Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 174

are required. Simulations assist in achieving net-zero energy by refining the
whole system and its components through numerous design iterations.
Coupling the HVAC system(s) and the RETs in the building model is ideal,
but often difficult because some models are not available or the coupling is
not easy to achieve (especially for controls). In lieu of an integrated model,
the contribution from the renewable energy system can be estimated by
modeling the HVAC systems without it (assuming adequate supply from the
RET). Then, the RETs can be simulated separately (e.g., solar photovoltaics,
geothermal heat pump, solar thermal, etc.) to obtain the resource
availability and the energy demand, and production can be compared to
demand to further optimize the coupling. This is, of course, a nonideal
procedure, but it allows dimensioning the production unit and estimating
how far the building is from reaching the net-zero goal. As described in
Section 4.3, this approach can lead to significant errors when RET
performance is dependent on demand or has tight thermal coupling with
the HVAC system(s). Thus designers and modelers should have a deep
understanding of the physics and operation of the system(s) before using
such simplified modeling approaches.
4.2.6 Technical Design
During the technical design stage, refinement of the solutions can occur but
it should not significantly modify the design development. In this phase, the
following details of the solution set are evaluated:
- Interior finishing details regarding walls, ceilings, floors, HVAC
terminals, and acoustics
- Technical details and location of lighting fixtures
- CFD simulation for critical zones (atrium ventilation, optimum
opening geometry)
- Control algorithms development and refinement (HVAC, lighting,
etc.)
- HVAC/RET: refinement of the calculations of the energy performance
- Dimensioning of the HVAC distribution network and terminal units.
Interior finishing for the walls, ceilings, and floors should be done in
accordance with the thermal inertia calculated previously. For example, if a
false ceiling is integrated and the thermal inertia of that ceiling was taken