Festschrift – An Homage to Les Norford and Building Science
Cover and Book Design Yoshiki Waterhouse Laoyout Akshata Atre Printed in the USA Copyright 2024, Building Technology Press All rights are reserved. No part may be reproduced in any form by any electronic or mechanical means without permission in writing from the publisher. Copyright for all photos are owned by the authors unless otherwise noted in the figure caption. Additional copies of this booklet are available from http://BuildingTechnologyPress.com
Festschrift An Homage to Les Norford and Building Science Les Norford Amir Aliabadi Peter Armstrong Alpha Arsano Ronita Bardhan Dave Blum Yuan Chao Eduardo Gascon Nick Gayeski Leon Glicksman Nebyu Haile Libby Hsu Ali Irani Steve Leeb Forrest Meggers Caitlin Mueller Negin Nazarian John Ochsendorf Christoph Reinhart Rob Stoner Nada Takhan Liping Wang David Warsinger Tea Zakula
Table of Contents 1 The Urban Environment 11 Modeling the Urban Environment Heat in the City Climate Modelling and Analytics for Urban Heat Risk Mitigation and Adaptation 2 Passive, Low Cost Conditioning 17 Efficient Dehumidification Passive System Demonstration and Instrumentation Natural Ventilation and Thermal Mass Integrated Design of Passive and Low-Energy Systems
3 Global South 25 How do we speak about the “Global South?” How do we get people interested in working on projects in the Global South? How do we make sure research and projects in the Global South are successful? How do we make our findings and research done in the global north more accessible and accurate for the global south? What are the exogenous factors that we might not be able to fix but must consider when working in the Global South? 4 HVAC Diagnostics and Controls 35 Non-Intrusive Load Monitoring Technology Toolbox for Design and Control of Ground Source Heat Pumps Living Laboratory as a Testbed and Teaching Tool Impacts and Future of HVAC Controls Analytics and Controls
7 Preface Welcome to Festschrift – An Homage to Les Norford and Building Science. This booklet documents the proceedings of a two-day symposium at the Massachusetts Institute of Technology on June 27 and 28, 2024, to mark the retirement of long-term faculty member Prof. Leslie (Les) Norford. For Les∙schrift, we invited former students and colleagues who accompanied Les during his four decades-spanning career in building science and discussed topics that he had worked on. We thank all of our guests for joining us for this special event and Les for being the best colleague, mentor and friend any of us could have wished for. With gratitude, Christoph Reinhart, Leon Glicksman, Caitlin Mueller and John Ochsendorf Cambridge, August 2024 Fig 1.1 Les Norford discussing the Urban Weather Generator Photo: Justin Knight
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11 1 The Urban Environment Summary by Nada Tarkhan | Session chair: Christoph Reinhart Panel Introduction by Prof. Les Norford The session highlighted the growing importance of addressing heat stress, particularly in urban areas. Cities tend to be warmer than their surroundings due to the Urban Heat Island (UHI) effect, primarily at night. The availability of extensive data allows for detailed measurements of urban temperatures within city environments, such as in urban canyons. Environmental modeling tools such as the Urban Weather Generator (UWG) and the measurement of the Universal Thermal Climate Index (UTCI) are essential in assessing outdoor thermal comfort levels. Our discussion also emphasized the mortality risks associated with extreme heat and the need for precise data tailored to specific analyses. Modeling the Urban Environment (Prof. Amir Aliabadi) Prof. Aliabadi's presentation focused on the significance of modeling the urban environment to better understand and address urban challenges. Various modeling tools – from white box models to data-driven approaches – offer differing levels of applicability and precision. Multidomain modeling, including sequential, co-simulation, and integrated methods, facilitates complex system analysis. EnergyPlus has been pivotal in the co-simulation domain, emphasizing flexibility, scalability, and modularity. The Urban Weather Generator (UWG) is increasingly used for weather file predictions to adjust for micro-climatic conditions. Towards the end of his overview, Prof. Aliabadi focused on the need for new, hybrid tools that incorporate modern data-driven methods and the potential for models to inform socioeconomic factors. This also includes an exploration of AI's role in modeling and the integration of social behavior and equity into models. Discussion The discussion addressed Artificial Intelligence's (AI) potential in modeling, emphasizing challenges such as trust and representing local context. Different approaches include co-simulation with various methods that can enable inter-model comparisons. Key questions involved model interfacing, required resolutions, and integration into existing tools. Opportunities exist to Fig 1.2 The urban environment (Design: Nada Tarkhan)
12 enhance data-driven techniques, move beyond restrictive models, and focus on comparative outputs to address gaps in both modelling and perception of the metrics utilized. Heat in the City (Prof. Negin Nazarian) Prof. Nazarian's presentation emphasized the drivers of urban heat: urbanization and climate change. Integrated assessments of urban overheating should consider heat hazards that are the outcome these multiscale drivers. More importantly, we need to understand how hot is too hot for people and urban systems. This requires that we consider heat hazards together with exposure as well as individual and population vulnerabilities (determined by their sensitivity with adaptive capacities). The presentation provided an integrated overview of research conducted across various (human to global) scales to better quantify heat hazards, exposures, and vulnerabilities. At the global scale, opportunities and challenges of remote sensing in understanding air temperature variations within cities were showcased. Transitioning to city and regional levels, integrated use cases of urban climate modelling and observation techniques were discussed, with a focus on achieving human-scale impact assessment within city-scale methodologies. Urban climate informatics methods, such as machine learning and crowd-sourced citizen weather stations, were Fig 1.3 Presentation by Prof. Nazarian (center, standing) Photo: Justin Knight
