C. F. Reinhart

Massachusetts Institute of Technology | MIT · School of Architecture and Planning

Humans spend over 90% of their time in buildings, which account for 40% of anthropogenic greenhouse gas emissions and are a leading driver of climate change. Incentivizing more sustainable construction, building codes are used to enforce indoor comfort standards and minimum energy efficiency requirements. However, they currently only reward measure...

Humans spend over 90% of their time in buildings which account for 40% of anthropogenic greenhouse gas (GHG) emissions, making buildings the leading cause of climate change. To incentivize more sustainable construction, building codes are used to enforce indoor comfort standards and maximum energy use. However, they currently only reward energy eff...

As the building stock is projected to double before the end of the half-century and the power grid is transitions to low-carbon resources, planning new construction hand in hand with the grid and its capacity is essential. This paper presents a method that combines urban building energy modeling and local planning of renewable energy sources (RES)...

With buildings accounting for 40% of global carbon emissions, cities striving to meet sustainability targets aligned with the Paris Agreement must retrofit their existing building stock within 30 years. Previous studies have shown that urban building energy models (UBEMs) can help cities identify technology pathways — combinations of energy efficie...

We work with policymakers in eight cities worldwide to identify technology pathways toward their near- and long-term carbon emissions reduction targets for existing buildings. Based on policymakers’ interests, we define city-specific shallow and deep retrofitting packages along with onsite photovoltaic generation potential. Without further grid dec...

Housing retrofits are essential for meeting societal decarbonization goals, alongside addressing energy insecurity, improving public health, and creating new jobs. Yet, despite their multiple benefits and comprehensive government efforts to incentivize retrofits, adoption rates across the world remain low, usually less than 1% per year. Barriers to...

Accommodating predicted population growth and urbanization within the UN Climate Goals poses a significant challenge for disciplines that engage with the built environment. High performing buildings of the future should offer spatial quality for their users while utilizing resources as efficiently as possible for both construction and operation. In...

We propose the use of solar exoskeletons, an integrated building system that combines material efficiency in structural load transfer with passive solar gain control. This offers an impactful way to respond to the UN climate goals, as the architecture and engineering disciplines face the challenge of delivering low carbon buildings. While reducing...

Views contribute to occupants’ visual comfort and health in the workplace—reducing stress, improving concentration, and bolstering creativity. In this work, we introduce two new metrics, based on a 3D simulation in the urban context, to assess potential view access in open floorplans; and using the metrics, we measure the economic impact of views o...

Policymakers are struggling to understand what specific mixes of building retrofitting upgrades are necessary to achieve carbon emission targets. Urban building energy modelling (UBEM) is a bottom-up simulation method to develop policy measures for building stocks. However, the use of UBEM tools requires hard-to-find individuals with training in mu...

The Universal Thermal Climate Index (UTCI) has been linked to outdoor activity patterns and used to evaluate the effectiveness of urban interventions to improve thermal comfort. This study investigates how simulating the urban environment at increasing levels of physical accuracy impacts UTCI values along three cycling routes in Cambridge, Massachu...

Urban building energy and daylight modeling are bottom-up, physics-based approaches to simulate the thermal and daylight performance of neighborhoods and cities. The field has flourished in recent years due to a wider accessibility of urban data sets which contain the required information regarding building geometry and program. However, key buildi...

Plant factories have developed within urban contexts following efforts to expand local food production, create local jobs, and provide alternatives to conventional agriculture with lower greenhouse gas emissions. One plant factory system, container farms, consists of artificially lit, vertically stacked hydroponic farms inside retrofitted shipping...

The European Unions (EU) Green Deal plans for a carbon neutral economy by 2050. Achieving this goal will require actions across all economic sectors, especially the building sector, which currently accounts for 40% of energy use. Residential energy use is a significant contributor, much of it due to an aging, poorly insulated building stock, much o...

