Posts Tagged ‘COP’

Total Concrete Housing Technology Analysis

September 27, 2015

Design, material and component selection.

The Design.

The
best design for the structure, (to ensure compatibility for design,
market acceptance as well as accurate test results), is to be a small
home complete with basement, targeting the low to mid income bracket.

Materials.

Advanced
Materials to be used in the structure include existing products such as
ICF wall system, basement insulated slab on grade system, composite
concrete intermediate floor system, High performance, dual glazed, low-E
and argon filled windows, with exterior stucco and cultured stone
systems.

New technologies developed include; A hybrid ICF
composite concrete cast in place roof forming system utilizing both
Formtech and Speedfloor components. A simplified radiant in floor
heating system. Earth coupled geothermal water to water hydronic
heating/cooling system, utilizing passive soils heat transfer methods to
reduce loop lengths, and engineered soils to increase performance. An
advanced air separator cleaning unit and fresh air energy recovery
ventilation system complete with an integral mid volume air conditioning
system.

New methods of installation including external vibration
methods utilizing new technology. More efficient design and detailing
methods. Introduction of new installation methods, which simplify and
demystify the processes involved in the construction. Multi function or
combined construction tasking, which combine two or more tasks into one.
Lowered experience and knowledge requirements through efficient
material selection, management practices, design, detailing, and
scheduling.

Criteria included in design and developed products and/or techniques

Over
the last years we have accumulated information and research into the
needs of the building market place, and determined that the following
base criteria for all products would have to be addressed within the
design and/or construction of the building.

1. Cost. Overall, the
cost of materials and/or labor would have to ensure that the current
construction methods associated with ICF construction would have to
decrease the total cost of the building by the offset cost of utilizing
these types of products installed to current standards.

2.
Efficiency. The material and labor components must comply with
efficiency in design to reduce construction time, and reduce material
requirements by a undetermined acceptable level. Material components
should perform two or more construction or building functions per item,
or combine several aspects required into the design, such as stay in
place formwork.

3. Methods of construction. The methods of
construction must simplify the construction process, allowing low skill
labor to be utilized effectively.

4. Quality of construction. The
Quality of the building must be increased to meet the new challenges of a
modern world including Longevity, durability, strength, esthetics,
operation, form and function.

5. Compatibility. The building must
be constructed in such a matter as to be identical in form and function
with current residential structures.

6. Versatility. Any normal
residential structure must be able to be designed and built with the
systems and methods, to ensure compliance with current designs in the
construction industry.

7. Needs and shortfalls. The building has
to address most, if not all, of the current needs and existing
shortfalls in residential dwellings.

8. energy-efficient. Energy
requirements should meet or exceed, even the highest standards of
current construction materials and methods.

9. Environmental
Friendly. The materials and methods should address as many environmental
considerations as possible, including waste, energy required for
production of materials, and energy required for construction. Low
environmental impact products and methods of construction would be a
must.

10. Manufacturing capability. All products and existing
labor markets must be able to be easily adapted to meet the needs for
construction of buildings of this type.

All materials and
components as well as the manufacturers have been selected based on the
product’s ability in speed, durability, workability, quality, strength,
warranties and market acceptance from existing raw materials and/or
processes.

Heat loss.

Component factors

Roof effectiveness.

Existing
energy efficiencies for ICF wall systems rate about 30% more effective
in overall heating and cooling when combined with current standards of
wood truss roof installation and slab on grade basement installations.
Knowing that the current energy loss’s in a heating climate for walls in
residential structures is about 23% of the overall loss of a home, and
the roof representing about 42% of the overall heat loss, I am assuming
the following: 42% (total roof loss on a normal home)/ 23% (total wall
loss on normal home)X 30% (the known effectiveness of ICF walls only on a
home) should in theory increase the effectiveness of the above slab
thermal envelope by about 54.78%.

This assuming comparative
R-value increases, combined with reduced air infiltration and thermal
conductance characteristic differences associated with ICF construction.

Below grade and under Slab effectiveness.

Although
smaller, below grade and under slab loss’s do count in the overall
building heat loss, and typically represent about 7% of the total heat
loss on the building. This can be reduced substantially through the use
of effective drainage of ground water, the inclusion of foil covered
Expanded Polystyrene insulation to isolate the slab from the ground as
well as ICF construction for the basement walls. By including 4″ of EPS
foam, a reflective layer of foil, and effective subsurface drainage, we
can increase the efficiency of slab on grades and below grade areas by
about 67% over the current accepted standard of 6 mil polyethylene
sheets only. Assuming these numbers to be accurate, we can include the
following, 7% (total heat loss through the sub structure area) X 67%
(effective increase in thermal performance of the slab) = 4.69% (total
added savings overall to the heat loss characteristics). Adding this to
the above slab thermal envelope effectiveness, we now have a building
which is 59.47% more effective than standard construction methods.