13 discussed to improve data coverage in cities where people are most exposed to heat. Smart watches, on the other hand, focus on monitoring individual heat stress, correlating temperature with activity levels and corresponding core body temperature to provide key insights on human risk impacts. Discussion The discussion evolved around covering the transition between indoor and outdoor environments. This presentation was focused on outdoor environment but there was an acknowledgement of the use of UCI for more realistic exposure between the two. The implications of the use of web scraping for data collection was then discussed, noting a consistent quality control method for low-cost sensors. Several points highlighted the need for high-precision measurements to inform policy, particularly in low-resource, high-risk areas, bridging gaps between technology and measurement. Climate Modelling and Analytics for Urban Heat Risk Mitigation and Adaptation (Prof. Yuan Chao) Prof. Yuan Chao's presentation highlighted the impact of climate resilience and the need to model heat flows. He noted that heat from neighboring buildings can raise temperatures by up to 2°C and discussed anthropogenic heat dispersion models that aid urban planning and climate resilience Fig 1.4 An image from the Microclimate Digital Platform shared during Prof. Yuan's presentation
14 measurements. Assessing response capability and fine-tuning risk assessments to reduce uncertainty are critical for evaluating heat stress. Indoor risks were addressed, considering air conditioning and natural ventilation as viable means to alleviate overheating. Prof. Chao also showcased a micro-climate digital platform that focused on helping the public and researchers assess urban morphology impacts. The presentation additionally explored layering different data streams, the impact of air conditioner condensers' placement, nighttime air temperatures, district systems, and the impact of urban morphology. Discussion The discussion focused on integrating diverse data types to create more representative results, considering the significant impact of building arrangements on urban temperatures. Nighttime air temperatures and district systems were emphasized as crucial to be considered when formulating solutions. The placement of building condensers (rooftop vs façade) was also discussed and was estimated to have a margin of 1°C difference. Effective urban morphology was also discussed, emphasizing the need for planners and designers to understand such impacts. Links to Presentations Les Norford, Panel Introduction Amir Aliabadi, Modeling the Urban Environment Negin Nazarian, Heat in the City Yuan Chao, Urban Climate Modelling and Analytics
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17 2 Passive, Low Cost Conditioning Summary by Eduardo Gascón | Session chair: Leon Glicksman Panel Introduction by Prof. Les Norford As the frequency of extreme weather events increases worldwide and the need to minimize the operational emissions of buildings becomes more pressing, there is a clear need to rethink how buildings are conditioned. The second panel of the Festschrift approaches this question through three key ideas. First, the understanding of thermal comfort as an energy balance defined by not air temperature but also radiant temperature, relative humidity, and air speed. This approach is critical in designing low-energy space-conditioning systems that focus on occupants, as demonstrated in many of talks throughout the panel. Second, leveraging available heat sinks and sources through passive/low-energy strategies offers a more sustainable and climate-specific approach to building conditioning: nightflush ventilation, radiative cooling, and ground cooling are some examples mentioned in the session. Finally, improving the ability of buildings to store heat through, for example, thermal mass, is an essential aspect to moderate temperature fluctuations and improve their resilience to extreme weather events. Efficient Dehumidification (Prof. David Warsinger) Cooling processes within buildings have a significant environmental impact, accounting for 10% of the total electricity consumed worldwide and 4% of global emissions. Prof. Warsinger’s presentation focused on the latent load associated with cooling (which represents half of its energy demand) and the potential for using membrane-based technologies as a promising low-energy solution to dehumidification. Conventional air-conditioning (AC) systems dehumidify air by over-cooling it below its dew point, an energy-intensive process that leads to condensation. Alternatively, selective membranes allow water vapor to permeate while blocking air molecule transportation. In this way, the sensible and the latent loads are decoupled and treated separately. The development of novel membrane technologies, many of which are led by Prof. Warsinger’s group, focuses on addressing the Fig 2.1 Passive, low-cost conditioning (Design: Nada Tarkhan)
