Key features of the Azanefreezer include:

  • Twin screw compressors
  • Low charge, low pressure receiver
  • Reverse cycle defrost
  • High efficiency, low charge aluminium evaporators
  • Integrated ammonia gas detection system
  • Fully automatic oil recovery
  • Welded steel pipework construction
  • Dual relief and standard three way changeover valve for ease of maintenance
  • Powder coated mild steel electrical panel (option for stainless steel) complete with anti-condensation heaters and light
  • PLC control
  • HMI user interface
  • Epoxy paint finish

Refrigerant type

Ammonia is produced by biological processes, is naturally decomposed, and does not add to the global greenhouse effect.

The Azanefreezer offers:

  • Quick installation
  • No plantroom required
  • Low installation costs
  • Low maintenance costs
  • No ongoing water, effluent and water treatment costs
  • High efficiency control including floating head pressure control and EC condenser fans
  • Low total cost of ownership (TCO)
  • Very low charge of ammonia - as low as 0.9kg/kW (5lb/TR)
  • Easy relocation should the need arise

Azanefreezer Case Studies

  • Pinneys Annan


    Pinneys of Scotland, part of the Youngs Seafood Group, is a leading processor of Scottish smoked salmon and are based at Annan, Dumfriesshire. Cooling is a key requirement for their production processes and the majority of the factory was installed using systems operating with R22 refrigerant. Under the Montreal Protocol and subsequent European and UK legislation, the phasing out of R22 comes to a conclusion at the end of 2014 and so Pinneys needed to develop a strategy to meet this deadline.

    Pinneys asked their existing maintenance provider, Star Refrigeration for support with their phase out strategy. This involved looking at a variety of high, medium and low temperature cooling requirements on site currently running on R22 and assessing an appropriate alternative solution. Key requirements were to keep the facility operational during the changeover from R22, provide  a solution that offered long term cooling security for the site and to deliver a solution that balanced efficiency and capital cost.

    A number of options were considered including retrofitting systems with alterative gases, installing new HFC refrigeration systems and switching to natural refrigerants. 

    A critical part of the R22 strategy was conversion of the factory’s cold store where frozen product is stored at -25°C before further processing.  This chamber was cooled by two existing R22 refrigeration plants housed in different plant rooms. Both plants were assessed for possible gas conversion but due to their age, condition and the need to retain the cold store operation during any conversion works, this was ruled out. A decision was therefore made to look at new equipment.  

    One of the R22 plant rooms had been earmarked as the location for a new ammonia/glycol refrigeration plant which would serve other areas of the factory and the other was ruled out due to access issues. This meant that any new equipment would need to be located elsewhere. Pinneys were keen to avoid the added cost of building a new plant room and so packaged equipment with its own enclosure was preferred.

    Options for refrigeration plant using synthetic refrigerants such as R404A and R407F were considered but Pinneys were concerned about the long term availability of these refrigerants following news of the phase down programme detailed in the European f-gas regulation earlier in 2014. A decision was made to look at natural refrigerant alternatives.

    Star proposed their Azanefreezer system, an air-cooled, ammonia refrigeration system for cold storage applications.  Its packaged design avoids the need for a plant room and it can be located at ground or roof level on either a concrete plinth or steel frame. Azanefreezer’s combination of ammonia refrigerant, Star low pressure receive technology, EC fan and PLC control technology delivers efficiencies 15% to 20% higher than traditional HFC technology and with a refrigerant charge that is 80% less than pumped circulation ammonia.

    Two pipes between the Azanefreezer package and cold store evaporators keeps site installation time to a minimum. All equipment requiring regular inspection is located within the package, simplifying maintenance and eliminates the need for roof void valve stations.

    Alex Henderson, Key Account Manager at Star Refrigeration said, “As a long standing maintenance customer, we have been working with Pinneys for a number of years. The latest project involved the development of a long term refrigeration solution for the Coldstore plant as well as the rest of the site. It has reduced the amount of refrigeration equipment and helped improve both operating temperatures and efficiency.

    Using our packaged Azanefreezer concept avoided the need for a new plant room and we were able to position and commission the new coldstore plant before decommissioning the existing equipment.”

    Gary Parker, Pinneys Engineering Manager, said “Star Refrigeration have a long history of installing and maintaining plants both at Pinneys and also across the wider Young's Seafood group. 

    This is our first ammonia system at Annan and Azanefreezer’s low ammonia charge was a big reason for selecting it over more conventional ammonia solutions. Since its installation, our cold store temperatures have noticeably improved.”

    Star Refrigeration is the UK’s leading independent industrial refrigeration engineering company. Star focuses on the design, manufacture, installation, commissioning and maintenance of industrial refrigeration systems. The company offers a turnkey package to all users of refrigeration plant.

    Established in Glasgow in 1970, Star has over 300 employees nationwide and provides fast response 24-hour technical support from a network of nine branches to customers throughout the UK. Star’s technical advisory arm, Star Technical Solutions (STS), operates as an independent consultancy providing advice on engineering issues. Star also owns food freezing and chilling equipment specialist Starfrost; mechanical and electrical contractor Star Mechanical and Electrical Solutions; internet-based learning solutions i-know.com; and Star Renewable Energy providing natural fluid district heat pump technology.


  • Snozone Milton Keynes


    Snozone provide the UK’s leading snow centres for indoor skiing and snowboarding on real snow. Snozone’s two indoor snow centres, located in Milton Keynes and Castleford, offer skiers and snowboarders an authentic slope experience. The facilities suit first time skiers or experienced snowboarders, and have taught nearly 2 million guests since opening in 2000.

