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Development of a Hardware-in-the-loop Testbed for Laboratory Performance Verification of Flexible Building Equipment in Typical Commercial Buildings



Zhelun Chen, Jin Wen, Steven T. Bushby, Caleb Calfa, Yangyang Fu, Gabriel Grajewski, Yicheng Li, L. James Lo, Zheng O'Neill, Vance (Wm.) Payne, Amanda Pertzborn, Zhiyao Yang


The goals of reducing energy costs, shifting electricity peaks, increasing the use of renewable energy, and enhancing the stability of the electric grid can be met in part by fully exploiting the energy flexibility potential of buildings and building equipment. Publicly available high-resolution datasets illustrating how control of HVAC systems in commercial buildings can be used in different climate zones to shape the energy use profile of a building for grid needs will facilitate the deployment of these kinds of strategies. This article presents the development and integration of a Hardware-In-the-Loop Flexible load Testbed (HILFT) that integrates physical HVAC systems with a simulated building model with the goal of generating datasets to verify load flexibility of typical commercial buildings. Compared to simulation-only experiments, the hardware-in-the-loop approach captures the dynamics of the physical systems while also allowing efficient testing of various boundary conditions. The HILFT integration in this article is achieved through reliable co-simulation among various software environments including LabVIEW, MATLAB (including MATLAB Simulink), and EnergyPlus (via Functional Mockup Unit). The mechanism behind the integration is described in detail. Although theoretically viable, such integration has encountered many real-world challenges, such as how to design the overall data infrastructure to ensure effective, robust, and efficient integration, how to avoid closed-loop hunting between simulated and emulated variables, how to quantify system response times and minimize system delays, and how to assess the overall integration quality. Detailed case studies and lessons-learned using examples of an AHU-VAV system, an air-source heat pump system, and a water-source heat pump system are presented.
Proceedings Title
ASHRAE Transactions - 2022 ASHRAE Annual Conference
Conference Dates
June 25-29, 2022
Conference Location
Toronto, CA
Conference Title
2022 ASHRAE Annual Conference


HVAC, hardware in the loop, heat pump, AHU-VAV, co-simulation


Chen, Z. , Wen, J. , Bushby, S. , Calfa, C. , Fu, Y. , Grajewski, G. , Li, Y. , Lo, L. , O'Neill, Z. , Payne, V. , Pertzborn, A. and Yang, Z. (2022), Development of a Hardware-in-the-loop Testbed for Laboratory Performance Verification of Flexible Building Equipment in Typical Commercial Buildings, ASHRAE Transactions - 2022 ASHRAE Annual Conference, Toronto, CA, [online], (Accessed June 13, 2024)


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Created June 27, 2022, Updated September 19, 2023