Located in the restad district, the Crowne Plaza Copenhagen is a luxury business hotel that incorporated sustainability as an initial design concept.
The Crowne Plaza Copenhagen, located in the Restad district, is a luxury hotel that consumes 77% less electricity and 25% less water than comparable Crowne Plaza International hotels. This result has raised the construction benchmark for hotels worldwide.
The project's outstanding energy and water conservation is attributed to a solid foundation combined with technological innovation and best practices. It has achieved ISO 14001 environmental certification and the internationally recognized Sustainable Tourism Award (SKAL), making it one of the world's most environmentally friendly hotels.
Innovative underground water cooling system
To minimize energy consumption and carbon dioxide emissions, the hotel consistently employs state-of-the-art energy technologies. Among the most important is an innovative underground water cooling system that provides heating, ventilation, and air conditioning for the hotel's 366 guest rooms, meeting rooms, kitchen, restaurant, and offices in the annex.
Allan Agerholm, Chief Hotel Management Officer of BC Hotels, summarized the results as follows: "I have to say, the collaboration with Danfoss on this project has been a tremendous success. We faced almost no challenges. In fact, the system has accomplished what was theoretically calculated, which is truly remarkable."
United Nations Global Compact
The Crowne Plaza Copenhagen meets the requirements of the EU's green building program. It is also the first hotel in Denmark to be registered under the UN Global Compact. The hotel has been built in accordance with the Danish building code "Low Energy Standard" (Level 2), which stipulates that energy consumption per square meter per year shall not exceed 42.6 kWh.
VLT® HVAC inverters provide basic capacity control, enabling Aquifer Thermal Energy Storage (ATES) systems to deliver the latest energy savings in hotel heating and cooling.
2,500 square meters of solar panels were installed.
The Crowne Plaza Copenhagen also features 2,500 square meters of specially modified solar panels installed on three of its exterior walls, providing year-round power to the hotel. This is the largest solar panel array installed on a building in Denmark, producing 200 megawatts of electricity annually, equivalent to the combined electricity consumption of 65 standard detached houses.
The 200 megawatt-hours of electricity generated annually by solar cells account for approximately 10% of the hotel's electricity consumption. The remaining 90% is purchased from green energy sources produced by EnergiDanmark, which provides basic capacity control using VLT® HVAC inverters from wind turbines, enabling the Aquifer Thermal Energy Storage (ATES) system to deliver state-of-the-art energy savings for heating and cooling.
The underground water heating and cooling system, along with solar panels, forms the basis of the hotel's "green" image. To maximize benefits through energy efficiency optimization, the system is equipped with VLT® HVAC inverters and Danfoss solar inverters.
Energy-saving underground water-cooled heat pump
At two locations near the hotel, the underground water cooling system needs to be installed in two phases, extending 110 meters underground. In the summer, groundwater at 7-9°C is pumped through a well to the hotel's storage tank, where it is then distributed to each room via heat exchangers. This lowers the room temperature to an ideal level without the need for air conditioning, while simultaneously collecting and storing the heat accumulated during the summer in thermal storage tanks. The COP (Coefficient of Performance) can be as high as 40, meaning the system's cooling capacity is 40 times that of its electricity consumption.
Only during peak load periods do the two chiller units assist the underground water cooling system to ensure sufficient cooling capacity. In winter, water from the reservoir, carrying the heat stored during the summer, is pumped back to the well via a heat exchanger. The heat energy from the heat exchanger is then used by two heat pumps to raise the temperature to 55°C, which is then used to heat the hotel rooms. The combination of underground water cooling and heat pumps is an innovative solution. “It allows us to use the heat recovered in the summer during the cold winter,” explains Peter Andersen, property manager of the Copenhagen Tower. As the first representative of an underground water cooling and heating system in Denmark, this installation saves the hotel 90% on its air conditioning energy consumption.
High-efficiency VLT® frequency converter
Two GEAGrenco heat pumps, each with a combined output of 2,400 kW, utilize a VLT® HVACDriveFC102 inverter to control the screw compressor, allowing the heat pumps to continuously adjust their thermal output from low to full capacity while maintaining the same efficiency. Since heat pumps do not always operate at full load, efficient energy consumption is crucial regardless of whether the system is at full or half load.
All groundwater pumps are controlled by VLT® HVACDriveFC102 frequency converters, which are also used for speed control of pumps used in the hotel's heating and air conditioning systems. This helps ensure good energy control and optimal energy savings for the pump system.
Electronic air volume control
The hotel also implemented other measures to reduce carbon dioxide emissions, contributing to its long-term sustainability goals. For example, all rooms were equipped with VAV (Variable Air Volume) ventilation systems. “This means that the hotel’s groundwater heating and cooling systems, as well as solar panels, are part of the hotel’s ‘green’ standards. Cooling water from heat exchangers circulates throughout the building to cool rooms to the desired temperature without the need for active cooling. Airflow is electronically controlled in each room as needed, and low-energy smart lighting systems were installed in the hotel’s corridors. Reading lights in the guest rooms also use LED lighting,” said Andersen. Another measure was the use of water-saving equipment, including energy-efficient and water-saving dishwashers. All unnecessary products and packaging were removed. Guest rooms featured LED flat-screen TVs, which were the most energy-efficient available at the time.
Computer-controlled equipment
All electronic devices are controlled by the front desk via computer, ensuring that power consumption in rooms is kept to a minimum when not in use. The refrigerator temperature is adjusted according to the time of day. All of the hotel's IT infrastructure, not just personal computers and laptops, was selected based on their energy characteristics and reusability. The hotel has even decided to abandon traditional hotel folders. All the information a hotel guest might need is displayed electronically and interactively on television in a familiar "internet page" format. "Our basic principle is to achieve sustainability without compromising service quality and guest comfort. I believe we have successfully achieved both goals," said Andersen.
