Analysis Of Load Match and Grid Interaction Indicators in NZEB with High-Resolution Data

A Net Zero Energy Building (Net ZEB) is succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “Net Zero” balance is attained by applying energy conservation and efficiency measures and by incorporating renewable energy systems. The main objective of this report is to analyze the usefulness and relevance of proposed Load Match and Grid Interaction (LMGI) for Net Zero Energy Buildings. The methodology is based in the analysis of available high-resolution data (mainly hourly) both from simulated and monitored Net ZEBs (Net Zero Energy Buildings) or nZEB (nearly Zero Energy Buildings). The central question is to find a limited set of indicators which provide relevant information to building owners, local grid Distribution System Operators (DSO) when information from building simulations are available at design stage

Price and carbon-based energy flexibility of residential heating and cooling loads using model predictive control

Model predictive controllers (MPC) have shown great potential for activating the energy flexibility of thermal loads, especially in buildings equipped with heat pump systems. In this work, an MPC controller is developed and tested within a co-simulation framework which couples an optimization software with a dynamic building simulation tool. The development phase is described in detail, in particular the methods to obtain simplified models to be used by the controller. The building envelope and the heat pump performance (based on experimental data) were thus modelled, both in heating and cooling seasons. Three different objective functions of the MPC are tested on a study case consisting of a Spanish residential building: promising results are obtained when the controller aims at minimizing operational costs (savings of 13–29%) or CO2 marginal emissions (savings of 19–29%). The development efforts, the required tuning and sensitivity of the MPC algorithm parameters, the adaptations needed between the cooling and heating operations are also discussed and put into perspective with the obtained benefits in terms of savings, comfort and load-shiftingPeer ReviewedPostprint (author's final draft

Cost-effective analysis for selecting energy efficiency measures for refurbishment of residential buildings in Catalonia

© 2016. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper presents the results of a detailed method for developing cost-optimal studies for the energy refurbishment of residential buildings. The method takes part of an innovative approach: two-step evaluation considering thermal comfort, energy and economic criteria. The first step, the passive evaluation, was presented previously [1] and the results are used to develop the active evaluation, which is the focus of this paper. The active evaluation develops a cost-optimal analysis to compare a set of passive and active measures for the refurbishment of residential buildings. The cost-optimal methodology follows the European Directives and analysed the measures from the point of view of non-renewable primary energy consumption and the global costs over 30 years. The energy uses included in the study are heating, domestic hot water, cooling, lighting and appliances. In addition, the results have been represented following the energy labelling scale. The paper shows the results of a multi-family building built in the years 1990–2007 and located in Barcelona with two configurations: with natural ventilation and without natural ventilation. The method provides technical and economic information about the energy efficiency measures, with the objective to support the decision process.Postprint (author's final draft

Review of transparent and semi-transparent building-integrated photovoltaics for fenestration application modeling in building simulations

Building-integrated photovoltaics (BIPV) have attracted interest due to their capacity to feasibly supply buildings with renewable power generation, helping to achieve net-zero or net-positive energy goals. BIPV systems include many different solutions depending on the application, the PV technology, and the envelope material they substitute. Among BIPV systems, the last two decades have seen a rising interest in transparent and semi-transparent BIPV (T- and ST-BIPV), which add features such as daylighting and solar radiation control. T- and ST-BIPV mainly consist of opaque PV cells embedded in fenestration systems (PV cladding), while most recent research considers semi-transparent PV cells (homogeneous PV glazing) with improved optical properties. The evaluation of T- and ST-BIPV systems in building performance is complex, as it needs to combine optical, thermal, electrical, and daylighting calculations. Therefore, adequate modeling tools are key to the development of these technologies. A literature review is presented on T- and ST-BIPV. First, the types of T- and ST-BIPV technologies present in the literature are summarized, highlighting the current trends. Then, the most common optical, thermal, and electrical models are described, finishing with a summary of the T-and ST-BIPV modeling capabilities of the most common building simulation tools. Regardless of the implemented modeling tools, the main challenges to be considered are the optical model, the inclusion of the PV output in the window energy balance, and the calculation of the cell temperature for the correct assessment of cell efficiency. Modeling research mostly considers conventional PV (Si-based PV and thin-film) technologies, and research studies rarely address the cost evaluation of these T- and ST-BIPV systemsThis work has received funding from the European Union H2020 Framework Programme under Grant Agreement no. 826002 (Tech4Win)Postprint (published version

