# Envisaging a European Digital Building Renovation Logbook: Proposal of a Data Model  
[PERSON]  
1 Built4 Life Lab, ISA-University of Zaragoza, 50018 Zaragoza, Spain; [EMAIL_ADDRESS] (M.G.-G.); [EMAIL_ADDRESS] (A.E.-E)  
[PERSON]  
2 Department of Informatics Engineering, Faculty of Science & Technology, University of Coimbra, 3030-290 Coimbra, Portugal; [EMAIL_ADDRESS] (S.K. ); [EMAIL_ADDRESS] (A.C.)  
[PERSON]  
3 INESC-Institute for Systems Engineering & Computers at Coimbra, 3030-790 Coimbra, Portugal; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Informatics Engineering, Faculty of Science & Technology, University of Coimbra, 3030-290 Coimbra, Portugal; [EMAIL_ADDRESS] (A.C.)  
[PERSON]
The concept of the DBL can be traced back to building use and maintenance manuals and Energy Performance Certificates (EPCs). Manuals are designed to prevent the occurrence of pathological symptoms due to improper use; enhance comfort, health, and safety; and promote water and energy conservation as well as pollution prevention [7], while EPCs assess the energy efficiency of buildings and suggest actions for improvement [8]. However, buildings' data collection tools became more closely associated with renovation when the Building Renovation Passport (BRP) emerged. The BRP aimed at providing clear roadmaps for staged, deep energy renovations, assisting owners and investors in planning the optimal timing and scope for interventions. According to the literature [9; 10], the BRP consists of two parts: a renovation roadmap and a DBL, which acts as a digital repository of all the relevant data and documentation of a building [1] necessary to create a renovation roadmap. Thus, the DBL emerged as a key component in the renovation process. In the last years, the idea has arisen to create an independent DBL (not necessarily linked to the renovation roadmap) that is common across the entire EU. Some H2020 research projects have been developed with the aim of establishing DBL proposals for different types of buildings. In the case of iBroad [11] and ALDREN projects [12], the DBL is considered a constituent part of the BRP, while, in X-Tendo project [13], the DBL is linked to the EPC. In parallel to the mentioned initiatives, some actions are being promoted by the EU to foster the design and implementation of the tool. One of the most significant developments was the inclusion of a definition for the DBL in the EPBD recast [1]. Additionally, the EC commissioned a detailed three-volume report titled 'Study on the Development of a European Union Framework for Building's Digital Logbooks\" [14; 15; 16], published in 2020, and a project named \"Technical Study for the Development and Implementation of Digital Building Logbooks in the EU\" [17], which was led by Ecorys, TNO, Arcadis, and Contecht. Finally, the EC awarded three research projects within the Horizon Europe called \"Demonstrate the use of Digital Logbook for buildings\", which are under development. In addition to these EU-promoted initiatives, independent research is also being conducted focusing on reviewing existing DBL proposals [18; 19], addressing new functionalities of the tool [6; 20], analysing its existing and future data sources [21; 22], and studying its data structure [23] and its relationship with digital twins (DT) [24]. Despite all the research that is being conducted on the topic, a full data model of the DBL has not been published so far. In this sense, only one paper proposing an Industry Foundation Classes (IFC) data structure and ontology focused on the operation and maintenance phase of buildings based on DTs was identified [24]. Also, a DBL ontology is proposed in [17]. It is also important to highlight that among all the research conducted, only in [PERSON] et al. [20; 21; 22] is the connection between DBL and deep energy renovation explicitly revisited. To address the existing knowledge gaps, this paper aims to introduce two key novelties:  
* The first is the introduction of a new variant of the DBL, the Digital Building Renovation Logbook (DBrL).