Author: Julia Ho

Journal Article Assessing ASHRAE Guideline 36 Published

Julia Ho on

Former SBS Lab member Cary Faulkner‘s paper titled “Simulation-based assessment of ASHRAE Guideline 36 (G36), considering energy performance, indoor air quality, and control stability” has been published in the journal Building and Environment.

The paper developed a VAV system in Modelica to test the influence of G36 on occupant thermal comfort, indoor air quality, control stability, and energy efficiency for air-side and water-side equipment. They found that although G36 slightly decreases thermal comfort, it significantly reduces annual energy consumption, increases indoor air quality, and eliminates CO2 discomfort through its use of demand controlled ventilation. The paper also found that local feedback control was important to ensure control stability when using G36. This study contributes to the body

This paper was the first to 1. assess the impact of G36 on indoor air quality, 2. consider control sequence interactions in water-side and air-side equipment for the system studied, and 3. examine short-term building behavior to evaluate control stability with G36.

The co-authors of the paper are Robert Lutes, former SBS Lab member Sen Huang, Wangda Zuo, and Draguna Vrabie. You can read the paper for free here until July 15, 2023.

Cary Faulkner’s Article on Fast Prediction of Indoor Airflow Distribution Published

Julia Ho on

Recent SBS Lab graduate Cary Faulkner’s journal article, titled “fast prediction of indoor airflow distribution inspired by synthetic image generation artificial intelligence,” was published in the journal Building Simulation. This article builds off Cary’s previous research in which he developed a conditional generative adversarial network (CGAN) model to decrease the amount of time needed to predict indoor airflow distribution, which can be prohibitively slow with computational fluid dynamics (CFD) modeling. This CGAN model uses AI image generation technology to predict airflow distribution much faster than physics-intensive CFD models. The research in this article modifies the original CGAN model by allowing a continuous input variable (such as a boundary condition) instead of a single parameter. Additionally, the new model, called BC-CGAN (boundary condition CGAN), was tested with a novel feature-driven algorithm that reduces the amount of computationally-intensive, potentially redundant data, allowing the model to be trained more quickly without sacrificing the quality of the training set. As a result, the BC-CGAN model predicted 2D air velocity and temperature distribution with less than 5% error and up to 75,000 times faster than reference CFD simulations.

Congrats to Cary on publishing this impressive research! The full paper can be found here.

Grid-interactive Efficient Buildings Literature Review Published

Julia Ho on

“System modeling for grid-interactive efficient building applications,” a literature review written by Yunyang Ye*, Cary Faulkner*, Rong Xu, Sen Huang*, Yuan Liu, Draguna Vrabie and Jian Zhang, has been published in the Journal of Building Engineering. The literature review analyzes over 300 articles on modeling grid-interactive efficient buildings (GEBs) with the goal of understanding best modeling practices for various applications as well as proposing future directions for the field. The authors found that the main challenges facing the GEB modeling field included the inability to consider all requirements in a single model, the inherent interdisciplinary nature of the models exposing limits in research expertise, and the lack of easily reusable system models. They suggest that future GEB modeling research studies focus on equation-based modeling, co-simulation, simulation workflow automation, and model-based co-design and machine learning to ensure that researchers take full advantage of GEB system modeling’s capabilities.

The full paper can be found for free here until April 29th.

*Current or former members of the SBS Lab.

Paper on Climate-Conscious HVAC Sizing and Design Published in Energy and Buildings Journal

Julia Ho on

Research work between Professor Wangda Zuo and other collaborators culminated in a paper published in the journal Energy and Buildings, titled “Climate change sensitive sizing and design for nearly zero-energy office building systems in Brussels.”

The paper analyzed climate change’s predicted impacts on European building performance and found that risk of overheating in buildings skyrocketed by the end of the 21st century. To address this issue, he researchers created an HVAC system design and sizing method to minimize climate change-caused overheating and cooling considering the changes in temperature, humidity, solar irrandiance, etc. of the building, which they found significantly decreased risks of overheating and overcooling during the investigated timeframe in a case study of a Brussels, Belgium office building model. They also suggested incorporating electric HVAC equipment and associated building renovations where possible, as electricity is predicted to become cleaner as more renewables are introduced to the grid.

The paper can be found here.

Jake Castellini’s Paper Accepted to Building Simulation Journal

Julia Ho on

SBS lab member Jake Castellini’s paper, titled “Quantifying Spatiotemporal Variability in Occupant Exposure to an Indoor Airborne Contaminant with an Uncertain Source Location,” was published in the journal Building Simulation this month. He worked with fellow lab member Cary Faulkner and Michael Sohn of Lawrence Berkeley National Lab to complete this project, which was sponsored by the Department of Energy’s Defense Threat Reduction Agency.

Most models simulating occupant exposure to contaminants in buildings use well-mixed zone models, which assume that contaminant levels are the same throughout a room (or zone). However, these models can under-predict high concentrations of contaminants because of this assumption. In contrast, CFD models are able to predict spatiotemporal variation but are computationally expensive. Jake’s paper describes a new method to parametrically characterize the spatiotemporal variability observed in CFD simulations as a first step in developing stochastic room surrogate models to replace well-mixed room representations.

