Event-based Green Scheduling of Radiant Systems in Buildings

This paper looks at the problem of peak power demand reduction for intermittent operation of radiant systems in buildings. Uncoordinated operation of the circulation pumps of a multi-zone hydronic radiant system can cause temporally correlated electricity demand surges when multiple pumps are activated simultaneously. Under a demand-based electricity pricing policy, this uncoordinated behavior can result in high electricity costs and expensive system operation. We have previously presented Green Scheduling with the periodic scheduling approach for reducing the peak power demand of electric radiant heating systems while maintaining indoor thermal comfort. This paper develops an event-based state feedback scheduling strategy that, unlike periodic scheduling, directly takes into account the disturbances and is thus more suitable for building systems. The effectiveness of the new strategy is demonstrated through simulation in MATLAB

Green Scheduling of Control Systems

Electricity usage under peak load conditions can cause issues such as reduced power quality and power outages. For this reason, commercial electricity customers are often subject to demand-based pricing, which charges very high prices for peak electricity demand. Consequently, reducing peaks in electricity demand is desirable for both economic and reliability reasons. In this thesis, we investigate the peak demand reduction problem from the perspective of safe scheduling of control systems under resource constraint. To this end, we propose Green Scheduling as an approach to schedule multiple interacting control systems within a constrained peak demand envelope while ensuring that safety and operational conditions are facilitated. The peak demand envelope is formulated as a constraint on the number of binary control inputs that can be activated simultaneously. Using two different approaches, we establish a range of sufficient and necessary schedulability conditions for various classes of affine dynamical systems. The schedulability analysis methods are shown to be scalable for large-scale systems consisting of up to 1000 subsystems. We then develop several scheduling algorithms for the Green Scheduling problem. First, we develop a periodic scheduling synthesis method, which is simple and scalable in computation but does not take into account the influence of disturbances. We then improve the method to be robust to small disturbances while preserving the simplicity and scalability of periodic scheduling. However the improved algorithm usually result in fast switching of the control inputs. Therefore, event-triggered and self-triggered techniques are used to alleviate this issue. Next, using a feedback control approach based on attracting sets and robust control Lyapunov functions, we develop event-triggered and self-triggered scheduling algorithms that can handle large disturbances affecting the system. These algorithms can also exploit prediction of the disturbances to improve their performance. Finally, a scheduling method for discrete-time systems is developed based on backward reachability analysis. The effectiveness of the proposed approach is demonstrated by an application to scheduling of radiant heating and cooling systems in buildings. Green Scheduling is able to significantly reduce the peak electricity demand and the total electricity consumption of the radiant systems, while maintaining thermal comfort for occupants

Model Predictive Control of a Radiant Floor Cooling System in an Office Space

This study presents an optimal control formulation for the operation of a radiant floor system in an open plan office space with an air-cooled chiller as a source. A simulation case study with different control schemes is used to evaluate the potential of the model predictive control for the radiant floor as well as the optimal control coordination of a radiant and air comfort delivery system. The comparison with a reference case of proportional control shows a saving potential for the radiant floor of around 10 to 15.8 %, which results from maintaining the temperature at upper bound and precooling or load shifting. Optimal control coordination of radiant floor and air system yields additional saving of around 2 %. The proposed intuitive formulation of linear programming can be implemented to other control problems with a linear building model and known COP with respect to weather prediction. The formulation is applicable to other complex systems with two or more control systems such as open-plan spaces with several control units or multiple zones (or buildings) with centralized plant

Intelligent Decision Support System for Energy Management in Demand Response Programs and Residential and Industrial Sectors of the Smart Grid

This PhD thesis addresses the complexity of the energy efficiency control problem in residential and industrial customers of Smart electrical Grid, and examines the main factors that affect energy demand, and proposes an intelligent decision support system for applications of demand response. A multi criteria decision making algorithm is combined with a combinatorial optimization technique to assist energy managers to decide whether to participate in demand response programs or obtain energy from distributed energy resources

Sustainability in the Worcester Arts Workshop

The Worcester Arts Workshop has served the community since 1974, but like other arts organizations struggles to maintain funding and support. The goal of this project was to assess how to Workshop could improve its social, economic, and environmental sustainability, especially by enhancing revenues and reducing expenditures. We solicited a wide range of stakeholder perspectives, assessed the current use of the building, and conducted an energy audit. We recommend several short term improvements, such as changing light bulbs, insulating lofts, streamlining the website, and increasing marketing and outreach, as well as long term improvements, such as replacing the boiler, increasing class offerings, adding new types of events, extending opening times, and diversifying its audience

Data Driven Energy Efficiency Strategies for Commercial Buildings Using Occupancy Information

