Civil Engineering Reference
In-Depth Information
per square foot per year. If we look and see how this KPI has been developed we can
see the typical pattern that has to be followed to generate any (key) performance
indicator in general, and also realize that it is not a simple task to create such valu-
able tools. As it was said earlier, the fi rst step is to defi ne the main systems that
contribute to generating this indicator. Therefore this KPI can originally be defi ned
as follows:
KPI (Energy Consumption per square foot per year) =
(Envelope system, HVAC
system, Hot water system, Electrical system, Miscellaneous system)
ˉ
Likewise each of the developing systems should be defi ned by its own sub-
systems such as:
Envelope system =
(fl oor system, exterior wall system, roof system, partition sys-
tem, location, and orientation system, glazing system, etc.)
˄
Furthermore each subsystem has its own subsystems, such as:
Exterior wall system =
1 (wall orientation system, wall net area system, wall con-
struction type system, etc.)
˄
And even more:
Wall construction type system =
˄
2 (wall heating characteristics system, wall color-
ing system, etc.)
Therefore it can be seen that a thorough and detail formulization should be uti-
lized to enable us to use all these systems and subsystems to calculate the amount of
heat loss or heat gain of the building throughout the year just for the envelope sys-
tem. The total heat loss or gain of this system then should be used as one of the
subsystems of HVAC system along with HVAC system's other subsystems. All
these information shall be combined in an energy modeling type approach to sum
up the fi nal function representing the building energy consumption per square foot
per year or the targeted KPI. When that overall formulas developed, adjusted and its
accuracy verifi ed then it can be used to calculate any other building KPI for com-
parison among the different buildings energy consumption.
As the third example, in the following illustrations typical procedure that can be
followed for developing different performance indicators for day-lighting system
for a building are shown. Figure 5.1 shows the logic to be followed for developing
demand and supply language for the targeted outcomes. In the demand (functional)
side of this simplifi ed chart the targeted performance desired by the owner or user
has specifi ed as “Provide a better indoor environment” and is shown on the top of
the chart and sublevels in order to provide this functionality have been developed
level by level below that. In the fi nal sublevel and just above the possible performance
indicator the “Day-lighting System” function is positioned, which is the main target
of this exercise.
Meanwhile on the technical system side, infl uential systems that could have
signifi cant effect on realization of the targeted performance have been written and
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