18 permeation-selectivity trade-off: using novel materials and intelligent system configurations to design membranes that are highly permeable to water vapor while, at the same time, have high selectivity values. Discussion The discussion pivoted around the at-scale fabrication and implementation of membrane-based dehumidification systems. Key questions tackled the sizing of membrane systems as a function of the room size and the fan energy use necessary to move air through such large membranes. In this regard, coupling membranes with hydronic systems such as chilled radiant ceilings (mentioned in Prof. Meggers and Eduardo Gascón’s talks) would be advantageous as the air movement through ducts is minimized. Other questions tackled the lifespan and maintenance of membranes. While Prof. Warsinger does not expect the former to be a crucial issue, he did mention that appropriate maintenance is critical to ensuring the adequate performance of these systems. Finally, the group debated the differences between desiccant and membrane-based dehumidification systems – despite the increased sensible cooling required in desiccant systems, their storage ability was highlighted as an advantage in a flexible demand scenario. Fig 2.2 Diagram shared by David Warsinger of Active Membrane Energy Exchanger (AMX) in a dedicated outdoor air system (DOAS)
19 Passive System Demonstration and Instrumentation (Prof. Forrest Meggers) Conventional air conditioning systems typically require minimizing the supply of fresh air to improve the system’s energy efficiency, an approach that is particularly problematic in a pandemic scenario as indoor air becomes a transmission pathway. Professor Meggers’s talk presented alternative space-conditioning strategies that allow for increased air exchange rates while providing a human-centered approach to thermal comfort. For instance, combining dehumidification systems (membrane or desiccantbased) with fan-assisted air movement can become an energy-efficient way to provide comfort while ensuring access to fresh air. Experiments conducted in Miami by Professor Meggers and collaborators in academia and industry provide quantifiable evidence that supports this novel thermal comfort pathway. Another promising alternative is using radiant panels covered by photonic membranes that prevent cooled surfaces from being in contact with humid air. This approach decouples convection from radiation, allowing panels to cool down below dew point temperatures. Professor Megger’s team applied these ideas in the design of an outdoor pavilion in Singapore, which resulted in visitors perceiving cold while standing outside on a warm-humid day. Fig 2.3 A photo of a structure that employs radiant panels covered in photonic membranes shared by Prof. Meggers
20 Discussion The discussion focused on the instrumentation and metrics required to quantify the benefits of the novel heating and cooling systems presented during the talk. For example, the group discussed the number of longwave radiation sensors necessary to capture the performance of radiant panels with enough resolution and their use in tandem with thermographic cameras. The discussion also focused on the importance of the view factor when designing these systems and the opportunities behind using reflective surfaces to fine-tune their performance. Other questions tackled existing challenges in the hydronic installation of radiant panels as a potential barrier for their at-scale implementation yet an opportunity to provide comfort in a customized way. Finally, the session ended with a reflection on metrics to help designers, engineers, and building occupants understand the importance of radiant temperature, air speed, and humidity in achieving thermal comfort. Natural Ventilation and Thermal Mass (Prof. Leon Glicksman) Passive low-cost conditioning can be accomplished using natural ventilation combined with thermal mass. Leon Glicksman described the requirements for such a system's successful design and operation. Effective cooling of a building interior requires a high airflow rate set up by wind or buoyancy Photo: Justin Knight Fig 2.4 Prof. Glicksman (front) in discussion with the group
21 forces. This is dependent on large openings to the exterior and low resistance within the building interior. A large thermal mass with extended surface area is required to utilize the diurnal, temperature differences. Glicksman described real-world challenges to implement such a system. Not only is detailed airflow analysis required, but building operators and control designers need proper training and experience. Monitoring of naturally ventilated buildings has shown as much as a 10°C difference between peak outdoor ambient temperature and interior temperatures. This technology is appropriate for low-cost housing in areas such as South Asia. Discussion In the discussion, real world issues concerning the control of automated windows for natural ventilation were raised. Model predictive controls highlight the importance of night-flush ventilation. However, in many cases, needless complexity in operations and controls has been encountered. During periods of low wind velocity, the use of fans to augment ventilation was suggested since its energy use is far less than the energy required for air conditioning. Questions around noise pollution and air quality must be addressed when natural ventilation is considered. A question was raised concerning the widespread promotion of the technology. Although natural ventilation has been utilized in individual high-end buildings, demonstrations Fig 2.5 A snapshot of Eduardo Gascon's research on shaped concrete slabs
