Civil Engineering Reference
In-Depth Information
Fig. 5
Energy performance of the existing building and refurbishment options considered
the production of electricity by PV which has been calculated according to the
CEN standard (CEN
2007b
). This electricity generation is converted to primary
energy using a conversion factor of 2.7, factor used in Ireland within the DEAP
methodology. Using this conversion factor, each square metre of installed PV
equates to primary energy savings of 304 kWh per year.
It can be observed that space heating is the main energy use for the existing
dwelling case study option, accounting for around 50 % of the total energy use. As
the different refurbishment strategies are considered, the energy use can be pro-
gressively reduced. As it can be observed, energy reduction for heating and hot
water can be greatly reduced with the first renovation option, which would include
insulation and windows upgrade, efficient lighting and solar thermal collectors.
Subsequent options to improve energy performance of the refurbished building do
not achieve such large energy savings, and by Options 6 and 7, the savings made
with 'passive' building measures are very small. The primary energy use at this
stage is, however, quite small, of about 50 kWh/m
2
for Option 7. To progress until
the zero-energy use objective, which is achieved for Option 10, additional
renewable energy has to be added which includes 18 m
2
of solar PV and 10 m
2
of
solar thermal panels.
For the second step of the proposed methodology, which is the quantification of
the AEE for the products, the embodied energy has been sourced from some of the
sources already commented in previous section such as ECOINVENT database
(Swiss Centre for Life Cycle Inventories
2010
) and the Inventory of Carbon and
Energy by Hammond and Jones (
2008)
. Some additional references were con-
sulted for domestic solar water heating systems with flat-plate collectors (Asif
et al.
2007
; Ardent et al.
2005a
; Kalogirou
2004
,
2009
; Crawford and Treloar