Urban building energy modeling (UBEM) is a bottom-up, physics-based approach to simulate the thermal performance of new or existing neighborhoods and cities. The field has flourished in recent years, creating increasingly robust urban data streams that lead from Geographical Information Systems, CityGML, Light Detection and Ranging, and tax assesso...

As part of their sustainability agendas, cities are promoting urban food production as a means to reduce the demand for agricultural land elsewhere and shorten food miles. However, from an environmental sustainability standpoint, some assessments have shown that increasing self-sufficiency through local production for certain crops is not necessari...

Advances in digital fabrication and additive manufacturing have enabled the creation of geometrically complex glass structures and building components, opening up new design opportunities across scales. Quantifying and evaluating their optical performance, however, remains a technical challenge. In order to accurately predict light behavior, common...

People's subjective response to any thermal environment is commonly investigated by using rating scales describing the degree of thermal sensation, comfort, and acceptability. Subsequent analyses of results collected in this way rely on the assumption that specific distances between verbal anchors placed on the scale exist and that relationships be...

Cities are a spatial nexus for a host of environmental issues including global climate change, urban air pollution, energy management, flood control, exposure to hazards, and so on. Research on these topics and others often requires geographic data on the urban landscape and occupation patterns at appropriate time and space scales to understand pro...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Thermal discomfort is one of the main triggers for occupants’ interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment...

The presence of natural light in indoor spaces improves human health, well-being, and productivity, particularly in workplace environments. Do the social benefits of daylight translate into economic value as measured by what office tenants are willing to pay? Using a sample of 5154 office spaces in Manhattan, we pair urban daylight simulation with...

We present a framework for evaluating views in open plan work spaces, such as offices and classrooms. Previously proposed analysis methods have evaluated views from a few select positions on a building's perimeter, looking outward to specific objects of interest. Our approach evaluates views in a spatially distributed grid, considering the occupant...

Accurate occupancy is crucial for planning for sustainable buildings. Using massive, passively-collected mobile phone data, we introduce a novel framework to estimate building occupancy at unprecedented scale. We show that, at urban-scale, occupancy differs widely from current estimates based on building types. For commercial buildings, we find typ...

Ensemble baseline development to simulate a range of future building energy scenarios. • Framework for rapid-response assessment of energy drivers for hundreds of buildings. • Procedures for campuses to track their energy policy effectiveness on an ongoing basis. • Proof-of-concept implementation for campus of Massachusetts Institute of Technology....

This is the second volume of the Daylighting Handbook series. Same as for the first handbook, eight chapters are divided into two parts, Daylight Simulations and Dynamic Façades. Chapters 9 to 12 discuss how to predict the overall amount of daylight in and around buildings at any given site using manual methods and computer simulations. Chapters 13...

This manuscript presents a new approach to design energy-efficient supply systems for districts with low-energy and low-carbon buildings. By taking the case of two neighborhoods located in Boston, a heating dominated climate and Mumbai, a cooling dominated climate, the study investigates alternative energy supply systems for these neighborhoods tha...

An occupant's visual experience within a space plays a key role in his or her feelings of exposure and privacy. Particularly in open workspaces, such as offices and classrooms, creating a comfortable plan with degrees of exposure is critical to occupant wellbeing and social engagement. In this paper, we present an analysis framework for evaluating...

Allowing for significant water savings and year-round yields, Controlled-Environment Agriculture (CEA) is oftentimes portrayed as a sustainable alternative to conventional farming, and its practice in urban areas as a food, income and employment generator is expanding worldwide. Particularly in today’s fast growing cities, where economic strength i...

As green technologies are becoming more frequently integrated into the architectural design, there is a growing need for tools to support architects conducting environmental analyses. Especially in urban-scale analyses, green technologies such as photovoltaics (PVs) and green roofs have led to significant electricity production and reduction in car...

Modern lighting systems typically provide a number of control parameters, e.g. colour and intensity, which allows nearly infinite possible configurations in one single room. The growing complexity of control makes it increasingly challenging for the user to configure the system and fully utilize the additional degrees of freedom. In contrast, an in...

