Predictive pre-cooling of thermo-active building systems with low-lift chillers

This article describes the development and experimental validation of a data-driven model predictive control algorithm that optimizes the operation of a low-lift chiller, a variable-capacity chiller run at low pressure ratios, serving a single zone with a thermo-active building system. The predictive control algorithm incorporates new elements lacking in previous chiller pre-cooling control optimization methods, including a model of temperature and load-dependent chiller performance extending to low-pressure and part-load ratios and a data-driven zone temperature response model that accounts for the transient thermal response of a concrete-core radiant floor thermo-active building system. Data-driven models of zone and concrete-core thermal response are identified from monitored zone temperature and thermal load data and combined with an empirical model of a low-lift chiller to implement model predictive control. The energy consumption of the cooling system, including the chiller compressor, condenser fan, and chilled-water pump energy, is minimized over a 24-h look-ahead moving horizon using the thermo-active building system for thermal storage and radiant distribution. A generalized pattern-search optimization over compressor speed is performed to identify optimal chiller control schedules at every hour, thereby accomplishing load shifting, efficient part-load operation, and cooling energy savings. Results from testing the system's sensible cooling efficiency in an experimental test chamber subject to the typical summer week of two climates, Atlanta, GA, and Phoenix, AZ, show sensible cooling energy savings of 25% and 19%, respectively, relative to a high efficiency, variable-speed split-system air conditioner.

[1]  James E. Braun,et al.  An Inverse Gray-Box Model for Transient Building Load Prediction , 2002 .

[2]  M. Deru,et al.  Radiant Slab Cooling for Retail , 2010 .

[3]  Michele De Carli,et al.  Applications of heating and cooling thermal slabs for different buildings and climates , 2003 .

[4]  Zhenjun Ma,et al.  Supervisory and Optimal Control of Building HVAC Systems: A Review , 2008 .

[5]  Gregor P. Henze,et al.  Impact of adaptive comfort criteria and heat waves on optimal building thermal mass control , 2007 .

[6]  James E. Braun,et al.  Evaluating the Performance of Building Thermal Mass Control Strategies , 2001 .

[7]  Standard Ashrae.  Thermal Environmental Conditions for Human Occupancy , 1992 .

[8]  T. Y. Chen,et al.  Application of adaptive predictive control to a floor heating system with a large thermal lag , 2002 .

[9]  John E. Seem.  Modeling of Heat Transfer in Buildings , 1987 .

[10]  E. Isfaelt,et al.  Heat storage in the building structure , 1974 .

[11]  Joseph H. Eto.  COOLING STRATEGIES BASED ON INDICATORS OF THERMAL STORAGE IN COMMERCIAL BUILDING MASS , 1985 .

[12]  Leslie K. Norford,et al.  Empirical Modeling of a Rolling- Piston Compressor Heat Pump for Predictive Control in Low Lift Cooling , 2010 .

[13]  Robert Michael Lewis,et al.  Pattern Search Methods for Linearly Constrained Minimization , 1999, SIAM J. Optim..

[14]  Viktor Dorer,et al.  Control of thermally activated building systems (TABS) in intermittent operation with pulse width modulation , 2009 .

[15]  Peter R. Armstrong,et al.  Variable-speed heat pump model for a wide range of cooling conditions and loads , 2011 .

[16]  O. SIAMJ.,et al.  ON THE CONVERGENCE OF PATTERN SEARCH ALGORITHMS , 1997 .

[17]  Viktor Dorer,et al.  Interaction of an air system with concrete core conditioning , 1999 .

[18]  Xudong Yang.  Study of building material emissions and indoor air quality , 1999 .

[19]  Kurt Roth,et al.  Cool Thermal Energy Storage , 2006 .

[20]  M. E. Snyder,et al.  Cooling cost minimization using building mass for thermal storage , 1990 .

[21]  Srinivas Katipamula,et al.  Cost-Effective Integration of Efficient Low-Lift Baseload Cooling Equipment: FY08 Final Report , 2010 .

[22]  Gregor P. Henze,et al.  Evaluation of optimal control for active and passive building thermal storage , 2004 .

[23]  David E. Claridge,et al.  Control Optimization for a Chilled Water Thermal Storage System Under a Complicated Time-of-Use Electricity Rate Schedule , 2005 .

[24]  V E Zakharov,et al.  Figure Captions , 1994 .

[25]  Simeng Liu,et al.  Experimental analysis of simulated reinforcement learning control for active and passive building thermal storage inventory: Part 2: Results and analysis , 2006 .

[26]  Charles Audet,et al.  Analysis of Generalized Pattern Searches , 2000, SIAM J. Optim..

[27]  Gregor P. Henze,et al.  Advances in Near-Optimal Control of Passive Building Thermal Storage , 2010 .

[28]  Robert Michael Lewis,et al.  Pattern Search Algorithms for Bound Constrained Minimization , 1999, SIAM J. Optim..

[29]  Steven B. Leeb,et al.  Control with building mass-Part I: Thermal response model , 2006 .

