Energy calculations are used for many purposes, for example during the design andconstruction phase to comply with Boverket’s building regulations, energy declarations or toachieve energy saving in a building. A main problem in the design process of a new building,is to accurately predict the energy performance. The energy calculations require data fromdifferent interacting components, which have been shown to be challenging to measure. Thisproblem arises in particularly for complex buildings, notably office buildings. Due to the lackof detailed energy models and analyses of the differences between the model and reality foroffice buildings in Sweden, this report aims to answer the question: What are the causes ofdeviations between the models and the measurements of energy usage and indoor airtemperature for the studied office building? The office building Sthlm New 04 was modeledas a whole-building within IDA ICE and the simulated data was compared with measureddata from 2021 that was provided by Skanska Fastigheter.During the design of the model, the simulation model was fed with external source files (withmeasured data) to make the model operate at the same time as the real system. Since therewas no logged occupancy data for this office building, it was assumed that occupancy wasdistributed equally in all office zones. The model has a detailed HVAC system to make themodel as accurate as possible.The result showed overall a good agreement with the measured data, especially for thesimulated district heating and cooling. However, a closer look revealed that there were somedifferences that the model did not account for. The building’s three Air-handling units alsoshowed a good agreement with an average of -0.3 °C, -0.2 °C and +0.2 °C. The resultshighlight several problems with modeling and measured data. Under the influence ofassumptions and hard to define input data, there may be misinterpretation by the modeler.Other reasons could be sensor errors or manufacturing errors by most of the errors could becorrected by a more detailed occupancy in the model. However, this study has shown thatthe detailed model can be used for a fair comparison between the simulated model and thereal building, although there may be some discrepancies. Undoubtedly, it is difficult to createa model that exactly matches the real building, but this model is a good representation thatcan be used for future research such as digital twin.

The UK building stock accounts for about half of all energy consumed in the UK. A large portion of the energy is consumed by nondomestic buildings. Offices and retail are the most energy intensive typologies within the nondomestic building sector, typically accounting for over 50% of the nondomestic buildings’ total energy consumption. Heating, ventilating and air conditioning (HVAC) systems are the largest energy end use in the nondomestic sector, with energy consumption close to 50% of total energy consumption. Different HVAC systems have different energy requirements when responding to the same building heating and cooling demands. On the other hand, building heating and cooling demands depend on various parameters such as building fabrics, glazing ratio, building form, occupancy pattern, and many others. HVAC system energy requirements and building energy demands can be determined by mathematical modelling. A widely accepted approach among building professionals is to use building energy simulation tools such as EnergyPlus, IES, DOE2, etc. which can analyse in detail building energy consumption. However, preparing and running simulations in such tools is usually very complicated, time consuming and costly. Their complexity has been identified as the biggest obstacle. Adequate alternatives to complex building energy simulation tools are regression models which can provide results in an easier and faster way. This research deals with the development of regression models that enable the selection of HVAC systems for office buildings. In addition, the models are able to predict annual heating, cooling and auxiliary energy requirements of different HVAC systems as a function of office building heating and cooling demands. For the first part of the data set development used for the regression analysis, a data set of office building simulation archetypes was developed. The four most typical built forms (open plan sidelit, cellular sidelit, artificially lit open plan and composite sidelit cellular around artificially lit open plan built form) were coupled with five types of building fabric and three levels of glazing ratio. Furthermore, two measures of reducing solar heat gains were considered as well as implementation of daylight control. Also, building orientation was included in the analysis. In total 3840 different office buildings were then further coupled with five different HVAC systems: variable air volume system; constant air volume system; fan coil system with dedicated air; chilled ceiling system with embedded pipes, dedicated air and radiator heating; and chilled ceiling system with exposed aluminium panels, dedicated air and radiator heating. The total number of models simulated in EnergyPlus, in order to develop the input database for regression analysis, was 23,040. The results clearly indicate that it is possible to form a reliable judgement about each different HVAC system’s heating, cooling and auxiliary energy requirements based only on office building heating and cooling demands. High coefficients of determination of the proposed regression models show that HVAC system requirements can be predicted with high accuracy. The lowest coefficient of determination among cooling regression models was 0.94 in the case of the CAV system. HVAC system heating energy requirement regression models had a coefficient of determination above 0.96. The auxiliary energy requirement models had a coefficient of determination above 0.95, except in the case of chilled ceiling systems where the coefficient of determination was around 0.87. This research demonstrates that simplified regression models can be used to provide design decisions for the office building HVAC systems studied. Such models allow more rapid determination of HVAC systems energy requirements without the need for time-consuming (hence expensive) reconfigurations and runs of the simulation program.

