Stirling Curling Rink- UK’s first National Curling Academy.
H&K arranged for planning approval for the new external plant. Noise surveys were taken before and after the installation to prove it was no worse than the existing installation to the surroundings, particularly considering a new hotel was being built across from the facility.
Liaison with the Landlord and affected tenants was also a key consideration to minimise the impact of the refrigeration upgrade during and after installation.
Continuity of business was extremely important to Snozone. Not only did they want to avoid any loss of skiing amenities for their customers, they could not afford to have any sustained cooling outage as it would result in loss of their ski slope and possible adverse release of water into the centre’s shopping and restaurant outlets.
The location of 2 off 9.7m long chillers on the paved area outside the plant room required careful survey to ensure that they did not obstruct any underground services or impact on traffic movement or parking adjacent on the site access road. A louvered perimeter wall was specified to screen the chillers from public access that also allowed adequate air flow onto the air cooled condenser coils.
Break ins to the glycol system were made in advance of the chillers being installed to provide secure isolated connection points for the new interconnecting piping between cooling plant and chillers. The piping was carefully routed to ensure one of the existing chillers was useable for as long as possible before being decommissioned.
A programme was prepared to manage overall works and the changeover from new Star chiller from hire chiller was achieved without any cooling outage.
The original hydraulic circuit was arranged to circulate 50% of the flow through one running chiller which cooled from -10 to -16C and then mixed with 50% bypassed flow to achieve an aggregate glycol temperature of -13C pumped to the ski-slope. The upgraded system was designed to circulate full flow through 1 chiller giving a glycol off temperature of -13C for improved efficiency.
The new installation included 2 off Star AA415MTE-1 Azanechillers 2.0 rated for 360kW capacity chilling ethylene glycol to from -10 to -13C. The chillers were equipped with Sabroe reciprocating compressors with flange mounted VSD electric motors allowing capacity control down to 17% load. Vahterus plate and shell evaporators allowed a close refrigerant approach while minimising ammonia charge to only 85kg per chiller. Acoustic enclosures around the compressor/motor assembly combined with EC condenser fans to present the lowest noise signature for the retrofit installation.
The new chillers have been operational since September 2017 and the effect has been transformational for site.
The new equipment has been easily able to maintain -13C glycol temperatures in the ski slope even on warmer days, whereas the previous equipment was struggling to achieve -8C at peak times.
Reliability of the installation is enhanced with a full 100% standby chiller available and no need to bring in hire chillers due to down time with original R404A chillers.
Energy savings have been dramatic. The table below shows monthly energy bills before and after the plant was changed over including refrigeration, pumps, lighting, electric defrosting and chairlifts. In the first 4-month period of operation, the electricity usage was 661,255kWh compared to 1,511,062kWh for the same period in 2016. This 56% saving improved the profitability of the business and helped to justify the investment in new plant.
The environmental impact of operations has been much improved with almost 700 tonnes of CO2 saved in indirect emissions from electricity in the initial 4 months running and saving of approximately 30kg of R404A per month for top up refrigerant on the old plant.
Given the uncertain future of HFC refrigerants, the chosen ammonia chiller solution offered a high integrity industrial plant with 20 year life and was future proof with no risk of phase out in future. This also allowed Snozone to fund their investment over a longer term in line with their financial targets.
Better operation control of cooling has allowed Snozone to manage the snow environment in the chamber and to optimise snowmaking and defrosting activities for an improved customer experience. On their company website Snowzone advertised “they now have a £1m investment in new chillers and have the best snow ever!”