Catalina Spataru

A review of the regulatory energy performance gap and its underlying causes in non-domestic buildings

This paper reviews the discrepancy between predicted and measured energy use in non-domestic buildings in a UK context with outlook to global studies. It explains differences between energy performance quantification and classifies this energy performance gap as a difference between compliance or performance modelling with measured energy use. Literary sources are reviewed in order to signify the magnitude between predicted and measured energy use, which is found to deviate by +34% with a standard deviation of 55% based on 62 buildings. It proceeds in describing the underlying causes for the performance gap, existent in all stages of the building life cycle, and identifies the dominant factors to be related to specification uncertainty in modelling, occupant behaviour and poor operational practices having an estimated effect of 20-60%, 10-80% and 15-80% on energy use respectively. Other factors that have a high impact are related to establishing the energy performance target, impact of early design decisions, heuristic uncertainty in modelling and occupant behaviour. Finally action measures and feedback processes in order to reduce the performance gap are discussed, indicating the need for energy in-use legislation, insight into design stage models, accessible energy data and expansion of research efforts towards building performance in-use in relation to predicted performance

The smart supper- European grid: Balancing demand and supply

This paper investigates the impact of renewable energy integration in the future smart grids in Europe, simulating the performance of the whole energy system so that renewable energy sources are matched to varying service demands. There are energy challenges and complexity issues associated with demand side management arising from the connection between micro-generation output, grid loads, the weather combined with transmission and distribution of energy throughout the network. Some issues of balancing demand and supply in energy networks are discussed. This helps to explore options for most reliable network configuration over the coming decades to ensure flexibility and to integrate unpredictable demands with a range of supplies under different conditions. It covers all sectors and includes demographic and technological developments. This could aid policy formulation in the European Union.

Optimizing Building Energy Systems and Controls for Energy and Environment Policy

This is an informal introduction to some aspects of energy system optimisation to provide sustainable services to people in dwellings. This paper advances data, methods and results of optimising building energy systems and controls for energy and environment policy using quantitative techniques. Optimisation can aid the design of systems to meet policy objectives efficiently and at low cost. Three optimisation methods were applied: genetic algorithm (GA), particle swarm optimisation (PSO) and steepest decent (SD). It was concluded that the higher the energy price, the greater the efficiency of the dwelling envelope and heating system to achieve least cost. Ultimately, optimisation should be done across all systems and stock, and simultaneously for configuration, size and controls.

Dynamic Simulation of Energy System

This paper investigates how society engenders demands for energy services that vary with time and climate, and how renewable and other energy resources can be deployed to meet these demands. Because the whole people-energy system is modeled, there is little detail about any component, instead an overall picture of how the entire system works is presented in this paper. It became apparent that the design and performance of dwelling energy systems, and to some extent the behavior of people, cannot be considered in isolation from the whole system. In order to get a picture of how the entire system works, the greater the diversity better overview can be obtained. But, from a practical perspective it is difficult to simultaneously model in detail a large number of people-dwelling combinations, alongside all other demands and electricity and other supply.

Smart Consumers, Smart Controls, Smart Grid

The grid has three components: demand, transmission/distribution and generation, with the latter being mainly dispatchable, conventional power generation. A future grid based on renewable energy sources will impose serious challenges due to the variable nature of resources (wind, solar). In the transition from the current grid based on fossil and nuclear energy to a more sustainable one, based on renewable energy sources and components such as storage and with possible active participation by consumers, controls will play an important role, providing essential infrastructure for end users and system managers to monitor and control their energy usage. The uncertainty in the supply due to the integration of wind and solar energy will require intelligent control and with possible ways for shifting demand. The paper will discuss challenges, issues and advantages of demand reduction and demand shifting within a future smart grid with some illustrative examples.

DynEMo: A Dynamic Energy Model for the Exploration of Energy, Society and Environment

This paper describes a dynamic energy model, called DynEMo, which is designed to investigate how society engenders time and climate varying energy service demands in the different sectors (domestic, commercial, industry and transport) and how renewable and other energy resources, can meet these demands over different time scales. Certain model inputs are surveyed and sample outputs of a modelled efficient, electrified, high renewable energy system with district heating and fuel synthesis are given. Over short time periods, DynEMo calculates demands and renewable supplies and the storage of heat, electricity and chemical energy, being used to examine the technical feasibility of proposed systems and contribute towards the design and control of dynamic, renewable systems.

A systems paradigm for integrated building design

This article points out a number of key failures of existing practice for building design and then promotes a new approach based upon advances made in the modelling of complex systems and systems engineering. This new approach involves the identification of building functions and modelling techniques to evaluate the performance of a building with respect to a range of criteria in different domains (e.g. spatial, structural, social, environmental, cognitive, organizational, and operational). A systems approach to building design has received limited acceptance to date but can be used to highlight inherent hierarchies and interdependencies between building subsystems, which have traditionally been viewed as being independent. There is currently little agreement as to how the design of different building subsystems should be best integrated in order to satisfy a large range of diverse building functions. Treating the building as a complex system, whereby the interaction of entities produces emergent behaviour that can be evaluated with respect to such building functions, can help to optimize building performance by considering how a change in one domain affects performance in another. The integrated approach described here increases potential added value through technological and information interoperability.

Vulnerability Assessment for Interdependent Gas and Electricity Networks

Strong coupling between the gas and electricity infrastructure introduces new kinds of vulnerabilities in energy systems. Identification and assessment of these vulnerabilities is a challenging task because of the complexity of the system and the non-trivial role of the weather, which is inherently random. Prolonged periods of cold weather can dramatically amplify the negative effect of common failure of the equipment. We propose a methodology for identification of the most dangerous scenarios that combine the outage of individual system components with unfavorable weather conditions in a system of coupled gas and electricity. The feasibility of the approach is illustrated on simulations of a detailed model of coupled Gas and Electricity infrastructures in Europe.

Energy networks: A modelling framework for European optimal cross-border trades

Understanding of gas and electricity networks and interconnected systems requires a benchmark system to test different methodologies. A mathematical modeling framework has been formulated for energy networks and solutions for optimal cross-border European trades were derived. The results show the importance of combining gas and electricity networks to assess cross-border trade to minimize risk and ensure security across borders and match supply with demand whilst minimizing cost for transmission, but also to provide a unified European energy market. Comparison of simulation results shows a good agreement when compared with the actual data, with an overall correlation of over 90%. A range of supplies options under different conditions can be explored with the dynamic model to ensure a reliable network configuration over the coming decades. This tool could be used in risk limiting dispatch analysis for decision makers to assess operational uncertainties in generation, demand and future trade.

Using a RTL System Based on RFID Technology for Monitoring Occupants Domestic Energy Use and Behaviour

Over the last decade people have become more aware of environmental issues due to the fact that these have been brought to their attention by media, politicians and researchers. Even though the public is more aware of the energy issue, this will not necessarily result in changes in the way people use energy. Therefore it is important to understand individual occupant behaviour and find solutions to influence their behaviour at a national level in order to reduce carbon emissions from existing buildings. The motivation of this study is to gain an understanding of how occupancy sensors can be used for tracking occupants’ patterns and to determine their activities within domestic buildings.Occupancy patterns in a test house are analysed using a real time location (RTL) system based on ultra wideband (UWB) radio frequency (RF) to track location and spatial relationship. Occupants’ activities were deducted from their profiles and energy consumption and it was found that the energy consumption profiles are related to the occupants.