This thesis considers the development of a Hammerstein-bilinear approach to non-linear systems modelling, analysis and control systems design, which builds on and extends the applicability of an existing bilinear approach. The underlying idea of the Hammerstein-bilinear approach is to use the Hammerstein-bilinear system models to capture various physical phenomena of interest and subsequently use these for model based control system designs with the premise being that of achieving enhanced control performance. The advantage of the Hammerstein-bilinear approach is that the well-structured system models allow techniques that have been originally developed for linear systems to be extended and applied, while retaining moderate complexity of the corresponding system identification schemes and nonlinear model based control designs. In recognition of the need to be able to identify the Hammerstein-bilinear models a unified suite of algorithms, being the extensions to the simplified refined instrumental variable method for parameter estimation of linear transfer function models is proposed. These algorithms are able to operate in both the continuous-time and discrete-time domains to reflect the requirements of the intended purposes of the identified models with the emphasis being placed on straightforward applicability of the developed algorithms and recognising the need to be able to operate under realistic practical system identification scenarios. Moreover, the proposed algorithms are also applicable to parameter estimation of Hammerstein and bilinear models, which are special cases of the wider Hammerstein-bilinear model class. The Hammerstein-bilinear approach has been applied to an industrial heating, ventilation and air conditioning (HVAC) system, which has also been the underlying application addressed in this thesis. A unique set of dynamic control design purpose oriented air temperature and humidity Hammerstein-bilinear models of an environmentally controlled clear room manufacturing zone has been identified. The greater insights afforded by the knowledge of the system nonlinearities then allow for enhanced control tuning of the associated commercial HVAC control system leading to an improved overall control performance.

Este trabalho tem por finalidade avaliar o desempenho energético do sistema de condicionamento de ar com distribuição pelo piso (Underfloor Air Distribution System UFAD) em ambientes de escritório, considerando diferentes possibilidades de arquitetura do sistema e seus modos de operação com ciclos economizadores. Por meio de simulação computacional, as avaliações foram realizadas para o clima da cidade de São Paulo ao longo de um ano metereológico típico, mantendo as condições de conforto térmico no ambiente. O programa de simulação selecionado como ferramenta foi o EnergyPlus 2.1.0.023, visto que modelos numéricos nele implementados representam adequadamente o sistema UFAD e os ciclos economizadores. Como referência para o desenvolvimento dos modelos de simulação foi utilizada uma câmara de testes representativa de um ambiente de escritórios. Esta câmara foi desenvolvida por Leite (2003) para avaliação do conforto térmico propiciado pelo sistema UFAD. As curvas de distribuição de temperatura resultantes das simulações foram similares às curvas resultantes das medições executadas por esta autora. As simulações foram realizadas para duas arquiteturas diferentes do circuito de ar (com e sem desvio do ar de retorno) combinados com três diferentes modos de operação relacionados à vazão do ar exterior. A análise dos dados climáticos da cidade de São Paulo demonstra que a tomada de ar exterior pode ser majorada com a utilização de ciclos economizadores, reduzindo o consumo de energia do sistema. Os resultados desta pesquisa indicam uma estreita relação entre arquitetura do sistema, controle dos ciclos economizadores, e dados climáticos, revelando que a combinação entre esses parâmetros pode reduzir em 34,5% o consumo de energia elétrica do sistema UFAD na cidade de São Paulo. / The purpose of this research is to evaluate the energy performance of the Underfloor Air Distribution (UFAD) system at office buildings, considering different air loops design and economizer cycles while keeping thermal comfort for the weather data of São Paulo city, Brazil. Simulations were held using the EnergyPlus software version 2.1.0.023, since its numerical models can well represent UFAD systems and economizer cycles. One chamber representing an office room was used as reference for the simulation models. This chamber was developed by Leite (2003) to evaluate the thermal comfort conditions provided by the UFAD system. The curves of temperature distribution obtained from simulation were similar to those experimentally obtained by Leite (2003). Simulations were performed for two different air loops (with and without return air bypass) combined with three different outside air controls. The São Paulo weather data analysis demonstrates that the outside air flow can be increased with the use of economizer cycles, reducing electric energy consumption of the UFAD system. The results of this research indicate that there is a tight relationship between the system air loop design, economizer cycle control and weather data, which reveals that the combination between these parameters can reduce about 34,5% the electric energy consumption of UFAD system at São Paulo city.

