Nudging the adaptive thermal comfort model

The recent release of the largest database of thermal comfort field studies (ASHRAE Global Thermal Comfort Database II) presents an opportunity to perform a quality assurance exercise on the first generation adaptive comfort standards (ASHRAE 55 and EN15251). The analytical procedure used to develop the ASHRAE 55 adaptive standard was replicated on 60,321 comfort questionnaire records with accompanying measurement data. Results validated the standard's current adaptive comfort model for naturally ventilated buildings, while suggesting several potential nudges relating to the adaptive comfort standards, adaptive comfort theory, and building operational strategies. Adaptive comfort effects were observed in all regions represented in the new global database, but the neutral (comfort) temperatures in the Asian subset trended 1–2°C higher than in Western countries. Moreover, sufficient data allowed the development of an adaptive model for mixed-mode buildings that closely aligned to the naturally ventilated counterpart. We present evidence that adaptive comfort processes are relevant to the occupants of all buildings, including those that are air conditioned, as the thermal environmental exposures driving adaptation occur indoors where we spend most of our time. This suggests significant opportunity to transition air conditioning practice into the adaptive framework by programming synoptic- and seasonal-scale set-point nudging into building automation systems

Integrating Smart Ceiling Fans and Communicating Thermostats to Provide Energy-Efficient Comfort

The project goal was to identify and test the integration of smart ceiling fans and communicating thermostats. These highly efficient ceiling fans use as much power as an LED light bulb and have onboard temperature and occupancy sensors for automatic operationbased on space conditions. The Center for the Environment (CBE) at UC Berkeley led the research team including TRC, Association for Energy Affordability (AEA), and Big Ass Fans (BAF). The research team conducted laboratory tests, installed99 ceiling fans and 12 thermostats in four affordable multifamily housing sites in California’s Central Valley, interviewed stakeholders to develop a case study, developed an online design tool and design guide, outlined codes and standards outreach, and published several papers.The project team raised indoor cooling temperature setpoints and used ceiling fans as the first stage of cooling; this sequencing of ceiling fans and air conditioningreducesenergy consumption, especially during peak periods, while providing thermal comfort.The field demonstration resulted in 39% measured compressor energy savings during the April–October cooling seasoncompared to baseline conditions, normalized for floor area. Weather-normalized energy use varied from a 36% increase to 71% savings, withmedian savings of 15%.This variability reflects the diversity in buildings, mechanical systems, prior operation settings, space types, andoccupants’ schedules,preferences, and motivations. All commercial spaces with regular occupancy schedules (and twoof the irregularly-occupied commercial spaces and one of the homes) showed energy savings on an absolute basis before normalizing for warmer intervention temperatures,and 10 of 13 sites showed energy savings on a weather-normalized basis. The ceiling fans provided cooling for one site for months during hot weather when the coolingequipment failed.Occupants reported high satisfaction with the ceiling fans and improved thermal comfort. This technology can apply to new and retrofit residential and commercial buildings

Indoor environmental quality and occupant satisfaction in green-certified buildings

Green building certification systems aim at improving the design and operation of buildings. However, few detailed studies have investigated whether green rating leads to higher occupant satisfaction with indoor environmental quality (IEQ). This research builds on previous work to address this. Based on the analysis of a subset of the Center for the Built Environment Occupant Indoor Environmental Quality survey database featuring 11,243 responses from 93 LEED-rated office buildings, we explored the relationships between the points earned in the IEQ category and the satisfaction expressed by occupants with the qualities of their indoor environment. We found that the achievement of a specific IEQ credit did not substantively increase satisfaction with the corresponding IEQ factor, while the rating level, and the product and version under which certification had been awarded, did not affect workplace satisfaction. There could be several reasons for this lack of relationships, some of which are outside the control of designers and beyond the scope of rating systems based primarily on design intent. We conclude with a discussion of the challenges and priorities that building professionals, researchers, and green building certification systems need to consider for moving us towards more comfortable, higher performing, and healthier green-rated buildings

Ten Questions Concerning Well-Being in the Built Environment

Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of well-being in the design and operation of the built environment. Placing a specific focus on some of the key physical factors (e.g., light, temperature, sound, and air quality) of indoor environmental quality (IEQ) that strongly influence occupant perception of built spaces, attention is also given to the value of multi-sensory variability, to how to monitor and communicate well-being outcomes in support of organizational and operational strategies, and to future research needs and their translation into building practice and standards. Seen as a whole, a new framework emerges, accentuating the integration of diverse new competencies required to support the design and operation of built environments that respond to the multifaceted physical, physiological, and psychological needs of their occupants

Indoor environmental quality and occupant satisfaction in green-certified buildings

