Diseño e implementación de un sistema de control en torre de enfriamiento y análisis de ahorro energético para la empresa Plastinovo S.A.S

El objetivo principal del proyecto es el diseño e implementación de un sistema de control automático para la empresa Plastinovo S.A.S y análisis de ahorro energético con su respectivo retorno de inversión, utilizando la técnica de control PID, con el fin de mejorar las condiciones de operación de la planta, calidad en los procesos y disminución del consumo de energía, generando rentabilidad para la compañia. Para el desarrollo del trabajo se toma como punto de partida el diagnóstico inicial del funcionamiento del ventilador como relación al consumo de energía, posterior a esto se plantea un sistema de control identificando sus elementos, tomando como referencia la variable más crítica del proceso, para este caso particular se toma como variable controlada la temperatura de salida de la torre, ya que lo que le interesa a procesos posteriores es la temperatura que se le suministre, finalmente y después de configurar el control PID y de poner en marcha el sistema se toman datos finales del comportamiento del sistema debido al consumo eléctrico, obteniendo así valores de comparación que establecen la relación del consumo de energía antes y después de la implementación del sistema de control, de esta forma es posible realizar el ahorro del sistema y el tiempo de recuperación de la inversión en aproximadamente 16 meses, generando a partir de esto rentabilidad para la empresa.Ingeniero Mecatrónicopregrad

A review of optimization approaches for controlling water-cooled central cooling systems

Buildings consume a large amount of energy across all sectors of society, and a large proportion of building energy is used by HVAC systems to provide a comfortable and healthy indoor environment. In medium and large-size buildings, the central cooling system accounts for a major share of the energy consumption of the HVAC system. Improving the cooling system efficiency has gained much attention as the reduction of cooling system energy use can effectively contribute to environmental sustainability. The control and operation play an important role in central cooling system energy efficiency under dynamic working conditions. It has been proven that optimization of the control of the central cooling system can notably reduce the energy consumption of the system and mitigate greenhouse gas emissions. In recent years, numerous studies focus on this topic to improve the performance of optimal control in different aspects (e.g., energy efficiency, stability, robustness, and computation efficiency). This paper provides an up-to-date overview of the research and development of optimization approaches for controlling water-cooled central cooling systems, helping readers to understand the new significant trends and achievements in this area. The optimization approaches have been classified as system-model-based and data-based. In this paper, the optimization methodology is introduced first by summarizing the key decision variables, objective function, constraints, and optimization algorithms. The principle and performance of various optimization approaches are then summarized and compared according to their classification. Finally, the challenges and development trends for optimal control of water-cooled central cooling systems are discussed

Estudo de caso de eficiência energética e controle de qualidade do ar interior em ambiente condicionado

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2018.O objetivo deste trabalho é realizar um estudo de caso sobre eficiência energética e controle de qualidade do ar interior (QAI) de sistema de ar condicionado com tecnologias de vazão de ar exterior variável (DCV), recuperação de energia (ERV) e free cooling no plenário Ulysses Guimarães, Brasília - DF. Uma simulação computacional com auxílio dos softwares OpenStudio e Energyplus acerca do sistema de climatização em estudo foi realizada para analisar o potencial de economia na utilização de recursos como ERV, DCV e free cooling. Para tal, foram consideradas condições climáticas locais, características arquitetônicas do plenário, bem como as eficiências dos equipamentos utilizados. Paralelamente, foi realizada uma avaliação da qualidade do ar interior e possíveis soluções de monitoramento. Os resultados mostraram que a combinação das tecnologias avaliadas foi capaz de proporcionar economias de até 20% nos custos operacionais do sistema de ar condicionado em ambientes que apresentam perfil de ocupação variável.The objective of this work is to perform a case study on energy efficiency and indoor air quality control (IAQ) of air conditioning system with variable outdoor airflow (DCV), energy recovery (ERV) and free cooling technologies in plenary Ulysses Guimarães, Brasilia DF. A computer simulation with the help of the OpenStudio and Energyplus software on the air conditioning system under study was performed to analyze the potential savings in the use of resources such as ERV, DCV and free cooling. For this, local climatic conditions, architecture characteristics of the plenary, as well as the efficiencies of the equipment used were considered. At the same time, an indoor air quality assessment and possible monitoring solutions were carried out. The results showed that the combination of the technologies evaluated was able to provide savings up to 20% in the operating costs of the air conditioning system in environments with variable occupancy profiles

Investigation of Some Self-Optimizing Control Problems for Net-Zero Energy Buildings

