Aggregated Performance and Qualitative Modeling Based
Smart Thermal Control
Afef Denguir
1,2
, François Trousset
1
and Jacky Montmain
1
1
LGI2P, Ecole des Mines d’Ales, 69 avenue Parc scientifique Georges Besse, Nîmes, France
2
LIRMM, Université de Montpellier 2, 161 rue Ada, Montpellier, France
Keywords: Energy Optimization, Smart Thermal Control, Thermal Comfort, Preference Model, Choquet Integral, Multi
Attribute Utility Theory, Utility Functions, Qualitative Modeling, Approximate Reasoning, Online
Learning, Preference Learning.
Abstract: In order to ensure thermal energy efficiency and follow government’s thermal guidance, more flexible and
efficient buildings’ thermal controls are required. This paper focuses on proposing an efficient, scalable,
reusable, and data weak dependent smart thermal control approach based on an aggregated performance and
imprecise knowledge of buildings’ thermal specificities. Its main principle is to bypass data unavailability
and quantitative models identification issues and to ensure an immediate thermal enhancement. For this, we
propose, first, an aggregated performance based smart thermal control in order to identify relevant thermal
setpoints. An extended thermal qualitative model is then introduced to guarantee an efficient achievement of
the identified thermal setpoints. Uncertainty about how relevant a thermal control is for a given thermal
situation is thus reduced using online and preference based learnings.
1 INTRODUCTION
Buildings’ energy efficiency has been widely
discussed in literature and supported by industrial
applications. In fact, buildings are responsible for
more than 40% of total energy consumption in
Europe (EP&C, 2012) which has led to restricted
energy policies for buildings’ energy control. As
47% of buildings’ energy consumption is used for
space heating and cooling (PNNL, 2012), buildings’
thermal control has particularly become an
important target in order to reduce buildings’ energy
consumption. Studies on smart thermal control are
thus relevant and are facing, nowadays, new
industrial challenges. The RIDER (Research for IT
Driven Energy Efficiency) project is one of recent
researches on smart thermal control which focuses
on the final solution deployment properties. It
considers the scalability and reusability of the
control solution which lead to a large application
area (i.e., form buildings to neighbor-hoods) and
deployment costs saving (i.e., neither specific
studies, nor particular information, are required for
the deployment) of the final solution. Moreover, the
RIDER project deals with data availability issues.
Indeed, it has to ensure as efficient as possible
thermal control whenever sufficient data are
available or not. For instance, a new-build that has
no historical data can immediately get advantage
from the RIDER solution without proceeding by the
new-build thermal behavior’ study or gathering
learning data. This work is part of the RIDER
project and proposes a new complete thermal
enhancement approach satisfying RIDER’s
deployment expectations. The proposed thermal
enhancement approach provides recommendations
starting from thermal setpoints to controls achieving
them. This paper explains our overall smart thermal
control and is organized as follows: first, some smart
thermal control related works are discussed. Section
3 explains our thermal enhancement approach
denoted by RIDER STC (RIDER’s Smart Thermal
Control) which fulfills RIDER’s deployment
expectations. Conclusions are finally presented.
2 RELATED WORKS
Most buildings’ thermal controls are simple and aim
to maintain the overall thermal state around a
conventional operational point (i.e., indoor tempera-
63
Denguir A., Trousset F. and Montmain J..
Aggregated Performance and Qualitative Modeling Based Smart Thermal Control.
DOI: 10.5220/0005063300630076
In Proceedings of the 11th International Conference on Informatics in Control, Automation and Robotics (ICINCO-2014), pages 63-76
ISBN: 978-989-758-039-0
Copyright
c
2014 SCITEPRESS (Science and Technology Publications, Lda.)
ture setpoints). Among well-known thermal
regulator, we name TOR (Tout-Ou-Rien), P
(Proportional action), PI (Proportional Integral
action), PID (Proportional Integral Derivative
action) control based regulators. P, PI, and PID
based regulators implement manual, automatic,
adaptive, and identification techniques in order to
define the regulator’s parameters. For instance,
(Zaheer-uddin, 2004) proposes a neural network
based approach to update PID control’ parameters.
Yet, adaptive and individualized thermal control
remains not supported by conventional thermal
regulators which requires an extra thermal control
level (Nassif, 2005); commonly denoted by the
smart thermal control. As buildings’ thermal
processes are usually characterized by a slow
dynamics and a high inertia, anticipating measurable
disturbances related to building’s usage, weather
conditions, and energy price variations, may lead to
a significant thermal control’ efficiency
enhancement (i.e., decreasing thermal energy
consumption, increasing occupants’ thermal
comfort). Hence, the smart thermal control is more
than a simple room’s temperature control. In order to
ensure the smart thermal control, additional
information on building’s usage (e.g., the requested
thermal comfort, the building’s occupancy profile,
etc.), climatic conditions (e.g., weather forecasts,
sunshine, etc.), and energy prices variations, need to
be introduced in thermal behavior models which
may quickly transform the smart thermal control
into a complex problem. To solve the complex
problem that the smart thermal control is, several
approaches based either on predictive control
techniques or advanced control techniques have
been proposed. For instance, we name Homes,
OptiControl (Oldewurtel, 2010), and the IC-
Berkeley’s energy storage (Ma, 2009) projects that
propose a predictive control based smart thermal
control. Applied to the thermal context, the
predictive control considers socio-economic
objectives such as minimizing energy consumption
and maximizing thermal comfort (Ma, 2009). It is
based on a mathematical thermal modeling which
considers precise quantitative physical aspects of the
thermal behavior and explains why mathematical
models are also called by white type models. In the
thermal context, mathematical modeling is
supported by software such as TRNSYS,
EnergyPlus, SPARK, and SIMBAD which offer a
convenient environment for detailed mathematical
thermal modeling and thermal simulation. Thus,
they can be directly deployed to ensure building’s
smart thermal control. Obviously, the more detailed
the thermal mathematical model is, the more
efficient the smart control would be. However,
detailed mathematical design requires expertise, as
well as, specific and precise quantitative data and
knowledge on buildings’ thermal behavior which
makes it intricate. Moreover these specific and
precise quantitative data are not commonly available
for most of buildings which has led to the grey type
modeling. This last tries to reduce the complexity of
mathematical modeling by introducing identification
(respectively estimation) techniques in order to
complete lacking parameters (respectively input
data). For instance, in order to build his monthly
energy consumption forecasting model, (White,
1996) has based his thermal modeling on monthly
average predicted outdoor temperature rather than
detailed forecasts. Identification techniques have
been also applied in order to automatically learn
thermal parameters such as (Wang, 2006) that has
used a genetic algorithm to identify thermal envelop’
parameters. Once all thermal parameters/inputs are
well identified/estimated, the grey type modeling
can lead to an efficient and accurate smart thermal
control. However, building’s thermal parameters can
only be identified through specific thermal tests also
known as building’s thermal excitement tests. These
tests add an extra deployment constraint to the smart
thermal control solution. In fact, depending on
building’s usage, some thermal tests are not
conservable which makes building’s thermal
parameters identification impossible. Although white
and grey models are efficient and accurate for the
smart thermal control, they do not fulfill RIDER’s
deployment expectations. In fact, focusing on the
accuracy of physical behavior decreases the
scalability of white and grey modeling. Collecting/
operating specific thermal information/tests entails
extra costs each time that the smart thermal control
solution needs to be deployed which means that the
thermal enhancement solution is not reusable and
cannot be immediately operated unless these
information/tests are available/allowed. Based on
those observations, Artificial Intelligence (AI)
techniques have been introduced 20 years ago in
order to ensure the advanced thermal control. They
provide a simple, efficient and adaptive smart
thermal control without requiring any a priori know-
ledge on thermal physical behavior. AI’ learning
techniques have been massively applied in order to
learn quantitative thermal models also known as
black type thermal models. (Kalogirous, 2000) have
proposed an ANN (Ant Neural Network) based
approach in order to learn building’s thermal
behavior. Therefore, ANN based smart thermal
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control becomes possible and can answer specific
questions such as when is the best moment to restart
a heating system after an inoccupation period
(Yang, 2003). Thus, a well-trained ANN thermal
model could lead to similar accuracy as white and
grey thermal models. (Aydinalp, 2002) has shown
that for cooling’ energy cost prediction ANN based
modeling is more efficient than the grey based one.
The supervised leaning technique SVM (Support
Vector Machine) has been recently applied in the
thermal control area. It has been used for large scale
smart thermal control (Dong, 2005) and HVAC
(Heating Ventilation and Air-Conditioning) systems
control (Li, 2009). (Li, 2009) has proven that the
SVM based smart thermal control is more efficient
than the ANN based one. Yet, the main advantage of
SVM based smart thermal control is that only little
information are required for the model training
compared to the ANN based one. Training-data are
usually collected through onsite measurements,
surveys, and available documentations. Data pre-
treatment and post-treatment are, hence, requested in
order to improve the model efficiency (Li, 2009).
Therefore, significant computation loads and
efficient training-data are required to learn a black
type quantitative thermal model. However, under
real application conditions, thermal data are subject
