What it takes to be the world’s greenest hotel

It takes a lot of black to be green. The facade of the Crowne Plaza and Copenhagen Towers, a 10-minute drive from Copenhagen Airport, is a case in point. The exterior of the luxury business hotel has a layer of ultra-thin high technology solar cell panels, so that solar energy accounts for up to 50 per cent of the hotel’s energy needs, depending on the weather. The installation constitutes one of Europe’s largest private arrays of solar cells, producing about 200,000 kWh. For the balance energy, the building purchases green power from utilities – mainly wind energy.

Equally important to Crowne Plaza’s energy efficiency ecosystem is its Aquifer Thermal Energy Storage (ATES) system, located in the basement. What the ATES does is harness groundwater and pump it through the building, cooling the rooms in summer and heating them up in winter. Groundwater from an 8°C cold well is circulated through an exchanger that cools water in the hotel’s hydronic air-conditioning system. The groundwater is heated and subsequently returned to a warm well in the aquifer. The warm well and the surrounding groundwater heat up to approximately 16°C during the cooling season. During this process no active refrigeration is required. The ‘free cooling’ process covers up to 60 per cent of the building’s total cooling needs.

During winter, the heat rejected from the chiller’s condenser is stored in the warm groundwater well. By reversing the flow, the warm groundwater is now available for heating the rooms. The process leads to some heat rejection, but this is again reused for heating, so that there is negligible energy loss. The hotel’s total annual energy consumption is 51 kWh per sq m for heating, air-conditioning, domestic hot water and ventilation, against 300 kWh per sq m in a typical international hotel.

The ATES system is powered by the Grundfos Thinking Buildings programme. “It is substantially cheaper to transport heating and cooling via water than air,” explained Jens Nørgaard, Application Manager for Grundfos Commercial Building Services, to a group of visiting journalists from India. The heating/air-conditioning systems used predominantly in the Americas and Asia depend on pushing warm/cool air, which is highly inefficient, he pointed out.

“It is in the Grundfos DNA to invest now and reap the dividend later,” said Nørgaard. The increased installation cost is amply compensated by the energy savings over the decades, he added. The ATES investment has a payback time of just six-seven years.

It helps that Copenhagen is low-lying, is on the seacoast, and has plenty of underground water that is too hard to be potable, and can, therefore, be harnessed for HVAC (heating/ventilation/air conditioning) systems. Several Indian cities – Chennai, Mumbai, Kochi and Visakhapatnam, to name a few – share the very same conditions, and therefore, the model is easily replicable back home.

However, it calls for a change in “cooling customs”, said Nørgaard. “Air-conditioning by circulating air is very inefficient. But, it is very common in the US, Middle-East, China and India. It’s a long journey to make buildings around the world energy-efficient. But, it is happening.”

It’s not just heating and cooling. Crowne Plaza is green in other ways, too. From the shampoo bottle to toothbrush, every consumable in the rooms is made of corn and potato starch. The organic material looks and feels like plastic but is both recyclable and biodegradable, according to the hotel management.

The kitchen has no gas stove – only induction heating is used. All food waste is ground and stored in a basement tank, from where it is transported to a biogas plant. The remains are used as fertilisers. Food deliveries are mostly accepted only from companies located within a radius of 300 km.

The hotel staff are given electric cars for transportation. These can be recharged in the car park.

The room rates are comparable with other leading hotels in the city, so guests do not bear the burden of additional ‘green’ investments. The hotel, opened in 2009, has bagged the EcoTourism Award for the ‘World’s Greenest Hotel’. A title that it holds close to its working style.

(The writer was in Copenhagen at the invitation of Grundfos)

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