Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 390

Fig. 7.31 Electricity consumption breakdown
Different indices are employed for describing the load matching. The
following equation defines the load match index ( f load ) (Salom et al. , 2011):
(7.4)
where g and l stand for generation and load, i stands for energy carrier,
t is the time interval used (e.g., hourly, daily, weekly, monthly), and N is
the number of events considered. The f load index is very dependent on time
resolution (Sartori, Napolitano, and Voss, 2012). The grid interaction index
( f grid ,i ) represents the variability (standard deviation) of the energy flow
(net export) within a year, normalized by the highest absolute value (Voss et
al. , 2010).
(7.5)
where e and d stand for exported and delivered, respectively, i stands for
energy carrier, and t is the time interval used. The LH does not completely
fulfill the Net ZEB targets previously defined; in the following sections the
magnitude of the deficit from the net zero target will be described through
the use of the above indices.