Thermal comfort preferences of occupants and their interactions with building systems are top influential factors of residential space heating demand. Consequently, housing stock models are sensitive to assumptions made on heating temperatures. This study proposes a heat balance approach, inspired by the classical degree-day method, applied to an e...

Owners of large building portfolios, such as university campuses, increasingly rely on physics-based building energy models, calibrated to historic energy data, to explore energy efficiency retrofits. These calibrated models, which require substantial effort to originally set up, are then typically only used once for analyzing a series of upgrade o...

University campuses increasingly rely on physics-based building energy models, calibrated to historic energy data, to explore energy efficiency retrofits. These calibrated models, which require substantial effort to originally set up, are then typically only used once for analyzing a series of upgrade options. This paper presents a methodology for...

To reduce global greenhouse gas emissions associated with building energy use, owners of large building portfolios such as university campuses frequently rely on building energy models (BEM) to better understand potential costs and benefits of retrofits. Model development workflows that are designed for individual buildings require a level of effor...

Flow of information protocols employed to collect measured energy use and weather data, to develop and auto-calibrate building energy models, and to deliver processed data to a web client.

Owners of large building portfolios such as university campuses have long relied on building energy models to predict potential energy savings from various efficiency upgrades. Traditional calibration procedures for individual building model are time intensive and require specially trained personnel, making their applications to campuses with hundr...

Building performance simulations and models of human visual comfort allow us to predict daylight-caused glare using digital building models and climate data. Unfortunately, the simulation tools currently available cannot produce results fast enough for interactive use during design ideation. We developed software with the ability to predict visual...

In today's growing cities, where land is an expensive commodity and direct exposure to sunlight is a valuable asset, rooftops constitute vast underexploited areas. Particularly with growing urban environmental concerns, the potential of transforming these areas into productive spaces-either for food cultivation or energy generation-has emerged as a...

Operational building energy has long been recognized as both a major contributor of as well as an opportunity to save carbon emissions. To do so, one may follow two paths, reduce the energy use in buildings (demand) or provide the required energy in more efficient ways (supply). In the literature, extensive research has been made on both fronts and...

The rising popularity of PV has prompted the creation of urban community solar projects. This study evaluates the combined effect of aggregating demand, photovoltaic generation and electricity storage, on-site consumption of PV and its impact on the grid. Data sets with real aggregated electricity demand from grid distribution transformers were use...

This study presents a novel approach to validate the capability of biometeorological indices to predict the likelihood of urban dwellers to be outside during midday. Over a period of ten months three Wi-Fi scanners were used in a public courtyard in Cambridge, MA, to record outside dwelling patterns. Based on encrypted MacIDs courtyard attendees co...

We propose a new design workflow that links environmental performance analysis and financial cash flow modeling. The purpose of this work is to associate sustainable design measures with their potential economic premiums. Our approach assumes that the value of a design intervention is correlated with its financial return: incremental increases in d...

One of the most widely discussed passive building design strategies is using natural ventilation for cooling. In addition to providing fresh air, which enhances occupant productivity and comfort, strategic implementation of natural ventilation in buildings reduces the energy needed for cooling. And this reduction in energy consumption significantly...

Architects must consider an entire year's worth of solar positions and climate data to design buildings with adequate daylight and minimal glare. However, annual simulations are time-consuming and computationally expensive, which makes them difficult to integrate into iterative design processes. In this paper, we compare the performance of several...

To support the implementation of urban energy efficiency strategies, a new generation of urban building energy modeling (UBEM) tools has been introduced which allows cities to simulate the expected energy demands of neighborhoods. In order to define simulation inputs, UBEM models usually use archetypes, in which occupant-related parameters like occ...

Building-Integrated Agriculture (BIA) in urban areas is claimed to be environmentally sustainable vis-à-vis conventional commercial agriculture practices by reducing food miles, minimizing land and water use and improving yields. However, as it is operated in controlled indoor environments, BIA can be highly energy-intensive. In order to better und...

