Civil Engineering Reference
In-Depth Information
The notable characteristics of a site SZEB method are its ease of implementation,
measurement, and understanding, while there is a lack of accountability for non-
energy related differences between different fuel types, such as its availability and
source distance to the site or the quantity of the generated pollution.
On the other hand the most notable characteristics of the source SZEB, is that by
using this method it is possible to include the energy value of different fuel types
used at site in the calculations, and it is easier to reach zero energy by this method.
Typically the cost SZEB is easy to implement and measure, but at the same time
it is very diffi cult to track the rapid energy source price changes.
Finally the emission SZEB requires proper means of emission eliminating tech-
niques that in some cases could add to the cost of the building considerably, while
it provides easier path of reaching SZEB, and capability of factoring in non-energy
differences among different fuel types in the energy evaluation of the building.
Independent of what defi nition and strategy is chosen to defi ne a SZEB, there are
always specifi c techniques and strategies to be employed in order to create on site
renewable energy. These techniques can not only cut the dependency of the building
on the energy provided to it by the electricity grid or other utility providing resources,
but also can eliminate the carbon emission of the building as well. Of course all
these techniques and strategies have a direct relation to the location of the building
and the available natural sources of energy in that region, such as year around avail-
ability of energy from the Sun, ocean, or wind.
A Building capable of providing a yearly energy quantity more than what it uses
and therefore allows its owner to sell the residuals back to the electricity grid is usu-
ally called energy-plus buildings and a building that is capable of generating energy
just short of its yearly energy requirement and therefore at least for a few percent of
its energy is dependent on the electricity grid is called a near zero energy building.
It is obvious that designing and operating a sum zero energy house is much sim-
pler than designing and operating a sum zero energy commercial building. A house
is usually only dependent on energy for a limited number of appliances such as
heating and cooling units for extreme outdoor conditions. Other energy consuming
elements in a house are kitchen appliances, lighting throughout the house, televi-
sion, computer, etc. Of course other than losing the functionality of the heating
equipment in some rare locations and occasions the loss of the functionality of a
house is not as critical as a loss of functionality of equipment or appliances in a
commercial building. Some commercial buildings rely on cooling system on a 24 h
basis during the week for places such as central computer rooms, electrical rooms
or elevator machine rooms. The whole business profi tability of some manufacturing
sites depends on year around access to reliable source of energy. Loss of such func-
tions can have a hard negative effect on the businesses in these buildings. Therefore
even the best sum zero energy commercial buildings should have grid-dependent
backup source of electricity or other source of energy as it is suitable. Means for
storing the excessive generated energy should be provided to store the generated
excess renewable energy and later use it when the original source of energy is not
available anymore.
