Crowne Plaza Copenhagen Towers The world s greenest hotel

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1 Crowne Plaza Copenhagen Towers The world s greenest hotel The new Crowne Plaza Copenhagen Towers in Copenhagen, has been designed with sustainability in top of mind. The hotel is one of the first hotels to meet the standards in the EU Green Building Programme. In terms of energy consumption and the environment, the hotel is several steps ahead of most other hotels in the world. By Jens Nørgaard, Application Manager for Grundfos Commercial Building Services Crowne Plaza in Copenhagen is a luxury hotel in international class when it comes to guest comfort, service, and conference facilities ect. At the first glance there is nothing green about the 85 m tall, black hotel, Crowne Plaza. However beyond the shiny facade there is a building that sets new standards for sustainability and low energy consumption. This hotel shows that comfort really can go hand in hand with sustainable solutions. Innovative energy solutions In order for energy consumption and CO2 emissions to be as low as possible, the hotel insisted on the most innovative energy technology throughout the building. In the basement of Crowne Plaza one of the worlds most advanced ATES (Aquafer Thermal Energy Storage) systems are located. With this system cold groundwater is used for cooling the guest rooms during summer. The heat rejected from this process is reused for heating during the winter. Combined with the building s variable airflow volume (VAV) ventilation system it is ensured that guest rooms, lobby as well as conference facilities are cooled, heated and ventilated individually and in accordance to the actual load. All in all the building s ATES and VAV systems ensure that costs for air-conditioning and heating is significantly lower than that of

2 other hotels. The system delivers 4.1 MW of cooling and 2.4 MW heating. The hotel was opened in 2009 but has already won recognition by winning several prizes. Latest by the organisation Skål International EcoTourism Award in October 2010 for the project The World s Greenest Hotel. Aquifer Thermal Energy Storage, (ATES) for heating and cooling To find the Copenhagen Tower s star performer in terms of reduction of energy consumption we have to go underground. Here, the ATES system Aquifer Thermal Energy Storage delivers cooling and heating for the building s high performance HVAC system. This system represents one of Denmark s first ground-water based cooling and heating systems. The hotel s total annual energy consumption is a remarkable 51 kwh per square meter for heating, air-conditioning, domestic hot water and ventilation. And the ekstra investment in the ATES system really pays off. The ATES system has a projected payback time of only six to seven years. This means that the Crowne Plaza Copenhagen Towers is both greener and in the long term more profitable than its competitors. Cooling mode during summer Groundwater from an 8 C cold well is circulated through an exchanger that cools water in the hotel s hydronic air-conditioning system. In this process the groundwater is heated and subsequently returned to a warm well in the aquifer. The warm well and the surrounding groundwater heats up to approx. 16 C during the cooling season. During this process no active refrigeration is required. The COP is as high as 41. The free cooling process covers up to 60% of the buildings total cooling need. Two ammonia chillers are standing by to cover peak loads between 60 and 100%. Heat rejected from the chiller s condenser is stored in the warm groundwater well too. By reversing the flow the warm groundwater is now available for heating during the winter season. Load [%] Capacity Groundwater Chiller Pumps Compressor COP ESEER [ratio] x28 2x x28 1x x x Table showing ATES system performance in accordance to the cooling load

3 Heating mode during winter During the heating season the chiller is turned into a heat pump. After the cooling season the warm well is charged with warm ground water which is utilized by the heat pump during the heating season. In this way the ground water is cooled and returned to the aquifier s cold well. The water is returned at a temperature similar to the temperature of the untouched ground water. In order to maintain a high COP on the heat pump, the hydronic heating system is designed as a low temperature system with a flow temperature of 60 C and a return temperature of 30 C. The ATES system must achieve thermal balance over the course of a full cooling / heating cycle. If there is excess heat in the warm well at the end of the heating season, this is removed using a back-up cooling tower. In peak load situations and when the aquifier s warm well temperature sinks to a temperature close to the temperature of untouched ground water, a stand-by heating source can be activated. This additional heating source is a district heating system. Load [%] Capacity Temperature set [ C] Pumps Compressor COP ESEER [ratio] /60 3x28 2x /55 3x28 2x /50 3x17 1x /45 2x7 1x Table showing ATES system performance in accordance to the heating load Highly compact measures The ATES system is designed extremely compact. The entire system - without distribution equipment - occupies only 8 x 10 meters. m 3 of water per hour. The upper 20 m consists of sands and gravel and larger stone, followed by a layer with relatively dense lime without any significant groundwater content. At a depth of approx. 40 m the more fractured bryozokalk is found. The upper 40 meters is fitted with a closed pipe that is permanently fixed in the soil and limestone layers with concrete. From approx. 40 to 100 meter the well is made as an open well in the cracked limestone layer. The wells are located in the building s two storey basement. The wells are artesian in basement level. The ATES system in outline To maximize energy savings and high heating temperatures, ammonia is used as a refrigerant. Moreover, refrigeration machines optimized application of frequency converter and open economiser. The ground water wells There are three cold water wells and three hot water wells (depth: 110 m) each supplying 80 Cooling capacity with groundwater only: 2.1 MW at 12/18 C, COP: 41 Cooling capacity with groundwater and chillers: 4.1 MW at 12/18 C, COP: 14 Heating capacity: 2.4 MW at 60/30 C, COP: 4.0. Chillers: Ammonia (NH 3 ) variable speed screw compressors with plate type evaporator and condenser with oil separator and cooler.