Este trabalho tem por finalidade avaliar o desempenho energético do sistema de condicionamento de ar com distribuição pelo piso (Underfloor Air Distribution System UFAD) em ambientes de escritório, considerando diferentes possibilidades de arquitetura do sistema e seus modos de operação com ciclos economizadores. Por meio de simulação computacional, as avaliações foram realizadas para o clima da cidade de São Paulo ao longo de um ano metereológico típico, mantendo as condições de conforto térmico no ambiente. O programa de simulação selecionado como ferramenta foi o EnergyPlus 2.1.0.023, visto que modelos numéricos nele implementados representam adequadamente o sistema UFAD e os ciclos economizadores. Como referência para o desenvolvimento dos modelos de simulação foi utilizada uma câmara de testes representativa de um ambiente de escritórios. Esta câmara foi desenvolvida por Leite (2003) para avaliação do conforto térmico propiciado pelo sistema UFAD. As curvas de distribuição de temperatura resultantes das simulações foram similares às curvas resultantes das medições executadas por esta autora. As simulações foram realizadas para duas arquiteturas diferentes do circuito de ar (com e sem desvio do ar de retorno) combinados com três diferentes modos de operação relacionados à vazão do ar exterior. A análise dos dados climáticos da cidade de São Paulo demonstra que a tomada de ar exterior pode ser majorada com a utilização de ciclos economizadores, reduzindo o consumo de energia do sistema. Os resultados desta pesquisa indicam uma estreita relação entre arquitetura do sistema, controle dos ciclos economizadores, e dados climáticos, revelando que a combinação entre esses parâmetros pode reduzir em 34,5% o consumo de energia elétrica do sistema UFAD na cidade de São Paulo. / The purpose of this research is to evaluate the energy performance of the Underfloor Air Distribution (UFAD) system at office buildings, considering different air loops design and economizer cycles while keeping thermal comfort for the weather data of São Paulo city, Brazil. Simulations were held using the EnergyPlus software version 2.1.0.023, since its numerical models can well represent UFAD systems and economizer cycles. One chamber representing an office room was used as reference for the simulation models. This chamber was developed by Leite (2003) to evaluate the thermal comfort conditions provided by the UFAD system. The curves of temperature distribution obtained from simulation were similar to those experimentally obtained by Leite (2003). Simulations were performed for two different air loops (with and without return air bypass) combined with three different outside air controls. The São Paulo weather data analysis demonstrates that the outside air flow can be increased with the use of economizer cycles, reducing electric energy consumption of the UFAD system. The results of this research indicate that there is a tight relationship between the system air loop design, economizer cycle control and weather data, which reveals that the combination between these parameters can reduce about 34,5% the electric energy consumption of UFAD system at São Paulo city.

The commercial buildings sector in the United States used 18 percent (17.93 Quads) of the U.S. primary energy in 2006. Office buildings are the largest single energy consumption category in the commercial buildings sector of the United States with annual energy consumption around 1.1 Quads. Traditional approaches used in commercial building designs are not adequate to save energy in both depth and scale. One of the most effective ways to reduce energy consumption is to improve energy performance of HVAC systems. High-performance HVAC systems and components, as well as application of renewable energy sources, were surveyed for buildings in hot and humid climates. An analysis of performance and energy saving potential estimation for selected HVAC systems in hot and humid climates was developed based on energy consumption simulation models in DOE-2.1E. A calibrated energy consumption model of an existing office building located in the hot and humid climate conditions of Texas was developed. Based on this model, the energy saving potential of the building was estimated. In addition, energy consumption simulation models were developed for a new office building, including simulation of energy saving measures that could be achieved with further improvements of HVAC system above the energy conservation codes requirements. The theoretical minimum energy consumption level for the same office building was estimated for the purpose of evaluating the whole building energy efficiency level. The theoretical minimum energy consumption model of the office building was designed to provide the same level of comfort and services to the building occupants as provided in the actual building simulation model. Finally, the energy efficiency of the building that satisfies valid energy conservation codes and the building with an improved HVAC system was estimated based on theoretically minimum energy consumption level. The analysis provided herein can be used for new building practitioners and existing building owners to evaluate energy reduction potential and the performance of innovative technologies such as dedicated outdoor air system, displacement ventilation, improved cooling system efficiency, air source heat pumps and natural gas heat pumps.

