Studying the feasibility of installing a temperature independent snowmaking system with heat recovery : Case study for the ski resort of Astún

Abstract: A research on analysing the feasibility and the benefits obtained from the utilisation of the heat surplus from temperature independent snowmaking systems is proposed. The interest of this research relies on the fact that it is a way of making it viable both economically and environmentally, to use these systems, which are the solution for snow scarcity due to global warming.This will be done by studying the performance of three different alternatives for the installation of a TIS, considering it with and without heat recovery in order to show the importance of the latter. The study will be performed for the ski resort of Astún, in the Spanish Pyrenees, considering the desire to guarantee a ski slope of 3 km from November till end of April. The three cases studied are: • Case I: Temperature Independent Snowmaking system without heat recovery • Case II: Temperature Independent Snowmaking system with direct heat recovery • Case III: Temperature Independent Snowmaking system with direct heat recovery and snow storage The feasibility of each of the cases will be studied based on costs and energy savings and consumptions, while ecological impact, maintenance costs or the interest rates will not be included in order to simplify the results. The heat recovery will be performed thanks to a CO2 heat pump that will deliver over 6 GWh through water at 70 ºC to the residential and commercial buildings of the ski resort. The heat recovery has only been studied in detail for direct recovery, but the possibility of indirect heat recovery would be interesting in other situations, therefore, it has also been briefly described.As a way of introducing and justifying the project, a literature review has been performed, on the impact of climate change and the need for snowmaking, and also on the different snowmaking technologies and their limitations, leading finally to the need for temperature independent snowmaking. Moreover, calculations and simulations including heat transfer, fluid dynamics and theory of refrigeration technology are conducted. Finally, putting that together with estimated investment costs and prices gathered either from available public sources or personal communication with suppliers, the final comparison of the cases is performed.Based on the obtained results, the most suitable solution for the ski resort of Astún, considering the current heat demand of its buildings, is the case II, installation of a TIS with direct heat recovery. This case has a total investment cost of 1.957.464 €, and due to the savings generated from the reused heat, it comes with yearly savings of -249.872 €, which implies a payback time lower than 8 years, making it the most viable alternative.