Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 173

climate, building type, and HVAC system, but is generally positive (Parekh
et al. , 2005).
4.2.5.4 RET and HVAC
Once all the measures discussed in the previous paragraphs are considered
in the architectural concept to limit the energy consumption, heating,
cooling,andelectricalload,energyconsumptionprofilescanbedetermined,
the HVAC system can be proposed, and the RETs can be refined. Analyzing
the heating and cooling load profiles helps determine the most suitable
HVAC systems and the required RETs to suit the demand. These systems
should account for the type of terminals and distribution network used to
heatand/orcoolthebuilding(e.g.,radiators,floorheating,andcoldceiling).
Generally, Net ZEBs have high-efficiency heating and cooling systems, such
as hydronic radiant floors, evaporative coolers, energy-efficient
air-conditioning units, and heat pumps. Low-temperature (32 to 35 °C)
heating systems generally provide more effective coupling with renewable
energy systems, such as solar thermal collectors or geothermal heat pumps.
Similarly, high-temperature cooling systems (15 to 20 °C) can typically be
directly coupled with renewable energy cooling systems like geothermal
heat pumps and can ensure better performance of the active cooling system.
Often, these technologies will be coupled with heat and energy recovery
ventilation systems (HRV and ERVS) with variable-speed fans.
RETs typically integrated in Net ZEBs include earth tubes, air and liquid
solar thermal collectors, building-integrated photovoltaics (BIPV), and
BIPV/thermal systems (BIPV/T) that produce both electricity and useful
heat from the same surface (see Chapter 2 ).
Net ZEBs' HVAC systems generally combine multiple pieces of equipment,
passive or active heat recovery and storage systems, as well as RETs that are
more than often unique and innovative solutions. Sometimes, certain pieces
of equipment can also be utilized in more than one system. For example,
a solar thermal collector and a geothermal heat pump will both be used
for water and space heating. Implementing such advanced systems requires
that complex simulation tools be used not only to model the systems, but
also to couple these systems with the building. EnergyPlus, ESP-r, and
TRNSYS are well suited for these requirements even though, sometimes,
they cannot support the full model implementation and some assumptions