High-rise residential building ventilation in cold climates: A review of ventilation system types and their impact on measured building performance.

Ventilation system performance in high-rise multi-unit residential buildings (MURBs) has a significant impact on resident wellbeing. While the importance of ventilation is well established, it is commonly overlooked since underperformance often goes undetected. This article presents a review and synthesis of ventilation system performance in high-rise MURBs located in cold climates as it relates to the three pillars of sustainability: economic (capital and operational cost), social (airflow control, indoor environmental quality, and occupant behavior and interactions), and ecological (energy and carbon). A meta-analysis revealed previous ventilation system designs generally prioritized economic sustainability, specifically, capital cost. However, priorities have recently shifted toward social and ecological sustainability. While this shift is positive, there is insufficient empirical evidence showing which ventilation system most effectively supports it. The decentralized heat/energy recovery ventilator (HRV/ERV) system shows the potential to improve upon the social and ecological sustainability of previous designs, such as the centralized pressurized corridor system, but the interconnected nature of performance metrics can cause improvements to one to negatively impact others. Therefore, further research is required to enhance ventilation system performance in cold climate, high-rise MURBs, and facilitate decision-making while designing and retrofitting these systems.

Inter-zonal airflow in multi-unit residential buildings: A review of the magnitude and interaction of driving forces, measurement techniques and magnitudes, and its impact on building performance.

Inter-zonal airflows within multi-unit residential buildings (MURBs) have profound impacts on an array of building performance metrics, including energy, indoor air quality (IAQ), fire and acoustical separations, and distribution of ventilation air. Although there are wide-ranging implications, most building codes/standards have yet to incorporate airtightness requirements for interior partitions in large, multi-zone structures, and instead focus primarily on exterior envelope airtightness. Despite the multi-disciplinary nature of the topic, previous reviews have been limited to one domain (eg, energy performance, IAQ, specific test methods). This paper presents a comprehensive summary of the literature on inter-zonal airflow in MURBs including the magnitude and interaction of driving forces; its relevance to/effect on building performance; current code requirements; testing methods; and previous measurements. While considerable efforts have been made in recent years to quantify and control inter-zonal airflows, most measurement techniques are still labor-intensive and disruptive, and there is no framework for how to implement performance-based requirements into building codes and standards. Further research efforts should be focused on refining testing methods and preparing the construction industry for code changes.

Residential HVAC runtime from smart thermostats: characterization, comparison, and impacts.

In North America, the majority of homes use forced-air systems for heating and cooling. The proportion of time these systems operate, or runtime, has a significant impact on many building performance parameters. The recent adoption of smart thermostats in many North American homes presents a potential data source for runtime. Smart thermostat data collected from over 7000 homes were compared with nine other investigations and a runtime estimation method based on exterior temperature. The smart thermostat runtimes have a median of 18% across all homes, but show considerable variation between homes, even at constant exterior temperature conditions suggesting that factors besides climate (eg, system sizing, user operation) have a significant impact on runtime. Results from other investigations suggest that smart thermostat runtimes are consistent with other measurement approaches. The practical implications of runtime include the impact on central filtration performance. At low to average runtimes, the filter efficiency matters much less for effectiveness because the system does not run enough for a sufficient air volume to pass through the filter and have a substantial impact on particle concentrations. This work illustrates the importance of measuring runtime for a particular home, and the value of data obtained from smart thermostats.

A Global Building Occupant Behavior Database.

This paper introduces a database of 34 field-measured building occupant behavior datasets collected from 15 countries and 39 institutions across 10 climatic zones covering various building types in both commercial and residential sectors. This is a comprehensive global database about building occupant behavior. The database includes occupancy patterns (i.e., presence and people count) and occupant behaviors (i.e., interactions with devices, equipment, and technical systems in buildings). Brick schema models were developed to represent sensor and room metadata information. The database is publicly available, and a website was created for the public to access, query, and download specific datasets or the whole database interactively. The database can help to advance the knowledge and understanding of realistic occupancy patterns and human-building interactions with building systems (e.g., light switching, set-point changes on thermostats, fans on/off, etc.) and envelopes (e.g., window opening/closing). With these more realistic inputs of occupants' schedules and their interactions with buildings and systems, building designers, energy modelers, and consultants can improve the accuracy of building energy simulation and building load forecasting.