From: apian@ise.fhg.de (Peter Apian-Bennewitz)
Subject: opening of the first self-sufficient solar house, Press Release
Summary: A week ago the first self-sufficient solar house in Germany was opened
Keywords: solar, energy, hydrogen, fuel cells, TI
Organization: FhG-ISE - Institute for Solar Energy Systems
Date: Tue, 10 Nov 92 12:10:22 GMT

Hi everyone,

PLEASE USE THE FAX NUMBER GIVEN for any questions you may have,
our Public Relations folks will be happy to answer questions.
Since *I* am not directly related to the project, the fax way
is faster than email. Thanx.
following is the official press release:

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                    P R E S S    R E L E A S E

   Official opening of the first self-sufficient solar house in

                             Germany


   The "self-sufficient solar house" in Freiburg will be the first
German house to have 100% of its lighting, heating and electricity
supplied by  the sun:  it has  neither a  grid  connection  nor  a
chimney, neither an oil tank nor a gas pipe connection, not even a
wood-fuelled stove.

   Nevertheless, its  residents will  not have  to forgo the usual
degree of  comfort. This  is ensured  by the  numerous examples of
energy-saving technology,  the passive  and active  use  of  solar
energy, and  energy storage, which combine to make the house self-
sufficient as far as energy is concerned.

   Planning for  the project  began in  1988. It  was led by Prof.
Adolf Goetzberger  and Dr. Wilhelm Stahl (Fraunhofer Institute for
Solar Energy  Systems) and  supported by  the BMFT (German Federal
Ministry  for  Research  and  Technology),  the  State  of  Baden-
Wuerttemberg, the  City of  Freiburg and many industrial companies.
Now, after a construction period of fourteen months, the house has
been completed.

Its appearance: open to the sun.

   A characteristic feature of the house is its ground-plan, which
opens toward the south to give a segment of a circle. The curve to
the south,  together with  the shorter,  straight northern facade,
was  the  result  of  a  computer  simulation  calculation,  which
simultaneously demanded  minimisation of  the area  which does not
see the  sun and  maximisation of  the south-facing areas to raise
the solar  energy gains. The roof area is dominated by solar cells
and a  new type  of solar  collector for  domestic hot water. Also
unconventional is the appearance of the walls, with their cladding
of "transparent insulation material", which enables them to act as
solar heaters  for the  building. When  heat is  needed, they look
black; when  it is  not, roller blinds are let down and the facade
has a silver gleam.

   The house has a living area of 145 m2. In the basement there is
a cellar  and equipment  rooms, on  the ground  floor there  is  a
kitchen/living room  and a  public lecture  room and  on the upper
floor there are four residential rooms. These floors are connected
by an  unheated stairwell, while the roof access is via an outside
spiral staircase.  The project  leader,  Dr.  Wilhelm  Stahl,  has
already lived  for a  week with  his family in the self-sufficient
solar house  and has  complete confidence in the sun as the energy
source.

Heating: 30 l oil would be enough!

   Thorough  energy-saving   measures,  in   particular  excellent
conventional thermal insulation on the north wall and for the roof
and basement  (the house  "stands" with  its foundation  block and
basement walls  surrounded by  an insulating  layer of glass foam)
and ventilation  heat recovery,  have greatly reduced transmission
and ventilation losses. However, the real technological advance is
the application  of "transparent  insulation" (TI) on the southern
facade, which  reduces the  supplementary heating  needed  to  the
equivalent of about 30 l oil. Using the TI technology developed at
ISE, the  house can be heated by the sun through the wall. Plastic
materials, which  transmit solar radiation well and simultaneously
are good  thermal insulators,  are mounted  in front  of the black
wall. The solar radiation passes through the TI material and heats
up the  solid wall behind it, thereby "loading" the wall as a heat
storage element.  The heat is released after a time delay into the
adjacent room.  Thus, it  is still  possible to have solar heating
after the sun has set. A roller blind system to regulate the solar
input  and   exterior  protective  glazing  complete  the  system.
Combined with high-quality windows, the TI heating provides a high
level of  comfort: During  the  day,  the  house  is  solar-heated
through  the   windows,  during   the  night   by  the   TI  wall.
Supplementary heating  is needed only on a few days each year, and
is provided by the hydrogen storage system as described below.

Hot water in winter: Highly efficient solar collectors provide
domestic hot water

   Hot water  for the house is supplied by a new type of collector
system, in  which the  collector absorber  is irradiated from both
sides. The  absorber is  insulated with  TI material,  and absorbs
radiation  directly   from  the  sun  on  the  upper  surface  and
indirectly, via  a reflective  trough, on  the lower surface. This
configuration  results   in  acceptable   water  temperatures  and
efficiency values  even during winter, with little solar radiation
and low  air temperatures. The hot water is stored in a commercial
1000 l tank. In addition, the exhaust heat from the fuel cell (see
below) also  heats the water, so this energy is not wasted either.
This example  illustrates the  integrative concept  for the energy
supply in the self-sufficient solar house. The simultaneity of the
demand for  supplementary heating  for domestic  hot water and the
exhaust heat  production from  the fuel cell was a result observed
in the computer simulation to model the energy flow in the house.

