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Frozen Choices: Propane, Ammonia, and CO2 Evaluated in a KTH Master Thesis for Ice Rink Efficiency

In the pursuit of sustainable development, the quest for energy-efficient solutions for commercial buildings becomes increasingly crucial. A recent Master's thesis conducted at EKA and KTH by Pendar Hemati, student from Universitat Politècnica de València, delved into the energy-intensive nature of ice rinks, aiming to unveil the most efficient energy systems. Titled "Comparative Analysis of Modern Energy Systems for Ice Rinks", the thesis explores innovative approaches to enhancing energy efficiency in these facilities.


Ice rinks, known for their substantial energy consumption, averaging around 1,000 MWh annually, require simultaneous heating and cooling, making their energy dynamics complex. The thesis's objective is to pinpoint the most energy-efficient energy system for ice rinks by evaluating various modifications and refrigerants, with a particular focus on ammonia, CO2, and propane systems, specifically in northern climates.

Key Findings:

Ammonia Energy System:

  • A traditional integrated ammonia ice rink consumes approximately 340 MWh per year.

  • Efficiency measures, such as using aqua ammonia and an auxiliary heat pump, result in noteworthy energy savings of 12.9%.

CO2 Energy System:

  • A state-of-the-art trans-critical CO2 system, incorporating parallel compression, stands out by consuming 42.6% less energy than a conventional ammonia system.

  • This superior performance is attributed to the unique ability of CO2 systems to operate as direct systems, eliminating the need for indirect heat transfer. By doing so, they significantly minimize auxiliary equipment energy consumption.

Propane Energy System:

  • Propane, introduced as a novel refrigerant in ice rinks, underwent a comprehensive evaluation and comparison against ammonia and CO2.

  • Findings reveal that a modern integrated propane system, featuring parallel compression and an auxiliary heat pump, is more energy-efficient than traditional ammonia systems. However, it requires more energy compared to modern ammonia or CO2 systems.

Waste Heat Recovery:

  • Waste heat recovery emerges as a pivotal feature across all systems, further enhancing overall sustainability.

Environmental Impact:

  • All systems utilize environmentally friendly refrigerants, with their environmental impact primarily tied to electricity consumption.

Read or download the whole Pendar Hemati’s thesis here:

More about the author:

Pendar Hemati holds a Master's degree in Sustainable Energy Engineering from KTH Royal Institute of Technology and an additional Master's in Energy Technologies for Sustainable Development from Universitat Politècnica de València. Currently serving as a Project Engineer at Atlas Copco, the author's expertise extends to a diverse range of roles, including Design Engineer at KTH Hyperloop and Research Intern at Chalmers University of Technology. The author's recent contribution involves a Master's Thesis at EKA - Energi & Kylanalys AB, focusing on a comparative analysis of modern energy systems for ice rinks, showcasing a commitment to sustainable energy solutions and innovative engineering practices.

Naturally sustainable engineering solutions.


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