to uncertainty (e.g., whether windows were opened
or not), imprecision (e.g., depends on sensors’
precision) and incompleteness. Therefore, a black
model based smart thermal control does not totally
meet the RIDER’s deployment expectations. In fact,
the availability of sufficient and efficient training-
data is an important factor to determine the smart
thermal control solution deployment potential.
Considering real application conditions, qualitative
modeling has been introduced in the thermal control.
It is based on the relevance of physical behavior
representation which makes it useful to understand
complicated physical phenomena. In fact, variables’
variation ranges are usually reduced to symbolic sets
(i.e., {negative, null, positive}) and qualitative
simulations are operated to compute the
recommended control option (Kupiers, 1986). In
literature, fuzzy thermal rules have been applied for
heating systems’ control and building’s temperature
regulation (Dounis, 1995). A review on thermal
fuzzy controller can be found in (Singh, 2006).
Qualitative model based smart thermal control has
particularly focused on thermal comfort regulation
(Calvio, 2004). Fuzzy predictive control has been
also introduced in the smart thermal control
(Terziyska, 2006). By focusing on the relevance
rather than precision, the complexity of the smart
thermal control is reduced through the qualitative
thermal modeling. Indeed, simple thermal control
rules expressed by the Energy Manager may appear
sufficient to ensure a smart thermal control which
entails no constraint on thermal data availability.
Thanks to its data weak dependency property, the
qualitative modeling meets all RIDER deployment
expectations in order to develop a scalable, reusable,
and data weak dependent smart thermal control
solution. However, ambiguities and lack of accuracy
may negatively affect the qualitative modeling
efficiency and longevity for a continuous thermal
control enhancement purpose.
3 RIDER STC APPROACH
In order to ensure an efficient, scalable, reusable,
and data weak dependent smart thermal control, we
first propose to focus our thermal enhancement
approach on thermal setpoints optimization rather
than efficiently reaching them. For this, we propose
an aggregated performance based reasoning which,
unlike the behavioral based reasoning, fulfills
RIDER deployment expectations. An aggregated
performance allows having an overall assessment on
the process. It is built through an aggregation
function defined over elementary performances.
These last come from the process’ output evaluation.
An aggregated performance corresponds to the
analytic formalization of user’s preferences.
Occupants’ social and preferential lines are then
considered once an aggregated performance is used
in the thermal enhancement reasoning. Moreover,
unlike behavioral models, the deployment of the
aggregated performance based enhancement solution
does not require any beforehand knowledge on the
thermal process which guarantees an immediate
improvement of the thermal control. In order to
evaluate the expected gain of thermal setpoints’
optimization, it becomes unavoidable to deal with
thermal behavioral models. For this, we propose an
extended qualitative model based smart thermal
control approach to efficiently reach the optimized
setpoints. Well-known qualitative enhancement
techniques have been used in our extended thermal
qualitative model. These techniques were proposed a
long time ago by (Williams, 1989), (Kuipers, 1986)
and others, such as (Dubois, 1989), in order to
improve qualitative models efficiency and reduce
their ambiguities. A survey is proposed in (MQ&D,
1995). For a better understanding, the RIDER STC
is explained on one building thermal scale but still
easily adaptable for larger thermal scales. For this,
AggregatedPerformanceandQualitativeModelingBasedSmartThermalControl
65
the thermal comfort is considered as the aggregated
performance used for setpoints optimization. To
simplify the optimization problem solving, we
introduced a new thermal comfort model denoted by
CIPPD
(Choquet Integral Predicted Percentage
Dissatisfied) which is a MAUT (Multi Attribute
Utility Theory) version of the
PPD
thermal comfort
standard (NF EN ISO 7730, 2006). The reason
behind using such formalism is explained in the next
section. Then, in order to efficiently reach the
optimized thermal setpoints, we introduced a
building scale’ Extended Qualitative Model (EQM).
Time-related information and available quantitative
observations have been used in order to improve the
EQM reliability and accuracy. Moreover, simplified
and generalized thermal behaviors have been
considered for the thermal control qualitative
modeling which is, also, recognized as a substantial
qualitative enhancement technique. Hence, the EQM
allows the abstraction of thermal specificities while
maintaining a sufficiently relevant representation for
thermal enhancement purposes. An EQM based
approximate reasoning can thus be generalized for
larger and various thermal scales and specificities.
Furthermore, the RIDER STC approach does not
either requires any particular setting data or
important computation loads to be deployed.
In order to ensure a continuous thermal control
enhancement, RIDER STC is operated for every
new thermal control situation. This last is triggered
for every new thermal context and objective. For
instance, whenever a thermal context variable (i.e.,
sunshine, humidity, etc.) significantly changes, a
new thermal control situation is created in order to
adapt the current thermal control. The same goes
true when occupants’ thermal comfort objectives
change (i.e., vacancy periods, personnel change,
preference change, etc.). The RIDER STC is then an
iterative approach which tries to improve
continuously the thermal performances. Figure 1
displays an overview of one enhancement iteration
of RIDER STC approach. According to thermal
context and thermal comfort objectives, the
CIPPD
based control compute new optimized setpoints that
are considered by the EQM based control as the new
thermal objectives. Depending on the available
quantitative data (i.e., historical data), the EQM
based control suggests quantitative
recommendations to the existing thermal control
system (e.g., an HVAC system in Figure 1) which
computes thermal equipment’s command laws. The
operated thermal control is then evaluated by the
RIDER STC (i.e., check how much thermal
expectations have been satisfied by the thermal
control) and saved in RIDER’s Database (DB).
Figure 1: Overview of RIDER STC iterative approach.
Figure 1 highlights, as well, the middleware
function of the RIDER STC. In fact, the RIDER
STC does not substitute any of the existing thermal
regulations but tries to continuously point the correct
energy amount (the minimum energy ensuring
thermal constraints) from the energy providers to
thermal regulators. For this, relevant
recommendations on thermal setpoints, heating/
cooling starting time, heating/cooling loads, and so,
ensure a personalized and efficient energy usage
depending on building/room’s thermal specificities.
3.1 CIPPD based Thermal Control
As discussed in section 2, today’s smart thermal
control is only conceived through behavioral thermal
process modeling. Considering the thermal comfort
performance rather than building’s thermal behavior
was inspired by bioclimatic architectures. In fact, in
such buildings’ architecture the economic (energy
consumption) and social (comfort) lines are
intimately related. The building’s location and
orientation are considered in the architecture design
in order to take advantage of naturally existing
climate. For instance, solar radiation and natural air
flow are used to, respectively, provide a natural
space heating and cooling. Thus, these natural
climate elements contribute to maintain occupants’
thermal comfort and also reduce thermal energy
consumption. Since the thermal comfort is a
complex multidimensional concept defined mainly
by the indoor temperature but also humidity, radiant
temperature, and air flow, we assume that thermal
comfort’ achievement could be delegated to
attributes other than the indoor temperature.
Therefore, achieving the expected thermal comfort
may be less costly once most of the thermal comfort
attributes are considered in the smart thermal
control. For instance, in winter time, adapting the
thermal control w.r.t. significant solar radiation
fluctuations contributes not only to maintain the
requested thermal comfort but also to make the most
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of solar radiation in order to ensure some free
heating needs. Hence, during the day, the indoor
temperature setpoint could be adjusted depending on
solar radiation prediction which may potentially
contribute to reduce buildings’ energy consumption.
Basing our smart thermal control on the thermal
comfort performance consists then in identifying,
from that last, thermal setpoints satisfying the
expected occupants’ comfort and leading to as less
costly as possible thermal energy consumption. For
this, we introduce the
CIPPD
thermal model which
matches RIDER’s deployment requirements and
simplifies its optimization purpose.
3.1.1 CIPPD Model Motivations
Despite thermal comfort inherent subjectivity,
standards have attempted to evaluate thermal
sensations. The most popular standards are
ASHRAE standard 55 and ISO 7730 that,
respectively, implement Gagge’s and Fanger’s
thermal comfort models. Gagge’s model defines
thermal conditions for which at least 80% of
individuals would feel comfortable from a thermal
point of view (Gagge, 1986). Fanger’s model
introduces the
PMV
(Predicted Mean Vote) and
PPD
(Predicted Percentage Dissatisfied) indexes
(Fanger, 1967). The
PMV
index corresponds to the
mean thermal sensation vote expressed on Fanger’s
scale (i.e., the scale range is defined in [-3,3] which
corresponds to human thermal sensation from cold
to hot and where the null value refers to the neutral
thermal sensation). It is defined through 4 thermal
condition variables (i.e., indoor air temperature Ta,
air humidity Hy, air velocity Va, and mean radiant
air temperature Tr) and 2 human parameters (i.e.,
metabolic rate Me and cloth insolation index Ci).
The
PPD
index is based on the
PMV
one and
indicates the percentage of thermal dissatisfied
persons (1). From a thermal point of view, a person
is considered not satisfied when his/her
PMV
index
belongs to [-3,-2]
[2,3]. Both of the thermal
comfort standards are statistical models. They are
evaluated in different world parts by asking
thousands of people about their thermal sensation in
different thermal conditions.