22 in simple low-income buildings are required to promote the use of natural ventilation Integrated Design of Passive and Low-Energy Systems (Eduardo Gascón) The last talk by Eduardo Gascón presented how an integrated design approach can lead to building solutions that provide low-energy cooling at minimal material cost. Earthen walls, for example, can be designed for enhanced thermal mass performance while minimizing weight, thanks to an efficient distribution of their mass and interior air pockets. How to fabricate these complex geometries was explored through a prototype built in collaboration with Sandy Curth using additive manufacturing techniques. Another promising avenue is shaping concrete slabs as structural elements and thermally activated chilled ceilings. Through a multi-domain design and optimization process, it is possible to remove material where it is not required structurally (cutting the material in half) while improving its thermal performance as radiant surfaces. Finally, Gascón presented the opportunity to design new urban developments that account for the availability of the ground and the night sky as heat sinks. This approach allows for minimizing the anthropogenic heat dissipated into the urban canyon while covering the cooling needs of buildings in a low-energy and climate-specific manner. Discussion The discussion revolved around how to make the presented solutions (and, more broadly, the idea of integrated design) more accessible to designers and practitioners. Different approaches to this question were suggested. Some focused on the tools (how to make them easier to use and integrated with existing design processes) while others focused on on the solutions themselves and their manufacturability. Regarding the latter, the group discussed the opportunities to engage with the manufacturing sector to create novel building solutions that are compelling to designers and consumers aesthetically and functionally. Other questions focused on the advantages of using analytical tools within design processes (providing a fast and physics-informed response) and the importance of understanding their scope and limitations. Links to Presentations Les Norford, Panel Introduction David Warsinger, Efficient Dehumidification Forrest Meggers, Passive System Demonstration and Instrumentation Leon Glicksman, Natural Ventilation and Thermal Mass Eduardo Gascón, Integrated Design of Passive and Low-Energy Systems
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25 3 Global South Summary by Nebyu Haile | Session chair: Cailtin Mueller How do we speak about the "Global South?" In discussions about regions where many social good or impact projects are focused—such as Sub-Saharan Africa, the Middle East, India, Southeast Asia, and Latin and Central America—academics and international organizations like the World Bank and the United Nations have historically used the term "Global South." This term has been in use since its inception in the 1960s and was popularized by economists in the 1980s. Now, fifty years later, it is crucial for academics and governmental bodies to consider finding a more accurate and respectful term that truly reflects the challenges faced by these regions. Similar to the Cold War rhetoric of "East vs. West," the Global North vs. Global South divide is not a clear physical or geographical line. Many of the countries considered part of the Global South are actually north of the equator, challenging the assumption that the equator serves as the dividing line. The North vs. South division was an arbitrary construct established by politicians and economists in the 1980s to separate high GDP countries of the North from the poorer countries of the South along a self-created line known as the Brandt Line. Fifty years later, it can be argued that this line should be retired, especially considering that countries like India and Brazil, which are part of the Global South according to this line, now have the 5th and 11th highest GDPs in the world. Given the general consensus that "Global South" is not the most accurate term, the question arises: what term should be used instead? A crude alternative might be "hot and humid countries," "brown countries," or "poor countries". While countries like Brazil, India, and China have high national GDPs, their GDPs per capita are still relatively low, aligning with the 1980s rhetoric and organization of countries into North vs. South. Acknowledging that many of these countries' challenges still lie in their disparity of economic success, terms that have become popular among aid organizations include Fig 3.1 Global South (Design: Nada Tarkhan)
26 "Less Economically Developed Countries (LEDCs)," "Low and MiddleIncome Countries," "Developing Countries," and "Emerging Countries." These terms eliminate the arbitrary geographical divide of North and South and are favored by many organizations. However, there is still some discussion that it is not fair to have the connotation of "poor" associated with these terms for these countries, noting that many of these countries, while appearing poor in terms of GDP, are rich in raw resources that power the modern world. One proposed alternative for a general term is "The Majority World." Previous terms tend to emphasize the economic challenges these countries face in a somewhat negative manner, making them seem like the minority or lagging behind the rest of the world. The term "The Majority World" shifts the focus, highlighting that the majority of the world's population lives in countries dealing with low economic output and related challenges such as high poverty, informal settlements, climate crises, and health challenges. This reframing underscores the importance of research, development, and funding to address these issues. For example, in the context of the built environment, acknowledging that many countries in the "Majority World" have hot and humid climates with limited budgets is crucial for designing efficient buildings using appropriate technologies. The ongoing discourse underscores the need for further discussion on Fig 3.2 Snippet from an article about D-Labs: Schools shared as part of Libby Hsu's presentation.
