The laws of physics are on our side, and so are the experts
who have done the research. The more you learn about the
subject, the better we look. Please just take the time to find
out the truth about what makes an efficient wall system.
Did you know:
Walls with equal R values do not always have the same
thermal performance?
Please read the following excerpts from Oak Ridge National Lab
reports, and when you get time, follow the links to the complete articles.
Enlighten yourself and your colleagues, and save money and energy.
http://www.ornl.gov/sci/roofs+walls/AWT/Theoretical%20Analysis/index.htm
http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/effects/index.html
Effects of Different Sequences of Materials in the Massive Walls on
Energy Consumption in Continuously Used Residential Buildings
Dr. Elisabeth Kossecka* Dr. Jan Kosny**
INTRODUCTION:
"Due to the increasing amount of new residential and commercial
constructions using massive exterior building envelope technologies,
it is very important to optimize the mass and insulation distribution
in walls. In comparing several massive walls with the same R-value,
it can be observed that some wall configurations are more thermally
effective than others [1]. This superior thermal performance can be
detected only for a specific distribution of mass and insulation inside
the wall.
Energy effects of different thermal mass and insulation arrangements
in massive exterior walls, have been studied by several authors [2-4].
For multilayer walls, three basic material configurations were considered:
insulation either inside or outside the massive layer, and insulation located
between two massive layers. The results of extensive parametric analysis
have shown explicitly that walls with the insulation outside always performed
better than those with the insulation inside. "
http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html
Thermal Mass - Energy Savings Potential in Residential Buildings
J. Kosny, T. Petrie, D. Gawin, P. Childs, A Desjarlais, and J.Christian
Buildings Technology Center, ORNL
ABSTRACT:
"In certain climates, massive building envelopes-such as masonry,
concrete, earth, and insulating concrete forms (ICFs)-can be utilized
as one of the simplest ways of reducing building heating and cooling
loads. Very often such savings can be achieved in the design stage of
the building and on a relatively low-cost basis. Such reductions in
building envelope heat losses combined with optimized material
configuration and the proper amount of thermal insulation in the
building envelope help to reduce the building cooling and heating
energy demands and building related CO2 emission into the atmosphere.
Thermal mass effects occur in buildings containing walls, floors, and
ceilings made of logs, heavy masonry, and concrete." "This data shows
that the most effective wall assemblies were walls with thermal mass
(concrete) being in good contact with the interior of the building
(Intmass and CIC). Walls where the insulation material is concentrated
on the interior side (Extmass) were the worst performing wall assemblies.
Wall configurations with the concrete wall core and insulation placed on
both sides of the wall (ICI) performed slightly better than Extmass
configurations. However, their performance was significantly worse
than CIC and Intmass configurations. The ICI configuration can be used
for approximate analysis of the very popular Insulated Concrete Forms
(ICFs) constructions, since ICF walls consist of the internal concrete
core placed between shells made of insulating foam."
Kossecka, E. and Kosny, J. - “Effect of Insulation and Mass Distribution
in Exterior Walls on the Dynamic Thermal Performance of a Whole Buildings”
- DOE, ASHRAE, ORNL Conference - Thermal Envelopes VII, Clearwater,
FL - Dec. 1998.
Dynamic Thermal Performance and Energy Benefits of Using
Massive Walls in Residential Buildings
INTRODUCTION:
"Utilization of thermal mass in buildings can be one of the most
effective ways of reducing building heating and cooling loads.
Several massive modern building envelope technologies (masonry
and concrete systems) have found their application in buildings
in the last decade. They suffer from the lack of an accepted measure
of their thermal performance. The steady-state R-value traditionally
used as a wall thermal performance measure does not reflect the
dynamic thermal performance of massive building envelope systems.
To show the benefit of these systems, thermal performance analysis
has to incorporate thermal mass effects.
A new measure of the wall thermal dynamic performance is proposed
in this paper - Dynamic Benefit for Massive Systems (DBMS).The
thermal mass benefit is a function of the material configuration and
climate conditions. DBMS values are obtained by comparison of the
thermal performance of the massive walls and light-weight wood
frame walls. The product of DBMS and steady-state R-value is called
“R-value Equivalent for Massive Systems.” It enables comparisons of
massive walls. It does not have a physical meaning. It should be
understood only as an answer to the question:
'What wall R-value should a house with wood frame walls have
to obtain the same space heating and cooling loads as a similar
house containing massive walls?' "
|