Calibration procedures for multidimensional heat transfer models based on on-site experimental data

An experimental and numerical approach to the characterization of thermal bridges is presented, based on on-site taken measurements. Commonly on-site applied numerical thermal assessments perform one-dimensional heat transfer analysis over planar elements such as facades. However, it is well known that within thermal bridges in a building one-dimensional heat transfer analysis cannot be applied. A procedure is proposed, based on the creation of a numerical 2D thermal model which is calibrated against experimental data from several temperature and heat flux sensors which are located at specific points in the thermal bridge elements. Results of one particular implementation of this method are discussed

Energy transition towards sustainable districts through renewable energy nodes

Actualmente, los edificios son los causantes del 36% de las emisiones de CO2 en Europa, lo que los convierte en uno de los objetivos principales de actuacion local para el cumplimiento de los objetivos energeticos y medioambientales de la Union Europea (UE). Para alcanzar la transicion hacia barrios sostenibles y neutros en carbono es necesaria una regeneracion urbana hacia los edificios de consumo casi nulo (nZEB) o incluso, siendo mas ambiciosos, edificios energeticamente positivos. Para conseguirlo, no solo se deben construir nuevos edificios para que cumplan estas exigencias, sino que el parque edificado actual debe ser rehabilitado con el fin de reducir su demanda energetica, la cual deberá ser cubierta en gran medida por energias renovables. Sin embargo, la integracion y gestion de algunas tecnologias, como la solar termica y fotovoltaica, en los edificios presentan un reto debido a la intermitencia de las mismas, el desajuste entre las horas de generacion y las de consumo en sectores como el residencial, o la disponibilidad de espacio para desplegarlas

Comparison between Energy Simulation and Monitoring Data in an Office Building

One of the most important steps in the retrofitting process of a building is to understand its pre-retrofitting stage energy performance. The best choice for carrying this out is by means of a calibrated building energy simulation (BES) model. Then, the testing of different retrofitting solutions in the validated model allows for quantifying the improvements that may be obtained, in order to choose the most suitable solution. In this work, based on the available detailed building drawings, constructive details, building operational data and the data sets obtained on a minute basis (for a whole year) from a dedicated energy monitoring system, the calibration of an in-use office building energy model has been carried out. It has been possible to construct a detailed white box model based on Design Builder software. Then, comparing the model output for indoor air temperature, lighting consumption and heating consumption against the monitored data, some of the building envelope parameters and inner building inertia of the model were fine tuned to obtain fits fulfilling the ASHRAE criteria. Problems found during this fitting process and how they are solved are explained in detail. The model calibration is firstly performed on an hourly basis for a typical winter and summer week; then, the whole year results of the simulation are compared against the monitored data. The results show a good agreement for indoor temperature, lighting and heating consumption compared with the ASHRAE criteria for the mean bias error (MBE).This research was supported by the A2PBEER project “Affordable and Adaptable Public Buildings through Energy Efficient Retrofitting” under grant number 609060 funded by the European Commission for providing resources for the monitoring system. The APC was funded by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund through the project called “Investigation of monitoring techniques of occupied buildings for their thermal characterization and methodology to identify their key performance indicators”, project reference: RTI2018-096296-B-C22 (MCIU/AEI/FEDER, UE)

Comparison between Energy Simulation and Monitoring Data in an Office Building

One of the most important steps in the retrofitting process of a building is to understand its pre-retrofitting stage energy performance. The best choice for carrying this out is by means of a calibrated building energy simulation (BES) model. Then, the testing of different retrofitting solutions in the validated model allows for quantifying the improvements that may be obtained, in order to choose the most suitable solution. In this work, based on the available detailed building drawings, constructive details, building operational data and the data sets obtained on a minute basis (for a whole year) from a dedicated energy monitoring system, the calibration of an in-use office building energy model has been carried out. It has been possible to construct a detailed white box model based on Design Builder software. Then, comparing the model output for indoor air temperature, lighting consumption and heating consumption against the monitored data, some of the building envelope parameters and inner building inertia of the model were fine tuned to obtain fits fulfilling the ASHRAE criteria. Problems found during this fitting process and how they are solved are explained in detail. The model calibration is firstly performed on an hourly basis for a typical winter and summer week; then, the whole year results of the simulation are compared against the monitored data. The results show a good agreement for indoor temperature, lighting and heating consumption compared with the ASHRAE criteria for the mean bias error (MBE).This research was supported by the A2PBEER project “Affordable and Adaptable Public Buildings through Energy Efficient Retrofitting” under grant number 609060 funded by the European Commission for providing resources for the monitoring system. The APC was funded by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund through the project called “Investigation of monitoring techniques of occupied buildings for their thermal characterization and methodology to identify their key performance indicators”, project reference: RTI2018-096296-B-C22 (MCIU/AEI/FEDER, UE)

Gatazken lorratzak. Euskal arazoen isla narratiban 1936tik gaurdaino

164 p.Gerra Zibila amaitu zela 75 urte badira ere, iragan hurbilean euskal gatazkak utzitako zauriek oraindik ere irauten dute. Zenbait euskal idazlek beren fikziozko prosan gatazken arazoa nola lantzen duten aztertzen da lan honetan. bitarteko poetikoez baliatuz historiatik narrazioara egindako hurbilketa da.Lan hau UPV/EHU-ren GIC 10/100 eta Eusko Jaurlaritzaren IT 495/10 ikerketa programei esker burutu da

