Groud source heat pump as part of the renewables-based arctic heating system

• Main Author: Nylund, Johanna
• Other Authors: Paatero, Jukka, Insinööritieteiden korkeakoulu, School of Engineering, Insinööritieteiden ja arkkitehtuurin tiedekunta, Sirén, Kai, Aalto-yliopisto, Aalto University
• Format: Master Thesis
• Language: Finnish
• Published: 2010
• Subjects: district heating; GSHP; GHE; BTES; heat pump; eco-efficiency; aluelämmitys; kalliolämpö; kalliolämpökenttä; lämpöpumppu; ekotehokkuus; Arctic; Sodankylä; Arktis*
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/98835

This thesis is part of the MATKA - project. MATKA - project is designed to explore and develop tourism in urban structure and examine how the tourism industry integrates sustainable regional development. The aim of this study was to dimension eco-efficient district heating system for the new tourist village in Ylläs. Heat pumps, biomass and solar energy-based system were examined for source of energy for district heating system. The new tourist village is planned to use passive and low-energy technology. Scenarios 1 and 2 with different district heating system extensions were constructed. Scenarios, however, proved to be almost identical that all the calculations for heating energy demand were done by using scenario two. In addition, the utility of low-energy technology was demonstrated through reference case. The annual saving of the heating energy was 7.6 GWh by using low-energy construction. Two different energy systems were explored. On the energy system 1 the basic energy is produced by heat pump and the peak energy by pellet. On the energy system 2 the basic energy was produced by wood chip and the peak energy by the pellet. The chosen energy shares based on an estimate and do not necessarily corresponds to economic optima. The solar energy can be used for production of hot water on the summer time and loading the boreholes in the ground. The conclusion was that it is hardly profitable to invest to solar energy. Boreholes of energy system 1 were dimensioned by EED which is a PC-program for borehole heat exchanger design. Several dimensioning were done by EED but the temperature of heat transfer fluid did not settled. Thermal energy was only extracted from the ground when the decrease in temperature of heat transfer fluid was expected. In addition, in Sodankylä district the ground surface temperature is -1 °C, which is risen by the geothermal gradient 1 °C / 100 m. These facts caused that heat transfer fluid temperature decreased so low, that it may call into question whether it merely is not even wise to ...