Journal of Process Control 24 (2014) 1282–1291
Contents lists available at ScienceDirect
Journal of Process Control
j our na l ho me pa g e: www.elsevier.com/locate/jprocont
Application of economic MPC to the energy and demand
minimization of a commercial building
Jingran Ma
a
, S. Joe Qin
a,c,∗
, Timothy Salsbury
b
a
Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 211, Los Angeles,
CA 90089, United States
b
Johnson Controls Inc., 507 E Michigan Street, Milwaukee, WI 53202, United States
c
School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
a r t i c l e i n f o
Article history:
Received 10 November 2013
Received in revised form 17 June 2014
Accepted 17 June 2014
Available online 19 July 2014
Keywords:
Economic model predictive control
Building
HVAC
Optimization
Simulation
Field tests
a b s t r a c t
This paper presents an application case study of an economic model predictive control (EMPC) method
for optimizing the building demand and energy cost under the time-of-use price policy. The control
strategy is comprised of an economic objective function that accounts for the combination of energy
and demand costs with a time-of-use rate structure, a dynamic thermal process and power model of the
building thermal mass dynamics, and a set of constraints to ensure the building is operated properly. The
optimization is a min–max optimization problem and is converted to a linear program. The EMPC method
is implemented in a commercial office building located in Milwaukee, Wisconsin, USA. An internet-based
control architecture is developed to carry out tests with the EMPC controller at a remote location. The
test results show that the EMPC strategy is capable of shifting the peak demand to off-peak hours and
reducing energy costs compared to a baseline case for the building.
© 2014 Elsevier Ltd. All rights reserved.
1. Introduction
The U.S. Department of Energy reported in 2009 [1], 73% of the
nation’s electricity consumption and 40% of greenhouse gas emis-
sions can be attributed to buildings. Buildings account for 39% of
total energy consumption among all sectors, costing $350 billion
per year [2]. Heating, ventilation and air conditioning (HVAC) sys-
tems are responsible for about one third of building energy usage
[1].
It is believed that most buildings are not operated as effi-
ciently as they could be. In general, there are two approaches
to achieve energy savings: by installing more energy efficient
equipment in buildings, or by managing energy consumption in
an efficient way via the building automation systems (BAS) [3].
The first approach requires capital expenditures and any result-
ing retrofit action would be disruptive to the building operation.
The second approach on the other hand optimizes the operation of
HVAC systems with existing equipment by simply changing control
settings with advanced control strategies [4].
In addition to reducing overall energy consumption, another
important need for building controls is to lower the peak power
demand. Owing to the fact that buildings, especially commercial
∗
Corresponding author. Tel.: +1 213 740 0317; fax: +1 213 740 8053.
E-mail address: sqin@usc.edu (S.J. Qin).
buildings, tend to consume energy simultaneously during peak
hours, the peak-average-ratio (PAR) in the electricity grid can be
high [5]. Both electricity suppliers and customers are concerned
with the peak demand due to economic and environmental chal-
lenges. New power plants are built every year merely to cope with
the rapidly increasing peak demand, which reduces efficiency in
off-peak hours and leads to higher energy costs [6]. Moreover,
uncontrolled high peak demand makes it difficult to integrate
renewable energy resources. Therefore, it is of great interest to
develop advanced technologies to flatten the peak demand relative
to base loads.
Demand response (DR) is a concept that has recently received
extensive attention in buildings as a promising means to lower
the peak demand. DR encourages end-users to alter their electric
usages from regular patterns, in response to incentives of electricity
price [7,8]. Advanced electricity rate structures are now commonly
applied by utilities, which include time-of-use (TOU), critical-peak-
pricing (CPP) and real-time pricing (RTP). It is demonstrated that
under these time varying rate structures, users are able to reduce
energy costs by taking certain DR actions [9–11]. The cost-effective
strategy for building HVAC control is to shift the energy usage away
from the peak hours while all the normal operation criterion such
as thermal comfort level and indoor air quality are maintained [12].
Most buildings are operated with a night-setback (NS) strat-
egy, in which the HVAC is turned on during the occupied
period and turned off otherwise. The setpoints of thermostats are
http://dx.doi.org/10.1016/j.jprocont.2014.06.011
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