Kungsbrohuset and Stockholm Waterfront Congress Centre are two examples of intelligently designed buildings that bring together a number of efficiency solutions to slash energy consumption.
From the reuse of construction materials to the use of energy-generating glass facades, Stockholm Waterfront Congress Centre is designed to cut CO2 emissions and minimise climate and environmental impact. Located between Stockholm Central Station and Stockholm City Hall, the congress centre was built in 2011 and comprises 72,000 sqm of space, with conference halls, offices and a hotel. Many of the materials used to build the centre were taken from the previous building on the site. Besides this, several other measures have been taken to enhance the property’s energy efficiency.
Facades as giant solar panels
The large glass facade of the congress hall faces due south and acts as a giant solar panel, with 1,040 sqm of solar collectors gathering 1 MW of heat energy a day on average. The air between the double glazing is heated by the sun and the warm air converted to hot water and distributed to other buildings.
Energy balanced between the buildings
Stockholm Water Front consists of three buildings with completely different energy requirements. The office building doesn’t use much energy in the evening and at night, while the hotel has its highest energy consumption in the morning and evening. This imbalance is used intelligently, so that energy is transferred between the buildings depending on demand.
Ice storage for cooling
The buildings are cooled by water drawn from the nearby Lake Klara. The water is stored in 250 tonne ice tanks in the basement at night and used at peak hours during the daytime. These measures make Stockholm Waterfront Congress Centre one of the most energy-efficient buildings in the world, achieving the LEED Gold standard.
Kungsbrohuset: halving energy demand
The other example is Kungsbrohuset, situated by Stockholm Central Station. Its energy solutions make the building so efficient that it only requires 51 kWh per sqm a year, which is half the energy consumption prescribed by the Swedish National Board of Housing, Building and Planning. Some of the other measures taken to enhance energy efficiency in the building are described below.
Weather forecasting to balance heat
Weather forecasting is used to plan and optimise heating. By using continuously updated weather forecasts, it’s possible to control heat consumption in the building. The method is to increase the heating supply several hours before an expected temperature drop outside, thus reducing the number of incidents of overheating.
Using waste heat and cold water from surroundings
The building recovers excess heat generated by the hundreds of thousands of commuters that pass through Central Station every day. This excess heat is transformed through heat exchangers into warm water, which supplies 15–20% of Kungsbrohuset’s heating requirements. Cold water from the Lake Klara is used for cooling.
The exterior facade is made entirely of glass, while the interior facade is 60% glass. This provides a unique method to reduce heat emission. Insulating materials keep the temperature between the facades about 5 degrees warmer than the indoor temperature. This significantly reduces the energy consumption required to heat the property. A Swedish invention that collects sunlight from the roof using fibre optics and brings it into the building’s interior also contributes to greater energy efficiency and a more pleasant working environment.
Other environmentally sustainable solutions
• The building has a green mode, which interrupts the energy supply to mobile phone chargers, TV receivers and other appliances to reduce unnecessary power consumption at night and weekends.
• The building offers charging facilities for electric cars.