The challenge of the characterisation of the building stock

The challenge of the characterisation of the building stock

It is well know that more than a third of the total final energy consumed in the European Union is consumed in residential and tertiary sector buildings. For this reason, in recent years, various directives and calls for proposals have tried to promote the renovation of buildings under energy efficiency criteria.

One of the directives in this field is the EPBD (2018/844 Energy Performance of Buildings Directive). This standard is the main European directive aimed at helping to reduce energy consumption and increase energy efficiency in buildings. This directive introduces the energy certificate as an official document that includes objective information about the energy characteristics of a property or building (you can learn more about energy certificates in our post ” Are energy performance certificates really useful?”). The information provided by these certificates (mainly energy demand and consumption, as well as associated CO2 emissions) is a valuable source of information to know the state of the buildings and thus be able to propose appropriate measures for the improvement of these buildings. Certification tools validated by a certification body are used to generate these certificates. You can check the tools validated in the case of Spain and technical documents that have been recognised by the Ministry for Ecological Transition and the Demographic Challenge and by the Ministry of Development in Spain and that can be used to support the building energy certification process. In these tools, the building information is introduced and the certification values are automatically calculated.

In addition to the validated energy certification tools on the market, there are many tools for modelling and simulating the behaviour of buildings. This is the starting point for the design of building renovation projects, since before the selection of the measures that could improve their consumption and emission parameters, a quantitative assessment of the building stock as realistically as possible is necessary. However, most of the tools available on the market works on a small scale (building,house,premises,etc.) and the generation and simulation of models for grouos of buildings (districts or cities) is a huge task. Undoubtedly, the problem of scale is one of the weak points of current tools when analysing districts or cities.

In CARTIF, for years, we have been working on the automatic generation of models to be able to characterise as automatically as possible the buildings of a certain location (district, municipality and even region) by calculating demand and consumption values using public information sources (cadastre and catalogue of constructive elements mainly) and different calculation engines. In addition, it has been proven that one of the fundamental aspects is certainly the addequate presentation of the results in an attractive, interactive visualisation that is able to provide all relevant information.

As a result of several projects in this line, CARTIF has designed and developed the visualisation tool GIS4ENER that offers the visualisation of several approaches:

(1) The estimation of demand calculation based on the automation of the CE3X certification tool for the calculation of large-scale buildings (neighbourhood or city)

(2) The generation of estimated values of demand, consumption and CO2 emissions through the application of automatically generated typologies with the study of the results reflected in real Energy Performance Certificates (EPCs). It also allows the results of both approaches to be compared with these EPCs.

You can access to a demo of the GIS4ENER tool. In this demo the functionalities of the tool are presented with results obtained for the municipality of Tordesillas in the province of Valladolid (Spain).

At the moment the tool has been tested in several municipalities but it has the potential to be applied in any municipality in Spain, except those located in Navarra and the Basque Country.

There are many user groups that could benefit directly from this tool. Among them: regulatory bodies; public administrations; consultancies and energy companies; engineers, architects and urban planners; and construction companies. Our tool would allow to obtain a mapping of energy demand and consumption (as well as CO2 emissions) associated with buildings in a district or region, in much shorter time compared to obtaining the same with conventional methods. Undoubtedly the simplification of this step could bring a great benfit to al these users in their energy planning processes at various scales, development of strategic and business plans in certain districts or cities.

From CARTIF, we will continue to work on the research and development of tools that can continue to help reduce the impact of human beings on the environment.

Improving our cities with ICTs

Improving our cities with ICTs

In the European Union 40% of the total final energy is consumed in residential and tertiary buildings. That is reason behind several European Directives established with the aim that the Member States develop long-term strategies encouraging the renovation of residential and commercial buildings applying specific energy efficiency criteria. In order to define efficient strategies they have to be established in a holistic way; beyond individual buildings and thinking in wider terms of districts and cities. For this reason, several research projects are nowadays exploring the best way to perform retrofitting activities with those results in mind.

Nonetheless, the definition of a retrofitting strategy for any neighbourhood or any city is a trivial issue. There are many factors that must be analysed before proceeding with such intervention. Although the objectives to be achieved are often clear (reduction of energy consumption, reduction of greenhouse gas emissions, including renewable energies, etc.), the method to achieve those objectives is variable and different measures can be applied to the same scenario with varying degrees of success. The analysis of the most effective measures in cost-benefit terms requires of a considerable amount of information about the considered area and carrying out a series of complex calculations that allow to obtain indicators associated with the several possible interventions that may take place.

So it is at this point that the use of ICT (Information and Communication Technologies) adds value: performing calculations through simulation tools (including energy, costs and environmental aspects among others) the analysis of the different scenarios is more accurate and also tedious manual processes prone to failures are automated. However, although different simulation tools are available in the market a single specific tool that fully automates retrofitting interventions just does not exist nowadays.

In this regard, CARTIF is currently working on several projects aimed at creating such tools for designing retrofitting projects in cities such as the new project Nature4Cities or OptEEmAL, started in 2015. Both projects are funded by the European Commission under the Horizon 2020 R&D programme.

Nature4Cities aim is the development of a tool to support design of energy retrofitting projects in urban environments by applying Nature Based Solutions (NBS). This type of solutions has already been covered by my colleagues in a previous post.

On the other hand, OptEEmAL project focuses on developing a design platform for energy retrofitting projects at district level. Working with input data provided by the user (BIM, CityGML and other type of data) the OptEEmAL platform automatically generates and evaluates possible retrofitting scenarios based on implementing a set of measures for energy conservation.

Such measures are contained in a catalogue according to a data model based on standards (such as IFC). The solutions included in this catalogue are both passive (envelope improvements, change of windows) and active (concerning energy generation systems, renewable energies or control strategies) and are applied both at building and district level. These measures may be generic solutions with default values or specific solutions provided by commercial entities.

In order to evaluate the various potential scenarios, a set of performance indicators are analysed and then categorised into different categories: energy, comfort, environmental, economic, social and urban. Once the optimisation has taken place, the OptEEmAL platform shows to the user the solution with better results in terms of indicators. As a result of the process OptEEmAL provides the user with very detailed information on the retrofitting project.

CARTIF will continue working in this area of knowledge with our strong commitment to support energy efficiency and ultimately improve the cities and places where we live.