Towering 500 metres above Lake Lucerne, this historic hotel complex was developed in the second part of the 19th century and is currently undergoing renovation to restore it to its former glory.
With sustainability a priority during the renovations, the planners and developers of the new resort took a page from the book of its founders, Franz Josef Bucher and Josef Durrer. In 1888, these pioneers acquired a concession to extract drinking water from Lake Lucerne; today, the same approach is being adopted to derive energy from the lake.
The new resort meets 80% of its thermal needs and 100% of its cooling needs through a network of highly insulated pipes connected to an energy distribution centre that is almost CO2 neutral.
The mastermind behind this ingenious scheme is Wirthensohn, which recently became part of WSP. As one of the largest engineering consultancies in central Switzerland, Wirthensohn’s services include project management and consultancy in energy optimization and efficiency. The company is well-known in Switzerland for its innovation and commitment to sustainability. Operating in many market sectors, it has provided building services systems and consultancy for a wide range of prestigious projects.
Wirthensohn’s solution involves pumping water via pressure pipes from a depth of 37m in the lake up to the Bürgenstock Resort. Starting at a temperature between 5 and 7ºC, the water is used in the resort for heating, hot water, cooling and irrigation. It is then returned to the lake, powering a turbine that generates electricity in the process and recovering 50% of the electricity used for pumping.
Heating and Cooling
The heat is generated in an energy centre that uses two 650 kW heat pumps, supplemented by two liquefied gas boilers during the coldest time of winter, to provide hot water heat at 52ºC to all the resort’s buildings. Small local heat pumps are used to boost the water temperature in the older buildings where the temperature of the hot water heat is insufficient.
The lake water is also used to provide cool water for the whole resort using a plate heat exchanger. Distributed to the buildings in long-distance pipelines, this cool water provides cooling for the buildings in summer and, boosted by a chiller, ice-making for the rink.
Long involvement in a prestigious project
Wirthensohn has been involved in the renovation of the Bürgenstock Resort since 2011, not only designing the heating, cooling and energy solution for the entire site, but also planning the heating, air conditioning, building automation and coordination of building services for the Palace Hotel & Conferences, the Grand Residence Suites and the Diamond Domes (tennis domes).
Aesthetic considerations were a high priority on this listed landmark site, adding to the complexity of a unique project which involved many adjustments during the nine-year construction process. The first hotels, restaurants and other facilities opened to guests in 2017, with the grand opening of the entire Bürgenstock Resort set to take place in the spring of 2018.
For more information about the Bürgenstock Resort, visit https://www.buergenstock.ch/en