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The Sotavento project intends to demonstrate that through architectonic design based on climatic conditions and the integration of buildings in their environment, it is possible to achieve maximum thermal comfort and reduce energy consumption and environmental impact.

*(ro-en) project_rw_responsible*

ROCKWOOL Peninsular S.A.U.
Calle del Bruc, 50; 3º
ES-08010 Barcelona

Phone:+34 93 318 90 28
Contact: Jordi Bolea or Mercedes Sánchez


*(ro-en) project_architect*

Emilio Miguel Mitre and Carlos Expósito Mora

To reach these goals, the Sotavento Foundation has opted for the ROCKWOOL Group as their supplier of insulation material.

This technical collaboration has been essential in order to comply with the educational objectives of the Sotavento Foundation, because it enables a demonstration of the importance of insulation in providing solutions that reduce energy losses.

What are the objectives of this project for the Sotavento Foundation?
In short, the project objectives are:

1. To reflect on the important energetic and environmental role of buildings as energy tanks and how to achieve sustainable development.

2. To demonstrate that highly efficient buildings are affordable, increase the quality of life and are more respectful of the environment.

3. To disseminate, via examples and real life installations, concepts relating to bioconstruction, bioclimatics, renewable energy, water management, domotics etc.

4. To investigate all phases of the process of housing development including construction solutions, bioclimatic behaviour, renewable installations, efficiency systems etc. in order to acquire data and experience that can serve as tools for the construction sector, specialists and the general public.

Who do you want to reach; architects, students, authorities?
In principle these projects will be directed towards people of all ages, educational background and interests. We understand that they will be particularly relevant for the construction sector, installers of renewable energy and researchers, but the information will be made available through environmental and educational communication strategies directed towards the general public.

The principles of bioclimatic architecture have been applied in the construction of the building. Can you tell us what those principles are?
From a location point of view:

1. To not limit the visual impression or break the harmony of the landscape: This is obtained thanks to the correct choice of location for the residence in conjunction with its dimensions: cornice height 3,41 meters, one floor and a gradient of 22°. In this way the aesthetic and constructive characteristics and the materials, colours and finishes are in agreement with the rural landscape and adjacent structures.

2. A minimum of earthworks: The original land is practically horizontal and therefore little preparation was required. The land excavated in order to lay the foundations is used for the creation of a protection mound against cold winds from the north.

3. Proximity to the Sotavento educational building: Already existing connections for water, electricity, telecommunications, sewers etc. have been used.

4. Orientation: The building has been placed in order to take advantage of the winter sun from the south. This was done by considering the geographical and not the magnetic south, and to calculate it the sun was taken as a reference, passing through its zenith in Sotavento at 12 h 31 min and 24 s (according to the longitude at the site, 7.86°). At this time, a perfectly vertical post is erected and via the line of shadow the direction of the solar south is determined.

In this way the main axis is fixed in the South-North direction, resulting in:

• The South facade receiving three times as much solar radiation in summer as in winter. 

• The East and West facades receiving 2.5 times as much solar radiation in summer than in winter.

• The North facade receiving very little radiation, nearly all of it being received during the summer.

Galleries and foundations of the highest thermal transmittance, together with the Trombe walls, are situated to the South, while in the northern area of the residence there are very few windows and it is protected by a mound of earth provided by the earthworks carried out in the laying of the foundations.

The main windows designed fundamentally for illumination purposes are on the east and west facades. The orientation of the residence and the consequent difference in solar radiation received on each of its facades is fundamental to the selection of insulation materials for each side.

From the point of view of material selection:
Using local materials which have undergone as little processing as possible.

From the point of view of energy sources:
The use of renewable and/or efficient sources such as thermal solar, photovoltaic, wind, geothermal heat pump etc.

From the point of view of domotics and control systems:
Over 300 sensors collect data and variables in order to achieve thermal comfort inside the residence, while using as little energy as possible. 

What role or relevance does insulation have in the construction of bioclimatic housing?

It is a fundamental aspect in any building, but more so if it is applied in accordance with the geographical location of the residence. The majority of energy in a building escapes due to inadequate insulation.

What type of insulation has been used in the project?

ROCKWOOL stone wool insulation; made from volcanic rock, over 80% of stone wool residual waste is recycled. The process used is similar to that which happens naturally in a volcano, where rock is melted. This insulation saves 100 times the energy invested in its manufacture, transport and removal thanks to its great insulation properties. It was the best possible option for this project.

With the application of renewable and efficient energy systems which improve the control conditions within housing, what palpable benefits do the tenants receive? What will this improvement lead to? How will the quality of life and comfort of the inhabitants be improved?

There are economic and environmental benefits as well as an improvement in the quality of life. A good example of this is the use of evaporation cooler to cool the residence. Consuming 80% less energy than air conditioning, it is also much healthier as it continually renews the air with which it works.

Another good example is the use of under floor heating which, given its low operating temperatures, does not dry out the indoor air. In addition, the uniform distribution of heat is perfectly adjusted to the needs of the human body.

The emission of pollutants to the atmosphere is greatly reduced by using efficient and renewable systems and reducing the use of energy from fossil fuels. The use of wood leads to significant energy savings and provides comfort and warmth, maintaining the ambient temperature in the residence due to its low thermal inertia.

Introducing these kinds of measures requires a certain level of economic investment, which raises the price of housing. Do you believe that the investment is compensated for by the benefits? What does the application of bioclimatic parameters mean financially?

They logically require a considerable initial investment, but in the long run they are economically and environmentally beneficial. Also, they improve our comfort and quality of life. In this type of building there are no disadvantages, despite the fact that nowadays:

• A lower initial cost for housing is sought, ignoring the fact that this will mean higher energy consumption in the future.

• Energy is "cheap".

• Saving energy tends to be associated with deprivation, lack of comfort and even a loss of social status.

• Up until now, governments and construction professionals themselves have not been initiated a widespread distribution of this type of building.

Do you think that the implantation of bioclimatic architecture within the building sector is an achievable goal in the near future? And is it a trend that contractors and developers are adhering to without making a firm commitment?
The European directives are going in this direction. The setting up of the Technical Building Code (TBC) and Energy Certification for Buildings appear to work towards this goal.  In Europe, people are aware that the construction sector, including the maintenance of buildings, is responsible for between 35% and 40% of the total energy consumption. This project is a great opportunity to explain and make clear the concepts related to both regulations from both a construction and an energy efficiency point of view. I consider administrative intervention to be key to the implementation of this very important type of building.

Could you share an anecdote from the project that stands out?
The residence has two Trombe walls. These are oriented towards the south in the northern hemisphere and north in the southern hemisphere, and in front of them is a glass surface, leaving an air chamber between the two. The glass produces a greenhouse effect, helping to reduce losses of energy to the exterior. Adjustable grills in the upper and lower part allow the movement of air in or out of the residence in such a way that some of the captured heat can be used immediately. It is easy, looking at the plans, to think it is a window, especially if glass has been ordered for the space. Explaining to workers with a wide knowledge and experience in the field of construction that they must block what they believe to be a window in order to construct these Trombe walls has been one of the many challenges in this complicated but very motivational project.