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BIOCLIMATIC Analysis Project: Derek Henderson - Monte Velho - Ourique ZEN Arquitectura 4th September 2013
WILDSophistication Lda ZEN Arquitectura
Av. da Gondra QdL, 8135-162 Almancil T 289 301 882 M 913248420 zen-arquitectura@sapo.pt
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Content:
1. Temperature & Humidity - Average maximum and minimum temperatures
2. Dominant winds - Average annual data , Analyses of the wind-impact & Orography
3 . Solar impact
4. Suggested changes shown in elevations
5. Conclusion
The analysed area is influenced by a Mediterranean climate which has two well defined annual seasons. Cold winters have an average minimum temperature of +1ºC, low winds (maximum wind gusts recorded of 50km/h and average maximum over the year of 18km/h) with very low rainfall. The summers are hot and dry with temperatures exceeding +40ºC in July and August. The average temperatures are +26-29ºC. There are dry periods of 80-100 days to consider during the summer. The predominant winds throughout the year are North-Western with some alternation to North-Eastern. The area is affected by the watersheds from the Sado and Mira the rivers. It influences the relative humidity of the area. Its morphology is defined by the Serra de Ouro Velho mountain and mount Monte de São Luís. Both are 243m in height.
Monte Velho _ Ourique
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1. Temperature & Humidity
Average climatology – Ourique station, Beja, Portugal Meteorological data from February
Monte Velho _ Ourique
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Meteorological data from July
Monte Velho _ Ourique
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2. Dominant winds - Average annual data
Direction and intensity of the winds – annual average
Monte Velho _ Ourique
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Direction and intensity of the winds – January
Direction and intensity of the winds – July
Monte Velho _ Ourique
Direction and intensity of the winds – February
Direction and intensity of the winds – August
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Cold winds (northern winds and slope winds) – lower velocity
Monte Velho _ Ourique
Hot winds – Humidification and cooling
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Analyses of the wind-impact & Orography
Monte Velho _ Ourique
Cold winds (northern winds and slope winds) – lower velocity Hot winds – Humidification and cooling
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Cold winds (Northern and slope winds) – lower velocity
Hot winds – Humidification and cooling
Analysis of the wind’s influence over rotated building (63° CW – Option B)
Regarding the building’s orientation to the winds, the current shape prevents option B from being better than A, as it exposes too much of the building to the prevailing winds.
Monte Velho _ Ourique
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Estudo de acção dos
ventos sobre edifício rodado 63° (CW) – Opção B
No que respeita a
resposta aos ventos, o factor forma actual impede que a opção B seja mais positiva
uma vez que será
igualmente potenciadora de zonas de obstrução aos ventos dominantes.
Analyses of the wind´s influence over rotated building (8° CCW – Option C)
Cold winds (northern winds and slope winds) – lower velocity
Hot winds – Humidification and cooling
Regarding the building’s orientation, option C is viable due to the protection it offers from the prevailing winds.
Monte Velho _ Ourique
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3. Solar Impact
Estudo de acção dos ventos sobre edifício rodado 8° (CCW) – Opção C No que respeita a resposta aos ventos, a opção C revela-se igualmente obstructiva aos ventos dominantes.
Plan of solar rays in the building (Summer Solstice) considering the current orientation Orange – Solar rays when sun is under 40° relative to Earth Red – Solar rays when sun is over 40° relative to Earth (potential to cause excessive heat).
During the Summer Solstice, the solar impact is too strong when the sun exceeds 40° reaching up to 73° which is the maximum solar height for this latitude. The current azimuth during this time of year is 120°.
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Plan of solar rays in the building (Winter Solstice) considering the current orientation Yellow – Solar gain throughout the day
During the Winter Solstice, the maximum solar height reaches 29°. The current azimuth during this time of year is 60°.
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Solar impact from the South
Solar impact from the East and West
Solar impact on rotated building (63° CW) – Option B
This option (B) allows higher solar gains in the winter period. The kitchen and living room would benefit from this orientation. However, the bedroom on the West side would be facing north and would not have solar gains (shown by thick black line).
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Solar impact from South
Solar impact from East and West
Solar impact on rotated building (8° CCW) – Option C
This option would offer more protection from the strong solar impact from the South and would benefit the solar gains in the West bedroom and kitchen, at the expense of the East bedroom and living room. Also the kitchen and living room would be more exposed to the Northern winds.