Energy efficiency achievements in 5 years through experimental research in KUBIK

The European construction sector (a fragmented SMEs dominated business with high economic and environmental impact and high technological inertia) faces a major challenge to reduce the emissions by almost 90% in 2050. This requires new innovative solutions and services to be rapidly implemented in the market. Research Infrastructures that give support for later-stage developments (high Technology Readiness Levels) can play a relevant role in both the technological development and market introduction of construction products for energy efficient buildings. The following paper describes such an infrastructure (KUBIKby (Tecnalia)) located in Bilbao (Spain) and its major outcomes in the period 2011-2015.Spanish Ministry of Education and Science, Spanish Ministry of Science and Innovation, European Regional Development Fund, European Union Seventh Framework Program, Basque Governmen

Temperature based maximum power point tracking for photovoltaic modules

In this article authors propose a temperature based Maximum Power Point Tracking algorithm (MPPT). Authors show that there is an optimal current vs maximum power curve that depends on photovoltaic (PV) module temperature. Therefore, the maximum power point (MPP) can be achieved in very few commutation steps if the control forces the PV module to work in temperature dependent optimal curve. Authors shows how this PV module temperature based MPPT is stable and converges to MPP for each temperature. In order to proof its stability, authors propose a Lyapunov energy function. This Lyapunov energy function has positive values for all values except into MPP given the PV module temperature. This Lyapunov energy function has negative increment along each time step. Hence, the stability of temperature based MPPT can be demonstrated. The proposed MPPT algorithm proposes a current set point. This current set point is obtained with instantaneous PV module power and temperature dependent maximum power vs optimal current curve. Stability is analysed for different temperature levels. Optimal current vs maximum power curve has been modelled by a line. The lines' coefficients depend on PV module temperature. Proposed Lyapunov energy function is not symmetric about equilibrium or MPP because MPPT algorithm and PV module dynamic have no symmetric behaviour about this equilibrium point."Development Agency of the Basque Country (SPRI) is gratefully acknowledged for economic support through the research project "Refrigeracion de dispositivos de alto flujo termico mediante impacto de chorro" (AIRJET), KK-2018/00109, Programa ELKARTEK.

Temperature based maximum power point tracking for photovoltaic modules

In this article authors propose a temperature based Maximum Power Point Tracking algorithm (MPPT). Authors show that there is an optimal current vs maximum power curve that depends on photovoltaic (PV) module temperature. Therefore, the maximum power point (MPP) can be achieved in very few commutation steps if the control forces the PV module to work in temperature dependent optimal curve. Authors shows how this PV module temperature based MPPT is stable and converges to MPP for each temperature. In order to proof its stability, authors propose a Lyapunov energy function. This Lyapunov energy function has positive values for all values except into MPP given the PV module temperature. This Lyapunov energy function has negative increment along each time step. Hence, the stability of temperature based MPPT can be demonstrated. The proposed MPPT algorithm proposes a current set point. This current set point is obtained with instantaneous PV module power and temperature dependent maximum power vs optimal current curve. Stability is analysed for different temperature levels. Optimal current vs maximum power curve has been modelled by a line. The lines' coefficients depend on PV module temperature. Proposed Lyapunov energy function is not symmetric about equilibrium or MPP because MPPT algorithm and PV module dynamic have no symmetric behaviour about this equilibrium point."Development Agency of the Basque Country (SPRI) is gratefully acknowledged for economic support through the research project "Refrigeracion de dispositivos de alto flujo termico mediante impacto de chorro" (AIRJET), KK-2018/00109, Programa ELKARTEK.

“Plug and play” modular façade construction system for building renovation to achieve nearly Zero Energy Building (nZEB)

Following energy performance improvement policies, there is a need for the massive renovation of the European building stock. The prevalence of multi-rise buildings with concrete structure and poor thermal performance offers a significant opportunity for renovation packages that facilitate the improvement of the building fabric, with its insulation, air-tightness and integration of building services and solar technologies. The RenoZEB project develops a "plug and play" modular facade construction system answering to this need. This prefabricated plug and play modular system has been tested by reproducing the holistic methodology and new technologies in the market by means of real and virtual demonstrators. The applicability and effectiveness of the methodology has been tested by means of a full-scale mock-up system has been constructed and installed in the KUBIK by Tecnalia test facility. The design, construction, manufacture & installation cycle has been tested. Its applicability for a real construction project for a multi-rise residential building in Spain is presented.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 768718

Plug and Play Modular Façade Construction System for Renovation for Residential Buildings

The present paper focuses on the architectural and constructional features required to ensure that building envelope renovation are safe, functional, and adaptable to the building stock, with particular focus on “plug and play” modular facade construction systems. It presents the design of one such system and how it addresses these issues. The outcome of early-stage functional test with a full-scale mock-up system, as well as its applicability to a real construction project is presented. It is found crucial to obtain high quality information about the status of the existing façade with the use of modern technologies such as topographic surveys or 3D scans and point cloud. Detailed design processes are required to ensure the compatibility of manufacture and installation tolerances, along with anchor systems that deliver flexibility for adjustment, and construction processes adapting standard installation methods to the architectural particularities of each case that may hinder its use or require some modification in each situation. This prefabricated plug and play modular system has been tested by reproducing the holistic methodology and new technologies in the market by means of real demonstrators. When compared to more conventional construction methods, this system achieves savings in a real case of 50% (time), 30% (materials) and 25% (waste), thus achieving significant economic savings.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 768718