RESSÒ: energy efficiency urban rehabilitation

Transcription

1 RESSÒ: energy efficiency urban rehabilitation Authors: Bodelon, Carmen 1 ; Gascón, Eduardo 1 ; Ramon, Guillem 1 ; Obiols, Martí 1 ; Palomar, Pablo 1 ; Escoda, Quim 1 ; Prat, Sandra 1 ; Illa, Sergi 1 ; Nadales, Víctor 1 ; Callejas, Xavi 1 1 RESSÒ-UPC-ETSAV, Sant Cugat del Vallès, CATALONIA Abstract: Ressò is an urban regeneration strategy that reinterprets the current lifestyle. Collectivization is our tool to optimize resources and improve users comfort. Ressò triggers a process in the local community that implies a new management of resources. Using this community space throughout years will bring economical savings that could be invested in an energetic improvement of the private space. Urban rehabilitation, energy efficiency, collectivization of uses, resources management URBAN CONTEXT AND STRATEGY The social, economic and environmental crisis in which Spain is immersed lead us to an unsustainable and complex situation that made us rethink about our way of life. In front of a large inefficient building stock and new housing with no demand, it makes no sense to keep building more, instead we must think how to improve the existent one. A big-scale rehabilitation plan is not only necessary, but also affordable. Unfortunately, it seems that nowadays is not working at all, mainly due to a lack of interest of the Government and institutions. However, early or late, we will be forced to do it because of the environmental pressure (20/20/20 objectives) and the cost of the energy. By the other side, we can not just keep complaining about the situation while is getting worse: the unemployment rate is up to 26%, and the energy price, the evicted families (30,000 just in 2013) and the fuel poverty (around 15%) are increasing alarmingly. We must act as soon as possible and we firmly stand that the key in this rehabilitation is the people. The solutions might arrive through the collectivization and the pedagogy. In time of crisis, when the usual models do not work, we must rethink and propose nonconventional solutions in order to change the situation. As a future professionals compromised with the society, we should impulse an energetic rehabilitation promoting the social cohesion, granting the comfort of the vulnerable people and spreading the awareness about the importance of the resources. The way to do it is working on the user behaviour, that is as important as to the intervention on the buildings. 1

2 In that way, we define Ressò as an urban temporary strategy, that reinterprets the way of life and its objective is to solve the social and energetic weaknesses of a specific urban context. This strategy is a working method applicable to different urban fabrics and would be materialized according to the complexity of every context. However, is just a theoretical strategy that we need to test and is indispensable to implement it in a real urban context. Consequently, we analysed different urban fabrics in our close surroundings that could be indicated places to implement the strategy. Beside they are quite different, they have common characteristics like low efficiency buildings or people with difficulty to pay their energy. These places are Badia del vallès (high density), Sant Cugat (medium density), Sant Muç (low density) and Can Montmany (super-low density) Diferents urban fabric proposals: Badia, Sant Cugat, Sant Muç and Can Monmany REAL URBAN CONTEXT In this case, we have chosen the low density suburb of Sant Muç to make real our strategy. The rehabilitation in low density is an interesting challenge for us due to is a difficult fabric to rehabilitate and most people in Europe live on a single-family dwelling. Moreover, Sant Muç is characterized by our target: high energy inefficiency housing and medium-low rent population, that many times is fuel poverty risk. On the other hand, the important lack of services force their inhabitants to move by car to the city of Rubí, which it is located 4 km away. The strategy in Sant Muç consists in a network of 5 collective houses. These Ressò houses will satisfy the needs that people could not satisfy in their homes allowing domestic and social activities, both collectively. Thus, Ressò will strengthen the social relations, allow energetic and economic savings by reducing consumptions and will be a shelter for vulnerable people. However, the most important is the function of the house as a teaching tool. The neighbours will satisfy their needs in a zero energy house, and through the experience they will learn about a new way of living responsible with the environment. Once they experienced the lowenergy systems of the house, they would be interested in apply the rehabilitation in their homes in a next future. 2

3 RESSÒ s EMBODIMENT Ressò space s materialization will depend on the reality of every single urban fabric where it is implemented and should be adapted to every particular case depending on the needs, resources and opportunities found there. However, Ressò always follows a material strategy based on the use of as less resources while accomplishing as much requirements as possible. According to this, we base the materialization on the balance between the following concepts: - Availability: real access to human resources and materials. - Affordability: in relation with time (assembly, transport, machinery...) and cost (sponsorships, institutional support, materials, manpower ) - Effectiveness: in accordance with the performance and accuracy to its aim which basically are functional, adaptation to the context and ecological requirements. Thus, we pursue equilibrium between a good functioning of the building, its economic cost and materials and humans resources needed to carry it out. Proposal s basis remains in the potential social synergy of collectivization- both in urban and in energetic needs. Ressò space may accomplish with some requirements: - The size will be defined as a balance between number of users, maximum surface (determined by the urban context) and an appropriate height. - The space has to be flexible and adaptable in relation to the needs of its use, allowing it to be either a single space to develop a single activity or multiple spaces for several activities. The adaptability of the space goes hand in hand with the users conditions. - It has to offer affordable comfort (affordable warmth),-by which we do mean it has to be provided at no cost to the users. It can be achieved if the space is self-sufficient; - energetically speaking- thus the space is disconnected from the main electricity supply. So it has to be able to generate all its demanding energy. - It may be self-buildable by which we do mean users have to comprehend how systems are applied in this space work. They may arrive to get basic knowledge of these systems that may allow to apply them to upgrade their own homes. - Both low technical and suitable-to-build solutions should be prioritized in order to reduce the use of machinery. There are two key reasons for this; Firstly, the comprehension of basic concepts of daily functioning of the home, secondly the 3

