Anna Noguera and Javier Fernandez won the 2014 competition for the Sports Centre Turó de la Peira in Barcelona. They designed a sustainable building with a public garden that is intended to provide new impulses for the urban development of the quarter. In our interview, Anna Noguera answers questions on early concepts, construction processes and her ideals.
Turó de la Peira is located in a very low-income neighbourhood of the city. How did this circumstance influence your design?
Anna Noguera: Barcelona’s north was originally characterised by agriculturally used areas and buildings. In the 1960s, when many people immigrated to Spain, large social housing blocks were built there, but hardly any public space or infrastructure. The construction site is located in the interior courtyard of one of these blocks. A run-down indoor swimming pool had already been located here. We transformed the existing concrete coverage into a public garden. It serves as a space of encounter for the entire quarter. We were able to create the space only because we stacked the new sports facility and indoor swimming pool. Aside from the immigrants who live in the quarter, there are also many Catalonian residents who have been here all along. They are all very dedicated. Through their aspirations and demands, they influenced the project in a positive way.
These days, many sports buildings are used in a multifunctional and flexible way. Is this the case here as well?
Since it is a public facility, the municipality also uses it for other events. Most of the time, clubs and school children use it for training and physical education. The two halls are independently accessible and only connected by an internal staircase. Access is very complex, due to the elevation difference of 8 m on the site. This is why the swimming pool is partially dug into the site and has its own entrance with locker rooms at the garden level. Small, handicapped accessible pathways along the terraced green spaces connect it to the street above and the main entrance to the sports hall. In addition, two pathways between the facade and the vertical green lead visitors directly into the hall: a ramp from the street level and a staircase from the garden level.
The green facade serves as a natural sunscreen. For this purpose, how does the vegetation need to perform?
We planned a 30 % share of deciduous plants. Only 10 % remained on the northern side of the building. The facade is supposed to be green all the time and we actually need sun protection on all sides. Not all plants adapted to the situation and we had to replace some species. We selected a lightweight hydroponic system with good water holding capacity. A tank on the lower level collects rainwater for watering plants. The vegetation was planted in a bed made of mineral wool, a compatible and durable solution. All planters are connected to lines for water and nutrients and feature a drain. The system is automated. Neither soil nor planting substrate are required. The steel plant lattice is suspended from the facade. The solution may seem rather technical and it needs to be controlled all the time. However, it has proven successful.
You worked with dynamic software programs. What exactly did you simulate?
We used a program to test our theory-based planning approach for a passive energy system. The sports hall operates without climate control or mechanical ventilation equipment and, instead, with natural lighting throughout the entire lifecycle. For a room with a capacity of 800 people who, perhaps, visit a celebration at summer temperatures of 30 °C we needed to be sure that the concept actually works well.
During early planning stages, had there been any discussions on choosing a material other than timber for the structure?
Timber was our first choice, always. In order to be sure that it was the best choice, we analysed many different options. Steel is recycled to 70 or 80 %. That is why it is also sustainable. We were able to use it for the green facade. However, it wasn’t suitable for the interiors of the swimming pool. Corrosive substances such as chlorine result in a strong need for maintenance. Concrete was out of the question, due to its bad environmental performance. Prefabricated concrete elements are also very heavy and in-situ concrete leads to long construction time.
A structure with timber columns, beams, roofs and walls is a great convenience. We worked with only one contractor and everything proceeded rather quickly. Prefabricated elements were delivered on-site and assembly took only eight weeks. The pine wood that we used comes from the Basque region. However, we found only one domestic company that had the capacity to work on a project of this size.
To which degree was the structure prefabricated?
The elements were completely prefabricated, including walls and ceilings. The roof beams above the swimming pool are 2.5 m tall and span 19 m in length. The lighter trusses of the sports hall have the same height, yet a greater span of 23 m. The columns are uninterrupted, 6.5 m tall on the lower level and 8 m tall on the upper level. That means 15 m altogether! Due to the length of the columns trucks delivered them directly from the Basque region. We planned for transport in August when the traffic volume is low.
Did the timber used for the swimming pool require any special treatment or finish?
That question led to a heated debate among the experts! Eventually we decided to omit any treatment of the timber. When we renovated a different swimming pool with a timber roof structure, in 20 years of operation the trusses were still in excellent condition, even though they had only been treated with an insecticide. In our new swimming pool we also have no problems whatsoever. Prior to that, we did a number of calculations, of course. The aim was to avoid all damage to the sports hall floors above the pool.
Is there anything that, in hindsight, you would have done differently?