42
0.03353* 0.2179*
100 95
PMV PMV
PPD e


(1)
Using statistical thermal comfort models for the
smart thermal control meets RIDER’s deployment
expectations. In fact, since these models are the
result of surveys, they do not require any adaptation
to ensure the smart thermal control of any building
that belongs to the survey’s scope. However, the
statistical based thermal comfort is usually complex
and does not help the optimization purpose that is
meant for in our RIDER STC. The complexity of a
statistical thermal comfort based control may then
significantly increase which entails efficiency
problems. Moreover, Gagge’s and Fanger’s models
deal with the thermal comfort concept as a physical
phenomenon. Although the body’s temperature is
related to thermodynamic interactions (i.e.,
convection, radiation, evaporation, conduction),
thermal sensation depends on people preferences
and their sociocultural backgrounds. Therefore
interaction between thermal comfort’ attributes are
preferential ones rather than physical which justifies
a preference based comfort model. Preference
modeling
is a central topic in the Multi Criteria
Decision Analysis (MCDA) and measurement
theory. Usually, it comes down to find a real-valued
overall utility function
:uX
that verifies (2)
where
X
corresponds to the alternative set. For
multidimensional alternatives, the Krantz’s
decomposable model (Krantz, 1971) is widely
studied. It implements the MAUT theory which
consists on assessing any measurement as a
satisfaction degree in the [0,1] scale where 0 refers
to the worst alternative and 1 to the best one.
Measurements are thus made commensurate and
interpretable (Fishburn, 1970). Accordingly, the
Krantz’s preference model is built through utility
functions
:
ii
uX [0,1] defined over each attribute
i
, where
i
X corresponds to the attribute
i
measurement scale, and an aggregation function
F
,
where
refers to this latter’s parameters (3).
,()()
x
yXxy ux uy