Significant research effort has gone into developing bottom-up, physics based, urban building energy modeling (UBEM) tools, which allow evaluating district-wide energy demand and supply strategies. In order to reduce the simulation inputs required in UBEM, groups of buildings are typically classified into representative “archetypes”. This approach...

The urban built environment maintains the alluring prospect of being a source for our future resource needs. This work imagines new local recycling paradigms for concrete and masonry waste within an existing urban environment. Using Lisbon, Portugal as a case study, we proposed three context-specific material recycling scenarios to make use of mine...

Life cycle impacts in buildings includes operational carbon for heating, cooling, hot water, ventilation, lighting, on the one hand, and embodied carbon for material supply, production, transport, construction and disassembly, on the other. Improved operational carbon has increased the percentage of embodied carbon in the total life cycle of buildi...

Until recently, detailed methodologies for predicting building energy use were unable to be applied to a neighborhood or a campus. Simplified urban energy models, which group buildings into a handful of archetypes, can predict energy from each archetype. For MIT, a long-term, owner-occupied, high-variety use campus, current models do not accurately...

The necessary simplification of building stock models to perform energy studies in cities can impact their accuracy. This paper assesses the impact of considering different levels of detail in the characterization of the building stock, by varying the number of archetypes considered, using a neighborhood in Lisbon as case-study. Each archetype repr...

2017 The Authors. The necessary simplification of building stock models to perform energy studies in cities can impact their accuracy. This paper assesses the impact of considering different levels of detail in the characterization of the building stock, by varying the number of archetypes considered, using a neighborhood in Lisbon as case-study. E...

Image-based visual discomfort analysis has strong potential to detect glare in order to predict occupant satisfaction with a space. However, in order to design buildings with occupant visual comfort in mind, architects need the ability to predict glare through renderings, rather than photographs. In this paper, we compare glare measurements from hi...

In this paper the authors present an algorithm that abstracts an arbitrarily shaped set of building volumes into a group of simplified ‘shoebox’ building energy models. It is shown that for generic perimeter and core floorplans the algorithm provides a faster but comparably accurate simulation results of annual load profiles vis-à-vis multi-zone th...

Providing healthy food for the world’s growing urban population is a recognized global challenge and it is likely that current modes of conventional, large-scale farming will over time be increasingly complemented by local, urban farming practices. Apart from its acknowledged social benefits, urban farming is also widely viewed as a more resource-e...

Between 2000 and 2015, annual electric peak demand in Kuwait has doubled to 15000 MW and the Ministry of Energy and Water expects this number to double once more by 2030 attributing 70% of this growth to new housing projects. Within this context, this manuscript evaluates the effect of incorporating PCM-wallboards in low-rise air-conditioned reside...

City governments and energy utilities are increasingly focusing on the development of energy efficiency strategies for buildings as a key component in emission reduction plans and energy supply strategies. To support these diverse needs, a new generation of Urban Building Energy Models (UBEM) is currently being developed and validated to estimate c...

Urban Building Energy Modeling (UBEM) is an emerging method for exploring energy efficiency solutions at urban or district scales. More versatile than statistical models, physical bottom-up UBEMs allow planners to quantitatively assess retrofit strategies and energy supply options, leading to more effective policies and management of energy demand....

Today's predictions of visual comfort are based on high-quality physically-based visualization renderings. Unfortunately, designers and practitioners rarely realize the full benefit of physically-based lighting simulation due to the amount of time required for these simulations. Visual comfort analysis is generally performed late in the design proc...

Building designers rely on predictive rendering techniques to design naturally and artificially lit environments. However, despite decades of work on the correctness of global illumination rendering techniques, our ability to accurately predict light levels in buildings—and to do so in a short time frame as part of an iterative design process—remai...

Increasing urban density leads to a conflict between space-use efficiency and daylight access. Cities have traditionally relied on zoning guidelines that consist of section-based geometric evaluation techniques and/or hours of access to direct sunlight. However, it is now possible to quantify the performance of detailed design proposals before cons...