27 how to characterize and speak about the countries and regions that are the focus of social good and impact projects without appearing condescending or superior. While politically correct but perhaps imperfect terms like "Emerging Countries" and "LEDCs" are likely to be adopted moving forward, and possibly "Majority Countries" in the future, it is essential to recognize that while these generalizations are somewhat accurate and necessary for broader discourse, academics and practitioners must avoid being overly reductive when trying to solve problems in these parts of the world . Each country has unique characteristics and challenges, and it is essential not to treat them uniformly under broad categorizations such as "economically challenged" or "hot and humid." How do we get people interested in working on projects in the Global South? Historically, we have relied on students, professors, and the broader academic community to address the world's pressing challenges. Today, with the severe consequences of climate change—such as rising temperatures, sea levels, and food insecurity—impacting those with the least resources in Less Economically Developed Countries (LEDCs) the most, it is crucial for us, as members of the academic community, to have more students and academics engaged in studying these issues and developing solutions. However, we are currently struggling to attract students to these fields and motivate them to work on or start ventures to solve these global challenges. One of the primary challenges in encouraging students to pursue studies and careers focused on addressing global social issues is exposure. In modern classrooms, assignments are often designed around hypothetical scenarios or problems that can be managed within the timeframe of a semester or a final project rather than being framed in the context of real-world problems. A study by MIT's D-Lab, which stands for "Development through Dialogue, Design, and Dissemination," found through surveys that students who took D-Lab courses—focused on using engineering and participatory design to solve real-world problems—left MIT with a 20-30% better understanding and confidence in areas such as "placing current problems in historical/ cultural/philosophical perspective," "developing global awareness," and "understanding the complexity of social problems." Furthermore, 34% of students who took a D-Lab course reported that it influenced their future career or academic paths to focus more on solving global challenges. This data suggests that exposing students to real-world problems through their coursework can significantly enhance their social awareness of the issues facing the "Majority World" and potentially inspire them to pursue social impact projects in their careers. While not every class needs to adopt a social impact lens, project-based classes could easily incorporate real-world problems. For instance, an IoT class could include a project on detecting
28 contaminants in water, or a product design class could focus on developing an affordable tool for harvesting a labor-intensive crop. Another significant challenge in motivating students to engage in social impact work and careers is the prospect of a lucrative career. Talented students from LEDCs, who have a good understanding of their countries' challenges and the skills to address them, often enter university but are drawn into high-earning fields like finance or tech by graduation, seeking economic security and freedom. While social impact ventures should not solely aim to maximize profits, the current narrative portrays them as akin to charities, offering limited financial rewards. This discourages individuals from pursuing careers in this area. To attract more people to social impact work, it is essential to reframe career paths in the field. Instead of likening them to organizations like UNICEF or the UN, framing social impact ventures as startups that can achieve social good while also generating solid income could better convince people that working on grand societal challenges is not only compatible with entrepreneurship and lucrative careers, but also offers a unique opportunity for personal growth and fulfillment. Fig 3.3 Image of Les and Prof. Bardhan conducting research on indoor air quality in India shared by Prof. Bardhan during her presentation.