(2)
Krantz’s preference model seems quite
interesting for the RIDER STC optimization
purpose. In fact, it is commonly known that for
verifying both the independence and weak
separability properties,
F
is strictly increasing.
Thus, comonotony between
u
and
i
u s holds on
i
X .
This property is useful to identify simple and
interpretable thermal comfort adjustment rules and
simplifies the RIDER STC’s thermal comfort
adjustment. For instance, thermal comfort may be
improved when humidity rate increases for one
given ambient temperature, whereas it can be
disturbed for another one. The coexistence of such
rules makes difficult for the Energy Manager to
AggregatedPerformanceandQualitativeModelingBasedSmartThermalControl
67
decide about attribute variations in order to adjust
occupants’ thermal control. Hence, Krantz’s
preference model would greatly simplify the thermal
comfort rules design.
111
( ,..., ) ( ( ),..., ( ))
nnn
ux x F u x u x
(3)
To identify
i
u and
through the one-
dimensional measurement scales
i
X
, the weak
difference separability property has to be fulfilled;
otherwise the multi-dimensional scale
X
has to be
considered. Hence, the MCDA has introduced
interview based approaches in order to identify
i
u
and
such as MACBETH which allows identifying
them over the decision maker’ preferences w.r.t.
alternatives defined on
X
. However, proceeding by
the interview based approaches to identify the
thermal comfort model adds an extra deployment
constraint to our RIDER STC solution. In fact,
occupants need to be interviewed about their thermal
preferences in every building which breaks RIDER’s
reusability requirement. Therefore, we introduce the
CIPPD
thermal comfort model where
i
u
and
are
identified from the
P
PD index. Basing the
i
u and
identification on a statistical thermal comfort
model enables the RIDER STC deployment in any
building that belongs to the statistical study scope.
The
PD choice is motivated by RIDER’s market
location which is the EU market. The ISO standard
has released an EU
PD version which fits well
with RIDER’s potential customers. For the
PD
identification into Krantz’s decomposable model,
the Choquet fuzzy integral
C
aggregation function
seems to be the most appropriate model. Namely,
fuzzy integrals provide adequate models to capture
relative importance of attributes but also preferential
interactions among them (Grabisch, 1997). It then
allows emphasizing preference relationships among
PD attributes and their relative contribution to the
thermal comfort achievement. Since the
P
PD index
is built over a cardinal scale and has a symmetry
property regarding the neutral thermal sensation (
0
PMV
), the
PPD
representation on a cardinal
positive scale seems to be sufficient which again
justifies the Choquet Integral. Moreover, the
C
has
linearity property by simplex which goes
accordingly with RIDER STC thermal comfort
based control.
3.1.2 CIPPD Identification
In order to identify the
CIPPD
model, (Labreuche,
2011) approach has been adapted to the
P
PD
context. In fact, when
F
is a Choquet Integral,
Labreuche has proposed an original approach to
compute both
i
u and
without any
commensurateness assumption. Thus, before
proceeding by the identification process, MAUT and
Labreuche assumptions have to be checked. Let
consider
N
the
CIPPD
thermal attributes’ set built
from
PD ’s thermal condition variables (
Ta
,
Va
,
H
y
, and
T
r
) and human parameters (
M
e
and
C
i
).
Independency, weak separability and monotony
assumption have then to be verified among
N
‘s
attributes. In next points, we develop and explain
these latter assumptions verification in order to
approximate the
PD into a Choquet Integral C
.
Independency Verification
Structural interactions, such as physical ones,
that may jointly influence the comfort overall utility
are not tolerated in our
CIPPD
model. Yet, physical
interactions entailed by
M
e
and
Ci
parameters
exist. In fact,
M
e
and
Ci
do not convey a
preferential point w.r.t. thermal conditions. They
rather illustrate the body energy contribution and
clothing insolation in the convective and radiative
physical phenomena which make physical
interactions with
Ta
,
Va
, and Tr attributes
obvious. Moreover, for simplification reasons, the
radiative phenomena, entailed by
Tr , has been
considered as convective ones in the
PD model.
This simplification leads to physical interaction
between
Tr and
Ta
. Therefore, only
Ta
,
Va
, and
H
y attributes can be considered in the
CIPPD
preference model. Hence,
{, , }NTaVaHy
corresponds to the
CIPPD
attributes’ set. The
CIPPD
can thus be identified for given values of
M
e
,
Ci
and Tr .
Since it is not conceivable to identify a
CIPPD
model for every possible
M
e
,
Ci
and Tr values,
we restricted our study to administrative buildings
where occupants have a sedentary activity rate (
1, 2
M
emet
) and similar clothing habits: pant and
shirt (
0,7Ci clo
). However, radiant temperature
Tr is necessary to evaluate thermal comfort and
adjust it accordingly to solar radiation variations.
The
CIPPD
model is then defined as (4) where
1, 2
M
emet
and
0,7Ci clo
.
To deal with
Tr variations, a fuzzy interpolation
has been considered. It is defined on five
CIPPD
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68
models over
T
r
T
where
:
{1 5
,
20
,
23
,
T
25,30}
and
*
()
Tr Tr
Tr
refer to the
*Tr Tr
CIPPD
membership
degrees for
[10, 40Tr
]. This decomposition gives
the best compromise between the
PD
approximation efficiency and the
CIPPD
complexity.
(,, ) ( (), (), ( ))
Tr Ta Va Hy
CIPPD Ta Va Hy C u Ta u Va u Hy
(4)
Weak Separability Verification
For every
Tr
CIPPD
,
T
r
T
model, The weak
separability property (5) has also to be verified for
each attribute
i
N
where
\{ }
(, )
iNi
x
y
refers to a
thermal alternative such as
i
x
corresponds to the
attribute
i
value and
\{ }Ni
y
to attribute’ values other
than
i
. To check the weak separability property, for
\{}
jN
i
, we have studied the
PPD
order
relationship w.r.t. the attribute
i
values. For
instance, Figure 2 shows same iso-temperature
shapes which may be interpreted that the
T
a
order
relationship w.r.t.
V
a
is invariant. However, the
minimum value of
PD is reached for slightly
different thermal conditions and, consequently,
entails order relationship variation (bordered by the
2 planes). Thus, the
PPD
does not fulfill the weak
separability property on the
Ta Va Hy
XXX
scale.
Yet, the weak separability property can be showed
on partitions of the
PD scale.
Figure 2:
23
( , , 50)
Tr
PPD Ta Va Hy
.
''
\{ } \{ }
\{ }
''''
\{ } \{ } \{ } \{ }
,,, ,
(, )(, ) (, )(, )
ii i Ni Ni j
jN i
iNiiNi iNiiNi
xx X y y X
xy xy xy xy