Window/Door factors.

Outside
issues, such as windows and doors have an overall heat loss
characteristic of about 17% on the total home, through infiltration,
loss/gain and conductance. Primarily by incorporating a higher quality
window, built with lower air infiltration rates. Less thermal
conductance and the inclusion of affordable low E glass with Argon gas
between two thermal panes. Existing studies and tests prove that these
types of windows and doors increase the thermal performance of such
units by about 30%. On a home, this a relatively high factor outside of
standard construction, due to the extensive use of window area in
design. We will be assuming normal use of about 15% of wall area.
Assuming these numbers to be correct, we can, in theory say that 17%
(heat loss through windows and doors in standard construction) X 30%
(increase in performance of higher quality windows) = 5.10% (savings in
heat loss for new structure). Adding this to total thermal envelope
effectiveness, we now have a building which is 64.57% more effective
than standard construction methods.

Overall factors.

Standard Ventilation factors

Ventilation
factors of.3 air changes per hour are a standard code requirement.
Current standards of construction achieve this through the use of
exhaust fans or air changers. The proposed standard will include a
high-efficiency, dual core system from NuTech, which operates to
effectively supply.3 air changes per hour with 87% effective heat
recovery from the exhaust air. Knowing that the mechanical ventilation
accounts for about 8.5% of the total loss to the building, we can
effectively assume the following. 8.5% (mechanical ventilation loss to
building) X 87% (effectiveness of Heat Recovery Ventilation unit used) =
7.39% (increase of performance for air exchange. Adding this to the
above effectiveness, we now have a building which is 71.96% more
effective than standard construction methods.

Radiant heating.

Further
energy savings, in the heating climate which would have a significant
impact on the study, include Radiant Heating and high-efficiency
boilers, through a hydronic installation, which is supported by existing
studies to increase energy efficiencies about 20% overall. The base
theory to support this the effectiveness of radiant heat over convected
or conducted heat transfer to occupants of buildings. Taking this factor
into account in a ratio for normal construction and the proposed ICF
shell, 20% (representing standard construction methods effective
reduction in heat requirements) X (100% – 71.96%) = 28.04% (representing
remaining energy required by incorporating ICF envelope) = a further
5.61% in total energy savings through the use of radiant technology.
This equates to 77.57% total energy savings included in the
calculations.

Thermal Mass and Heat Storage

By utilizing a compromise, the home is designed to
take advantage of off-peak heating through the use of concrete in the
structure. Effectively, the building would be utilizing the off-peak
hours to store heat energy in the thermal mass of the concrete floors,
for daytime use. This to be achieved simply through the use of
programmable thermostats, which would store heat in the concrete slabs
during the early morning hours. The overall effectiveness is currently
undetermined.

Geothermal Applications.

Through the use of
passive solar collectors, installed below the roof shingles, and
integral with the ICF roof assembly, on warmer winter days, solar heated
water would be used in a closed parallel loop to increase the
geothermal bed temperatures, thereby effectively storing heat for later
use in the ground. During summer months, the same parallel loop, will
utilize rain water and cooler nighttime temperatures, in an effort to
reduce ground temperatures. Over the loops, a new product, “InsulTarp”
will be installed to prevent excessive loss’s to the earth surface. This
being studied in an effort to reduce trench depths, and loop lengths
from the current standard, as well as increase efficiency of the
geothermal heat pump system. Overall effectiveness is currently
undetermined.

Geothermal units operate much more efficiently as
the load decreases on the unit. When any fluid material, (including air
which acts in the same way as a fluid) requires a large delta T
temperature increase, (the difference between the return fluid
temperature and the supplied fluid temperature) a geothermal heat pump
has to work very hard to pump enough heat to supply the demand, so the
efficiency of the unit drops. This called the COP or “coefficient of
performance”. Most geothermal units operate with a heating COP of about
3. What the COP represents is the comparison of the overall energy
output from the unit, over the energy input to the unit. A COP rating of
3, means that for every 1 unit of energy or “watt” we put into the
geothermal heat pump, we get 3 watts of heat out of it.

Now here is where it changes when we combine it with ultra efficient structures, hydronic in floor heating and thermal mass.

The
much lower heat loss of the building, means a lower Btu output per
square foot of floor area, In the case of some of our research
structures, this equates to about 10-13 BTU per square foot in areas
such as Michigan USA and Ontario Canada. Now, water entering the radiant
system of a concrete floor, needs only be 76 degrees F to maintain a 71
degree F temperature for the occupants. This means that the radiant
system only needs to supply a 6 degree temperature rise. This means that
the coupled geothermal system now only needs to combat a heat pressure
difference (for lack of a better word) of only 5 degrees F instead of a
normal 50 degree rise for non concrete, radiant systems. Less
temperature difference means more efficiency as the geothermal system
works less, to produce more. An easier way to look at is to think of
water, in which much higher volumes can be moved a small vertical
distance with the same amount of energy, as compared to a large vertical
distance. More water per energy unit can be moved, ergo a geothermal
system can move more heat per energy unit. COP ratings up to 10 can be
achieved.

