The Intersolar Europe, traditionally held in Munich in June, is the leading global trade fair for the photovoltaic and solar thermal energy sectors. This year, once again, trends have been evident here that will influence construction and renovation projects in the years to come.
The projects of the EU initiative CONCERTO already illustrate how ideas presented at the trade fair can be put into practice. In the scope of the CONCERTO 58 cities and communities in 23 European countries are collaborating on the development of sustainable, energy-efficient urban districts. In the process they are utilising a varying blend of efficiency technologies and renewable energy, depending on local conditions. The CONCERTO communities already generate electricity from renewable energy to the extent of 200 GWh per year. This is joined by 300 GWh of thermal heat.
There are numerous examples for the use of solar technology in CONCERTO. One of these is the residential district of Lehen in the Austrian city of Salzburg, as part of the Green Solar Cities project.
Lehen is a district with a very high population density. The transformation has been underway since 2006. One of the construction projects is the residential area Stadtwerk Lehen, which comprises 289 apartments, kindergarten and student residences on a former commercial site, it has been completed in November 2011.
The highly modern combination of different heat generation processes is a particularly interesting development. Small heating networks in the households are supplied from a 2000 m² thermal solar unit incorporating a heat pump, which is operated using electricity from the roof. "We have the largest accumulator still capable of being transported, with a capacity of 200 m³," reports project manager Inge Strassl of SIR Salzburger Institut für Raumordnung & Wohnen.
The heat pump integrated into the solar thermal system was developed especially for the project. "The customer, gswb, tested it in a preceding project and achieved solar fractions of 50 percent in the process," reports Strassl. This means that half of the energy volume required for heating and hot water is solar energy. Micro networks are used in Salzburg to minimise energy losses on the way to homes.
These deliver hot water with a temperature of 60 degrees to the relay stations in the homes, where the hot water is also generated decentrally. "This means that we have no problem with legionnaire's disease," says Strassl.
The CONCERTO project in Zlín, Czech Republic, also aims to reduce the consumption of fossil fuels by a third with the aid of solar thermal energy and photovoltaic. Solar thermal energy is projected to supply 20 single-family dwellings, an industrial plant and the municipal swimming pool, with large-scale PV plants under construction. A highlight in the eco-village Jizni Chlum near Zlín is earth-sheltered houses.
Their energy consumption is close to those of passive houses, with 60 - 90% of the heat provided from renewable sources.
But it is not just the southern countries of the EU, the energy of the sun is also being utilised in the north to reduce the consumption of finite fossil energy sources. One example is the CONCERTO project in Valby, Denmark. In Vigerslev Vænge / Hornemanns Vænge it is aimed to include renovation of 330 concrete housing units and use of 66 new climate optimised low energy prefabricated rooftop extensions with PV and solar heating. 3 of the 6 blocks with 144 apartments can be renovated within the CONCERTO timeframe. Construction work started in August 2011 and new roofs with PV panels were established on 3 blocks in April 2012, reports project manager Jakob Klint. A 3,230 m² newly-built public swimming pool with service areas was built to the Danish standard low energy class 2. Part of the electricity consumption is supplied by a 19.1 kWp PV system and heat is supplied by the district heating network. The building start was in March 2010 and commissioning of the building was 15 March 2012.
CONCERTO website: www.concerto.eu