(5)
Labreuche’s Assumption Verification
In order to avoid saturation problems, Labreuche
has supposed strictly increasing
i
u
functions. In fact,
saturation problems are commonly known in
interview based
i
u identification and consists on
similar thermal sensation assessments for slightly
different thermal alternatives:
\{ }
(, )
iNi
x
y
and
\{ }
(', )
iNi
x
y
, where ,'
ii i
x
xX and
\{ }
\{ }
Ni j
jN i
y
X
.
Figure 2 shows saturation phenomenon w.r.t.
V
a
variations. Moreover, iso-temperature functions
(Figure 2) show a
PPD
gradient sign variation w.r.t.
T
a
. This observation can also be intuitively noticed.
In fact, in winter time, it is obvious that an
increasing
Ta
is appreciated until an upper
threshold, above it people get hot and their thermal
sensation progressively decreases which implies at
least one monotony variation of the
Ta
u
function. In
the next section, we explain how the weak
separability and monotony property have been
verified to identify
Tr
CIPPD
.
3.1.3 CIPPD Thermal Comfort Model
Since the
P
PD does not fulfill the weak separability
and monotony properties on the
Ta Va Hy
XXX
scale, one Choquet Integral cannot be identified for
each
Tr
CIPPD
model,
T
r
T
. Yet, the continuous
and regular
PD variation w.r.t. its attributes let
think that
Tr
CIPPD
can be identified on
PPD
’s
scale partition
'''
Ta Va Hy
X
XX
that satisfies MAUT
and Labreuche assumptions. According to Figure 2,
2 partitions seems sufficient to cover most of the
PPD
scale for each
Tr
CIPPD
,
T
r
T
. Therefore,
the Labreuche approach has been applied in order to
compute
i
u and
for each
Tr
CIPPD
partition
without any commensurateness assumption.
The
Tr
CIPPD
models’ partitions have been
defined using Labreuche commensurateness
verification approach. In fact, to check
N
’s
attributes commensurateness and automatically
compute attributes’ commensurate values:
i
1 and
i
0
(i.e.,
() ( )
ii j j
uu
11
and
() ( )
ii j j
uu00
,
,ij
N
and
ij
) which refer, respectively, to good and
unacceptable satisfaction degrees w.r.t. the attribute
i
, Labreuche has proposed to study the gradient
function related to
i
x
w.r.t.
\{ }
j
Ni
x
variations. It
comes on studying function (6)’s shape: a constant
function means that no interaction exists between
attributes
i
and
j
; otherwise, preferential
interactions exist between attributes
i
and
j
, and
the commensurate value
*
j
x
, where
()
ii
ux
*
()
jj
ux
,
can, thus be computed. For this, at least one attribute
reference values
i
1
and
i
0
need to be given in order
to compute other attributes commensurate values.
For more information please refer to (Labreuche,
2011) (Denguir, 2012).
\{ } \{ }
,,,0
:(,)(,)
ij i Ni iNi
ij Ni j
fx PPDx x PPDxx


(6)
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69
For the
Tr
CIPPD
construction,
Ta
1 and
Ta
0
references have been considered. They come from
the
PD iso-temperature functions study where
Ta
1
have been chosen according to
P
PD ’s minimum
value which, consequently, entails the best
occupants’ thermal satisfaction. Therefore, basing on
(6),
Va
1 ,
Va
0 ,
H
y
1
and
H
y
0
commensurate values
have been atomically computed and the
Tr
CIPPD
partition scales identified. Utility functions
Tr
i
u
and
Choquet Integral parameters
Tr
i
can, then, be
identified for every partition
'
ii
XX
, where
T
r
T
,
i
N
. For numerical details please refer to
(Labreuche, 2011).
3.1.4 Thermal Comfort Adjustment Rules
Our thermal comfort model relevance can
immediately be proven through its ability to auto-
generate thermal comfort adjustment rules. In fact,
thanks to the co-monotony between
Tr
CIPPD
and
Tr
i
u functions,
i
N
, interpretable thermal
adjustment rules can easily be identified as (7)
where
Tr
i
u
and
Tr
CIPPD
refer to the approximate
gradient of
Tr
i
u and
Tr
CIPPD
.
'
,,sng()sng( )
Tr
iTr
iNX X u CIPPD
(7)
Moreover, in each
Tr
CIPPD
partition the
influence of each thermal attribute (
i.e.,
T
a
,
V
a
,
and
H
y
) on the
Tr
CIPPD
can easily be estimated
(8), where
Tr
i
refers to the Choquet Integral
approximate parameter. This result is all the more
useful than the Choquet integral is linear by simplex
(Denguir, 2012). Obviously, the efficiency of the
estimated gain can be discussed since it corresponds
to the fuzzy interpolation result; however, it remains
helpful for recommendation purposes. These thermal
comfort rules can immediately be applied by the
Energy Manager since they are interpretable as
satisfaction degrees which is different from the
PPD
where thermal attributes’ influences on the
PPD
are neither obvious to identify nor
interpretable for the Energy Manager.
1.2, 0.7,
..
Tr Tr
Me Ci Tr i i
CIPPD u i



(8)
3.1.5 CIPPD based Energy Consumption
Optimization
The
CIPPD
based smart thermal control consists on
adjusting thermal setpoints in order to reduce
thermal energy consumption while maintaining the
requested thermal comfort. For this, room
specificities (
i.e., occupant thermal comfort
requirement, solar radiation exposure) can be
considered to ensure a room customized thermal
control. For instance (9) corresponds to thermal
setpoints variation identification in order to ensure
as less as possible energy consuming thermal
comfort
*
k
c , where
k
belongs to the building room’
set
R . (9) assumes that the indoor temperature
control is the most energy consuming. Therefore,
minimizing
T
a
entails energy saving. It has to be
noted that thermal setpoint adjustment depends on
the equipment availability. For instance,
H
y
adjustment is only relevant when humidity control
kits are available in the building.
*
*
'' ' '
min
..
(,, )
'\{} (,,)
k
Tr k k k k k k k
Tr k k k k
Ta
sc
CIPPD Ta Ta Va Va Hy Hy c
k R k CIPPD Ta Va Hy c