4 awareness of the users. Make them understand that they may improve the habitability of their homes taking an active part in its performance. - Promoting the change from a passive user to an active user, conscious of both the importance of resources and a more responsible way of living according to the current situation. Ressò triggers both a process in the local community that implies a new management of resources (water, energy, food, mobility and waste) and a space which may meet urban fabric needs. The fact of collectivizing may be a strategy to generate new programs and activities which may arrive to supply new future realities. RESSÒ s ENERGY STRATEGY Ressò prototype interior view Occupancy and activities in Ressò space can be so many and so different that we can not understand comfort as a fixed number. For that reason, we use comfort as a much wider range that depends on many factors (relative humidity, radiant T, occupancy...) and that is adaptable to the different situations. Also, we must understand the prototype on its second live as a place where the society awareness of a correct and efficient use of energy and resources is basic (energy culture). To achieve this, we suggest the prototype s energetic self-sufficiency as a didactic method. In this way, the building will offer affordable warmth as many days as possible, making use of low technified climatic systems that allow the user get to know bioclimatical architecture concepts they could apply to their own homes. The main passive strategies of Ressò space are: - PROTOTYPE S ENVELOPE Ressò s envelope has a bioclimatic design formed basically by: a) Three insulated faces in order to minimize energetic losses where the building exchanges more energy with the exterior: the roof and façades oriented to northwest and north-east respectively. 4

5 b) One face with thermal mass in order to provide inertia to the building. This allows the prototype to flatten its temperatures and to depend less of the exterior conditions. c) Two faces oriented to south-east and south-west in order to follow the sun path and therefore manage the radiation that arrives to the building throughout the day. - FLOOR S THERMAL INERTIA Ressò s soil embodiment made as a huge mass which absorbs energy and releases it later to balance the interior temperature when needed. In summer, during the day it absorbs the excess of heat in the prototype and at night, ventilation is forced so the floor is able to dissipate all the accumulated energy. In winter, it receives direct solar radiation and stores energy in order to condition the space passively. - DOUBLE SKIN FAÇADE It manages the radiation that arrives to the prototype and has three basic positions: a) Summer: using a screen inside the double skin we avoid radiation entering the prototype. Also, due to the temperature and pressure differences between the upper and lower part of the façade inside chamber, solar chimney effect occurs in order to evacuate the overheated air not only from the double skin, but from the interior space too. b) Winter day: let the radiation come inside in order to heat the floor. Also, the hot air inside the chamber is recirculated inside the prototype by opening the inner skin windows. c) Winter night: the double skin works as thermal buffer, improving the façade s U value. - VENTILATION Ventilation strategy is mainly based in the crossed and night ventilation of the space. The last one helps inertia to start in the morning at a lower temperature to absorb more heat during the day. Both - PARTITIONING The prototype must be able to adapt to different occupation situations. Therefore it is necessary to have a system of partitioning the space which is easy to mantle and dismantle and that increases the efficiency of the underfloor heating by reducing the volume. 5

6 - AIR RENOVATIONS 4 of the double-skin panels are specialised on air renovations and air quality. Inside them, plasterboard is accumulated in order to maintain hot air inside the façade chamber. A vent in the upper part puts hot and clean air inside the prototype and therefore minimizes energy looses during air renovations. Our prototype is a machine but plugged to the environment, as it achieves comfort basically through these passive systems. But we do assume that depending on the weather and internal conditions the prototype might be beyond comfort ranges during some periods of time. To maintain comfort also in those moments, we use active systems. Our only HVAC system is the underfloor heating and its objective is, by circulating hot or cold water, to strengthen what the floor s inertia achieves in a passive way: to flatten the interior temperatures. It is a system that influences very positively in the user s comfort as it modifies the operative temperature of the space. This means that it not only changes the air temperature, but also the radiant temperature of a surface that is in constant and direct contact with people. The system consists of 10 panels of 2x5 m. each, and it is possible to activate all of them or only some (as in the case of the SDE competition). The temperature of the supplied water is the same for all the pieces (40 ºC) and the way of controlling the power of each panel of the floor is regulating the water flow. Hot water is obtained from vacuum tubes and cold water from a dissipation system under the prototype. Using Design Builder and similar tools we searched for an optimal design of the floor. First, regarding the final position of all its components (distance between the water pipes and the inner surface, total thickness of the floor...) and then regarding the usage schedules. CONCLUSION Ressò s final aim is to speed up the individual rehabilitation process through the pedagogic task done by the prototype. The individual rehabilitation will be financed through a low-interest credit supported by the Government and that would be returned with the future individual Ressò prototype exterior view 6

7 house savings in energy costs and a little amount of money saved thanks to Ressò. For those who can not pay their comfort, they will not be able to upgrade their home or they will do it at a very long term. In these cases their comfort will be granted by using more often the Ressò house. 7