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4. Suggested changes shown in elevations Shade, marked red is not needed as facing north
Exact calculated shades and ideally green roof cover
Perennial vegeta-
Smaller windows and per-
Ideally pro-
Perennial vegeta-
tion
ennial vegetation in front of
vide a glass
tion
them
in this opening
Shade, marked red should
Exact calculated shades and ideally green roof cover
be extended
Larger windows for direct
Protect the windows with evergreen tree species
solar gain and perennial vegetation Exact calculated shades and ideally green roof cover Larger shade
Larger shade
Larger & eventually more windows for direct solar gain
Exact calculated shades and ideally green roof cover Bigger Shade
Protect the windows with evergreen tree species
Larger windows for direct solar gain in the Winter
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Conclusion The plot has a shallow slope and we understand that the plot has been slightly leveled already. The analysis locates the building in a South-East facing downward slope with a low profile. The building area is reasonably sheltered from the winds and has lower temperatures due to the proximity to the water. The difference in temperature compared to its surroundings can be 3°C cooler on the South side and 7°C cooler on the North side close to the water. The gradual slope of the hill has few negative effects but countless positive effects against the North West winds. The planted perennial vegetation such as olive trees and holly/holm oak trees can influence the temperature by a reduction of 1°C in the Summer. Location The strategic location on a South-East facing slope partially protects the building from the prevailing winds so the only concern is the South-East alternate winds. Large perennial trees can be very helpful against these. Shape relevance The shape relevance is what we call the influence of the shape of the building on the heating and cooling performance. The chosen shape with its windows allows good ventilation and thermal performance during the Summer, but should ideally be more closed up to the North, North East and North West in order to function as a closed barrier for the North East and North West winds. Slight changes in the North East facade could lead to a better passive solar performance. We understand the idea of the chosen orientation, but would like to point out that the actual orientation of the building is not ideal in relation to the shape. High vegetation is advised. Orientation The orientation of the passage areas to the North are acceptable. However, the layout of the entertainment areas such as the living room to the North and Northeast is not ideal. A clockwise rotation of the building as shown in (Option C) would allow a better solar impact on the West rooms, but also cause the North areas to be considerably cooler. Rotating to the opposite direction (Option B) would promote solar gain in the Winter but would also increase the influence of the prevailing and alternate winds. Option B would also completely eliminate the solar gains in the North West facing rooms. Dimension of openings in the facade The small northwest facing windows will reduce the impact of the prevailing winds on the building and the interior temperature.The size of the North windows in the kitchen and living room create a thermal imbalance of these rooms.We advise to enlarge the windows to the East, South and West as shown the elevations above. We understand the idea of having small windows in order to reduce the solar impact to the south (due to the dry climate and hot summer), but this closing up of the south facade also reduces dramatically the passive solar gains in the winter. The chosen orientation reduces the solar impact in the summer but also completely eliminates its beneficial effects during the winter period. If properly shaded, it would be beneficial for the winter period to increase the size and number of openings in this façade without impacting too much the thermal balance in the summer. Monte Velho _ Ourique
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Vegetation We advise the use of native plant groups, as they require less water and maintenance and fit to the local ecosystems. The predominant winds come from Northwest and occasionally from the Northeast. To protect the building from these winds, we recommend to plant a diverse range of evergreens and thereby create a barrier to the Northeast. Large perennial and deciduous species as shown in the elevations above should be planted. Shading The shading to the South is adequate, but would derive additional benefit from the solar influence in the South by designing larger openings (windows) and appropriately sized shades. Larger windows to the East and West would provide additional passive solar gain. We advise increasing the size of the openings according to above elevations.Deciduous vegetation close to the South and East facade will reduce excessive solar impact during the Summer. Insulation Insulating the whole facade with XPS will improve the thermal mass and be beneficial for the thermal performance of the building in the Summer and Winter. We will calculate the exact thickness of the insulation that should be applied on the building material used. We strongly recommend the use of green roofs to balance the interior thermal performance of the building year round. Humidification and cooling During the Summer months, the hot South winds will be humidified and cooled by the lake. To create a more advanced cooling system, we would advise considering the use of water features or passive cooling water technology. Surface runo Surface runoff is the water flow that occurs when the soil is infiltrated to full capacity and excess water from rain or other sources flow over the land. This is a major component of the water cycle, and the primary agent in water erosion. Due to the low rainfall, there is no need to be concerned about the surface runoff. Only in the North-East of the building can rainfall accumulate some precipitation water.These levels need to be considered when calculating the watershed. Renewable energies The Monte Velho area lends itself well to the use of renewable energies due to the proximity to strong water forces and the high amount of sun exposure. Others We generally recommend the use of LED lamps as they offer comparatively longer life and reduced energy consumption despite the higher initial outlay. Natural swimming pools respect the local ecosystem and benefit from reduced maintenance cost.
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Summary The original project design is viable taking into account the local climate. However in order to design a passive house or low energy house a few amendments would need to be made, such as adjusting the shape, its orientation, window size, vegetation, shading, insulation, humidification and cooling, surface water flow, renewable energies and other factors. Further considerations Basement By rotating the building as suggested we would adjust the space below the house according to the natural site elevation. We understand that the basement was intended to be used mainly for storage and potentially for a boat, garden machinery etc, and maybe even for use as a sauna/steam-room at some time in the future and will consider this in our design suggestion. Also the eventual possibility of making the existing garage block and laundry into a self-contained annexed bedroom will be looked at. Pool The swimming pool shown in the illustrations above is not taken into account in the Bio-study. We understood that the clients wish to reposition the pool in the enclosed garden somewhere on the South/South-West side of the house. We will give you advice on the ideal location for the pool after agreeing on the final position of the house. It will be used primarily for swimming and be approximately 15m x 3m x 1.2-1.5m deep. Site Once we have visited the site, we will be able to more accurately assess the actual elevations. However, we don’t believe that this will result in dramatic changes to the proposed design changes. We understand that the clients would like to keep the building a reasonable distance from the edge of the lake due to the reasons discussed.
Monte Velho _ Ourique