[30]  T. Y. Chen,et al.  Real-time predictive supervisory operation of building thermal systems with thermal mass , 2001 .

[31]  Gregor P. Henze,et al.  Primary energy and comfort performance of ventilation assisted thermo-active building systems in continental climates , 2008 .

[32]  Srinivas Katipamula,et al.  Efficient Low-Lift Cooling with Radiant Distribution, Thermal Storage, and Variable-Speed Chiller Controls—Part II: Annual Use and Energy Savings , 2009 .

[33]  James E. Braun,et al.  Application of building precooling to reduce peak cooling requirements , 1997 .

[34]  Moncef Krarti,et al.  Planning horizon for a predictive optimal controller for thermal energy storage systems , 1999 .

[35]  Stanley A. Mumma,et al.  Achieving Dry Outside Air in an Energy-Efficient Manner , .

[36]  James E. Braun,et al.  Reducing energy costs and peak electrical demand through optimal control of building thermal storage , 1990 .

[37]  James E. Braun,et al.  A Simplified Method for Determining Optimal Cooling Control Strategies for Thermal Storage in Building Mass , 1996 .

[38]  Kyoung-ho Lee,et al.  Assessment of demand limiting using building thermal mass in small commercial buildings , 2006 .

[39]  Gregor P. Henze.  Impact of real-time pricing rate uncertainty on the annual performance of cool storage systems , 2003 .

[40]  Moncef Krarti,et al.  Development of a Predictive Optimal Controller for Thermal Energy Storage Systems , 1997 .

[41]  Peng Xu,et al.  Case Study of Demand Shifting with Thermal Mass in Two Large Commercial Buildings , 2006 .

[42]  Srinivas Katipamula,et al.  Cost-Effective Integration of Efficient Low-Lift Base Load Cooling Equipment , 2008 .

[43]  Viktor Dorer,et al.  Control of thermally-activated building systems (TABS) , 2008 .

[44]  Gregor P. Henze,et al.  Sensitivity analysis of optimal building thermal mass control , 2007 .

[45]  M. Kintner-Meyer,et al.  Optimal control of an HVAC system using cold storage and building thermal capacitance , 1995 .

[46]  Nicholas Gayeski,et al.  Predictive pre-cooling control for low lift radiant cooling using building thermal mass , 2010 .

[47]  Moncef Krarti,et al.  Parametric analysis of active and passive building thermal storage utilization , 2005 .

[48]  Kyoung-ho Leea,et al.  Development of methods for determining demand-limiting setpoint trajectories in buildings using short-term measurements , 2007 .

[49]  L. K. Norford,et al.  Efficient Low-Lift Cooling with Radiant Distribution, Thermal Storage, and Variable-Speed Chiller Controls—Part I: Component and Subsystem Models , 2009 .

[50]  D. G. Stephenson,et al.  Cooling load calculations by thermal response factor method , 1967 .

[51]  Moncef Krarti,et al.  The impact of forecasting uncertainty on the performance of a predictive optimal controller for thermal energy storage systems , 1999 .

[52]  Shengwei Wang,et al.  Hybrid Model for Building Performance Diagnosis and Optimal Control , 2003 .

[53]  L. K. Norford,et al.  Peak load reduction by preconditioning buildings at night , 1991 .

[54]  B. Olesen.  Control of slab heating and cooling systems studied by dynamic computer simulations. , 2002 .

[55]  J. Braun,et al.  Model-based demand-limiting control of building thermal mass , 2008 .

[56]  Nobukazu Kobayashi.  Floor-supply displacement ventilation system , 2001 .

[57]  Viktor Dorer,et al.  Application range of thermally activated building systems tabs , 2007 .

[58]  Michael Kintner-Meyer,et al.  Cost optimal analysis and load shifting potentials of cold storage equipment , 1995 .

[59]  Tea Zakula,et al.  Heat pump simulation model and optimal variable-speed control for a wide range of cooling conditions , 2010 .

[60]  Marcel Lacroix,et al.  Fuzzy and feedforward control of an hybrid thermal energy storage system , 2006 .

[61]  David E. Claridge,et al.  Use of Calibrated HVAC System Models to Optimize System Operation , 1998 .

[62]  Steven B. Leeb,et al.  Control with building mass-Part II: Simulation , 2006 .

[63]  Simeng Liu,et al.  Experimental analysis of simulated reinforcement learning control for active and passive building thermal storage inventory: Part 1. Theoretical foundation , 2006 .

[64]  John Dieckmann,et al.  Using Off-Peak Precooling , 2009 .

[65]  Güntensperger Werner,et al.  CONTROL OF CONCRETE CORE CONDITIONING SYSTEMS , 2005 .

[66]  S. H Cho,et al.  Predictive control of intermittently operated radiant floor heating systems , 2003 .

[67]  Kyoung-ho Lee,et al.  An experimental evaluation of demand limiting using building thermal mass in a small commercial building , 2006 .