Ensuring passenger comfort in airport terminals is a goal that all airport operators strive to achieve, but the process of delivering heating and cooling can be expensive and have an adverse impact on the environment. The design and construction of new airport terminals provide developers with the opportunity to explore the latest innovations in environmental management technologies so as to reduce costs and carbon footprint.
Oslo Airport, Gardermoen, is the main international and domestic hub in Norway, connecting to 28 domestic and more than 160 international destinations. It is the second busiest airport in the Nordic countries handling 28 million passengers in 2018. In order to accommodate growth in passenger numbers, a new terminal was built that to increase capacity. The new 120,000m² terminal and 63,000m² North Pier were constructed with an aim to achievie a BREEAM rating of 'Excellent', and will use 50% less energy compared with the existing terminal.
One innovative element of the technologies that will contribute to the BREEAM rating is the cooling system which will utilise snow. The snow cooling system has been designed to use up to 30,000m³ of snow collected during winter and stored in an 8,000m² basin on the north side of the terminal. The basin will be covered with wood chips for insulation purposes. When the new terminal was opened in 2017, Oslo Airport became one of the first airports in the world to use snow as an energy solution.
Whereas the snow cooling system is highly innovative and carbon friendly, it does rely on established technologies to make it work. Amongst the range of technologies are pumps, valves and filters for transport the melting snow from the basin into the heat exchanger to produce cooling fluid at the correct temperature.
Selection of equipment done by experts
The selection of pumps and developing the most appropriate working environment has been a job for experts in fluid handling, which is why AxFlow Norway with its long association of providing pumping equipment at Oslo Airport was brought in for the cooling station development project. "Having been a long term supplier of pumps for Oslo Airport for applications such as wastewater and de-icing water, our engineers were wholly familiar with the airport's pumping systems and requirements," reports Thor Woldvik "Also, engineering personnel at the Airport were also familiar with the Hidrostal pumps that we provide, so it made sense to continue working together on this new project."
The cooling system starts with melted snow entering the pump house via filters that remove grits and other solids that are gathered up when snow is collected from runways and other parts of the airport. As debris inevitably builds up on the filters, cleaning them on a continuous basis was seen as a necessity.
For pumping the filtered chilled water to the heat exchanger, AxFlow recommended using two Hidrostal FO6G-SMNIpumps mounted above wet pit containing the chilled water. Running at 1490rpm, the two 115mm diameter impeller pumps each have a capacity to handle 120lt/sec, but there is space for a third unit to accommodate future demands.
At the heart of this Hidrostal pump is a screw centrifugal impeller. This impeller comprises a single spiral vane, with large open passages, which makes a long slow turn from the axial inlet to the radial outlet. Extremely versatile in its applications, the impeller provides efficient handling of a range of liquids, often highly abrasive or corrosive in nature.
The pumps are particularly suited for both dry and wet pit applications where the combination of the screw centrifugal impeller and immersible motor can be considered the state-of-the art technology. Leakage of the pumped product is eliminated by tandem seals running in an oil bath, avoiding a situation commonly experienced with soft-packed glands.
Working in an operating and standby configuration, the pumps employ variable speed drives to control the water flow in accordance with the requirements of the terminal's heating and cooling needs. AxFlow's remit also included supplying the pipework and instrumentation for the pump house.