At the Crowne Plaza Copenhagen Towers, they have consistently applied state-of-the-art environmental and energy technology in order to become a sustainable hotel with a CO2 neutral building operation. One of the key initiatives is the installation of an innovative groundwater cooling system which provides both heating and cooling to 366 hotel rooms, the conference room section, kitchen, restaurant and the ancillary office building. Danfoss frequency converters regulate the speed of the heat pumps needed to control the heat in the groundwater-based cooling and heating system. This is the first of its kind in Denmark, and it saves up to 90% of the energy used for heating and cooling the hotel.
Frequency converters make cooling and heating system more efficient
Cold groundwater is pumped up during the summer and directed to the hotel’s basement where it cools down the water in the internal cooling-heating system. In this way, a comfortable room temperature is achieved – even on hot days. The groundwater is then returned into the ground, where the water accumulates heat during the summer for use in the winter. During winter, the water which was heated during the summer is pumped up again and distributed through the heating system and back into the ground. While the groundwater was used for cooling during the summer, it is now used for heating. The heat energy is sent through two heat pumps which raise the temperature to heat the hotel rooms and offices. Danfoss frequency converters adjust the heat pump capacity by regulating the speed and it results in very high energy-efficiency.
“The combination of groundwater cooling and heat pumps is an innovative solution. With this, we can reuse the heat accumulated during the summer and use it in the winter,” says Peter Andersen, real estate director at Copenhagen Towers.
Moreover, there is a whole range of other pumps in the building that circulate water in the hotel’s internal heating and cooling system. They are variably speed controlled by frequency converters from Danfoss and contribute to major energy savings on the pump system.
Danfoss solar panel inverters convert sunlight into electric power
Copenhagen Towers has been installed with 2,500 custom-made solar cell panels on the hotel’s three facades facing the sun. It is northern Europe’s largest building-integrated solar cell park and it produces 170,000 kWh annually – equalling 10% of the hotel’s power consumption. Solar cell inverters from Danfoss convert direct current from each section of the solar cell facility to alternating current, which is distributed into the hotel’s power network. The inverters automatically optimise the output according to the quantity of power produced by the solar cells. If not enough solar power is produced, the inverters shut down automatically.
Lots of energy-saving initiatives
Meanwhile, many other energy-saving and environmentally-friendly measures have been introduced – such as the intelligent control of lighting and low-energy light sources, LED flat screens in every hotel room and computer-control of all electronic equipment from the reception so the consumption is kept as low as possible when rooms are vacant. Furthermore, all of the components of the hotel’s IT infrastructure – not least computers and laptops – were chosen on grounds of energy-efficiency and degree of reusability.
“It is our basic principle to be a sustainable hotel, without compromising quality and the comfort of the guests. I think we obtain both,” says Peter Andersen.
Facts on the hotel’s sustainability:
Copenhagen Towers complies with the Green Building standard, as required by the EU. It is also the first hotel in Denmark to have joined the UN’s Global Compact. The hotel was built according to the Danish Low Energy Class 2 standard, which means that the energy consumption must not exceed 42.6 kWh per m2 per year. This corresponds to savings of 53% when compared with conventional buildings. Copenhagen Towers is estimated to save 1,373 tons of CO2 on an annual basis.
Picture to the right: Peter Andersen, real estate director at Copenhagen Towers with one of the frequency converters that adjust the heat pump capacity.