Green building certification systems aim at improving the design and operation of buildings. However, few detailed studies have investigated whether green rating leads to higher occupant satisfaction with indoor environmental quality (IEQ). This research builds on previous work to address this. Based on the analysis of a subset of the Center for the Built Environment Occupant Indoor Environmental Quality survey database featuring 11,243 responses from 93 LEED-rated office buildings, we explored the relationships between the points earned in the IEQ category and the satisfaction expressed by occupants with the qualities of their indoor environment. We found that the achievement of a specific IEQ credit did not substantively increase satisfaction with the corresponding IEQ factor, while the rating level, and the product and version under which certification had been awarded, did not affect workplace satisfaction. There could be several reasons for this lack of relationships, some of which are outside the control of designers and beyond the scope of rating systems based primarily on design intent. We conclude with a discussion of the challenges and priorities that building professionals, researchers, and green building certification systems need to consider for moving us towards more comfortable, higher performing, and healthier green-rated buildings

Mixed-mode cooling.

However, the availability in the 1950s of large-scale mechanical cooling, along with other technologies such as curtain walls and fluorescent lighting, led to the more common building forms we see today in North America—typically all-glass, flush-skin buildings with large floor plates and no operable windows.Our technological capabilities allow architects greater design freedom while they can relinquish responsibility for environmental control to the engineers, who use their ingenuity to design mechanical systems that will ensure (ideally) thermal comfort regardless of the loads that are imposed. In air-conditioned buildings, thermal conditions generally are perceived to be predictable and controllable, with the goal of maintaining consistent indoor thermal conditions uniformly across space and throughout the day, regardless of the outdoor climate

Mixed-mode cooling.

However, the availability in the 1950s of large-scale mechanical cooling, along with other technologies such as curtain walls and fluorescent lighting, led to the more common building forms we see today in North America—typically all-glass, flush-skin buildings with large floor plates and no operable windows.Our technological capabilities allow architects greater design freedom while they can relinquish responsibility for environmental control to the engineers, who use their ingenuity to design mechanical systems that will ensure (ideally) thermal comfort regardless of the loads that are imposed. In air-conditioned buildings, thermal conditions generally are perceived to be predictable and controllable, with the goal of maintaining consistent indoor thermal conditions uniformly across space and throughout the day, regardless of the outdoor climate

Learning from experience

Ask anyone who designs, owns, or manages an office building if they want the occupants of their building to feel comfortable, healthy, and productive, and the answer would of course be 'yes'. But ask again if they know what occupants actually feel about the space, and the answer will be quite different.The facility manager is most likely to have a sense, but often it’s only anecdotal. The building owner might eventually have an inkling about occupant sentiment if they see a financial effect because an environment is inadequate.  Yet, sadly, very few architects or other members of the design team are likely to know how well their building is working after it is completed and occupied, the fees have been paid, and they are on to another project. Without learning from experience in an objective way, building industry professionals are less likely to make design or economic decisions that will truly enhance the performance and experiential quality of their buildings.And while this information would be valuable for any project, it is particularly essential if one is claiming to have designed or built a green building, where the quality of the indoor environment is a critical dimension of sustain- able design. The only way to back up those claims is to evaluate a building’s actual performance, in terms of energy consumption or indoor environmental quality, and compare the performance to design intent.Without question, it is absolutely crucial to reduce energy consumption in buildings and help avoid the potentially devastating impacts of climate change. But in terms of the building owner’s pocketbook, energy costs are still relatively small compared to worker salaries, which represent over 90% of the total operating costs of a commercial building. In addition, the cost of worker recruitment and retention is significant. Thus, from the building or company owner’s point of view, perhaps the most persuasive argument for sustainable design is one that makes the connection between a higher quality indoor environment, and increased comfort, health and productivity of the workers.So, how does one learn about the quality of the indoor environment? While there are many physical measurements one can take, they need to be interpreted in terms of the impact on occupants. Occupants themselves are a rich yet underutilized source of direct information about how well a building is working, but the challenge is how to collect both the positive and negative feedback in a systematic way. This has been at the core of research underway at UC Berkeley

Window Signaling Systems: Control Strategies & Occupant Behavior

Signaling systems that tell building occupants when to open and close windows have become a popular strategy for balancing the comfort benefits of manual windows with the efficiency benefits of automation in mixed-mode buildings. Data from surveys, interviews and site observations in 16 U.S. buildings reveal a diversity of design objectives, control sequences and circumstances to anticipate when designing buildings with window signaling systems.Signals influence window use patterns for a minority of occupants, although greater participation is possible if the signals are linked to an internal policy with clear, tangible comfort benefits. Low levels of participation likely occur because most occupants (though not all) tend not to pay attention to their windows, or the signals, unless they're uncomfortable, at which point it matters little what the signals say.However, occupants who do discover value in the signals are more likely to be more satisfied with their personal control