(9)
The optimization problem (10), where
'kk
is an
approximate thermal exchange rate between rooms
k
and
'k
, considers the solar radiation exposure and
variation during the day
()
T
rt
in order to adjust
thermal setpoints depending on radiant temperature.
Therefore, for every significant
k
Tr
, thermal set-
points are adjusted. Thus, the requested thermal
comfort is maintained and natural elements such as
the solar radiation is used in order to ensure parts of
heating necessities and then reduce the thermal
energy consumption.
'
'
*
()
min | |,
.. ,
(,, )
k
kkk kk
kR k R
Tr t k k k k k k k
Ta
sc k R
CIPPD Ta Ta Va Va Hy Hy c





(10)
The
CIPPD
based smart thermal control can,
also, be used to adjust thermal setpoints according to
the context variation such as: raining days and
building’ occupancy variation. Note that these
optimization problems are simplified thanks to the
Choquet linearity by simplex property.
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70
3.2 EQM based Thermal Control
The EQM based smart thermal control tries to
reproduce an approximate reasoning in order to
efficiently achieve the optimized thermal setpoints
computed in Section 3.1. In fact, when we are not
familiar with buildings’ thermal behavior, thermal
control of buildings may seem intricate. Uncertainty
about how relevant a thermal control is for a given
thermal situation, is then in its highest level. The
same reasoning remains true for the control of any
complex system. However, objective observations
(
i.e., vaguely identified physical behavior) and
subjective ones (
i.e., human preferences) may
contribute to reduce uncertainty about thermal
control. Therefore, we introduce our EQM which is
used to represent simplified thermal control rules. It,
also, defines how these thermal control rules should
be applied to ensure the control enhancement for
different thermal situations. The EQM design is
based on influence approximations relating thermal
control parameters to thermal performances. In order
to extend thermal qualitative modeling, the EQM’s
parameters and performances display time-related
information about thermal general behavior. The
influences, among parameters and performances, are
vaguely identified from thermal general behavior
and their accuracy is constantly improving through
online thermal quantitative observations. Therefore,
keeping track of predate thermal control, as well as,
their performances allow recalling them in similar
control situations. A Thermal Control Manager
(TCM) has then been conceived in order to maintain
thermal historical data. For each thermal control
attempt, the thermal situation, controls and
performances are, then, stored by the TCM. This last
is described by the following set
TCM
{1
.. ,
k
n
(, , )}
kk k
S CMD PERF
where
n
is the number of
previous thermal experiences and
k
S ,
k
CMD and
k
PERF
are, respectively, the
th
k thermal situation
(
i.e., outdoor and indoor temperatures, etc.), controls
and performances. To support comparison over the
previous attempts and apply approximate reasoning,
AI techniques have been deployed. Figure 3 displays
the EQM based
smart thermal control general
approach;
new
S refers to a new thermal situation for
which an efficient thermal control needs to be
computed. It, mainly, involves indoor and outdoor
thermal current situations, as well as, thermal
setpoints, computed by the
CIPPD
, that need to be
reached before occupants show up.
Since the EQM uses quantitative thermal
experiences to improve its accuracy, TCM’s
quantitative knowledge need to be filtered before
proceeding by the EQM accuracy enhancement.
Therefore, step 1 of Figure 3 allows quantitative
linear reasoning around
new
S . The most favored
thermal experience
** *
(, , )S CMD PERF
(w.r.t. the
current situation) for the linear quantitative
reasoning is computed by step 2. The EQM thermal
enhancement rules are applied in step 3 in order to
compute a more likely
better command law
new
CMD
from
*
CMD . In fact, since the EQM influences have
been approximated using thermal objective and
subjective knowledge, thermal enhancement control
can be operated. Contradictory influences on thermal
performances can, simply, be resolved by
considering user’s priorities. For instance, building’s
occupants may be more demanding about their
thermal comfort. The EQM will, thus, give priority
to optimize thermal comfort related performances.
Hence, thanks to the EQM influences, it becomes
possible to recommend control parameters
increase/decrease.
new
CMD is finally applied and
evaluated in Figure 4’s step 4. In this paper, we
particularly focus on particular features used to
extend the qualitative thermal modeling. For this, we
explain the time-related, simple behavior analysis,
and quantitative observation used in order to extend
our EQM’s qualitative modeling.
EQM STC (
new
S
,
TCM
)
if
TCM
then call the energy manager else
1. Compute
*
TCM TCM
where,
*
(, , )S CMD PERF TCM
,
S
is similar to
new
S
if
*
TCM
then call the energy manager else
2. Find
** *
(, , )|S CMD PERF
*
(, , )S CMD PERF TCM
,
*
CMD
is most favored for
new
S
3. Compute
new
CMD
for
new
S
based on the EQM and the
quantitative information of
*
CMD
4. Apply
new
CMD
and update the
TCM
with the new attempt
,,
new new new
S CMD PERF
end if
end if
end
Figure 3: EQM based smart thermal control approach.
3.2.1 Time-Related Information
In order to ensure RIDER deployment expectations,
our EQM applies an event-based representation
(Montmain, 1991) for thermal control laws. This
latter is more relevant than a classical sampled time
representation in a qualitative approach. It is, also,
considered sufficient for the thermal control laws’
description since steps and ramps signals are usually
AggregatedPerformanceandQualitativeModelingBasedSmartThermalControl
71
used for the thermal regulations. In order to involve
time-related information, the EQM considers
thermal control starting time which is useful to
improve control delays. Therefore, for each thermal
control law
t
L( )
we associate a control parameter
vector
(
,,
)
C
tpy

