Sep 28 2009
Integrated heating and cooling systems in sport halls were the main topic of this research project. Also, the use of carbon dioxide as a heat transfer medium and periodic heat pump process with storage tanks was studied.
CO2 case facility was Vahterus skiing ring in the city of Uusikaupunki. The skiing ring is 1 000 meter long and 5 meter wide built using prefabricated elements. The maximum difference in altitude is 7 meter. CO2 is used as heat transfer media both in cooling pipes under the skiing track and in the pipelines supplying the air heat exchangers.
Collecting of data in Uusikaupunki was done with two individual measurement systems. The first one was property monitoring system collecting data from the skiing pipe, such as temperatures, moisture etc. The other system was connected to cooling equipment of the skiing pipe. The aim of measurements was to analyze operation of CO2 pipes in skiing pipe and produce data for modeling purposes. The indoor temperature was steady being 0 °C and - 3 °C in the snow track.
The second objective was to further develop a CO2 pipeline model, using the skiing pipe as case facility. The aim was to study how carbon dioxide operates as a heat transfer medium for cooling the skiing pipe. A network model was constructed, which enables networks of both glycol water and carbon dioxide to be calculated and analyzed. Carbon dioxide cooling process takes advantage of the phase change energy by evaporating carbon dioxide to achieve the cooling effect. Liquid carbon dioxide is pumped to the cooling pipes under the skiing track and air heat exchangers where it evaporates. The evaporation is not complete in order to avoid the need for larger heat exchanger area due to low heat transfer coefficient in high qualities. The return flow is in two phases.
The potential of using condensing heat gained from cooling processes in ice hockey halls for heating swimming halls, sporting halls or other public buildings located close enough was investigated.
Source: http://www.vtt.fi/inf/pdf/tiedotteet/2009/T2476.pdf