29 How do we make sure research and projects in the Global South are successful? A prevalent challenge in social impact initiatives within higher education is the frequent failure of ideas to be actualized beyond the scope of Master's or Doctoral work. This often occurs because academic work emphasizes the scientific aspects of projects while under developing the economic and implementation dimensions essential for success outside the educational context. Ensuring the success of research and projects in the Global South necessitates a comprehensive approach that addresses governmental, commercial, and social viability. One method to better ensure that these varied goals are met in academic social impact projects is to frame research projects as if they were startup businesses, thus increasing their likelihood of adoption. Successful business ventures require a holistic approach; not only must the idea be sound, but there must also be an understanding of the economic market, the product's viability, and the feasibility from a political perspective. In terms of governmental viability, this entails understanding policy obstacles and the perspectives of policymakers in various regions, aiming to make a significant impact. Commercial viability involves identifying existing market solutions, their weaknesses, and how the project can exploit these gaps. Social viability necessitates considering the opinions and acceptance of individuals across different social classes, including those who will use the product and those who might administer it, if applicable. Another fundamental principle for successful projects in the Global South is integrating feedback from individuals who are intimately familiar with the local context, culture, and realities. The best solutions often come from those closest to the problem. Long-term field visits, where individuals can become fully immersed in local communities and contexts, are crucial for understanding nuances that remote studies cannot capture. Projects should incorporate local knowledge and inputs to ensure that interventions are relevant and effective within the specific context, thereby valuing the contributions of local stakeholders. Beyond conducting rigorous research, effective communication and dissemination of research findings are critical yet undervalued aspects of a successful social impact project. Research findings must be tailored to different audiences and time horizons to maximize impact. For example, while academic data on poor ventilation in buildings might be vital for policymakers making long-term decisions, practical demonstrations (in local languages or languages most understood by the people) of improving ventilation can be more beneficial for current tenants. By presenting information that resonates with the audience and addressing their immediate concerns, researchers can ensure their findings lead to actionable and
30 meaningful changes at both immediate and large-scale levels. Finally, the roles of governments and continuous evaluation are crucial in ensuring the relevance and effectiveness of projects. While academic institutions play a vital role, they should not dominate; their primary role should be as powerful conveners, bringing together various stakeholders to propose solutions. Ultimate decision-making and implementation should rest with governments and local constituents. Continuous evaluation is essential for success when working with multiple stakeholders. Regular assessments for all parties involved should be conducted, allowing for necessary adjustments and ensuring projects evolve to meet the changing needs and contexts of the researchers and the communities they aim to serve. How do we make our findings and research done in the global north more accessible and accurate for the global south? In order to make research and findings from the Global North more accessible and accurate for the Global South, it is essential to customize tools and resources to suit the technological context and local conditions of these regions. One effective strategy is to develop web-based applications optimized for simple computers and low-bandwidth internet connections. Fig 3.4 Snapshot of Prof. Arsano's research into African residential building typologies. The full graphic is available in the pdf linked at the end of this chapter.
31 This ensures that the tools are usable and practical for individuals who may not have access to high-end technology. Incorporating relevant data sets and features into these tools is also crucial. This means including climate data and building typologies specific to the Global South. Integrating regional specifics makes the tools more relevant and valuable for local users, allowing them to apply the research findings more effectively to their contexts. For instance, incorporating data on local weather patterns, soil types, and traditional building materials can significantly enhance the applicability of these tools. Modernizing and incorporating vernacular knowledge within tools is a crucial step. Local, traditional knowledge often contains valuable insights and solutions that have been refined over generations. By contemporizing this knowledge and integrating it into modern tools, researchers can create more holistic and effective solutions that resonate with local communities. This approach not only respects and preserves indigenous knowledge but also enhances the accuracy and relevance of the research findings for the Global South, making the tools more comprehensive and impactful. What are the exogenous factors that we might not be able to fix but must consider when working in the Global South? When working in the Global South, several exogenous factors might not be able to be fixed, but we must consider them to ensure the effectiveness and sustainability of our projects. These factors include intersectional issues, governance quality, and the reliance on governmental support and enforcement. Firstly, intersectional issues play a significant role in the success of solutions. Solutions might not address the needs of men and women equally, and this disparity can impact the overall effectiveness of the project. Gender dynamics, cultural norms, and societal roles can vary greatly and influence how different groups interact with and benefit from proposed solutions. Acknowledging and addressing these differences is crucial to creating more inclusive and equitable outcomes. Secondly, governance quality is a critical factor. Many solutions assume that the governments we are working with are stable, protect liberties, ensure property rights, and are free from corruption. However, this is not always the case in the Global South. Projects that do not consider the possibility of weak or corrupt governance might struggle to be successful. It is essential to recognize that the effectiveness of projects relying on government intervention, subsidies, or enforcement is inherently linked to the capability and integrity of the local government.