Green buildings are sustainable buildings designed to be environmentally responsible and resource efficient. The Net-Zero Energy Building (NZEB) concept is anchored on two pillars: reducing the energy consumption and enhancing the local energy generation. In other words, efficient operation of the existing building equipment and efficient power generation of building integrated renewable energy sources are two important factors of NZEB development. The heating, ventilation and air conditioning (HVAC) systems are an important class of building equipment that is responsible for large portion of building energy usage, while the building integrated photovoltaic (BIPV) system is well received as the key technology for local generation of clean power. Building system operation is a low-investment practice that aims low operation and maintenance cost. However, building HVAC and BIPV are systems subject to complicated intrinsic processes and highly variable environmental conditions and occupant behavior. Control, optimization and monitoring of such systems desire simple and effective approaches that require the least amount of model information and the use of smallest number but most robust sensor measurements. Self-optimizing control strategies promise a competitive platform for control, optimization and control integrated monitoring for building systems, and especially for the development of cost-effective NZEB. This dissertation study endorses this statement with three aspects of work relevant to building HVAC and BIPV, which could contribute several small steps towards the ramification of the self-optimizing control paradigm. This dissertation study applies self-optimizing control techniques to improve the energy efficiency of NZEB from two aspects. First, regarding the building HVAC efficiency, the dither based extremum seeking control (DESC) scheme is proposed for energy efficient operation of the chilled-water system typically used in the commercial building ventilation and air conditioning (VAC) systems. To evaluate the effectiveness of the proposed control strategy, Modelica based dynamic simulation model of chilled water chiller-tower plant is developed, which consists of a screw chiller and a mechanical-draft counter-flow wet cooling tower. The steady-state performance of the cooling tower model is validated with the experimental data in a classic paper and good agreement is observed. The DESC scheme takes the total power consumption of the chiller compressor and the tower fan as feedback, and uses the fan speed setting as the control input. The inner loop controllers for the chiller operation include two proportional-integral (PI) control loops for regulating the evaporator superheat and the chilled water temperature. Simulation was conducted on the whole dynamic simulation model with different environment conditions. The simulation results demonstrated the effectiveness of the proposed ESC strategy under abrupt changes of ambient conditions and load changes. The potential for energy savings of these cases are also evaluated. The back-calculation based anti-windup ESC is also simulated for handling the integral windup problem due to actuator saturation. Second, both maximum power point tracking (MPPT) and control integrated diagnostics are investigated for BIPV with two different extremum seeking control strategies, which both would contribute to the reduction of the cost of energy (COE). In particular, the Adaptive Extremum Seeking Control (AESC) is applied for PV MPPT, which is based on a PV model with known model structure but unknown nonlinear characteristics for the current-voltage relation. The nonlinear uncertainty is approximated by a radial basis function neural network (RBFNN). A Lyapunov based inverse optimal design technique is applied to achieve parameter estimation and gradient based extremum seeking. Simulation study is performed for scenarios of temperature change, irradiance change and combined change of temperature and irradiance. Successful results are observed for all cases. Furthermore, the AESC simulation is compared to the DESC simulation, and AESC demonstrates much faster transient responses under various scenarios of ambient changes. Many of the PV degradation mechanisms are reflected as the change of the internal resistance. A scheme of detecting the change of PV internal shunt resistance is proposed using the available signals in the DESC based MPPT with square-wave dither. The impact of the internal resistance on the transient characteristics of step responses is justified by using the small-signal transfer function analysis. Simulation study is performed for both the single-string and multi-string PV examples, and both cases have demonstrated successful results. Monotonic relationship between integral error indices and the shunt internal resistance is clearly observed. In particular, for the multi-string, the inter-channel coupling is weak, which indicates consistent monitoring for multi-string operation. The proposed scheme provides the online monitoring ability of the internal resistance condition without any additional sensor, which benefits further development of PV degradation detection techniques

分散型エネルギーシステムにおける設備保全とシステム最適化に関する研究

Owing to the continuous growth in the world\u27s energy demand, the problems of energy consumption, greenhouse gas emission, and environmental pollution have become increasingly prominent. The distributed energy resource (DER) system is a high-efficiency energy system that can promote energy-saving and decrease carbon emissions. the focus of this research is on the equipment maintenance and system optimization of DER. In the maintenance optimization stage, a maintenance priority assessment method is used to allocate maintenance management resources based on the assessment results to help managers develop reasonable maintenance strategies and reduce maintenance costs. In the system design optimization stage, the capacity and operation strategy of the system is optimized for the energy demand of users to achieve the purpose of improving economic benefits and promoting energy saving and emission reduction.北九州市立大

Multi-criteria Evaluation of a Distributed Energy System Focusing on Grid Stabilization and Carbon Emission Reduction

北九州市立大学博士(工学)Distributed energy systems can save energy cost, reduce environmental impact and improve the reliability of the power grid. However, its high investment and improper capacity caused poor economic benefits. Moreover, the current evaluation method with a single criterion is relatively simple and one-sided, which cannot reflect the comprehensive benefits of the DES. Therefore, this research proposed a distributed energy system (DES) composed of photovoltaic, energy storage and gas engine, and its grid stabilization and carbon reduction potentials were analyzed. Focusing on these advantages, a multi-criteria evaluation method was established to optimize the system. Finally, different case study scenarios of the DES utilization were demonstrated. It is hoped to improve the core competitiveness of the DES and promote its development.doctoral thesi