Virtual testbed for model predictive control development in district cooling systems

Zabala, Laura; Febres, Jesús; Sterling, Raymond; López, Susana; Keane, Marcus

doi:10.1016/j.rser.2020.109920

Cited by 32 publications

(19 citation statements)

References 32 publications

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“…This is currently more than any other country, but global installations are growing rapidly, particularly in the Middle East [2]. With buildings consuming 36% of global energy [3] and space cooling growing faster than any other end use [4], many are looking to DC for its energy efficiency and economic benefits [5,6,7]. Rather than individual buildings producing their cooling needs with individual air conditioning equipment, centralized plants produce chilled water (CHW) that can be distributed to multiple buildings connected to the district.…”

Section: Introductionmentioning

confidence: 99%

“…Several groups have made valuable contributions to DC modeling literature. High-fidelity and reduced-order modeling techniques have been adapted to reduce plant energy consumption [12], peak loads [13], and implement model predictive control [7,14], to name a few. While a variety of chiller types have been studied -including compressor, absorption, turbo, and double-effect varieties -to the authors' best knowledge, none of the previous literature modeled chiller plants with waterside economizers (WSEs) in DC applications.…”

Section: Introductionmentioning

confidence: 99%

“…While a variety of chiller types have been studied -including compressor, absorption, turbo, and double-effect varieties -to the authors' best knowledge, none of the previous literature modeled chiller plants with waterside economizers (WSEs) in DC applications. Further, we only found one study that used Modelica for DC plant modeling [7], yet Modelica is a promising platform for these applications due to its acausal modeling scheme, multitude of variable time-step numerical solvers, and rich open-source libraries with high re-usability potential. This work demonstrates how the open-source Modelica Buildings library can be applied for detailed modeling of chiller plants with WSE for DC applications.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Case Study on Condenser Water Supply Temperature Optimization with a District Cooling Plant

Hinkelman¹,

Wang²,

Fan³

et al. 2021

Preprint

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District cooling (DC) continues to proliferate due to increasing global cooling demands and economies of scale benefits; however, most district-scale modeling has focused on heating, and to the best of our knowledge, researchers have yet to model cooling plants featuring waterside economizers in DC settings. With the Modelica Buildings library expanding its capabilities to district scale, this study is one of the first to demonstrate how the open-source models can be used for detailed energy and control analysis of a DC plant. For a real-world case study, we developed and calibrated high-fidelity models for a DC system central plant at a college campus in Colorado, USA, and we optimized the condenser water supply temperature (CWST) setpoint for a DC plant across multiple time horizons using the Optimization library in Dymola. Results indicate that annual CWST optimization saves 4.7% annual plant energy, with less than 1% of additional energy savings gained through daily optimization. This confirms previous studies' findings that high frequency CWST optimizations are not necessary for the studied system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Case Study on Condenser Water Supply Temperature Optimization with a District Cooling Plant

Hinkelman¹,

Wang²,

Fan³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Further, the Modelica community has rich open-source libraries, and the widevariety of solvers available in Modelica simulation environments allows the above-mentioned numerical challenges to be addressed. The case study by Zabala et al [11] leveraged the benefits of Modelica for DC applications, creating reducedorder models of a chiller plant based on high-fidelity Modelica models for real-time, model predictive control (MPC) applications. As part of this work, the District Cooling Open Source Library was publicly released [12].…”

Section: Introductionmentioning

confidence: 99%

“…As part of this work, the District Cooling Open Source Library was publicly released [12]. While Zabala et al [11] developed their chiller models from Modelica, they simulated the entire DC system externally using Python. This approach was highly effective for MPC, but numerous benefits of Modelica for DC analysis remain unexplored.…”

Section: Introductionmentioning

confidence: 99%

Modelica-Based Modeling and Simulation of District Cooling Systems: A Case Study

Hinkelman¹,

Wang²,

Gautier³

et al. 2021

Preprint

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While equation-based object-oriented modeling language Modelica can evaluate practical energy improvements for district cooling systems, few have adapted Modelica for this type of large-scale thermo-fluid system. Further, to our best knowledge, district cooling modeling studies have yet to include hydraulics in piping network nor waterside economizers. These are critical details to include when looking to make energy and control improvements in many physical system installations. To fi?ll these gaps, this study applies newly developed open-source models from the Modelica Buildings library. For a real-world case study, we modeled and simulated a district cooling system at a college campus in Colorado, United States, with six buildings connected to a central chiller plant featuring a waterside economizer. Several energy saving strategies are pursued based on the validated model, including control setpoint optimization, equipment modification, and pump setpoint adjustments. Results indicate that optimizing the condenser water supply temperature setpoint can save 2.5% to 4.4% energy; the nonintegrated waterside economizer saves 6.4% energy while cutting down the chillers' run times by 201 days/year, reducing maintenance costs, and extending chiller life; and adjusting the condenser water pump flow settings can save 10.2% energy. Through a combinationof the studied measures, the campus can annually save 84.6 MWh of energy, 8.9% of electricity costs, and 58.0 metric tons of carbon dioxide emissions. Further, the numerical results of simulating districts from tens to hundreds of buildings are presented.

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Green Building Clusters for Residential Developments: Developing District Cooling Systems

Illankoon

Tam

Lê

et al. 2021

Proceedings of the 25th International Symposium on Advancement of Construction Management and Real Estate

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Virtual testbed for model predictive control development in district cooling systems

Cited by 32 publications

References 32 publications

A Case Study on Condenser Water Supply Temperature Optimization with a District Cooling Plant

A Case Study on Condenser Water Supply Temperature Optimization with a District Cooling Plant

Modelica-Based Modeling and Simulation of District Cooling Systems: A Case Study

Green Building Clusters for Residential Developments: Developing District Cooling Systems

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