32 Moreover, projects that depend on government support for subsidies or enforcement must be realistic about the limitations. A project idea that relies heavily on government action can only be as effective as the government's willingness and ability to enforce it. This dependency can be a significant risk factor, especially in regions where government institutions are unstable or ineffective. Being honest about these limitations and planning contingencies can help mitigate some risks. Links to Presentations Les Norford, Panel Introduction Alpha Arsano, Toward Contemporary Vernacular for the Majority World Ronita Bardhan, Built Environment, Climate & Health Libby Hsu, Building Technology for the Future of Education and Development Robert Stoner, Reflections on Building Technologies for Hot, Crowded, Poor, Resource-Constrained Countries Sometimes Referred to as "The Global South"
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35 4 HVAC Diagnostics and Controls Summary by Ali Irani | Session chair: John Ochsendorf Panel Introduction by Prof. Les Norford Prof. Les Norford introduced the last discussion topic, focusing on HVAC diagnostics and controls. The presentations and discussion in this section focused on emerging technologies such as using power lines as data sources and using sensors for load disaggregation. The focus of the section was also on better understanding HVAC systems, considering policy and occupant comfort, and developing frameworks to better control buildings and more intelligently diagnose problems. Non-Intrusive Load Monitoring Technology (Prof. Steven Leeb) Prof. Steven Leeb first presented his work on non-intrusive load monitoring technology. This is primarily motivated by the reality that a building has to run correctly, however many controls are shockingly incorrect and set up wrong, which can have significant impacts on both operational energy usage as well as occupant comfort. Prof. Leeb’s work tries to identify dual uses in building systems, such as using power lines to transmit data. This non-intrusive load monitoring understands patterns of power usage as a way to determine building loads and identify signature load demands from various pieces of equipment. This kind of non-intrusive monitoring is ideal for mission-critical applications. In the case that the power lines can’t be accessed, remote sensing systems, such as the VAMPIRE sensing node can be deployed. Prof. Leeb is also considering a case study with a vacuum pump, in which understanding of vibrations can help diagnose the performance of the pump. In conclusion, simpler controls and diagnostics are better. Since people ultimately want operational capability out of their systems, it is important to identify key performance parameters to measure and understand fault detection. Discussion In the discussion, participants asked about the potential application of Fig 4.1 HVAC Diagnostics and Controls (Design: Nada Tarkhan)
36 Artificial Intelligence (AI) and Machine Learning (ML) technologies to diagnose buildings and controls. Prof. Leeb noted that while AI and ML can be leveraged to process data, he cautioned about the widespread deployment of the technologies since they are based on finding and understanding patterns in data, not necessarily understanding the underlying physics. Toolbox for Design and Control of Ground Source Heat Pumps (Peter Armstrong) Peter Armstrong presented his work on understanding and modeling of ground source heat pump (GSHP) systems, with a specific focus on a reduced-order ground heat exchange model suitable for optimization and model-predictive control. Armstrong first outlined the key challenges associated with meeting heating demands with heat pumps (mainly increased peak electricity demand) and the required solutions which could include over-building renewable resources in the face of poor utilization costs, improving transmission lines, shifting peaks by using thermal energy storage, reducing peaks through weatherization, energy recovery in exhaust flues, and improving heat pump efficiency at low temperatures. Ground source heat pump technology has elements of thermal energy storage and peak reduction due to lower ground temperatures and is a technology Fig 4.2 Diagram of non-intrusive load monitoring presented by Prof. Leeb
37 that can help reduce the peak electricity demand in the winter. Armstrong noted that while GSHP systems are expensive, proper sizing of the ground loop, better coupling to ground mass, dual-source heat pumps (i.e. both air and ground can be used as a heat source), variable speed pumps, and optimizations in the condenser and evaporator systems can dramatically reduce first and operating costs and ultimately deliver better performance for the occupants. Armstrong also discussed an engineering model he has developed to better size ground source heat pumps using building loads and weather data as well as a 3D finite element model developed to determine the spatial and seasonal variation in ground temperatures. Discussion The discussion after the presentation focused on the importance of balancing heating and cooling loads for the ground heat exchanger, otherwise the system will inadvertently increase or decrease ground temperatures dramatically reducing the long-term efficiency of the system. The discussion also noted that, while simply increasing borehole depth is a great way to increase system efficiency, optimization is the most effective path to a least life-cycle cost solution. Photo: Justin Knight Fig 4.3 Prof. Norford presenting to the group
38 Living Laboratory as a Testbed and Teaching Tool (Prof. Tea Žakula) Prof. Tea Žakula outlined her research work in collaboration with the Ruder Boškovic Technical School in Zagreb, focused on developing the “RCK Rudera Boškovica” Living Laboratory. This laboratory serves as a testbed for exploring various HVAC systems and controls, with a strong emphasis on occupant input and comfort as key performance indicators. Prof. Žakula first outlined the "Smart Readiness Indicator" (SRI), a recent addition to the European Energy Efficiency Directive for Buildings. The metric refers to a building’s ability to sense, interpret, communicate, and actively respond in an efficient manner to changing conditions in relation to operations, the external environment, and demands from building occupants. A typical new commercial building has an SRI of around 40%, whereas the Living Laboratory is set to achieve an SRI of around 85% in the near future. The goal of this research work is to improve the scalability of predictive controls in buildings in order to find an optimal predictive control architecture that minimizes the implementation cost for a variety of buildings. In the Living Laboratory, this research involves a variety of sensor availability scenarios. The goal of sensors is to reduce first cost and reduce electricity costs and the research aims to use less sensors but gain more insights from them. Another goal of the Living Laboratory is to develop human-centered predictive control - a user-oriented control system and apply it to an actual building. They tested Fig 4.4 Images shared by Prof. Zakula of the deployment of human-centered control in a high school building