This means that by building with concrete, and
incorporating good design and material selections, we can extend the
efficiency of geothermal heat pump systems to gain efficiencies 2 to 3
times that of existing geothermal pump capabilities.

Strength and durability.

Strength.

As
the entire shell, including all interior structural components consist
of steel reinforced concrete, known to be much stronger and more
resistant to active loading conditions. Typically, the components used
have proven, through existing engineering, testing and analysis to far
outperform standard construction methods when subjected to dynamic loads
suffered from earthquakes, tornadoes, projectiles etc. Due to the
decreased risk of material failure, the occupants can enjoy a safe
environment, and the structure will unlikely suffer damage in the event
of such natural or mechanical damages, which other structures are likely
to fail at.

Used independently, each system suffers from weak
connections, such as the ICF wall with a truss roof, in which the roof
becomes separated from the structure due to uplift, exposing the
interior. Although this test model does not incorporate a product line
of windows and doors, designed to withstand these types of occurrences,
they are currently being manufactured. The hope is that one day we may
be able to see the results from this type of construction, when
including windows and doors with comparatively high strength ratings.
This decision was made upon evaluation of the location in which this
home was to be built, in which it would be impractical to include.
Future studies of this technology should be incorporated in a coastal
structure in the state of Florida, for a more accurate investigation
into these types of components.

It is suggested that the ICF
walls, in existence today are about 10 times stronger than standard wood
frame construction methods, it may be safe to assume, that the roof
system may now have that same capability.

Durability.

All of
the buildings structural components are of concrete and steel. It is
known that reinforced concrete is truly capable of spanning several
centuries. Although it is not known as as to the overall life expectancy
of concrete, many researchers have suggested periods in excess of 5,000
years. The secondary insulating component, Expanded Polystyrene, in a
non-degradable plastic component, in which it is expected to last
several hundred if not thousands of years, if suitably protected from
Ultra Violet breakdown. As all of the EPS foam which is in the building
is covered and protected from both this and mechanical damage, we can
safely assume that the life of the structure would be in excess of 100
years. Potentially it could be equivalent to that of the concrete, which
is expected to be several thousand.

The exterior stucco and stone
coverings are highly durable. Utilizing Acrylic stucco compounds, these
face coverings are almost impervious to degradation and breakdown,
although they may be subject to mechanical damage, as they are exposed.
However, these types of finish materials are easily repaired or
replaced, and can be maintained with much lower cost/year ratios than
wood, vinyl or aluminum. By replacing the shingles with long-lasting
Acrylic stuccos, which are also highly resistant to the effects of acid
rain or frost action, we can extend the life of the roof finishes well
beyond those of standard asphalt shingles. The stuccos longevity is
further enhanced as the ICF base construction on which it is applied is
not only an ideal substrate, however it is dimensionally stable during
temperature and humidity shifts.

Mechanical Considerations.

Although
the strengths of the mechanical components are relatively unimportant,
durability issues such as usable life span are reflective primarily of
the wear and tear of the components. These units are expected to last a
relatively short duration, as compared to the building itself, and
actually should be replaced periodically as newer and more efficient
units or means become available. However, current technology has
expanded to include such items as Heat Recover Ventilators, Air
Cleaners, high-efficiency boiler systems, and radiant heating systems
which are both energy-efficient as well as cost-effective to install and
operate. Most importantly, they systems need to be de-mystified and
standardized sufficiently to not only operate properly, however allow
for less complicated installation methods and materials, and make the
technologies easier for the public to access.

Future Development.

This
initial structure will utilize components which are readily available
in the marketplace to achieve the basic structure and mechanical
considerations, through modification of such products or methods. It is
forecasted that this structure will cost 14.6% more than an equivalent
structure built to code standards for wood frame construction. Due to
the costs associated with prototype manufacturing for single project
purposes of some components, this forecasted shortfall should easily be
reduced. The projected forecast, once all manufacturing and
standardization is in place for the products and methods of
installation, is projected to be at or below the cost of wood frame code
construction.

The benefits associated with this type of building
should not be compromised as a result. We are expecting that as products
and people become more readily available, that cost competitiveness
will reduce the prototype buildings construction costs sufficiently.
Market acceptance should be relatively good, as there are no detracting
features or concerns associated with efficient buildings such as dome
structures or plastic buildings. The final product will present itself
esthetically and functionally, identical to current residential
structures.