Electricity + Control August 2017

TEMPERATURE MEASUREMENT

Ground Water Cooling System

Jesper Thurbo, Danfoss

I guess it comes as no surprise to hear that the essentials of running a luxury hotel are something to do with exquisite catering, gorgeous interior design, and innova- tive technology.

Take Note!

Natural groundwater reservoirs arewell suited to storage of thermal energy over long periods. Use of ATES technology significantly reduces en- ergy consumption and therefore CO 2 emissions. An ATES plant is easy to establish in a manner that has no conflict with groundwater extraction for drinkingwater supply.

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D o you know that the high-tech installations include cutting-edge heating, ventilation and air conditioning? This is precisely the secret to the luxurious Crowne Plaza Copenhagen Towers Hotel having trimmed its CO 2 footprint and the energy bill. Thanks to a groundbreaking heat- ing and cooling system hidden in the basement, electricity consumption is now 60% lower than 4 800 comparable hotels in the InterContinental Hotel Group (IHG). Due to this and other initia- tives this hotel runs five times as efficiently as the IHG standard. It has won numerous international awards, including that of the most environmentally friendly hotel in the world. Yes. The ground water heating and cooling system installed here is known as Aquifer Thermal Energy Storage (ATES). ATES is an innovative open-loop geothermal technology, in use at over 1 000 sites mainly in Scandinavia and the Netherlands as an energy-conserving measure for large buildings. It is gaining popularity with good reason. For a start, it can reduce the total energy consumption for cooling and heating of a building by approximately 70%; and more than 90% for cooling alone, com- pared to conventional technologies. The ATES system delivers a Coefficient of Per- formance (COP) of up to 40, which means that the 90% energy savings thanks to smart HVAC alone?

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consumption and therefore in CO 2 emissions aris- ing from fossil-fuel-based energy production. An ATES plant is easy to establish and has only lim- ited thermal effect upon the natural groundwater reservoir. It can be established in a manner that ensures no conflict with groundwater extraction for drinking water supply. New territory pays off Allan Agerholm (Chief Hospitality Officer, BC Hos- pitality Group A/S) was on the Crowne Plaza team that originally established the ATES system, and sums up the results: “When you venture into new territory, as we did, putting in the first groundwa- ter based heating and cooling system in Denmark, you’re always a little bit worried; will your partners deliver? And I have to say that working with Dan- foss on this project has been a tremendous suc- cess. “We’ve had very few challenges. In fact, the system has delivered precisely what it was calcu- lated in theory to do; that is to deliver in the re- gion of 90% energy savings during the summer months, and in the region of 60% during the win- ter, which is really outstanding.” So how does it work? The Crowne Plaza ATES used a suitable natural ground water reservoir, known as an aquifer, into which two thermal wells were installed, for stor-

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The system has delivered precisely what it was calculated in theory to do – 90% energy savings in

summer, and 60% in winter

cooling power is up to 40 times the electricity consumed by the installation. Normally the COP for a building of this size would be only four or five. The Danish expert in ATES is Stig Niemi Sørensen, PhD, who explains that natural groundwa- ter reservoirs are well-suited to storage of thermal energy over long periods. Use of ATES tech- nology is well-proven to enable significant reduction in energy

abbreviations

ATES – Aquifer Thermal Energy Storage COP – Coefficient of Performance HVAC –Heat, Ventilation, Air Conditioning IHG – InterContinental Hotel Group VSD – Variable Speed Drive

18 Electricity + Control

AUGUST 2017