Congratulations to Jake! His paper can be found for free here: https://rdcu.be/c7j8C

 

Katy Hinkelman Receives 2022-23 Boyer Graduate Scholarship

Julia Ho on

Congratulations to SBS Lab PhD candidate Katy Hinkelman, who recently received the Lester L. Boyer Graduate Research Scholarship for the 2022-23 academic year. Katy is a senior PhD student in the lab who has made invaluable contributions to the lab’s research on district energy systems and sustainable communities. Katy’s current research focuses on incorporating patterns and processes found in nature, a technique called biomimicry, into energy distribution networks. Biomimicry has been adopted in many engineering fields and Katy is helping to pioneer its use in the building and energy sectors. Katy, like Dr. Boyer, also started her own family during graduate school.

We thank the late Dr. Boyer and the Penn State Architectural Engineering program for their generous support. We are very grateful.

SBS Lab Attends ASHRAE Winter Conference

Julia Ho on

What a great way to start the year!

Current and graduated SBS Lab members had a big reunion February 3-8 at the ASHRAE Winter Conference in Atlanta, GA, where we attended many insightful seminars, paper sessions, and technical committees on topics ranging from the economic feasibility of CHP (combined heat and power) to modeling grid resilience to exploring extremely low-temperature refrigerants. It was inspiring to meet so many professionals who are leading their fields toward a healthier and safer tomorrow.

We thank ASHRAE for the amazing conference and the city of Atlanta, the birthplace of MLK, for its generous hospitality.

 02/23: Lab reunion dinner at Paschal’s in Atlanta

Biomimicry Literature Review Published

Julia Ho on

Katy Hinkelman, an SBS Lab PhD candidate, is in the midst of an impressive research project that integrates biomimicry into district energy design and operation. For those of us less versed in such topics, biomimicry is a growing technique defined by the Biomimicry Institute as “a practice that learns from and mimics the strategies found in nature to solve human design challenges.” As part of said research, Katy wrote a recently published literature review on the prevalence of biomimicry research in engineering applications with fellow labmate Yizhi Yang. The review systematically sifts through papers related to biomimicry and bins their biomimetic case studies into physical systems, cyber systems, or cyber-physical systems. In this way, Katy clearly lays out trends in biomimetic research by field and research goal and provides a comprehensive reference for engineers interested in biomimetic research practices that have previously been intimidated by the lack of pertinent, accessible literature.

This literature review has been published in the journal of Bioinspiration and Biomimetics and is open access here.

See Katy’s and Professor Wangda Zuo’s related LinkedIn posts here.

Jake Castellini Presents at ASHRAE Conference

Julia Ho on

SBS Lab PhD candidate Jake Castellini presented at the 2023 ASHRAE Winter Conference with a generous scholarship from the ASHRAE Rocky Mountain Chapter. He presented on his paper using computational fluid dynamics (CFD) modeling to investigate the impact of different portable air cleaner (PAC) locations on the transport of airborne contaminants like COVID-19 within a conference room. Great job on your well-received presentation, Jake!

We send a grateful thank you to the ASHRAE Rocky Mountain chapter for supporting our lab members.

You can find the paper on which Jake based his presentation here.

SBS Lab Members’ Novel Method to Assess Carbon Reduction Potential of Buildings Published

Julia Ho on

Yizhi Yang, Yingli Lou, Chris Payne, and Yunyang He have developed a model to “comprehensively assess the long-term carbon intensity reduction potential of aggregated commercial buildings on a county-by-county basis in the continental U.S.” Yizhi Yang is a current PhD student in the SBS Lab, and Yingli Lou and Yunyang He are lab graduates. Their paper summarizing the model and its application to U.S. K-12 buildings has been published in the Energy and Buildings Journal and is available for free until March 11, 2023.

Their case study weighed the effects of climate, energy sources, and building retrofits on K-12 buildings in 14 different climate zones from 2022 to 2050. By considering these effects simultaneously, they were able to predict what retrofits would be most effective and when; for example, they predicted that in 2022 reducing lighting power density in Oregon schools would most effectively increase energy savings, but in 2050 improving roof insulation will be a more effective energy saver because Oregon will have transitioned to clean energy sources for the majority of their electricity. They also concluded that there was a wide range of energy-saving potential across schools and that, depending on the primary energy source, energy savings potentials are not guaranteed to decrease (the example of this phenomenon being Mississippi’s predicted 2044 nuclear plant shutdown, which might be replaced with coal and natural gas plants.)

This case study demonstrates the capabilities of the author’s model, which can help policymakers, engineers, and community members estimate the impacts of different retrofits on buildings in their communities. Future work includes considering future weather predictions in the model, potential policies such as a carbon tax, and increasing the accuracy of buildings estimated in the model with building codes and climate zone geometrical information for climate reduction.

You can read the paper here: https://lnkd.in/efqdSVTr