Ventilated façades are among the existing measures to reduce the energy demand in buildings. The combination of this passive heating and cooling strategy with photovoltaics (PV) can drive new buildings towards the current European targets near or even to net zero energy Buildings (nZEB). The present work studies the thermal behavior of the PV integrated ventilated façade applied in the nZEB known as “LUCIA” (acronym in Spanish for “University Centre to Launch Applied Research”) at the University of Valladolid, Spain. The aim is to evaluate the interest of recirculating indoor air within the façade during winter, as an alternative to the present preferred operating mode during the target season, in which the façade acts as further insulation. First, the radiant properties of the PV façade are measured to use the values in a mathematical model that describes the behavior of the ventilated façade in its current operating mode in winter. Then, the solar radiation available, the air-dry bulb temperatures indoors, outdoors and inside the ventilated façade are monitored to obtain experimental data to validate the model. The results show that air recirculation can entail favorable heat gains during 10% of winter, being this alternative preferable to the present operating mode when outdoor temperatures are over 18.4 °C.

High upfront costs that district energy retrofitting entails, implies long-term financing schemes. Moreover, multi-private ownership in Spanish residential sector hinders the decisionmaking process. In the case of CITyFiED project, an innovative business model has been developed between an Energy Services Company and a Building company for Torrelago district renovation. This paper addresses this demo case from a global perspective, identifying the elements of the business case using the Canvas methodology approach and analysing the financing scheme. After a total investment of 16.5 M€, the energy savings achieved enable the payback without increasing the Community fees to the dwellings' owners.