To be honest, the basic things I would do just the same. Many people have a say in the course of a project, such as city councilpersons or members of sports clubs or the residents. In this case, it had a positive impact on the project. The green facade and the timber structure were questioned, but we were able to successfully defend the most important decisions. Elsewhere, we adopted justified suggestions for change. Barcelona’s city council organised three presentations of the project for the approval of the residents. I think that makes a lot of sense. Here’s an anecdote: The sports centre received high quality interior finishes. Yet during construction, inexpensive flooring was selected for the hall floors. After all, it’s a public building and you don’t want it to be luxurious. But the residents demonstrated in front of city hall. For their timber building, they also wanted high-quality timber flooring! Eventually, they succeeded with their demand.
What was particularly important to you during the planning of the sport centre?
A sports building doesn’t have to be a purely functional, cold building. In the case of other public sports facilities, surfaces are typically concrete, composite materials or plastic, and lighting is rather austere. Our building, on the other hand, conveys a different impression. It’s a big difference whether people play basketball at 8 o’clock in the evening in a hall lit by natural daylight or artificial lighting. The light in the hall is truly spectacular. Another example: do you see plants in front of the facade, or instead, a concrete wall? The sports hall can be accessed from the green gallery, where flowers appear in your field of vision, again and again. Visitors appreciate this very much and that makes us very happy.
“We found only one timber construction company in Spain that was capable of handling a project of this dimension.”
Aims and concepts
When we developed the concept for the sports centre it was important to us to act in an environmentally sound way and, at the same time, create a comfortable space for people. We used passive systems that are calculated by simulation programs and complemented by highly efficient technologies. We were able to minimize energy consumption and produce or reclaim energy through renewable sources to meet the remaining demand. The building consists of local, recycled or reused materials and recently received the LEED Platinum certification.
Innovative systems for passive architecture
In order to keep energy consumption as low as possible, the building features a compact design. This reduces the facade surface and resulting heat losses. The heated indoor swimming pool is partially embedded into the sloping site. The thermal storage mass of the surrounding earth contributes to maintaining stable temperatures indoors and reduces heating and cooling loads. Corresponding with the sun’s orientation and spatial requirements, dynamic simulation programs selectively calculated the building envelope: Energyplus by DesignBuilder optimises ventilation and temperature, while Radiance does the same for natural ventilation. Openable areas, materials and insulation thickness are determined to meet the best possible criteria for comfort and wellbeing in relation to the particular climate conditions.
Nearly Zero Energy – the sports hall
Based on the calculations and the coordination of facades and facade openings the sports hall permits near-complete natural ventilation, temperature control and lighting. Sensors monitor temperature, humidity and CO2 concentration and activate the openings. 24 skylights and 11 windows enable cross ventilation. The system makes use of summertime air streams and wintertime sunlight intake. The aim is to maintain the required temperature range of 14° to 27 °C in the hall. Double glazing (U=1.24 W/m2K) in combination with polycarbonate panels proved sufficient for the facade. The polycarbonate’s capacity to let daylight pass through it, the glazed surfaces and the skylights guarantee that natural daylight can enter the hall throughout the entire day. The green curtain wall facade provides the necessary sun protection and serves as additional temperature buffer.
Efficient technologies – the swimming hall
In the swimming hall, air temperature needs to be constant at 30 °C and water temperature needs to be 29 °C. The hall features triple glazing (U=0.80 W/m²K). To limit energy consumption further, a highly efficient aerothermal system with heat reclamation utilises the residual heat of cooling processes to heat up shower water and supplies more than 90 % of summertime energy demands. The dehumidifier is in operation throughout the year and includes a heat pump that contributes to heating the pool water. During specific hours it can cover the entire daily hot water demand. Mild temperatures contribute to better performance, therefore production takes place during summertime nights and during winter days. Environmental conditions can be utilised this way only because the heat pump was combined with an adequate hydraulic configuration that permits storing up to 110 % of estimated daily water demand and making it available at a later time. The primary energy demand of the building is 45.13 kWh/m² per year. Within the simulation, energy demands were reduced to 58 % by configuring all areas to receive daylight as long as possible. Sensors can supplement highly efficient electrical lighting if daylight intake becomes insufficient. The circulation spaces and the locker rooms are equipped with motion sensors and timer switches that activate the electrical lighting as soon as someone enters.
Renewable energy and consumption
Aside from the heat pump, photovoltaic panels on the roof provide energy that corresponds to an output of 97 kWp or 95,534 kWh per year. This amount of energy can cover one quarter of the overall energy demands of the building. Continuous monitoring of the building during two years of operation indicated that project prognoses were met and the energy demands matched only 35 % of a comparable building with similar characteristics. The concept not only contributes to countering climate change through energy efficiency, but also offers its users a sustainable and comfortable environment.