La réduction des besoins dans les bâtiments à basse consommation d'énergie (BBC) nécessite un réexamen de l'approche de modélisation des systèmes énergétiques dans les outils de simulation. L'approche proposée repose sur une modélisation plus fine des phénomènes physiques incluant la régulation en boucle fermée du système énergétique couplé au bâtiment. A partir de l'identification des phénomènes propres au comportement énergétique des BBC, des recommandations, ou règles de modélisation, sont établies pour le développement des modèles de leurs systèmes énergétiques. Ces recommandations sont mises en application dans deux études. Tout d'abord, une simulation dynamique d'un bâtiment et de son système conduit à un dimensionnement plus adapté comparé aux méthodes classiques dans le cas de BBC avec des répercussions sur les appels de puissance et la consommation d'énergie. Ensuite, une analyse de sensibilité par la méthode de Morris sur une représentation générique du système énergétique a permis d'identifier les paramètres nécessitant d'être connus avec précision. La différence entre l'approche développée et la simulation horaire avec régulation idéale n'est que de quelques pourcents en besoins énergétiques pour un bâtiment existant mais elle passe à plus de 20% dans un bâtiment BBC. Un écart du même ordre de grandeur peut être identifié pour la détermination de la performance énergétique globale du système par une prise en compte plus détaillée des phénomènes de cyclage, de charge partielle ou de consommation des auxiliaires. / The decrease of heat demands in low energy buildings requires to examine again modeling approaches in building energy simulation tools. The developed approach is based on a more accurate modeling of physical phenomena including the closed loop control between the HVAC system and the building. From the identification of the phenomena that specifically impact the energy behavior of the low energy buildings, some recommendation, or modeling rule, are established for the development of their HVAC systems. Those recommendations are applied in two case studies. Firstly, a dynamic simulation of a building and its system offers a better evaluation of the design power for a low energy building, affecting power demands and energy consumption. Then, a sensitivity analysis from Morris method on a generic representation of the HVAC system identifies the parameters to be accurately known. The difference between the developed approach and an hourly simulation with an ideal control is low for the evaluation of the heat load in an existing building but it is more than 20% in a low energy buildings. A difference of the same order of magnitude can be identified in the determination of the overall energy performance of the system by a more detailed consideration of the phenomena of cycling, the part load or the consumption of auxiliaries.

The building sector accounts for approximately 40 percent of our energy use. To reach existing environmental targets energy use will have to be reduced in all building types. At the European level, the main legislative instrument for improving the energy efficiency of the building stock is the Energy Performance of Buildings Directive (EPBD). The EPBD requires all member states to implement the directive in the building code and it also requires energy declarations to be performed at the building level. The first objective of this thesis is to describe energy use in shopping malls in Sweden and to suggest how this energy use can be reduced. The second objective is to determine whether current regulatory requirements are effective in promoting energy efficiency measures in Swedish shopping malls. Only limited background information was found from national energy statistics and scientific papers that deal specifically with energy use in shopping malls. The data available are difficult to analyse and compare due to inconsistencies in terminology regarding nomenclature and system boundaries. An improved terminology is presented in the thesis, with a distinction between organisationally and functionally divided energy, to facilitate future studies. Furthermore, when it comes to designing shopping malls and evaluating their energy use, correct input data are required. For calculations and simulations of energy demand in buildings, internal and external load patterns are important input data. The thesis provides occupancy, lighting and infiltration load data for shopping malls. Energy use in one shopping mall was investigated in detail and resulted in a validated calculation model for the prediction of energy use. To develop the calculation model an iterative empirical-theoretical methodology was used. It involved cross-checking measured data, assumptions related to operational and technical data, and model calculation results. The calculation model was then used for a more general analysis of energy efficiency measures and an evaluation of regulatory requirements. The thesis illustrates how the current building code and energy declarations are implemented in shopping malls today together with associated strengths and weaknesses.

The aim of this work is to create a unified control and supervision system, SCADA, for controlling the heating and cooling of the company. The system is controlled by UniPi PLC units. Node-RED is used as control software. The user interface is created by an extension "dashboard". For communication between elements using the MQTT protocol. The InfluxDB database is used for data storage. The Grafana tool is used to visualize historical data. The majority of the created system consists of open software. The system is universal, expandable and it is possible to connect it with another system. The system can be used or adapted to similar problems of advanced heating control.

Energy recovery ventilation (ERV) systems are designed to decrease the energy consumed by building HVAC systems. ERV’s scavenge sensible and latent energy from the exhaust air leaving a building or space and recycle this energy content to pre-condition the entering outdoor air. A few studies found in the open literature are dedicated to developing detailed numerical models to predict or simulate the performance of energy recovery wheels and desiccant wheels. However, the models are often computationally intensive, requiring a lot of time to perform parametric studies. For example, if the physical characteristics of a study target change (e.g., wheel diameter or depth) or if the system runs at different operating conditions (e.g., wheel rotation speed or airflow rate), the model parameters need to be recalculated. Hence, developing a mapping method with better computational efficiency, which will enable the opportunity to conduct extensive parametric or optimal design studies for different wheels is the goal of this research. In this work, finite difference method (FDM) numerical models of energy recovery wheels and desiccant wheels are established and validated with laboratory test results. The FDM models are then used to provide data for the development of performance mapping methods for an energy wheel or a desiccant wheel. After validating these new mapping approaches, they are employed using independent data sets from different laboratories and other sources available in the literature to identify their universality. One significant characteristic of the proposed mapping methods that makes the contribution unique is that once the models are trained, they can be used to predict performance for other wheels with different physical geometries or different operating conditions if the desiccant material is identical. The methods provide a computationally efficient performance prediction tool; therefore, they are ideal to integrate with transient building energy simulation software to conduct performance evaluations or optimizations of energy recovery/ desiccant wheel integrated HVAC systems.