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Active heat capacity : models and parameters for the thermal performance of buildings

Jóhannesson, Gudni (1981) In Report TVBH 1003.
Abstract
The thesis concerns the characterization and evaluation of nonsteady

heat transfer in building components and building enclosures.

The major aim of the underlaying research has been to

assemble and develop simplified calculation procedures for this

purpose. To establish a simple model for heat balance calculations

three main items are treated: simplification of the heat

transfer operators, the description of the solar gain through

windows and reduction of the number of transfer paths. For nonsteady

heat conduction in opaque construction solutions are

given in the frequency domain and by finite differences.



Based on the frequency response... (More)
The thesis concerns the characterization and evaluation of nonsteady

heat transfer in building components and building enclosures.

The major aim of the underlaying research has been to

assemble and develop simplified calculation procedures for this

purpose. To establish a simple model for heat balance calculations

three main items are treated: simplification of the heat

transfer operators, the description of the solar gain through

windows and reduction of the number of transfer paths. For nonsteady

heat conduction in opaque construction solutions are

given in the frequency domain and by finite differences.



Based on the frequency response different types of RC-models are

derived. The simplest network is a single capacitance giving the

same ratio between the amplitudes of heat flow and temperature

as the real surface. This quantity is called the active heat

capacity of the wall. To estimate this quantity a simplified

calculation procedure is given. For the combination of surfaces

with different active heat capacities addition rules are established

that take into account the limited mutual radiation exchange

between the surfaces. In that way the room is transformed

into a model with two nodes, one representing the surface temperature

and one representing the room air. A solution in the time

domain allows the thermal loads to be represented as time series

and the mode of operation can be freely defined and varied during

the calculated period. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • unknown], [unknown
publishing date
type
Thesis
publication status
published
subject
keywords
Time domain solutions, RC-models, Admittance, Frequency response, Simplified models, Non-steady state, Building heat transfer, värmeflöden, transienta förlopp, byggnader, beräkningsmodeller
in
Report TVBH
volume
1003
pages
165 pages
publisher
Byggnadsfysik LTH, Lunds Tekniska Högskola
defense location
Sektionen för väg- och vattenbyggnad, John Ericssons väg 1, Hörsal V:A, Tekniska fakulteten vid Lunds universitet
defense date
1981-06-02 09:15
external identifiers
  • other:TVBH-1003
ISSN
0349-4950
language
English
LU publication?
no
id
ab42594f-90c3-4d3e-a659-3b840e5ac448 (old id 8056125)
alternative location
http://www.byfy.lth.se/fileadmin/byfy/files/TVBH-1000pdf/TVBH-1003GJ.pdf
date added to LUP
2015-10-14 16:14:19
date last changed
2016-09-19 08:44:52
@phdthesis{ab42594f-90c3-4d3e-a659-3b840e5ac448,
  abstract     = {The thesis concerns the characterization and evaluation of nonsteady<br/><br>
heat transfer in building components and building enclosures.<br/><br>
The major aim of the underlaying research has been to<br/><br>
assemble and develop simplified calculation procedures for this<br/><br>
purpose. To establish a simple model for heat balance calculations<br/><br>
three main items are treated: simplification of the heat<br/><br>
transfer operators, the description of the solar gain through<br/><br>
windows and reduction of the number of transfer paths. For nonsteady<br/><br>
heat conduction in opaque construction solutions are<br/><br>
given in the frequency domain and by finite differences.<br/><br>
<br/><br>
Based on the frequency response different types of RC-models are<br/><br>
derived. The simplest network is a single capacitance giving the<br/><br>
same ratio between the amplitudes of heat flow and temperature<br/><br>
as the real surface. This quantity is called the active heat<br/><br>
capacity of the wall. To estimate this quantity a simplified<br/><br>
calculation procedure is given. For the combination of surfaces<br/><br>
with different active heat capacities addition rules are established<br/><br>
that take into account the limited mutual radiation exchange<br/><br>
between the surfaces. In that way the room is transformed<br/><br>
into a model with two nodes, one representing the surface temperature<br/><br>
and one representing the room air. A solution in the time<br/><br>
domain allows the thermal loads to be represented as time series<br/><br>
and the mode of operation can be freely defined and varied during<br/><br>
the calculated period.},
  author       = {Jóhannesson, Gudni},
  issn         = {0349-4950},
  keyword      = {Time domain solutions,RC-models,Admittance,Frequency response,Simplified models,Non-steady state,Building heat transfer,värmeflöden,transienta förlopp,byggnader,beräkningsmodeller},
  language     = {eng},
  pages        = {165},
  publisher    = {Byggnadsfysik LTH, Lunds Tekniska Högskola},
  series       = {Report TVBH},
  title        = {Active heat capacity : models and parameters for the thermal performance of buildings},
  volume       = {1003},
  year         = {1981},
}