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Publications

Publications by CPES

2017

Using a calibrated building energy simulation model to study the effects of improving the ventilation in a school

Authors
Bernardo, H; Quintal, E; Oliveira, F;

Publication
INTERNATIONAL SCIENTIFIC CONFERENCE - ENVIRONMENTAL AND CLIMATE TECHNOLOGIES, CONECT 2016

Abstract
This paper aims at presenting the development of a calibrated building energy simulation model of a school building to study the impact of improving the ventilation system on energy performance. The simulation model was developed with the DesignBudderlEnergyplus software and it was calibrated based on data collected during an energy audit to the school building. Schools need high outdoor airflow rates to remove indoor air contaminants related to occupants and building components, thus requiring mechanical ventilation systems. Due to budget restrictions, school managers decided to schedule the building management system to keep the HVAC systems active only between 6:00 am and 10:00 am. According to the values measured in this school, it was patent that the CO2 concentration was too high in certain periods. Too high peak values undermine the indoor air quality in the remaining occupancy time of the classroom, harming the work conditions for teachers and students. To solve this problem, an extended usage schedule of the mechanical ventilation was simulated (8:00 am to 5:00 pm) according to the required enhancement of indoor air quality, which together with the adoption of the new calculated fresh air flow rates will enhance air quality while avoiding excessive cost, thus increasing energy efficiency. (C) 2017 The Authors. Published by Elsevier Ltd.

2017

An integrated approach on energy consumption and indoor environmental quality performance in six Portuguese secondary schools

Authors
Dias Pereira L.; Neto L.; Bernardo H.; Gameiro da Silva M.;

Publication
Energy Research and Social Science

Abstract
A major rehabilitation programme of secondary school buildings has been carried out in the last few years in Portugal. With the introduction of HVAC systems in buildings that were previously naturally ventilated, an increase on energy consumption has been verified. During the first occupancy periods of new and refurbished buildings, energy and indoor climate quality audits are important strategies to improve the buildings’ energy use. In this context, this paper aims at showing the relations between the energy consumption and indoor environment quality (IEQ) parameters, obtained from the energy and IEQ audit in six representative modernised secondary schools – part of a larger R&D project untitled 3Es – geographically and climatically distributed in Portugal mainland. The monitoring period during the mid-season 2013 varied between schools, between two and three weeks. Air exchange rates, more specifically infiltration rates, were quantified aiming at determining the current airtightness condition of the refurbished schools. A subjective IEQ assessment was also performed, focusing on occupants' feedback, providing insight on the potential linkages between energy use and occupants’ comfort. A reflection on the energy consumption indicators and the indoor conditions obtained in the classrooms was proposed, and some suggestions were anticipated.

2017

An application of a multi-criteria decision support system to assess energy performance of school buildings

Authors
Bernardo, H; Gaspar, A; Antunes, CH;

Publication
CISBAT 2017 INTERNATIONAL CONFERENCEFUTURE BUILDINGS & DISTRICTS - ENERGY EFFICIENCY FROM NANO TO URBAN SCALE

Abstract
This work presents a multi-criteria classification system considering multiple, conflicting and incommensurate evaluation aspects influencing energy efficiency in school buildings. The multi-criteria ELECTRE TRI method is used to classify energy performance of school buildings into categories of merit using the IRIS software. The alternatives under evaluation are assigned to predefined ordered categories according to their absolute performance and not in comparison with the performance of other alternatives. Each alternative is assessed using reference profiles defming the boundaries of the categories in which the alternatives should be sorted. The model was applied using a set of performance indicators obtained in the framework of a research and development project aimed at assessing the energy performance of a sample of Portuguese school buildings. IRIS allowed inferring robust conclusions by indicating the range of categories for each alternative, considering the decision maker's preferences, captured by the parameters of ELECTRE TRI. (C) 2017 The Authors. Published by Elsevier Ltd.

2017

An approach for energy performance and indoor climate assessment in a Portuguese school building

Authors
Bernardo, H; Antunes, CH; Gaspar, A; Pereira, LD; da Silva, MG;

Publication
SUSTAINABLE CITIES AND SOCIETY

Abstract
The main goal of this paper is to present a set of well-defined and structured procedures to establish guidelines for the application of an integrated assessment of energy performance and indoor climate in schools. Increasing the knowledge about how energy is consumed in schools is a way to enhance the awareness of school managers (board of directors) about the importance of improving energy efficiency and reducing energy costs. The proposed methodology helps to identify major energy consuming equipment in school buildings and potential energy conservation measures. The assessment of indoor climate identifies potential corrective measures to problems related to indoor air quality and thermal comfort, also supporting the study of further energy conservation measures associated with ensuring environmental quality. Results of a case study showed that the expected energy consumption reduction is about 11.2% due to a better usage of daylighting and 4.5% due to the reduction of fresh air flow rates, while extending the ventilation operation time. In addition, there is a considerable non-calculated potential for energy savings and improvement of indoor environmental conditions in school buildings, promoting students and teachers productivity and wellbeing.

2016

Implementation of Dynamic Tariffs in the Portuguese Electricity System - Preliminary Results of a Cost-Benefit Analysis

Authors
Saraiva, JT; Fidalgo, JN; Pinto, RB; Soares, R; Afonso, JS; Pires, G;

Publication
2016 13TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
The current Portuguese Tariff Code dates from December 2014 and requires that the Distribution Network Operators (DSO), submit to the Portuguese Energy Services Regulatory Agency, ERSE, a plan for a pilot experiment and a Cost Benefit Analysis (CBA) regarding the introduction of dynamic options in the Access Tariffs in Portugal. In view of this request, EDP Distribuicao, the main Portuguese DSO, established a contract with INESC TEC to conduct these studies and to prepare a report to submit to ERSE by June 2016. In this scope, this paper reports the results obtained so far namely regarding the CBA analysis. This analysis includes the identification of critical hours during which dynamic tariffs can be activated, the estimate of the impact of demand transfers to adjacent hours on the electricity market Social Welfare Function, on network losses, on the investment network avoided costs due to the possible deferral of reinforcements or expansions and on the costs of contracting reserves. These items were estimated along a period of 15 years and together with the estimate of the implementation costs of dynamic tariffs were used to conduct the mentioned CBA analysis.

2016

The worth of network upgrade deferral in distribution systems - Truism or myth?

Authors
Fidalgo, JN; Couto, M; Fournie, L;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
A considerable number of classic and modern control applications in distribution systems are developed aiming at make the most of the existing infrastructure. Under this perspective, investments postponement in grid upgrade appears as a good expectable result. The advent of smart grids enhances this expectation since it promises ubiquitous system monitoring, secure and trustworthy communication technologies and advanced control schemes. These features will allow the implementation of innovative algorithms for better operation and management of system assets. New possibilities arise for DSM, microgeneration control, electric vehicle charging and intelligent operation of energy storage devices. The scientific literature has countless examples that illustrate the benefits of such tools. A frequent outcome of these studies highlights the advantage of investments deferral in network reinforcement. This paper analyzes the combined effects of these control actions with the investments required for network upgrade, namely in lines and transformers reinforcement. Contrary to other research papers, our results demonstrate that investments deferral could lead frequently to higher costs in a long-term perspective.

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