Modeling and Design of Net ZEBs as Integrated Energy Systems - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 22

and natural ventilation have a reduced need for auxiliary cooling. Similarly,
appropriate sizing of the near-equatorial facing fenestration systems will
satisfy most heating requirements on sunny days.
Frequency domain analysis techniques with complex variables may be
employed for steady periodic analysis of multilayered walls and zones. They
provide a convenient means for periodic analysis, in which parameters,
such as magnitude and phase angle of room temperatures, and heat flows
are obtained. The well-known cooling load temperature differential (CLTD)
method proposed for many years by ASHRAE (McQuiston, Parker, and
Spitler, 2005) for cooling load calculations is essentially an
admittance-based technique, with magnitudes and phase lags of important
frequency domain transfer functions. In the United Kingdom, an
admittance-based technique is used to calculate room temperature swings
andtimelagsbetweencause(e.g.,sol-airtemperaturepeak)andeffect(peak
of room temperature rise). 3)
2.1.2 Detailed Frequency Domain Wall Model and Transfer
Functions
Building heat exchanges may be represented by a thermal network , and
transferfunctionsareobtainedbyperforminganenergybalanceatallnodes
in the Laplace domain. Both lumped and distributed elements can be
considered using this approach. Simple models that do not represent in
detail infrared radiation heat exchanges between room interior surfaces
can usually be solved analytically. Transient heat conduction (assumed to
be one-dimensional) in walls can be accurately represented without
discretization using the approach that follows.
2.1.2.1 Distributed Parameter Model for Multilayered Wall
Consider a slab and assume one-dimensional transient conduction with
uniform properties k , ρ , c . We have
(2.1)
where α = k /( ρc ) is the thermal diffusivity