David Blum is a Principal Scientific Engineering Associate in the Building Technology and Urban Systems Division.  His research focuses on the development and implementation of next-generation computational tools for buildings operating in isolation or within broader energy networks.  The majority of this work is applied to model predictive control (MPC), where a model of building performance can be used to optimize its energy consumption, occupant service, and energy network interactions.
David received his B.A.E degree from the Department of Architectural Engineering at The Pennsylvania State University in 2011 and his M.S. and PhD degrees in Building Technology from the Massachusetts Institute of Technology in 2013 and 2016 respectively.  At MIT, his research focused on improving the use of commercial building HVAC systems to provide ancillary services to electric grids through dynamic modeling and MPC.  He is a member of the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) and the Institute for Electrical and Electronics Engineers (IEEE), as well as the International Building Performance Simulation Association (IBPSA). 

Milica Grahovac is a Senior Scientific Engineering Associate for the Energy Efficiency Standards Group at the Lawrence Berkeley National Laboratory.

Milica performs analysis in the scope of energy conservation standards for commercial and industrial products. She holds expertise in policy analysis, energy efficiency, renewable energy systems, including HVAC systems and controls, and economic analysis. 

She also supports the Simulation Research Group's R&D with energy system modeling and the development of high performance control algorithms.

Milica combines her skills to develop sophisticated software tools targeting research, education and industrial audiences.

Philip Haves is the retired Leader of the Simulation Research Group. He has worked on different aspects of commercial buildings since 1986, with particular interests in simulation and in building operations. He is a Fellow of ASHRAE, the chair of its Technical Committee on Energy Calculations and a former Chair of its Technical Committee on Building Operation Dynamics. He is the immediate past president of IBPSA-USA, the US affiliate of the International Building Performance Simulation Association. He has a BA in Physics from Oxford University and a PhD in Radio Astronomy from Manchester University.

Projects: EnergyPlus

Dr. Tianzhen Hong is a Senior Scientist, Principal Investigator, and Deputy Head of the Building Technologies Department. He leads the Urban Systems Group and a research team working on a portfolio of projects, focusing on data, methods, modeling and simulation tools, and policy for design and operation of low energy buildings and sustainable urban systems. He is leading the EnergyPlus development at LBNL. He established and chairs the ASHRAE Multidisciplinary Task Group on occupant behavior in buildings. He actively contributed to international collaborations such as the U.S.-China Clean Energy Research Center on Building Energy Efficiency, IEA EBC Annex 21, 53, 66, 79, and 81. He was co-Operating Agent of Annex 66 and co-lead of Subtask 3 of Annex 79. One of his software toolkit, CBES, won the 2019 R&D 100 Award. He received B.Eng. and Ph.D. in HVACR, and B.Sc. in Applied Mathematics from Tsinghua University, China.


Urban Systems Research

Urban Systems Group, 

City Building Energy Saver (CityBES),

Occupant Behavior Research


Occupancy Simulator,

IEA EBC Annex 79 (2018-2023): Occupant-centric building design and operation

IEA EBC Annex 66 (2013-2018): Definition and simulation of occupant behavior in buildings

IEA EBC Annex 53 (2008-2013): Total Energy Use in Buildings: Analysis & Evaluation Methods

ASHRAE Multidisciplinary Task Group on Occupant Behavior in Buildings, ASHRAE MTG.OBB

Building Energy Modeling and Analysis Tools

Commercial Building Energy Saver: California version,; National version,




Projects: Modelica, EnergyPlus

Jianjun Hu is Principal Scientific Engineering Associate in Simulation Research Group of Building Technology and Urban Systems Division. His major focus is the development of open platform tool for designing building control and system commissioning. He is also playing major role on developing next generation of EnergyPlus. Before joining LBNL in Feb., 2017, Jianjun was a Senior Research Engineer in United Technologies Research Center (China), in where, he acted as principal investigator of projects associated with super tall building airflow management, like stack effect mitigation, smoke control and wind effects on HVAC system. At there, he also worked on developing virtual building test bed on Dymola platform.

Jianjun received PhD degree in Civil Engineering from Purdue University in August 2014. His PhD research focused on applying model predictive control strategies on buildings with mixed-mode cooling, to minimize HVAC energy usage while ensuring occupant thermal comfort through dynamic modeling and strategy optimization. Prior to the PhD program, he was a two-years visiting researcher in School of Mechanical Engineering of Purdue, and investigated the algorithms for fast fluid dynamic simulation in building. He received master and bachelor degree from University of South China in 2006 and 2003 respectively.