The silent power station on the roof: Solar cells generate
electricity from light.

   The photovoltaic solar generator with an area of 36 m2 supplies
4.2 kW  electricity under  full sunlight. When needed, this can be
converted by  a  completely  electronic  inverter  to  alternating
current and  fed directly into the domestic circuit (230 V/50 Hz).
Excess electricity  is stored  in lead batteries (19.2 kWh), which
can tide  over several  overcast days.  If the  lead batteries are
charged, the  solar electricity  is used to electrolyse water into
the gases,  hydrogen and oxygen. Both gases are stored in pressure
tanks and can be used to generate electricity and heat in winter.

   The house  is equipped  with conventional household appliances,
which were  chosen on  the basis of their energy-saving qualities.
Without reducing  comfort, the electricity consumption was reduced
to about one third of that for an average family.

Storing solar energy from the summer for winter: The hydrogen
system.

   The core  of the  house is  the seasonal  energy storage system
based on  hydrogen. Use  of this  technology made  the  difference
between a  minimal-energy house  and a truly self-sufficient solar
house.

   By  electrolysing  water  into  its  components,  hydrogen  and
oxygen, and  storing both  gases in pressure tanks, about 1500 kWh
energy can  be saved  from summer  for the  winter. When needed in
winter, the  fuel cell  (alkaline fuel  cell, 0.5 kW) can generate
electricity  directly   (reverse  process  to  electrolysis).  The
exhaust heat (temperature 70 C) produced during the conversion is
used  for   supplementary  heating  of  the  domestic  hot  water.
Flameless catalytic  combustion  of  hydrogen  provides  heat  for
cooking on  the hydrogen  gas stove and for the minimal additional
room heating  needed under unfavourable conditions in winter. Both
the advanced  electrolyser (membrane  pressure electrolyser, 2 kW)
and  the   systems  for  catalytic  combustion  of  hydrogen  were
developed in ISE. The hydrogen tank next to the house has a volume
of 15  m3, the  oxygen tank  holds 7.5 m3. The tank pressure is 30
bar.

How much do we have to pay and what is the effect on the
environment?

Price and energy amortisation.

   The self-sufficient  solar house  does not  require any further
conventional energy for operation. However, this independence must
be purchased with a greater energy input to produce the additional
technical systems. Thus, this house, as compared with a low-energy
house, must  be inhabited  for longer until it achieves a positive
energy balance.  Nevertheless, considering  the long  lifetime  of
such a building, this is acceptable.

   When the capital investment is discussed, it must be remembered
that this  is a  prototype building.  In addition  to the building
costs of  approx. DM  900,000 for  the low energy house (including
the   conventional   building   services   and   the   transparent
insulation),  a   further  DM  700,000  was  spent  on  additional
technical  equipment  and  measurement  systems.  Apart  from  the
photovoltaics,  the   hydrogen  technology   represents  a   major
component of  these costs.  By contrast,  the active  and  passive
thermal systems  are relatively  inexpensive and offer much closer
economic competition to conventional energy sources.
   
   A demonstration object for everyone, a case study for
scientists:
the measurement and demonstration phase.

   With such  an ambitious  aim, it  must be anticipated that some
difficulties will  arise with  the  sophisticated  components  and
their integration,  despite  the  careful  planning  supported  by
detailed simulation  calculations. Now  that the  construction has
been completed, the measurement and observation phase has started,
from which  the ISE  scientists expect  to gain valuable knowledge
for the  future operation  of this  and other similar projects. At
the same  time, the  house serves  as a  demonstration object  for
scientists and  the general  public. Several inspection tours each
week are  planned for  groups of  interested visitors, who wish to
gain an impression of the house and its wide range of technology.

House of the future?

   The self-sufficient  solar house  combines a  great  number  of
concepts which  originated or  were developed  further at ISE, and
are  integrated  by  a  well-planned  process  management  system.
Several of  these concepts  have  reached  a  stage  of  technical
maturity, which  would allow  them to be applied on a broad scale.
Others, particularly  the  hydrogen  technology,  require  further
effort in research and development and will probably not achieve a
technological breakthrough for one or two decades. Thus, the self-
sufficient  solar   house  serves   two  purposes   at   once:   A
demonstration model  for the house of today and tomorrow, but also
a research  laboratory for  progressive  energy  technology,  with
applications extending far beyond the residential sector.

   
Freiburg, 30.10.1992
Dr. Armin Zastrow
Public Relations Officier
Tel: +49/761/4014-147
Fax: +49/761/4014-116
   
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Would you please consider the FAX number above before replying via
email ? Thanx.
(No disclaimer at all.)

Peter
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 Peter Apian-Bennewitz				apian@ise.fhg.de
 Fraunhofer Institute for Solar Energy Systems	Tel +49-761-4014-118
 D-7800 Freiburg   ,  Oltmannsstrasse 22	Fax +49-761-4014-200
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