.
CMD
refers to the set of
control parameters vectors
C
applied on all
building’s actuators. These 3 control events are
described by the thermal example showed in Figure
4 and refer, respectively, to
t
L( )
delay (time-gap
between
t
L( )
starting time
1
t
and thermal control
starting time
0
t
), gradient (characterized by the time-
gap between
t
L( )
highest
1
y
and lowest
0
y
values)
and amplitude (height-gap between
t
L( )
highest and
lowest values). Moreover, time-related information
are considered in the EQM’ performances modeling.
In fact, rather than building’s thermal profiles,
thermal performances are considered to ensure
RIDER deployment expectations. Indeed, the
performance vector
P
(
,,cost com
f
ort
)
fl
exi
b
i
l
ity
describing thermal energy consumption, stationary
thermal comfort and setpoints’ achievement delay,
ensures building’s thermal assessment.
fl
exi
b
i
l
ity
shows time-related information which makes time-
related control enhancement possible.
PERF
corresponds then to the set of all building’s rooms
thermal performance vectors
P
.
Figure 4: EQM’s control events.
3.2.2 Simple Thermal Behavior Analysis
General and simple thermal behaviors have been
studied in order to identify how each control
parameter influences the considered thermal
performance. For instance, (11) describes one room
temperature profile
()
T
t
when applying the
command law
t
L( )
, where
T
e ,
and
refer,
respectively, to the outdoor temperature, room
passive resistance coefficient and thermal loss
coefficient. Hence, identifying the
and
coefficient does not concern the EQM modeling
since it implies buildings’ excitement scenarios
constraints, however, (11) is useful to study thermal
performance monotonies
w.r.t. command parameters
variations. The result of this study can, thus, be
immediately applied on any building without
requiring any extra information on building’s
thermal process.
()
(())(())0
dT t
tTt TeTt
dt

L( )
(11)
Table 1 describes gradient directions computed
over each performance
w.r.t. each control parameter.
Considering gradient directions rather than precise
derivative values ensures the RIDER deployment
expectations. For each performance
j
, where
P
j
S
and
P
S
is the considered thermal
performance set (
e.g.,
{, , }
P
S cost comfort flexibility
), and control parameter
i
, where
C
iS
and
C
S is
the considered control parameter set (
e.g.,
{, , }
C
Stpy

), an influence function
:
ij
F
CP
ij
VV
{
,
0
,
}
is defined, where values of
thermal control parameters
i
c ,
iC
cS , and
performances
j
p
,
jP
pS
, are, respectively,
defined in
C
i
V
and
P
j
V
.
ij
F
indicates whether the
performance
j
increases (+) or decreases (-) w.r.t.
i
variations. A (0) valued
ij
F
function indicates that
i
has no influence on
j
. The
ij
F
qualitative gain can,
thus, be represented by the EQM and results from
studying gradient directions of simplified thermal
behaviors such as (11). For instance, it is commonly
known that, in winter time, thermal energy
consumption (
cos
t
) increases by increasing the
command law height (
y
). This is illustrated, in
Table 1, by a constant influence function describing
a gradual rule type on
CP
y
cost
VV
such as the greater
the heating step amplitude is, the greater the thermal
energy consumption would be. Therefore, regardless
of buildings thermal specificities,
ij
F
can be
deduced from simplified physical behaviors (
e.g.,
ycost
F
).
Table 1: EQM influence modeling (0 means no influence).
C
S
P
S
t
p
y
cost
,
tcost t cost
Fcp

comfort
0
0

,
y comfort y comfort
Fcp

f
lexibility
Buildings’ special features can occasionally be
responsible of
ij
F
’s sign variations (e.g.,
tcost
F
). In
this case, influence functions are subject to
uncertainty problems that are handled by
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72
considering quantitative observations in the EQM
based reasoning.
3.2.3 Quantitative Observations
Uncertainty about some influence function may
negatively affect the EQM efficiency. However
considering thermal quantitative observations,
uncertainty about gradient directions is reduced
according to new thermal observations. Moreover,
the qualitative based reasoning may seems lacking
for continuous enhancement purposes. Nevertheless,
combining the qualitative reasoning to quantitative
observations makes the control enhancement more
accurate and seems to be sufficient for the EQM
based smart thermal control. In this section, we
explain how quantitative knowledge has been
considered to reduce uncertainty about influence
functions and how the EQM reasoning has been
made more accurate using the TCM quantitative
thermal experiences.
Decreasing EQM’s Uncertainty
In order to reduce uncertainty about the EQM
influence functions, objective and subjective
knowledge has been considered. Objective
knowledge corresponds mainly to interpretable
physical phenomena. When uncertainty about
ij
F
functions holds, simple learning techniques are
applied over TCM’s previous thermal experiences in
order to specifically identify each building’s bending
points. For instance,
tcost
F
depends on building
ventilation and insulation properties: starting the
heating process earlier or later impacts differently
the thermal energy consumption. Figure 6 shows
some possible shapes of the continuous function
relating
t
c
to
cost
p
values. The shape of this
function is obtained from the simplified thermal
behavior model (i.e., in some cases, the continuous
function relating
t
c
to
cost
p
displays a maximum.
Otherwise it is decreasing for any
t
c
value). The
maximum remains to be identified. Figure 5’s
displayed maximums can be explained by the fact
that, when outdoor temperature is lower than the
indoor one, building’s ambient temperature
decreases until the control law is started. The
t
c
’s
interval for which
cost
p
increases refers to situations
where it is more costly to start heating for a short
time from a low temperature than heating the
building for a longer time but starting from a higher
temperature. The decreasing
cost
p
w.r.t.
t
c
refers to
the opposite behavior. Furthermore, the HVAC
system is responsible for the rapid decrease of
building’s ambient temperature when the heating
system is off. In fact, the HVAC continuously
injects a weak percentage of the outdoor air for
ventilation purposes. Therefore, we propose to use
TCM’s quantitative knowledge to capture, for each
building, the
C
tt
cV

value that entails sign
variation in the continuous function (Figure 5) and
finally online learn
tcost
F
influence function. We
have introduced a possibility based approach in
order to continually reduce uncertainty about EQM’s
influence functions. More complicated buildings’
thermal dependent influence functions have been
thus considered. For more information, please refer
to (Denguir, 2014).
Subjective knowledge can also be used in order
to reduce uncertainty about buildings thermal
control. For instance, the
CIPPD
thermal comfort
model can contribute to identify the
ycomfort
F
function (Table 1). Therefore, building’s occupants
thermal sensations and thermal context variations
(i.e., humidity and sunshine) are considered while
identifying
ycomfort
F
. In fact, depending on the
thermal context, an increasing
Ta
may either
improve or distract the occupant’s thermal comfort.
Hence,
ycomfort
F
acknowledge sign variations since
thermal command law height influences
Ta
. The
CIPPD
formalism helps
ycomfort
F
identification
since
sng( )
Tr
Ta
u
provides its values.
Figure 5:
cost
p
w.r.t.
t
c
variations from different
ventilation perspectives.
Improving EQM’s Accuracy
Step 3 of Figure 3 shows that the EQM based
smart thermal control is built from the EQM
qualitative reasoning on the quantitative thermal
command
*
CMD which makes it more accurate. For
instant, (12) shows how one actuator
t
parameter (
new
t
C
) can be precisely evaluated considering predate
quantitative experience and particularly the
*
t
C
command parameter and
*
flexibility
P
performance.
Therefore, deciding about the most likely favored
TCM predate thermal experience, to be used in the
EQM reasoning, is an important issue and
corresponds to Figure 3’s step 2.
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73
**new
t t flexibility
CCP


