Since the late 1990s, France launched a large program of demolition in public housing located at the periphery of the city. By its extent, spectacular nature and conjunction of interests, this program constitutes a good analyzer of references and institutional representations of space that guide urban policy. The authoritarian action "breaking the ghettos" and "finishing with large ensembles” by blasting them, seems a typical case where political, architectural and urban planning practice can be seen in its full extent. Indeed, these operations of "ground zero", which the equivalent is in brownfields (Graçon, 2002), show you the criteria of normal and pathological judgments in the urban area. These evaluative and praxeological framework, underlying the disqualification of the built environment, reveal, by the negative, but in a "detonating" way, the figures of acceptable and unacceptable urban. With the demolitions we can observe the system of idea of policymakers, technicians and the media. Demolitions make particularly clear the imputation system governing the action on and by space. The postulates and attributes that lead to a reading of large ensemble on the mode of disappointed expectations, failure, deficiency are also those that lead to the formulation of the expected judgments that the media refer to as "criminogenic". Therefore, the “wrecker discourse" appears as a way to capture the socio-political contemporary imagination of space and the city. We therefore consider demolition as an intervention that reveals especially social and institutional expectations vis-à-vis space and action – action being presumed efficient. Our research does not focus on the spatiality («uses of space, the arts do with the space in the everyday life by individuals and groups") but on the space in the meaning of the ecological-ethologism (how configurations of physical space could determine social relations). The demolition of housing estates represent the quintessence of the ecological-technocratic ethologism of the past and it allows to update the way whose the founding postulate of the urban action is redefined today in the system of beliefs of both public actors of urbanization and, often to a lesser degree, the private stakeholders.

« Stock-air 2 » project aims at developing and controlling a technical solution where an air-to-air heat pump is coupled to a thermal storage made of Phase Change Material (PCM) in order to erase the electricity demand during the peak hours between 6 p.m. and 8 p.m. This technical option is relevant for refurbishment of domestic heating by electrical resistance of the current installed base of buildings as well as for the future low-energy buildings. Indeed energy storage by solid-liquid phase change stabilizes the condensing temperature of the heat pump and leads to choose the temperature level leading to the maximization of the seasonal heat pump performance. On another hand the phase change allows steady operation of the thermodynamic system and limits drastically energy losses due to short operation cycles associated to low thermal loads. This project aims at developing upstream research on new materials and applied research on heating d systems including energy storage tested in real operating conditions. Developed PCMs will present phase change levels of temperature adapted to air heating systems i.e. 30 to 50°C. Those PCMs will be integrated in energy storage / delivery heat exchangers. Two main technical options will be studied in parallel: - PCM integration in heat pump condenser taking advantage of high heat exchange coefficients - PCM integration in the air circuit associated with enhance heat exchange surface with circulating air Stock – Air2 project is performed under a double approach: a systemic approach based on numerical simulation, and technologic approach for material and system development with an adapted speed for energy storage and delivery of the chosen heating system. One of the .project originalities is based on solving issues related to phase change delay and incomplete phase changes by integration of PCMs in high heat exchange coefficient surfaces (40 to 500 W/m2.K). One of the project work packages addresses PCM container design. The container required qualities are: a very low permeance to the active material, a good resistance to corrosion, sufficient fatigue strength, a good heat exchange performance. The program will lead to test Two physical demonstrators of storage / delivery heat exchangers: one integrated in a heat pump condenser (indoor unit) and the other integrated into ventilation ducts or plenum. Once those systems are validated by laboratory tests, they will be tested in individual houses with ordinary occupants. The energy performances as well as the comfort felt by occupants will be analyzed.

The long-term depletion of fossil fuel resources and the need, in front of the challenge of climate change, to reduce greenhouse gases leads to energy transition. This new energy and environmental paradigm defines from now on the context in which the city of tomorrow must be built and implies to consider a new space organization that would bring about the sustainable city. Households and companies choices of location contribute to shape the spatial organization of the city. Those choices are now in total contradiction with the new energy, environmental, economic and social requirements. If households and businesses plebiscite of suburban areas is clearly in conflict with the principles of urban sustainability, it is still possible that new environmental and energy constraints will not be enough in themselves to influence private actors spatial dynamics. On the environmental front, the double movement of jobs and residences dispersal to suburban areas made possible by widespread access to an automobile mobility at low costs contributes to increase greenhouse gas emissions. These are related to higher energy consumption of transport and housing, reflecting the longer distances traveled by car and by the expansion of living space linked to the preference for individual house. On the social front, individual home ownership in suburban areas where land is cheaper proves for some households likely to carry an increased instability. Households budgets are already burdening budgets because of transportation costs and indebtedness generated by housing acquisition. This situation threatens to be reinforced in forthcoming years by the sharp rise in energy costs, energy vulnerability accentuating the social vulnerability of some households. Finally, on the economic front, employment easing from center to periphery, an easing both chosen and sustained by businesses, results often in a deterioration of the access to employment for the least qualified employees. In a context of rising energy costs, this situation could pose problems for some employees but also to companies, which, in addition to having to reconcile economic imperatives and environmental requirements, may face problems of recruitment and loyalty of their workforce. In a context marked by a new energy and environmental paradigm, the TRANS-energy project objective is to provide researchers and practitioners with knowledge of households and businesses coping strategies and their contribution to the challenge of reducing greenhouse gas emissions. This project is based on comparative work conducted on the cities of Lille and Lyon. TRANS-energy project is based on a systemic approach, both exploratory and comparative which allows, through a prospective approach, to analyze households and businesses facing these new energy, environmental economic and social constraints abitrations. In addition to the coordination task (T1) the project is structured around four complementary tasks: an analysis of Lille and Lyon spatial organization conducted from various statistical databases (general censuses, household travel surveys, SIRENE files) (T2), a field survey of firms choices of location taking into account the constraints of mobility of their employees (T3), and a field survey of workers of these enterprises and households in homeownership choices of location as well as their mobility patterns and use of housing will be carried (T4). In parallel to these tasks will be carried out methodological work on measuring CO2 emissions generated by households (T5) at a macro level, in conjunction with Task 1, then at the micro level, in conjunction with Task 3.