4 Frequency converters throughout The two chillers are fitted with frequency controlled screw compressors which enable the chillers to adjust the capacity to the actual load, with the same efficiency. Chillers rarely run at full capacity and it is important that the efficiency is high, regardless of at which duty point the chillers are running. Ground water pumps and all other pumps both in the ATES system and in the hydronic air-con and heating systems are provided with frequency converters in order to let the pumps adapt to variations in flow requirements. Frequency converters are both built-in and delivered seperately. Grundfos TPE in-line pump, with built-in frequency converter Solar cells on three facades All sunny facades on Copenhagen Towers are equipped with ultra-thin high technology solar cell panels. The installation constitutes Northern Europe s largest private array of solar cells, producing annually more than 200,000 kwh. This constitutes around 15% of the hotel s annual power consumption. The total solar cell capacity is 270 kw. The remaining 85% is bought as green energy produced by wind turbines. Both the energy efficient ATES system and the solar cells are part of the hotel s green profile. More green initiatives Several other initiatives have been taken to reduce CO2 emissions as far as possible and to ensure that the hotel achieves its aim of sustainability. The hotel s guests literally get to feel the green profile of the hotel. Everything from the shampoo bottle to the tooth brush is made of corn and potato starch. The revolutionary, organic material looks and feels like plastic but is both recyclable and biodegradable. And of course the products contain no parabenes or allergenic substances. The hotel information folder and similar printed products have been done away with. All information to the hotel guests are now delivered electronically in an interactive TV screen information system that is very similar to web pages and is therefore intuitive. All components in the hotel IT infrastructure both switches, routers, access points and not least laptops- are chosen from the energy consumption and recyclability even taking the packaging into consideration. The kitchen is wherever possible built up around the latest induction technology. Induction stands out by turning on and off instantly and heating immediately and only where it is needed. Thereby heat waste in the kitchens is minimized drastically. Handling of waste products from the kitchen is another substantial investment in technology and environment. All food waste in the hotel is grinded and stored in a tank in the basement. The waste is transported to a biogas plant and the remains from this process are used to fertilize farm land. Food is delivered only 3 times a week instead of once or twice every day. The aim is to reduce the carbon emission from transportation of goods and collection of packaging. Food deliveries are as far as possible only accepted from companies located within a radius of 300 kilometres. The traditional company car solution has been eliminated. Crowne Plaza has bought two electric Citroën C1 s which are mainly used by the hotel s sales team. The hotel s staff is encouraged to use public transportation, as there is no employee parking at the hotel. All guest rooms are ventilated with VAV (Variable Air Volume). The air volume is

5 automatically adapted according to temperature and to occupancy. Grundfos products Grundfos delivered all pumps for the buildings air-con, heating, water boosting. Following products were supplied specificlly for the ATES system: 3 pcs. NB /219 end-suction pumps with external frequency converters. Primary pumps in the buildings hydronic heating system 3 pcs. NB /290 end-suction pumps with external frequency converters. Primary pumps in the buildings hydronic cooling system 2 pcs. NBE /254 end-suction pumps with internal frequency converters. The pumps are dedicated for the chillers condenser cirquits. 2 pcs. NBE /195 end-suction pumps with internal frequency converters. The pumps are dedicated for the chillers evaporator cirquits. One TPE /4 in-line pump pump with internal frequency converter. Serves primary cooling tower cirquit. One TPE /4 in-line pump pump with internal frequency converter. Serves secondary cooling tower cirquit.