(12)
Our EQM quantitative enrichment is decided
among the TCM prior experiences considering 3
decision criteria:
i. Similarity between previous situations
S
and
the new one
new
S : it allows overcoming non-
linearity problems related to thermal controls (step 1
of Figure 3) since maximizing the similarity allows
linear quantitative reasoning around a setting point.
Similarity between thermal situations is based on a
distance
'"
(, )dist S S
, where
'
S and
"
S are two
thermal situations. The smaller
'"
(, )dist S S
is, the
more similar
'
S and
"
S would be. Since thermal
situations are only defined by temperature
measurements, there are no commensurateness
problems in
'"
(, )dist S S
definition.
ii. Thermal performances: Obviously, the better
the resulting thermal performances
PERF
are, the
more favored the control experience would be. For
this, MCDA techniques have been deployed. A
preference model over the considered performances
P
S
is identified. Firstly, utility functions (
cost
u ,
comfort
u
and
f
lexibility
u
) are defined for each
performance to ensure commensurability. They
allow the assessment of each performance over the
same scale which is the satisfaction degree or utility
scale [0,1]. Secondly, an aggregation function is
required in order to ensure the overall thermal
evaluation
k
r
P
for each room
rR
(
R
corresponds
to the building rooms’ set) and prior thermal control
experience
k
. These steps are related to the Energy
Manager
preferences which depend on his Energy
Policy
. Interview based approach such as
MACBETH can be applied in this case. We assume
that a weighted sum is sufficient to capture this
preference model. When thermal control is related to
a subset of rooms
'RR
, overall thermal
assessment has to consider all thermal performances
over
'
R
. Thus, our EQM proposes to proceed firstly
by aggregating all performances over
'
R
from the
energy consumption (
s
um
), thermal comfort (
min
)
and flexibility (
max
) points of view; secondly, the
preference model defined for one room is applied for
'
R
. We denote by
k
P
the overall building thermal
assessment associated to the
th
k (
k
PERF
) prior
thermal experience stored by the TCM.
iii. Previous enhancement results: predate
controls that have led to thermal enhancement
failures are penalized in future TCM evaluations.
Therefore, we associate a set
k
Bad to each
(, , )
kk k
S CMD PERF TCM
.
k
B
ad gathers prior
thermal experiences that were computed from
(, , )
kk k
S CMD PERF
and led to thermal performance
decreases.
Considering these 3 criteria, an overall score
k
s
core (13) can be computed for each TCM
experience in a limited neighborhood of
new
S (to
satisfy the thermal process linear quantitative
behavior expected property). The quantitative
information
**
(, ,SCMD
*
)
P
ERF
TCM
favored for
our EQM enrichment verifies:
*
k
s
core score
(, ,
kk
SCMD
)
k
PERF
TCM
. Quantitative
knowledge can then be used to make more accurate
the EQM reasoning.
''
'
{1, . . , } , {1 ( , ) } . *
{1 ( , ) }
k
kknewk
knew k
kBad
knscore distSS
dist S S

P
P
(13)
4 CONCLUSIONS
In order to fulfil RIDER deployment expectations,
we have proposed the RIDER STC solution which
considers the CIPPD and EQM based reasoning in
one building scale. The CIPPD based reasoning
allows the identification of the most relevant thermal
setpoints in order to improve the thermal comfort
and reduce thermal energy consumption. Once the
optimized setpoints are provided, the EQM based
reasoning says how they can be efficiently achieved.
It implements an iterative approach that provides
thermal control recommendations as soon as it is
deployed without needing any
a priori learning or
identification. These control recommendations are
then refined thanks to quantitative observations and
qualitative physical aspects related to thermal
processes. When using the CIPPD based control, our
experimentations let expect about 10% of thermal
energy consumption decease. Combined to the EQM
based
smart thermal control, RIDER STC solution
reveals, for one room, about 7 to 31% of thermal
energy consumption decrease and 12 to 24% for
multi-room thermal enhancement. Average thermal
energy consumption decrease ensured by the RIDER
STC is evaluated to 16% which is significant
considering energy prices. How the RIDER STC can
bypass frequent thermal control deployment issues
such as quantitative data availability, can be
considered as an outstanding point compared to the
existent thermal control solutions. Just the CIPPD
based
smart thermal control can be considered as a
ICINCO2014-11thInternationalConferenceonInformaticsinControl,AutomationandRobotics
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remarkable shift in how smart thermal control has
been considered till these days. Comparing the EQM
based
smart thermal control efficiency with
commonly used approaches (based on white, grey or
black thermal models), is unbalanced considering
their different application conditions. In fact, trying
to operate an MPC (Model Predictive Control) in
few days on a completely unknown building is not
conceivable. It goes the same when asking the EQM
based control for the same efficiency as a MPC
based control in a fully identified building’s thermal
process. Yet, perspectives remain possible to
improve RIDER STC efficiency. For the CIPPD
based
smart thermal control, adaptive and dynamic
thermal comfort model could be considered in order
to ensure more personalized and individualized
thermal comfort adjustment. Yet, the PPD’s choice
satisfies the data unavailability issues. The transition
toward an adaptive and dynamic thermal comfort
model shall, thus, be supported by
online learning
techniques. The CIPPD identification could also be
improved by using bipolar utility scale wish gives
more expressivity to the thermal comfort models and
could lead to a better approximation of the PPD
function. The EQM based
smart thermal control
provides a methodology in order to improve the
qualitative based thermal control efficiency.
Therefore, each step implementation technique
could be discussed. For instance, uncertainty
management in influence functions can be improved.
Ambiguous measurements coming from thermal
disturbances (
i.e., windows and door opening)
should complete this point. Sensors data precision
can be studied as well. Qualitative interactions
between the control enhancement parameters could
also be studied in order to compute enhancement
recommendations based on subsets of control
parameters variations instead of singletons. This will
warrantee the EQM control convergence to a global
improved control experience
rather than a local one.
The scalability of the RIDET STC solution could
also be discussed. In fact, we have shown in section
3.2.3 that multi-room transition needs some settings
and it goes the same for any scale transition. The
scalability could have been made automatic by
providing different scales templates in the RIDER
STC final solution. This task is simplified thanks to
the EQM modularity.
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