Performance-Based Standards - Energy-Efficient HVAC Design - page 35

and:

Human system  



 GMFC , , ,

( 5.3 )

with:

“ T ” representing temperature
“ H ” representing humidity
“AD” representing air direction
“AV” representing air velocity
“HV” representing heating, ventilating, and air conditioning System
“ L ” representing lighting system
“ O ” representing space exterior exposure and orientation system
“ M ” representing metabolism
“ G ” representing gender
“ F ” representing function

and fi nally:

“ C ” representing clothing

Obviously the next step will be to designate a weighting value to each of these
parameters, which could again come from literature, expert input, multiple experi-
ments and actual fi eld data, calculations or even owners emphasize on a specifi c
need for his project. By working through the above-explained steps, fi nally the per-
formance indicator could be expressed as follows, as a function (

ʲ ) of these multiple

factors:

          

 

aT bH c d
eG fF gM hC
iHV jL kO

 , , AD , AV ,







            

( 5.4 )

PI Occupant comfort level   ,  , , ,

       

 , ,

 

With multipliers “ a ” to “ k ” each represents the overall weight of each factor for
constructing the targeted performance indicator. After setting up the proper formu-
lation for each of these subsystems, the overall PI shall be verifi ed and adjusted
based on actual tested data. Only then we can have a legitimate PI describing the
human comfort condition.
After establishing such a formula for this specifi c PI, a specifi c value then could
be generated for this PI for any given condition. Now by calculating PIs for each
condition and comparing the generated PIs for each of these conditions, the perfor-
mance of different systems in relation to each other can be determined.
Even though for different specifi c purposes different PIs can be generated, but
usually there is one PI which has the highest importance from a specifi c point of the
view such as the owner's perspective, designer's perspective, etc. This performance
indicator is known as the key performance indicator (KPI) which usually includes
the most important parameters and their relative weights from that specifi c point of
view. This KPI can be used to set the main design achieving goal(s).
Let's look at another example. One of the most popular key performance indica-
tors in building design and construction industry is building energy consumption