IIR Member news: Star Refrigeration installs ammonia chillers in an indoor skiing facility

After 90 years of existence, indoor skiing now uses modern and energy efficient technologies. Star Refrigeration participates in this evolution with its ammonia chillers.

The IIR corporate member Star Refrigeration was founded in 1970 and has grown to become the largest independent refrigeration and heating, ventilation and air conditioning (HVAC) contractor in the United Kingdom (UK). They work with various industries from different sectors, including temperature controlled storage, food and drink processing, chemical, and HVAC among others.


One of the sectors covered by Star Refrigeration is "leisure and ice". The company has designed over 80% of the ice rink facilities in the UK and provided cutting-edge cooling technologies to maintain the low temperatures necessary in this kind of infrastructures. Recently, Star Refrigeration has been involved in the improvement of a cooling system in a more original facility: an indoor skiing centre.



A little bit of history



The first indoor ski hall was opened in Vienna (Austria) in 1927 in the abandoned Nordwestbahnhof train station. Called Schneepalast (meaning Snow Palace), it had a 4,000 m2 surface and was equipped with a 20 metres high ski slope built on a coconut scaffolding.The artificial snow was conceived by the British chemist Laurence Clarke Ayscough. It was made of washing soda or similar crystals for 65%, of filling material such as sawdust or wood pulp for 28%, and of water for 7%1. 152 tonnes of snow were manufactured in a chemistry factory located in Lower Austria. The Schneepalast closed in 1943.









In the last decades, the indoor ski resort built in Dubai (Saudi Arabia) got a great deal of media attention because of the exceptional climatic conditions in which it was built: the park maintains a temperature of -1°C to 2°C throughout the year, even in summer, when outdoor temperatures exceed 40°C. It also was the largest indoor ski resort in the world, with a 400 metre slope. In 2015 Dubai announced it was about to build an even larger indoor ski resort, with a 1.2 kilometre run2. But indoor skiing is in fact a relatively common practice in Europe.

In the United Kingdom for instance, 6 facilities already exist (five in England and one in Scottland). The first one opened in 1994 in Tamworth, Staffordshire. A second snow centre, called Snozone, was opened in 2000 in Milton Keynes, Buckinghamshire. Its ski slope is 170 metres long. Star Refrigeration recently worked for the latter.




Snozone Milton Keynes case study



In 1999, the year before the snow centre of Milton Keynes opened, R404A chillers were installed to maintain at -4°C air temperature and to contain 1500 tonnes of snow and ice. But as the years went by, the system became more unreliable, especially in summer, when outside temperatures increased. A temporary chiller plant was required during this season to augment cooling from the R404A chillers. Since HFCs are being phased out and should be banned by 2020, Snozone decided to change the refrigerant in its cooling plant. They already used ammonia in their other facility, located in Castleford, Yorkshire, and they were satisfied with this refrigerant, which they found extremely reliable, according to Kyle Bell, Snozone's Operations Director3.



Star Refrigeration had to overcome two main challenges to move from R404A to ammonia:


  • ensure continuity of business during the project;
  • find a new location for the new chiller plant, since the ancient one was unsuitable to retrofit a new ammonia plant.
The change over ancient chillers to the new ones was achieved without any cooling outage.


The two ammonia chillers (Azanechillers 2.0) measure 9.7 metres long. They are rated for 360 kW capacity chilling ethylene glycol from -10 to -13°C. Vahterus plate and shell evaporators allow a close refrigerant approach while minimising ammonia charge to only 85 kg per chiller. The chillers were installed on the paved area outside the plant room. A careful survey was conducted to ensure that they did not obstruct any underground services or impact on traffic movement or parking adjacent on the site access road. A louvred perimeter wall was specified to screen the chillers from public access that also allowed adequate air flow onto the air cooled condenser coils.


Since the installation of the new chillers, drastic energy savings have been achieved: in the first 4-month period of operation, the electricity usage was 661,255 kWh compared to 1,511,062 kWh for the same period in 2016. This 56% energy saving improved the profitability of the business and helped to justify the investment in new plant. The environmental impact has also been improved with a drop in emissions of 700 tonnes of CO2.



View of Snozone, Milton Keynes © Star Refrigeration


1 LAURENCE CLARKE AYSCOUGH. Improvements in or relating to tracks for skiing, tobogganing and like purposes. Patent GB285998A. November 26, 1926.


2 IIR. World's largest indoor ski slope in Dubai. IIR news, October 12, 2015. Link



3 STAR REFRIGERATION. Star’s low charge ammonia chillers catapult Snozone’s savings on electricity and CO2 emissions. Star Refrigeration website. Link