Recommendations for model identification for MPC of an all-Air HVAC system

Rule-based control (RBC) strategies are often unable to execute the optimal control action, which leads to unnecessary energy consumption and suboptimal comfort. Model predictive control (MPC) is a dynamic control strategy for heating, ventilation and air-conditioning (HVAC) systems that is mostly m...

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Main Authors: Carton Quinten, Merema Bart, Breesch Hilde
Format: Article
Language:English
Published: EDP Sciences 2021-01-01
Series:E3S Web of Conferences
Online Access:https://www.e3s-conferences.org/articles/e3sconf/pdf/2021/22/e3sconf_hvac2021_11006.pdf
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author Carton Quinten
Merema Bart
Breesch Hilde
author_facet Carton Quinten
Merema Bart
Breesch Hilde
author_sort Carton Quinten
collection DOAJ
description Rule-based control (RBC) strategies are often unable to execute the optimal control action, which leads to unnecessary energy consumption and suboptimal comfort. Model predictive control (MPC) is a dynamic control strategy for heating, ventilation and air-conditioning (HVAC) systems that is mostly more capable of performing optimal control actions. The identification process of predictive models is an essential aspect of MPC. However, this model identification process remains time consuming due to the large variation in buildings and systems. The aim of this paper is to determine guidelines to identify predictive grey-box models more time efficient, thus enhancing the applicability of MPC. This paper focusses on a case study building equipped with an all-air HVAC system, which combines ventilation, heating and cooling. Making both temperature and CO2-concentration key parameters to predict. The grey-box model represents an open zone in a landscaped office, making the influence of neighbouring zones an additional challenge. Different models for predicting the zone temperature and CO2-concentration are identified, evaluated and validated using CTSM-R. The following aspects are studied: the dataset size, the influence of neighbouring zones, the difference between winter and summer conditions, number of states and the prediction horizon. A three state RC-model with the implementation of the zone temperature of one neighbouring zone is preferred for predicting the indoor temperature with an acceptable prediction horizon of one day. However, this temperature model is not suitable during sunny periods. A simple model representing a mass balance obtains accurate predictions of the zone CO2-concentration for a timestep of 15 minutes. For both model types the utilization of 5-day datasets is favoured over 12-day datasets due to a shorter monitoring period, lower prediction error and an easier parameter convergence. The usage of 12-day datasets is only preferred when an accurate estimation of the thermal inertia is pursued.
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spelling doaj.art-e7d99fccf17448f785cad74274262faf2022-12-21T22:00:05ZengEDP SciencesE3S Web of Conferences2267-12422021-01-012461100610.1051/e3sconf/202124611006e3sconf_hvac2021_11006Recommendations for model identification for MPC of an all-Air HVAC systemCarton Quinten0Merema Bart1Breesch Hilde2KU Leuven, Department of Civil Engineering, Building Physics and Sustainable Design, Ghent Technology CampusKU Leuven, Department of Civil Engineering, Building Physics and Sustainable Design, Ghent Technology CampusKU Leuven, Department of Civil Engineering, Building Physics and Sustainable Design, Ghent Technology CampusRule-based control (RBC) strategies are often unable to execute the optimal control action, which leads to unnecessary energy consumption and suboptimal comfort. Model predictive control (MPC) is a dynamic control strategy for heating, ventilation and air-conditioning (HVAC) systems that is mostly more capable of performing optimal control actions. The identification process of predictive models is an essential aspect of MPC. However, this model identification process remains time consuming due to the large variation in buildings and systems. The aim of this paper is to determine guidelines to identify predictive grey-box models more time efficient, thus enhancing the applicability of MPC. This paper focusses on a case study building equipped with an all-air HVAC system, which combines ventilation, heating and cooling. Making both temperature and CO2-concentration key parameters to predict. The grey-box model represents an open zone in a landscaped office, making the influence of neighbouring zones an additional challenge. Different models for predicting the zone temperature and CO2-concentration are identified, evaluated and validated using CTSM-R. The following aspects are studied: the dataset size, the influence of neighbouring zones, the difference between winter and summer conditions, number of states and the prediction horizon. A three state RC-model with the implementation of the zone temperature of one neighbouring zone is preferred for predicting the indoor temperature with an acceptable prediction horizon of one day. However, this temperature model is not suitable during sunny periods. A simple model representing a mass balance obtains accurate predictions of the zone CO2-concentration for a timestep of 15 minutes. For both model types the utilization of 5-day datasets is favoured over 12-day datasets due to a shorter monitoring period, lower prediction error and an easier parameter convergence. The usage of 12-day datasets is only preferred when an accurate estimation of the thermal inertia is pursued.https://www.e3s-conferences.org/articles/e3sconf/pdf/2021/22/e3sconf_hvac2021_11006.pdf
spellingShingle Carton Quinten
Merema Bart
Breesch Hilde
Recommendations for model identification for MPC of an all-Air HVAC system
E3S Web of Conferences
title Recommendations for model identification for MPC of an all-Air HVAC system
title_full Recommendations for model identification for MPC of an all-Air HVAC system
title_fullStr Recommendations for model identification for MPC of an all-Air HVAC system
title_full_unstemmed Recommendations for model identification for MPC of an all-Air HVAC system
title_short Recommendations for model identification for MPC of an all-Air HVAC system
title_sort recommendations for model identification for mpc of an all air hvac system
url https://www.e3s-conferences.org/articles/e3sconf/pdf/2021/22/e3sconf_hvac2021_11006.pdf
work_keys_str_mv AT cartonquinten recommendationsformodelidentificationformpcofanallairhvacsystem
AT meremabart recommendationsformodelidentificationformpcofanallairhvacsystem
AT breeschhilde recommendationsformodelidentificationformpcofanallairhvacsystem