ZEMCH 2015 - International Conference Proceedings | Page 599

were grouped according to their efficiency until each total was lower than each limit (excluding
certain measures that proved incompatible) to make up “retrofit packages”. These packages were
then simulated and were found to offer reductions of around 35%, 50% and 65% of total heating
energy demand by each package. This corresponds to increases of between 2°C and 4°C in indoor
winter temperatures and a rise in the commercial value of the home of between 2% and 8%, according to the lifecycle financial assessment based on ASTM E-917. Investment return estimates
depend on the type of fuel used and the interest rates on loans, which varies greatly depending
on whether interventions are funded by government subsidy, bank loan or personal savings.

Fig.4. Presentation of retrofit packages to residents (left), execution of thermal rehabilitation (center)
and computer platform developed (right).
A graphic presentation was then developed of the three packages for each home to explain options to residents and installers (Fig.4 left). A survey subsequently assessed whether residents
were able to understand the presentation, appreciate the options available to them and whether they were willing to carry out the suggested measures. In three of the cases, retrofitting was
carried out funded by the house owners and in one low-income home (and its neighbour) financed by donations of private companies, such was arranged by the students collaborating in
the research project (Fig.4 center). This last case was monitored after the retrofit and was seen
to achieve the predicted performance improvements and meet the satisfaction of the owners,
although there were some construction difficulties during installation.
The analysis strategy was also developed into a computer implementation tool (Fig.4 right). This
could be used to help professionals record simulation results and calculate retrofitting packages.
This programme could also calculate estimates, according to demand levels proportional to the
floor area of the home and average percentages of energy use reductions for each solution. These
could be used to project possible solutions that may be useful to the general public.

New Designs
In order to review general design aspects (shape and location of the houses) that might affect the
environmental performance of dwellings in the zone, comparative simulations were carried out
on a hundred models with similar constructive and functional conditions but different geometric configurations and solar orientations (GARCIA, GONZALEZ; 2014). These configurations were
determined according to the main differences in form found in the records of existing houses
in the Concepción zone with the same floor area and typical layout and material specifications.
The house models selected were all one or two storeys high, with compact, extended or irregular
shapes. A selection of detached, semi-detached and terraced houses was chosen with models
representing orientation towards all four cardinal directions (which generated certain symmetrical layouts). All the models had similar numbers of window openings (about 20% of outside wall
area) and higher heat transmittance in walls than roofs, as indicated in Chilean building standards
in place since 2007. The parametric analysis revealed few differences of comfort levels between

Eco-friendly materials for the energy retrofit of existing buildings

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