Configurations of model predictive control to exploit energy flexibility in building thermal loads

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A model predictive control (MPC) framework is developed in the present study, with the final objective to improve the energy flexibility of building thermal loads through demand-side management. Three different configurations are tested and tuned, with the following objective functions: minimizing the delivered energy to the building, the electrical energy used by the HVAC system (heat pump) or the cost of this electricity use. To validate these MPC configurations, a Matlab-Trnsys co-simulator is also created, in order to run the MPC on a virtual plant composed of a detailed building model. The MPC strategy manages to run effectively on the chosen study case (a residential building with heat pump in Spain), and the differences between configurations are discussed.Peer ReviewedPostprint (author's final draft

Energy-efficient ventilation control strategies for surgery rooms

Surgery room specific energy use is among the highest in the built environment due to stringent indoor environmental quality and infection control requirements. This study uses a calibrated energy model to evaluate the environmental and economic performance of a variety of ventilation control strategies that reduce surgery room energy use while maintaining indoor environmental quality and infection control performance. The individual control strategies evaluated in this study are (1) temperature and relative humidity reset, (2) air recirculation, (3) airflow reset, and (4) particle concentration based airflow control. Combinations of these strategies are also evaluated. The best performing combinations of control strategies can reduce surgery room primary energy use, CO2 emissions, and energy costs by up to 86% relative to the standard practice. Temperature and relative humidity reset is the strategy that offers the largest benefits. Particle concentration based airflow control shows modest results partly due to the conservative infection control performance target. Future research should define infection control performance thresholds during operation.Peer ReviewedPostprint (author’s final draft

Characterisation of the thermal performance of a novel roof ridge solar hot water system

The development of novel systems for the on-site integration of renewable energy in buildings is increasingly demanded for the reduction of the energy consumption resulting from domestic hot water, heating and cooling usages. Within this context, the development of efficient solar collectors for domestic hot water demand production that benefit from their architectural integration in buildings is of high relevance. In the present study a novel solar collector device with a tube-in-tube concept that integrates domestic hot water storage and absorber in a single unit, is tested under the standard ISO 9459-5. The thermal performance of the collector is evaluated by means of the so-called DST (Dynamic System Testing) method that allows prediction of its annual energy efficiency under different climate condition scenarios. The study concluded that three collector modules in series can provide a high annual DHW energy coverage between 62-70 % for Southern European climates and in the range of 30-40% for Central and Northern European climates. Along with its compactness and efficient design that allow easier architectural integration on roof ridges, an additional advantage of the system is that its cylindrical geometry makes it possible to rely on a significant surface for full diurnal radiation absorption, independently of solar orientation. With the objective for this new development to be technically and economically competitive compared to available solar domestic how water systems (SDHW), it is currently under the pre-production phase and ready to enter the market in 2018

Review of control strategies for improving the energy flexibility provided by heat pump systems in buildings

Peer ReviewedPostprint (author's final draft

Analysis of load match and grid interaction indicators in NZEB with high-resolution data

© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Postprint (author’s final draft

The uncertainty of the energy demand in existing mediterranean urban blocks

The objective of the paper is to describe a stochastic model that has been developed to obtain load profiles for household electricity. For the study, several profiles have been generated in order to simulate the electrical demand of a residential building block or neighbourhood and evaluate the uncertainty of its energy use. The paper is divided in three different parts: development of the model, validation and determination of the uncertainty demand. In the first parts the basis of the model and how it works is explained. The second one represents the validation of the model, the input data and its results. The last step is focused on a statistical analysis of the electricity demand of a block of dwellings to evaluate minimum number of dwellings needed to estimate the average demand representative of the Mediterranean dwelling with different levels of accuracyPostprint (author’s final draft