site energy costs also decreases in the same manner. It is also visible that heat loss and heating output are also decreasing from Scheme 1 to Scheme 9.

Peak loads comparison for Schemes 1-9. It can be seen in the second column that the net fueal consumed on site decreases from Scheme 1 to 9 in coordinance with changing design strategies. Site energy costs also decreases in the same manner. It is also visible that heat loss and heating output are also decreasing from Scheme 1 to Scheme 9.

9. Pollution Emissions Comparison

It can be seen from pollution emissions chart that although there is no change in carbondioxide, nitrogen oxides, sulphur oxides and mercury emissions after the addition of solar water heating system, there is a sudden decrease in these after the photovoltaic panels are added to the building. This shows how green energy makes a difference.

10. Total Loads

Total loads for Scheme 1 on the right and Scheme 9 on the left. It is visible that the building loads have been slightly stabilized after design changes towards a more passive building.

11. Total Energy Costs

Total energy costs of Scheme 1 which barely meets the energy code; compared to Scheme 9, which produces more energy than it uses by solar panels on site.

Doors

12. Individual Component Loads for West Windows and

In this 3D chart we can see the indiviual loads for Windows and doors on the West side. There is a clear decrease in Scheme 9 on the left compared to Scheme 1 on the right. This is because in Scheme 9, according to design principals, Windows have been placed mostly on the southern faรงade to maximize daylight heat gain.

Conclusion

The maintenance cost table of Schemes 1-9 can be seen above. It is visible that a huge part of the cost stems from heating energy. A house in Annecy, France where climate is cold and wet, can be designed in a way that it produces more energy than it uses, by decreasing the energy it uses with passive house strategies, energy efficient applications and building mass and orientation. However, it needs a lot more effort to do this than a house in a warmer climate because of the heating energy needed.

References .epw data for Annecy is taken from: http://climate.onebuilding.org/ Climate based design strategies and images are taken from: Climate Consultant Software 3D images and building performance evaluation are taken from: HEED Software

Bengi Bayar, 2021