Hygro-thermal model for estimation of demand response flexibility of closed refrigerated display cabinets

In this article we present and validate a novel methodology for estimating the temperature development and heat extraction demand of closed refrigerated display cabinets (RDCs) in operating conditions, for near-future prediction and optimisation in smart grids. The approach is based on an in-house developed hygro-thermal model of an RDC, in which the conditions in each of the three main calculation domains, representing the internal air, heat exchanger and interior, are estimated at a temporal scale of seconds. The interior air temperature, heat extraction rate and run-off condensate were validated towards experimental data with good conformity. Moreover, for demand response purposes, in this article, we provide examples of how the model can be used to evaluate the temporal flexibility in heat extraction demand of RDCs. In a hypothetical supermarket with 11 RDCs exposed to various thermal loads and customer interactions, it is estimated that the heat extraction demand could be reduced to 0 for up to 83∕127 s during opening/non-opening hours respectively. With a strategic pre-cooling, the latter time could be extended to 322 s. For the case of a demand response signal requesting the supermarket to absorb excess energy, all RDCs would be able to run at full power for up to 17∕29 s, and approximately half of them for additional 20 s during opening hours. These findings are based on a total of 44 five-minutes-ahead simulations of possible scenarios for the 11 RDCs, all calculated by the presented model in approximately 10 s. In conclusion, the model provides fast and reliable results for real-time predictions in refrigeration control systems either for the benefit of the electrical grid by demand response or for energy efficiency purposes

Consumo inteligente de energia elétrica

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Redes de Comunicação e MultimédiaEste trabalho realiza uma solução de Demand Response(DR) que tem como objetivo, implementar um sistema informático distribuído para controlo do consumo de cargas elétricas. A implementação deste sistema baseia-se na norma OpenADR2.0, onde são definidas as entidades Virtual Top Node(VTN) e Virtual End Node (VEN). O VTN é responsável por gerir e controlar todas as atividades de DR (ex. utilities, Independent System Operators) que são depois enviadas para os VENs. Os VENs têm como função controlar cargas, mediante um conjunto de mensagens definidas na norma OpenADR2.0. É implementado um VTN, com a criação de uma aplicação Web. O servidor Webutilizado no trabalho foi o Apache Tomcat versão 8.0.23. O VEN, é implementado com uma aplicação Java. Realiza-se também um ensaio onde o VEN é instalado num Raspberry PI paraa ativação de uma lâmpada que simboliza uma carga no consumidor. É também proposto a criação da noção de estado de um VEN, e um programa de DR que cumpra os objetivos deste trabalho. O programa de DR proposto tem dois modos de funcionamento. No modo para diminuição de picos de carga despacham-se as cargas de forma a diminuir os valores máximos do diagrama de carga previsto. No modo para aproveitamento máximo do potencial renovável o despacho das cargas desloca o início do seu funcionamento, quando o valor da previsão de produção renovável em relação á previsão de carga é mais elevado. Como principais conclusões, tem-se que a aplicação da norma OpenADR2.0, revelou-se ser vantajosa permitindo criar um modelode dados e padrões de troca de informação de forma eficaz e simples. Tanto o VTN como o VEN implementados realizam todas as funcionalidades idealizadas para este trabalho. O programa de DR proposto cumpre também os objetivos propostos.Abstract: This work presents a Demand Response (DR) solution, which aims to implement a distributed computing system to controlthe consumption of electrical loads. The system implemented is based on OpenADR2.0 standard, which defines the entities Virtual Top Node (VTN) and Virtual End Node (VEN). The VTN is responsible for managing and controlling all DR activities (eg. Utilities, Independent System Operators) which are then sent to VENs. The VENs have the function to control loads, through a set of defined messages in OpenADR2.0 standard. This work implements a VTN, with the creation of a Web application. The Web server used was the Apache Tomcat version 8.0.23. The VEN, is implemented with a Java application. This work conducts also an experiment where the VEN is installed on a Raspberry PI for activation of a lamp, which symbolizes a load on the consumer. A VEN state notion, and a DR program that meets theobjectives of this work are also proposed. The proposed DR program has two modes of operation. In the Peak Clipping mode, the loads are dispatched in order to decrease the maximum values of predicted load diagram. In Renewables Maximum Rate mode the dispatch of loads moves their operation start, when the renewable production forecast in relation to the load forecasting is higher. The main conclusions are that the application of OpenADR2.0 standard, has proved to be advantageous allowing the creation of a data model and information exchange standards effectively and simply. Both theVTN as VEN perform all idealized features for this work. The proposed DR program also meets the objectives proposed

Emerging energy management standards and technologies : challenges and application prospects

The continuously rising costs and the environmental impact of energy generation, transmission and consumption are a major concern for governments, industry and society alike. Among research in renewable energy sources as well as in energy efficiency of buildings, electrical appliances, vehicles etc., a considerable amount of attention has been devoted to effective energy management. In this paper, we present a survey on emerging energy management standards with focus on enabling application layer Information and Communications Technologies (ICT) that are a central part of these standards. The presented work includes an analysis on the challenges, future trends, security and application prospects of energy management standards. As part of the survey, the emerging Open Automated Demand Response (OpenADR) version 2.0 and Smart Energy Profile (SEP) version 2.0 were identified as the most promising and complete solutions. The presented survey provides an important insight on the future developments in the area of energy management protocols and highlights a number of key ICT solutions and challenges.Validerad; 2012; 20120604 (rumkyu)Architecture for Service-Oriented Process – Monitoring and Contro