Most building automation systems operate with settings based on design assumptions with fixed operational schedules and fixed occupancy, when in fact both schedules and occupancy levels vary dynamically. In particular, the heating ventilation and air conditioning (HVAC) system provides a minimum ventilation airflow calculated for the maximum room capacity, when rooms are rarely fully occupied. Energy is wasted by over-supplying and conditioning air that is not required, which also leads to thermal discomfort. In higher educational institutions, where classroom occupancy goals vary from 60% to 80% of their maximum capacity, potential savings are substantial. Existing occupancy and schedule information from academic registration can be integrated with the facility data and the building automation system, allowing dynamic resetting of the controllers. This dissertation provides a methodology to reduce HVAC energy consumption by using occupancy information from the academic registrar. The methodology integrates three energy conservation strategies: shortening schedules, modifying thermostat settings and reducing the minimum airflow. Analysis of the proposed solution includes an economic benefit estimation at a campus level with validation through an experimental study performed on a LEED platinum building. Experiment results achieved an electricity savings of 39% and a natural gas savings of 31% for classrooms’ air conditioning consumption. Extending these savings to the campus level yields 164 MWh of electricity savings per year, 48MMBtu natural gas savings per year, 35.16 MTCO2 of greenhouse gases emissions reduction per year, approximately $20k economic savings per year

Final Causality in the Thought of Thomas Aquinas

Throughout his corpus, Thomas Aquinas develops an account of final causality that is both philosophically nuanced and interesting. The aim of my dissertation is to provide a systematic reconstruction of this account of final causality, one that clarifies its motivation and appeal. The body of my dissertation consists of four chapters. In Chapter 1, I examine the metaphysical underpinnings of Aquinas’s account of final causality by focusing on how Aquinas understands the causality of the final cause. I argue that Aquinas holds that an end is a cause because it is the determinate effect toward which an agent’s action is directed. I proceed by first presenting the general framework of causality within which Aquinas understands final causality. I then consider how Aquinas justifies the reality of each of the four kinds of cause, placing special emphasis on the final cause. In Chapter 2, I consider final causality from the perspective of goodness and explore the reasons why Aquinas thinks that the end of an action is always good. For even if one was convinced that the end of an action is indeed a cause, one might still resist attributing any normative or evaluative properties to the end, much less a positively-valenced normative property like goodness. In this chapter, I show how, given Aquinas’s metaphysics of powers and his characterization of goodness as that which all desire, it follows that every action is for the sake of some good. In Chapter 3, I consider Aquinas’s account of the relation between final causality and cognition. In many passages throughout his corpus—most famously in the fifth of his Five Ways—Aquinas advances the claim that cognition plays an essential role in final causality. In this chapter, I explore Aquinas’s account of the relation between final causality and cognition by reconstructing his Fifth Way and investigating the metaphysical foundations on which it rests. While the first three chapters of my dissertation focus on Aquinas’s account of final causality from the perspective of the ends of individual agents, in Chapter 4 I broaden my focus to consider the way in which the account of final causality developed in these earlier chapters shapes Aquinas’s philosophical cosmology. I argue that, on Aquinas’s view, when an individual agent acts for an end, it is plays a role in a larger system, e.g. a polis, an ecosystem, or the universe itself

Performative Threshold

Threshold is defined by Limen as transitional between two fixed states in cultural rites of passage or between two dissimilar spaces in architecture. The study of rites of passage provides an analogy from which principles can be drawn for the design of a transformative space. The experience of liminal space poses a discontinuity and leads the occupant to question their surroundings, thus leading to heightened awareness of the space as a transformative threshold between distinct spaces. All buildings have in-between space, the quality of life is directly affected by these spaces. The way of using space cannot be changed as long as architectural space is designed by its form, materials, details, and joints therefore the threshold becomes the key elements that defines the architecture. Façade is exterior of the threshold that protecting environment inside. However with today’s advanced technologies and materials, we can design performative façade system that can create different yet comfortable space for people inside. The threshold of inside and outside can be integrated through performative façade system to control heating and cooling, energy generation or other sustainable system through understanding architecture and movement. High performance building integrates and optimize high performance building criteria that involves with energy efficiency, durability, life-cycle performance, and occupant productivity. This term became important as modern architecture design become more sustainable. As architects explore sustainable design in architecture, performative façade system work efficiently in saving energy consumption. Therefore the research started with 3 different case study involve with performative façade, first one was active surface which is deployable structure base façade that change shapes to create comfort area for people with different experience to people by dynamic movement of its nature. Second version of research is response surface, it evolving measures actual environmental conditions to enable building to adapt their form, shape, color or character responsively. This responsive system creates aesthetic quality to building to changes the experience of architecture that static form cannot not give. Third version is environmentally adaptive, this system changes surface by environmental changes. Instinct change of surface or shell will manage building better to increase life-cycle of building by protecting the structure. Exploring Threshold will be measured by 3 different key elements which include energy and emission, adaptation, and resilience. The performative design will reduce or possibly produce no carbon dioxide emissions in building operations and minimize embodied carbon for building materials and construction. Research and exploring performative façade will project and respond to climate changes, such as responsive to climate changes, heat effect, heat waves, and extreme weather conditions. These factors will be considered in project site and context. Resilience enable continued habitability and rapid recovery unexpected events, natural disaster, absence of power, or other projected climate interruptions. Façade – how it links and separate inside and outside with intend of creating high performance building in private Environmentally public architecture Outline strategy Atlanta more energy efficient for 2020 Case study exploring with intend to create to environmentally friendly architectur