The building of Modern Languages and the Rector's Office of the University of Gdańsk in Gdańsk certainly stands out among the buildings erected within the campus. The building with an area of 20,000 m2 was awarded by the President of Gdańsk for the best architectural projects in 2011-2015. Students of modern language studies have at their disposal the most modern building in Northern Poland with lecture halls, classrooms and a theater hall. It is equipped with multimedia projectors, interactive boards, state-of-the-art infrastructure for the training of translators, actors and teachers.
Not only the architecture is worth noting, but also the engineering solutions. Although these are not very visible to an ordinary observer, because they are hidden under the outside parking lot.
The clou of the technical solution is the use of an alternative source of geothermal energy in the form of a ground air heat exchanger (GPWC). The idea behind the operation of GPWC is to use the ground temperature oscillating at the level of approx. 8-12 ° C (at a depth of approx. 1.5 m below the ground ordinate) to heat or cool the air flowing through the exchanger duct system and further used by air handling units.
Experience shows that thanks to the use of GPWC it is possible to increase the temperature of the supplied air by 22 ° C in winter and to lower it by a maximum of 16 ° C in summer. However, the practice of the implemented installations has shown that the average temperature increase or decrease is approx. 10-12 ° C. Thanks to this, the air supplied to the air handling unit is pre-warmed in winter and cooled in summer. This translates into lower consumption of thermal energy needed to prepare fresh air to the level of the required temperature of the air supplied to the building.
This solution also has a great advantage in very low winter temperatures. In a traditional heat recovery unit, under such conditions it is necessary to either reduce the efficiency of heat recovery or to partially bypass the recuperator, which results in increased heat consumption by the air heater due to the anti-frost protection. Thanks to GPWC, even at extremely low outside temperatures, there is no risk of frosting the heat recovery exchanger in the AHU.
From among several types of GPWC for the Neofilology building, a system working with 250 mm diameter tubular ground heat exchangers was selected. Cables have been designed with an internal antibacterial layer made of special polypropylene with increased thermal conductivity. They are placed in two layers, one above the other, buried in the ground to a depth of about 3.0 m. The total length of the pipelines is impressive and amounts to 5142 meters. The whole is divided into 3 sections, and the total air capacity is quite large and amounts to 55,000 m3 / h, making it one of the largest GPWC installed in Poland.