Critical Opportunity Areas for Building Performance

Green buildings are a proposed holistic solution to reduce energy consumption while simultaneously improving an array of factors affecting the indoor quality of life for building occupants. However, green building performance varies and may not achieve intended design goals. Research has concluded that no single factor determines the actual energy performance of buildings. To deliver energy-efficient buildings an integrated design that considers climate, technology, operation and maintenance and occupant behavior should be implemented. This work aimed to employ a holistic lens to relate human-building interaction and building performance characteristics. Specifically, systems theory and complex-problem solving techniques were employed to capture the dynamic interactions between the social and technical parts and processes of building systems and identify gaps causing the underperformance of buildings. Synergies not captured in the current design process but impact the ability of a building system to achieve its design goals were outlined. Performance metrics that a single system inadvertently affects along social, physical and economic dimensions were identified as well as high-impact opportunity areas for the creation of high-performance buildings. Addressing these synergies in the building equipment and full building design will enable stakeholder-centered systems integration, improving the efficiency and efficacy of buildings

Performance and Operating Characteristics of a Novel Positive-Displacement Oil-Free CO2 Compressor

Research activities towards developing CO2 compressors have increased drastically during the last couple years. Since the transcritical CO2 cycle operates at much higher absolute pressures as compared to the conventional vapor compression cycles, it is necessary to develop new compressors or modify existing ones. In this paper, a novel positive-displacement oil-free CO2 compressor will be introduced. The compressor’s mechanical linkage system will be described. In addition, preliminary compressor test results will be presented, including volumetric efficiency, overall isentropic efficiency, discharge temperature and mass flow rate. The compressor was designed and manufactured to provide cooling capacities from 10 kW to 100 kW. The novel compressor design introduces a new low-friction drive mechanism. The displacement of the compressor can be mechanically varied while keeping a small constant head clearance. A test stand was constructed to map the compressor efficiency, mass flow rate, power consumption and discharge temperature. The test stand is based on a hot gas bypass design, where parts of the discharged refrigerant flow bypasses the condenser, whereas the other part of the flow changes phase as it flows through a condenser. The two streams are mixed to obtain the desired compressor super heat at the suction side of the compressor. The prototype compressor has been tested under different pressure ratios (5, 4, 3, 2, 1.6) and at different speeds (900 rpm, 1200 rpm, 1500 rpm, 1800 rpm)

Reimagining Building Efficacy: An Exploratory Study

This dissertation focuses on the creation of a paradigm shift in building innovation. Challenges in achieving building energy-efficiency at scale highlight the complexity of the building performance problem, which is embedded with social, cultural, physical, environmental, and economic factors. Traditional approaches to building design have difficulty accounting for these multi-faceted variables and related longitudinal barriers and intangible impacts. Firstly, key stakeholders and their economic constraints change throughout time, and this variability is not traditionally considered upfront or addressed throughout a building’s operation. Secondly, buildings have social, cultural, environmental and economic implications that are difficult to quantify and evaluate against strictly functional design objectives. Therefore, current deeply technical and often system-specific building design strategies could benefit from whole-building solutions that account for this complexity and enable a paradigm shift in design toward human-centered outcomes (i.e., well-being, health, financial sustainability) and effective (i.e., equitable and sustainable) buildings. To drive this shift, an impact-based innovation framework was employed to pursue system-level and ecosystem-level strategies to optimize longitudinal building value assessment and distribution. First, a grounded theory study was pursued which identified gaps in current design practice that miss underlying building subsystem interactions which influence building performance. A system-level taxonomy of the building was then defined, linking identified sub-system synergies to functional, emotional and social building benefits for inhabitants. Then, an exploratory mixed-methods study was pursued, yielding a longitudinal building value framework that helps characterize key stakeholders, building design choices, and shared efficacy metrics. Building on these inputs, a multi-stakeholder, longitudinal building value assessment model was developed. The model was tested on two residential building development scenarios, highlighting its ability to capture the true impact of buildings on affected stakeholders over time in terms of tangible and intangible building costs and benefits. Finally, business model innovation concepts were employed to identify specific changes in stakeholder value delivery and capture strategies that could redistribute building costs and benefits over time, and thereby facilitate a shift in the paradigm of design and value capture in the residential building industry