Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 194

the major subsystems of a net-zero energy house. It indicates that the PV
andthehousehavenomajorthermalcoupling;andtherefore,thehousecan
be modeled as a separate entity from the PV. For this case, the performance
of the house does not significantly affect the performance of the PV system
and vice versa. It should be noted that this is only valid for grid-tied PV
and BIPV systems that are essentially thermally isolated from the house's
interior with insulation. For off-grid applications, the issue of electrical
storage becomes important, at which point there is value in modeling an
integrated system (e.g., to attempt to shift and reduce the peak electrical
load to ensure that the PV system can meet it and that the battery charge is
maintained within limits).
Fig. 4.11 Example Venn diagram showing the level of interactions between
systems in a net-zero energy house
For solar thermal systems that solely provide energy for domestic hot water,
decoupling is normally reasonable because the thermal interactions
between the system and the building are minimal. For instance, the storage
tanks and the building envelope upon which the collectors are mounted are
both well-insulated. Critical inputs to the solar domestic hot water systems
(draw profile, component efficiency, and controls) are not dependent on