At 09:26 2-7-01 -0500, Erik Reuter wrote:
> > The Dutch Dept. for the Environment (http://www.minvrom.nl) (sorry,
> > it's in Dutch too) puts the cost of a 1 m^2 panel at ~NLG 2,000
> > (including all needed equipment and cost of installation). So, it
> > would cost roughly 40 x NLG 2,000 = NLG 80,000 (or ~USD 32,000) to get
>
>Are you sure that it includes EVERYTHING NEEDED? (sorry, can't read
>Dutch). For example, does it include a large bank of storage batteries,
>which are very expensive but obviously essential unless you have
>sunlight 24 hours a day over there :-)
The figures I mentioned are for a so-called net-connected system (it's
connected to the regular power grid). With this system, energy isn't stored
in batteries but used immediately. When the system produces more energy
than you use, the surplus flows into the regular power grid.
The system you are referring to is an autonomous photovoltaic system; that
one does use batteries. Autonomous systems have two bad sides, compared to
net-connected systems. First, the panels only produce an average of 40 kWh
per year (net-connected: 80 kWh). Second, the total costs per panel
(including all equipment and installation) are ~NLG 3,500 (net-connected:
NLG 2,000).
> > So far, 5 projects (a total of over 200 houses) have been completed;
> > average reduction in energy consumption in these houses is 45%. A few
> > dozen similar projects (for a total of 10,000 houses) have already
> > been started.
>
>That sounds great. I wish I could read Dutch to get some more details
>about this project.
Key in all this is the Energy Performance Coefficient (EPC). An EPC of 1.0
means that per year approx. 930 m^3 of natural gas is needed for warm water
and heating. Houses that are built as part of these projects have an EPC of
0.75 or better. For these houses, a maximum of 500 m^3 of natural gas is
needed.
So, how did we do it? By thinking before we acted. <grin>
Windows on the north side are kept small to minimize the loss of heat. The
south side has a so called "sun porch": a large tilted glass roof, with
large glass sliding doors. The roofs, floors and walls have isolation.
Windows are made of HR+ glass (basically, two layers of glass with a
heat-reflecting layer between them). Ventilation is done with a heat
exchange mechanism: warm air goes out, but the heat is transferred to the
cold air coming in, thereby limiting the amount of incoming cold air to a
minimum. For heating, the houses don't have individual heating systems but
use hot water from a power plant. By using thin radiators with a large
surface, the water only has to be 60 degrees Celsius to adequately heat
rooms. Water is saved by using efficient taps and toilets. The washing
machine and dish washer can be connected to a "hot fill" point. These
machines need hot water of a certain temperature; a hot-fill provides warm
water, so less energy is needed to heat the water to the required
temperature. Each house has 4 photovoltaic panels of 1 m^2 each, and up to
27 additional panels can be installed.
Note: the above info is for the first project; details may vary per project.
A key player in these projects is the World Wildlife Fund. The WWF wanted
to proof that it is possible to build very energy-efficient houses, using
today's regulations and technologies, without considerably higher costs,
and without government subsidies.
The WWF got together with five project developers and started five building
projects to prove it could be done. As you can see, they succeeded... :)
Jeroen
_________________________________________________________________________
Wonderful World of Brin-L Website: http://go.to/brin-l
