Jun 29 2007
Nearly one third of Germany’s primary energy production goes into heating private households. The average older apartment building consumes more than 20 liters of heating oil per square meter every year. And this has consequences, both for the tenants because they have to pay ever higher heating bills, and for the environment, because heating produces considerable amounts of the greenhouse gas carbon dioxide (CO2). But something completely different is going on at the zero-heating cost house in the Pfingstweide district of Ludwigshafen. The apartments there don't even have conventional radiators, not to mention stoves. Instead, a sophisticated compound system with innovative insulation and ventilation ensures that the residents always enjoy comfortable temperatures and that hardly any CO2 is released. Both the design and the modernization work were done by BASF's housing company Luwoge and its subsidiary Luwoge consult, a consulting firm for energy-efficient construction.
For several years now, Luwoge has been showing that BASF products and other components can be used to construct or modernize buildings and apartments to save energy. In 2001, for example, the company modernized a 1950s-era building into a low-energy house – making it the first building from that period to be transformed into a 3-liter house. Since then, the annual heating oil requirements for this building have remained below three liters per square meter of living space. According to Karl Arenz, the director of Luwoge's Competence Center for Housing Construction and Modernization, "We have lots of expertise in transforming old buildings into modern low-energy houses. Our 3-liter house was just a pilot project. Back then we wanted to show what was technically feasible – the profitability aspect was secondary. Now with the zero-heating cost house, we're demonstrating that energy-efficient modernization of buildings also makes a lot of business sense."
In order to actually eliminate heating costs, a multi-stage compound system is used. First of all, the building is well lined with thermal insulation panels made of Neopor®. In the insulation sector, the newcomer Neopor® has far outpaced its ancestor Styropor®. It contains tiny graphite particles that reflect thermal radiation and give the material a silver-grey hue. The windows in the zero-heating cost house also provide the best possible protection against energy dissipation – they are triple-glazed and contain an inert gas filling between the panes.
Another component in this building's energy-efficient strategy is its actual heating system. There isn't a single radiator in the entire building – although the "zero-heating cost" house is not a "zero-energy consumption" structure. Although this may look like a paradox, it simply means that the building earns its own (low) heating costs. To do so, it uses solar energy. Solar cells on the roof generate electricity, which is fed into the municipal grid. Revenues from this contribution cover the costs for keeping the apartments warm. The zero-heating cost house also takes care of its own hot water needs – with solar panels on its southern side. As Karl Arenz explains, "A controlled incoming and outgoing ventilation system with thermal recovery ensures excellent air quality and also makes optimal use of the heat in the outgoing air." The ventilation system extracts used air from the kitchens and bathrooms, and uses it to temper the cool incoming fresh air via a heat exchanger. More than 80 percent of the heat in the outgoing air can be used in this manner, which also means that a continuous stream of fresh air is always flowing into the house.
The heating system itself is so well hidden that one doesn't notice it at first – it's integrated into the windows. The inner pane of the triple-glazed windows is furnished with an extremely thin and invisible metal coating which conducts electricity. When a low-voltage current is applied, the coating heats up like a resistance heater which enables the windows to radiate warmth. In order to prevent heat loss to the outside, the outer pane has a heat-reflective coating. Moreover, the spaces between the three panes are filled with an inert gas that conducts heat less efficiently than air. This quickly produces a pleasant interior atmosphere, and uses less energy than conventional heating systems. Window heating is not designed for long-term usage, however, but rather for when outside temperatures are extremely low.