Performance of Balanced Ventilation with Heat Recovery
in Residential Buildings in a Cold Climate
Juha
Jokisaloa,
Jarek Kurnitskia,
Mika Vuolleb,
Antti Torkkic
aHelsinki
University of Technology, HVAC-Laboratory, Finland
bFinnish Society of Indoor Air Quality FiSIAQ, Finland
cYIT Installation Ltd, Finland
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Abstract
This study simulated the performance of various
mechanical supply and exhaust ventilation systems, incorporating heat
recovery, in a typical Finnish residential apartment building. Dynamic
thermal simulations were undertaken, representing a period of a year.
These simulations incorporated the building details combined with
information about the HVAC-systems, internal thermal loads and outdoor
climate. The ventilation systems investigated included a simple
centralised constant air volume (CAV) mechanical supply and exhaust
ventilation system and a decentralised air handling unit that included an
option for variable air volume (VAV) for demand-controlled ventilation.
Energy consumption, thermal comfort, indoor air quality, pressure
conditions, and air infiltration flows were simulated.
It is shown that, in the cold climate studied, energy
efficiency in a residential apartment building can be improved remarkably
by using a ventilation heat recovery system. Results show that a
traditional exhaust ventilation system can use up to 67% more energy than
a heat recovery system having 80% efficiency and 41% more energy than a
heat recovery system having 60% energy recovery efficiency.
Increasing the heat recovery efficiency from 60 to 80% was
approximately as effective an energy saving measure as using
demand-controlled VAV. A simple centralised CAV ventilation system with
60% heat recovery efficiency proved to be particularly energy efficient
because of low electricity consumption. The decentralised ventilation
system did not show a clearly improved energy performance, because of the
relatively high electricity consumption of the fans and electrical
reheating coils used. However, it allowed a reduction in the district heat
consumption by means of higher heat recovery efficiency and VAV control.
Key words:
balanced ventilation, dynamic simulation, centralised ventilation
system, decentralised ventilation system, heat recovery.
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