    The facility in Milton Keynes has a run 170m long is maintained at -4C air temperature and contains 1500 tonnes of Snow and Ice.  The cooling system provides low temperature glycol for circulation in pipework under the slope, to air coolers in the room and snow guns to maintain the Alpine environment for the customers enjoying their winter sports.

    The facility is also an anchor tenant in the purpose built Xscape leisure and retail complex and is a key attraction in Milton Keynes which celebrated its 50 year inauguration in 2017.

    Snozone contacted M&E Building Services Consulting Engineer, Hulley & Kirkwood, to help them with problems they were experiencing with the refrigeration system.  In recent years the plant was becoming more unreliable and was having difficulty coping with Summer ambient temperatures.  This resulted in problems with maintaining temperatures in the snow chamber and meant that temporary chiller plant was required on a seasonal basis to augment cooling from the R404A chillers installed in 1999. 

    The striking architectural line of the Xscape roof structure mean that all building services were located inside the building with air intakes/ outlets taken through the perimeter walls.  The plant comprised 2 x 100% primary circuits with screw compressors and shell and tube evaporators inside the machinery room.  Heat rejection equipment comprised air cooled condensers located in a dedicated chamber and air blast oil coolers also in the plant room.   The secondary refrigerant system pumps glycol through the chillers to 16 coolers mounted in the roof of the ski slope and to the underfloor pipe grid.

    The screw chillers were rated for 360kW at -16C glycol off temperatures.    As the original manufacturer, Tri-Therm are no longer in business the plant was being maintained by a local contractor.

    For this reason, it was difficult to obtain information about the plant so site surveys and some original drawings provided some background data.

    The customer decided to invest in a future-proof, brand new refrigeration plant and since they had good experience using ammonia at their other location in Castleford, they sought to use this refrigerant at Milton Keynes.

    The existing plant room was unsuitable to retrofit a new ammonia plant so the decision was taken to locate the new system outside.  A site survey revealed that it was impractical and costly to install the chillers in the car park so a location was chosen on the public thoroughfare outside the existing plant room.  This location offered short tie in connections for power and glycol but also allowed improved airflow for the new chillers and  the ability to create a secure compound.

    It was recognised early in the project that it would be necessary to engage a specialist consultant to conduct an Ammonia Hazard Assessment to identify all safety measures required for installation of the new outdoor refrigeration system. Star Technical Solutions (STS) attended site and specified a number of project enhancements for the safety of building employees and the general public.

    • Secure compound which did not obstruct fire exit stairway
    • Relief valves piped to a dispersion tank sized to absorb any ammonia releases
    • Ammonia gas detection sensors on both chillers tie back to a building alarm system
    • Alarms to isolate air intakes in the vicinity of the chillers
    • Delivery of ammonia awareness training to Snozone staff

     

    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!”


     


  • Brakes, Bishops Stortford


    A leading distribution company has recently upgraded its existing freezer plant system to the modular air-cooled, low charge ammonia Azanefreezer. Located in Bishop's Stortford, Brakes supplies the UK food service industry with a comprehensive range of fresh, grocery, frozen and non-food products.

    The existing 40 year old ammonia refrigeration system had come to the end of its operational life and replacement equipment was required. The traditional approach would have been to replace with a pumped circulation ammonia system but the customer wanted to improve operating efficiency and reduce refrigerant charge. Star was invited to propose an upgrade solution focusing on these two key criteria.

    The solution was to install Star’s AF250 Azanefreezer. This air cooled, packaged unit incorporates twin screw compressors, air cooled condenser, electrical panel and reverse cycle defrost system inside a compact housing. This avoids the need for a new plant room and minimises installation time, with the package being installed on the roof of the existing refrigeration plant room.

    The high performance industrial freezer boasts a range of eco-friendly benefits, including the low ammonia charge requested by Brakes. Azanefreezer reduces Brakes existing ammonia system refrigerant charge from an estimated 5,000kg to just 188kg. 

    Alex Henderson, Key Account Manager - Food Market, says: “This reduction in charge, coupled with zero global warming potential, provided Brakes with the environmentally responsible solution they were looking for.”

    He adds: “As a natural refrigerant system, Brakes have invested in a long term solution that will be exempt from any future environmental legislation laws. With a 25 year life cycle when run at maximum operational performance, the system is a cost effective choice that will ensure Brakes produce stays fresh.”

    Modular, air cooled and incorporating a range of energy efficient features, the new system will help to reduce running costs as well as combat greenhouse gas emissions.

    Azanefreezer combines efficiency, reliability and unrivalled build quality, which will ensure Brakes continues to deliver its clients an unmatched level of service. The innovative modular design makes it efficient to relocate if necessary, thereby making it a cost effective option in a dynamic business. Also integrated into the system is an exclusive reverse cycle defrost function - currently the only system to offer this – which defrosts more efficiently as opposed to the alternative of installing electric heaters in the cooler.

    The upgraded system complies with European health and safety regulations and offers Brakes operators and management the peace of mind that they are working with premium quality equipment.

    Over the years, Star has built a strong working relationship with Brakes and is the food service supplier’s go-to solution for refrigeration upgrades, new built facilities and maintenance contracts across its UK plants.

    Ian Hunt, Brakes' Group Engineering Manager, said, “Star has a long history of installing and maintaining plants for Brakes. The Bishop’s Stortford Azanefreezer represents another successful collaboration and follows on from the recently completed distribution centre at Newhouse, Glasgow, which in turn followed on from Warrington last year and Reading before that.”