Jianjun is associate member of the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE). He is also member of International Building Performance Simulation Association – USA (IBPSA-USA).

Jared Langevin is a Research Scientist at Lawrence Berkeley National Laboratory, where he models the national impacts of building efficiency on long-term energy use and CO2 emissions, develops decision support algorithms for energy flexible building operations, and researches human-building interactions. Based in Washington, D.C., Jared was previously a Science and Technology Policy Fellow at the U.S. Department of Energy’s Building Technologies Office (BTO), where he co-created BTO’s Scout program for national building efficiency impact analysis. Jared holds a Ph.D. in Architectural Engineering from Drexel University, where his research focused on measuring and modeling the adaptive interactions between building occupants and their surrounding thermal environments, examining the links between these interactions and building energy use. Before entering into his graduate studies at Drexel, Jared received a Bachelor’s degree in Architecture from Carnegie Mellon University.

Sang Hoon Lee is a senior scientific engineering associate in the Building Technology and Urban Systems Division. He received a Ph.D. in Building Technology and M.S. in Integrated Facility Management from the Georgia Institute of Technology. He is a LEED accredited professional with USGBC and a Facility Management Professional with IFMA. His current work focuses on the building energy simulation and modeling method in different fidelities and for diverse needs. Prior to joining LBNL, he worked at the Georgia Institute of Technology for developing energy modeling methods that are implemented in tools such as Energy Performance Standard Calculation Toolkit for easy use by building owners, architects, and engineers and Network Energy Performance Toolkit for campus-scale energy evaluation.

Na Luo is a Postdoctoral Researcher in the Building Technology and Urban Systems Division at Lawrence Berkeley National Laboratory. She received B.Eng. in Engineering Physics and Ph.D. in Safety Science and Technology from Tsinghua University. Her research focuses on experimental and numerical analysis of heat transfer and fluid field variation caused by human behavior (movements), as well as the building performance simulation and urban resiliency.

Ms. Xuan Luo is a Scientific Engineering Associate with the Building Technology and Urban Systems Division. She works as a member of EnergyPlus development team since 2016, engaging in the development of new features to enhance EnergyPlus for building energy modeling. She also engaged in the Multiscale Coupled Urban Systems under the DOE Office of Science's Exascale Computing Project, developing, running and testing a co-simulation platform for urban system models on high-performance computers. She contributed to the development of of the City Building Energy Saver (CityBES), a web-based platform to support the urban system researches, and Commercial Building Energy Saver (CBES), a web-based tool for energy benchmarking, electric load shape analysis, and retrofit analysis. She also works on occupant behavior research and is the lead developer of a building occupancy simulation tool Occupancy Simulator.


Multiscale Coupled Urban Systems

Occupancy Simulator,

City Building Energy Saver (CityBES),

Commercial Building Energy Saver (CBES),

Commercial Building Energy Saver Pro,


Kaiyu Sun is a Scientific Engineering Associate in the Building Technology and Urban Systems Division at Lawrence Berkeley National Laboratory. She received her M.S. in Building Technology Department from Tsinghua University. Her current work focuses on energy modeling with EnergyPlus and OpenStudio, automatic model calibration, development of OpenStudio measures, development of Variable Refrigerant Flow system model in EnergyPlus and occupant behavior research.

Michael Wetter is a Staff Scientist at LBNL. His research includes new generation computing tools for building and district energy design and operation. He did his dissertation at the University of California at Berkeley and at LBNL, where he created the GenOpt optimization program and the BuildOpt building simulation program and where he developed the first building energy optimization technique that provably converges to the optimal building design. He created various software for building energy simulation and optimization, including the Building Controls Virtual Test Bed, the Modelica Buildings library, and the GenOpt optimization program. He has been co-operation agent of IEA EBC Annex 60 and of the IBPSA Project 1. He is a recipient of the Outstanding Young Contributor Award of the International Building Performance Simulation Association (IBPSA), an IBPSA Fellow, a past president of IBPSA-USA, past Treasurer of IBPSA, a member of the board of directors of IBPSA and of the Modelica North America Users' Group, and a member of ASHRAE.