Civil Engineering Reference
In-Depth Information
system based on fuzzy logic that allows them to control thermal environment inside
a building in which a certain user can adopt a tradeoff solution (by means of a
weighting factor) between economy and comfort is proposed. Besides, this strategy
takes into account measurable disturbances (mainly related to outdoor climate) and
non-measurable ones (associated to the occupancy of the room). Meanwhile indoor
air temperature is controlled by means of specific devices, relative humidity and CO
2
concentration are attached, and therefore, it is necessary to include the air exchange
rate as an auxiliary control variable.
Another field of application of this kind of techniques, is in the resolution of
optimisation problems, for example, in Yu and Dexter (
2007
) a hierarchical control
scheme of three layers based on fuzzy logic is proposed. Its main objective is to
maximise thermal comfort and, at the same time, to optimise energy efficiency inside
a building. More specifically, the first layer uses a decision tree based on fuzzy logic
to choose an appropriate set of rules that will be used in the second and the third
layers as a function of the information available about climate and occupancy. On the
other hand, rules in the second layer generate an optimal energy profile and the ones
in the third layer are responsible for determining the operation mode of the installed
devices, and selecting the adequate control variables to reach this optimal energy
profile in the most efficient way. However, in most literature where these techniques
are used, fuzzy logic appears combined with adaptive strategies, an example of this
can be observed in Huang and Li (
2006
).
5.1.2 Visual Comfort Control Strategies
As was pointed out previously, one of the key aspects which define visual comfort
inside a certain environment is the indoor luminance level. Besides, the luminance
level inside a room depends on two different factors: artificial lighting and day-
lighting. Therefore, it is necessary to look for a tradeoff between them to achieve
an appropriate luminance level and, at the same time, to increase energy saving. It
is very common to use different kinds of shading elements, such as venetian blinds
or rolling shutters, that allow the user to regulate the amount of day-lighting and
the glare inside the room, and regulative artificial lighting. Hence, several works
can be found in the literature of this research field which presents different control
approaches to maintain visual comfort in an efficient way. These control techniques
range from classical control approaches to intelligent controllers based on fuzzy
logic.
For example, in Zanoli and Barchiesi (
2012
) a control approach to increase users'
visual comfort and energy saving by optimising the use of solar energy is proposed.
This control system estimates the appropriate control signals for the rolling shutters,
a heat pump and the lighting system. More specifically, the lighting system control
is performed by means of two PID in cascade, and the rolling shutter control signal
is provided by an override selector.