39 this control strategy in the Living Laboratory and the results indicated that there is a 17% increase in occupant satisfaction. The research from the lab with 1000 surveyed people also indicates that 75% of people want to have access to control, but only 55% want to share data with human-centered control. Around 85% prioritize indoor air quality (IAQ) as the top comfort factor, followed by thermal and visual comfort, highlighting the need to give IAQ just as much focus to thermal comfort in built environment research. On the other side, 60% of users want to engage in grid flexibility actions showcasing the potential to leverage end users in demand response actions in smart grids. Prof. Žakula also presented the work of her research group on intelligent infrastructure for electric vehicles to develop an algorithm for the real-time optimization of electric vehicle charging. This optimized approach can reduce charging costs by more than 20% compared to standard methods. Discussion In the discussion, participants asked about developing personal comfort model. In their work, Prof. Žakula's research group uses personalized comfort models developed based on individual preferences and then creating comfort boundaries that satisfy most people sharing a room. This is a feasible solution to facilitate the integration of individual preferences into HVAC systems by considering user preferences. Future work will Fig 4.5 Dave Blum (left) and Prof. Žakula (right) in conversation with the group Photo: Justin Knight
40 further investigate different groups to understand variation in personal comfort models. Impacts and Future of HVAC Controls (Dave Blum) Dave Blum outlined his research work focusing on the building and gridscale impacts of HVAC controls and newly developing technologies. Blum indicated that multi-zone HVAC systems are incredibly complex to control. His work considered a 21 zone VAV system in three different climates with varying operating conditions. Control strategies produced savings between 2-75%, with an average savings of 31%, indicating the significant impact of controls on system performance. Blum also presented the challenges of electrifying heating for central plants for mid-large commercial buildings due to the presence of natural gas or fossil fuel boilers. Oftentimes, both heat recovery chillers and heat pumps are required. In one scenario, this included 20 operating modes and a 45-page sequence of operation for the central plant. One other issue associated with the future of the grid and controls is the "duck curve," when PV generation vs. demands are not synchronous. Grid flexibility is key to address this and model predictive controls can be used to shift peaks. Blum noted that model predictive control (MPC) are better compared to reinforcement learning (RL). RL is weak since it is not necessarily physics based but rather based on interpreting data, while MPC uses a physics-based model. Discussion The discussion considered questions such as how will data, models, optimization, and AI be used to control buildings? Another topic include understanding what are practical challenges in providing predictive and optimal control and how to address them? Blum noted that modeling and simulation tools-- Modelica and Spawn of EnergyPlus-- are key in helping to develop effective MPC. Analytics and Controls (Nick Gayeski) Nick Gayeski presented the last topic in the HVAC diagnostics and controls section focused on data analytics, controls, and the Clockworks Analytics platform. Gayeski, co-CEO of Clockworks Analytics, noted that there are 470,000 pieces of HVAC equipment on the Clockworks systems. Gayeski first outlined the challenges associated with controls and comfort. Currently, 30% of energy in buildings is wasted due to inefficiency and 80% of equipment in buildings fail for non-age-related reasons. In the coming years, 100k HVAC technician jobs will be unfilled in the US labor market. Meanwhile, more than 40% of workers are dissatisfied with comfort in their space. Gayeski then presented the typical maintenance routine for buildings in FDD (fault detection and monitoring). According to the ASHRAE 180 standard, 955 preventative maintenance items per year are required. This is
41 very few checks compared with the over 4000 automated checks every day using the Clockworks system. The platform works by accessing a software gateway and subsequent polling of BMS to inform a model (including BMS data, control sequences, equipment schedules) which produces a diagnostic report for facilities teams. The impacts of this advanced analytics platform for building operators are energy savings, extended asset life, better reliability, and maintenance efficiency. For example, at the University of Iowa, 47 buildings were monitored for 3 years and $2.8 million were saved. The information model and expert system can also be integrated with artificial intelligence. Gayeski noted that the automatic conversion of energy usage to carbon metrics ultimately depends on the organization or client for the project. Discussion During the discussion, participants considered the subject of data privacy. Gayeski noted that data aggregation and anonymization are critical for use, since the building owner still ultimately owns the metered data. Links to Presentations Les Norford, Panel Introduction Steven Leeb, Non-Intrusive Load Monitoring Technology Peter Armstrong, Toolbox for Design and Control of Ground Source Heat Pump Systems Tea Žakula, Living Laboratory as a Testbed and Teaching Tool Dave Blum, Impacts and Future of HVAC Controls Nick Gayeski, Analytics and Controls
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