Chapter 2 - Proposal of design strategies
In this chapter we want to discuss, through the Watson&Lab matrix, about the possible design strategies in order to guarantee the comfort inside the buildings, using as much as possible passive strategies, which can be related to the building shape and orientation, air permeability, solar opening, colours, type of construction and exploitation of gains.
Arkhangelsk
According to the Köppen classification of climate, Arkhangelsk is a very subarctic climate, which means cold climate with humid winter, where the coldest month can reach temperatures of -38°C and only few months are above 10°C, as the climatic analysis showed us. For this reason, according to Climate Consultant, only the 2.9% of the hours will be comfortable: in fact, the value of the heating degree days for Arkhangelsk is 6019,4°C, and the value
of the cooling degree days is 13,4°C, which support the fact that in this cold country, there is no need to cool down but a huge need to heat to stay in the
comfort zone.
For this reasons we should try to increase heat gains and reduce heat losses, both in winter and summer, by:
CONDUCTION:
- using high mass interior surfaces to store winter passive heat
- keeping the building well insulated to exploit heat gains from people and equipments
VENTILATION:
- reducing air infiltrations
RADIATION:
- maximizing the area of south-exposed windows to exploit the solar gains, even if they are not very high (about 7000 Wh/m2 in summer and 1000 Wh/m2 in winter)
Looking to the vernicular architecture of this region, we easily notice that the majority of the buildings were made of wood, not only because of its availability, but also because it is a material with good proprierties of thermal trasmittance and durability. Also, we can see that all the houses have small windows, which help to keep the heat inside, and tilted roof, which is good to let the snow slip off.
Hurghada
According to the Köppen classification of climate, Hurghada is a hot desert climate, with average annual temperature above 18°C and very few annual precipitation. From our climatic analysis, we found out that it can reach even values of 36°C. For this reason, according to Climate Consultant, only the 25.3% of the hours will be comfortable: in fact, defining a set point temperature between 20°C and 26°C, the value of the heating degree days is 242,9 °C, and the value of
the cooling degree days is 785,8°C. This means that the need of cooling is much more important that the one of heating.
For this reason, we should design our building thinking especially on the summer period, trying to reduce heat gains and increase heat losses, by:
CONDUCTION:
- using high mass interior surfaces to store winter passive heat and summer night cooling
- in winter, exploiting passive solar and internal gains to keep it warm
VENTILATION:
- promoting natural ventilation both in daytime and night-time, considering wind direction
- using open plan interiors and openings on opposite sides to promote natural cross ventilation
RADIATION:
- maximizing clear glasses in the south for winter sun exposure, but keeping them small
- providing movable shading to prevent overheating
- minimizing west facing glazing to reduce summer and fall afternoon heat gain
- providing glasses with Low-E in north, west and east facades
OTHERS:
- painting the building of a light colour
- humidifying hot dry air with fountains, wet pavements or cooling towers
- designing a flat roof or green
Of course to reach an 100% of hours of comfort we should add some mechanical system to cool down.
The vernicular architecture of the region shows us a great use of sun-baked mud brick, with a very big wall thickness, and flat roofs. This kind of solution is particularly effective because it increase the thermal inertia and the thermal gap, which means that they remain hot in winter nights and fresh in summer days.
Chapter 3 - Climate Responsive Architectures
This third chapter aims to provide examples of existing climate responsive architectures, designed following some strategies quoted above, and using the concept of vernacular architecture.
In order to show relevant case studies, linked to our two locations, we found two projects built in the same range of climate conditions.
1. Luuku House, Finland & Spain
The first case is the "Luuku House", a Finnish project, first place winner of the European Solar Decathlon, a home optimized for both the cold Finnish winter months and the hot Spanish summer. It is a zero-energy house in the Finnish climate and a plus-energy building in Spain. The vernacular concept is well used in this project, following the concept of traditional Finnish House, closely linked to nature and using the longstanding Finnish tradition of extensive and intensive use of wood, a low embodied energy material.
The wood is used for the structure, insulation, cladding, interior floor, wall and ceiling finishes, for moisture and heat buffering qualities and applications in very wet areas such as bathrooms.
The focus in this building envelop is on insulation in order to prevent the heat losses during winter. This is achieved through the high air tightness of the core and thermal-break exterior elements, thick insulation and careful detailing. The windows use a quadruple glazed frameless unit fixed directly to the frame. This results in excellent thermal insulation with no thermal bridges. Moreover, the wooden interior panels are profiled to expose a high surface area to circulating air. These act to absorb and release moisture balancing the humidity levels in the house.
Finally, in terms of energy production, the building uses the sun as the only source of energy.