Freezing and Chilling

Star offers a range of freezing and chilling solutions to meet customer's specific requirements. Our group business, Starfrost, design and manufacture industrial inline cooling equipment including spiral freezers/chillers, IQF freezers, contact freezers and carton freezers. We can also provide solutions for blast freezing/chilling and plate freezing. In all cases, we offer industrial refrigeration equipment to meet the required cooling duty with a choice of refrigerants, including ammonia and carbon dioxide. This includes our low charge ammonia Glacier range, which has been designed for spiral and blast freezing applications.

Our experience covers a wide range of applications and products, including ready meals, meat processing, seafood, bakery, and vegetable cooling.


Rob Lamb

Group Sales & Marketing Director


Rob Long

Sales Director

Related Products

Related Case Studies

  • Associated Seafoods

    Aging gracefully is never easy, unless you are a good Scottish single malt.  So, we’ll settle for gracefully-ish. With a remarkably ripened appearance, scoured painted components and the original controls systems mounted on slightly aged metal and wooden panels with gauges and cut-outs, Star Refrigeration’s oldest cooling plant might seem a relic from another era to the untrained eye, but the proud owners will tell you a different story.

    A leading supplier of some of the finest seafood caught right on its doorstep, Associated Seafoods has been in business since 1913. Experiencing steady growth over the years, the company now owns a specialist group of seafood companies comprising Moray Seafoods, Lossie Seafoods and GlenIsla Shellfish. The company is internationally recognised for the premium quality of their langoustines, prawns, crabs, scallops, shellfish, and the famous Scottish smoked salmon, The pride of Scotland.

    In 1979, Star Refrigeration provided the company with two refrigeration packages for their cold storage and production facilities located on the Moray Firth coast of Scotland, in Buckie. According to Wikipedia, ‘1979 (MCMLXXIX) was a common year starting on Monday of the Gregorian calendar’, but for Star Refrigeration, it marks an era as this represents the oldest operating plant in Star’s history. And to add a time perspective, here are a few things some of you might remember: Margaret Thatcher was elected prime minister, Sony introduced the ‘Sony Walkman’, YMCA was in the charts and Superman, the movie, had just been released.

    Built to last, each package consists of a single compressor, LPR, four way valve with patented reverse cycle defrost technology, an evaporator and twin circuit condenser. This industrial system is true Star quality through and through. “It’s a great system, it still hits -25 in the cold store”, says Roddy McDonald, Associated Seafoods Maintenance Manager in charge of routine checks to the system.

    “I’ve been here for around 27 years, and the system was already in place when I started. It is always running – 24/7. We worked out that it’s been running for 324,342hours non-stop. When we need to do maintenance work we shut one down and keep the other one running”, Roddy adds.

    The systems initially ran on ozone-depleting R502. Although very common in the 1970s and 1980s, it is now illegal to use HCFCs, and the system has since been converted to non ozone-depleting and low global warming potential refrigerant.  Star Refrigeration was a precursor in the use of natural refrigerants since its inception in 1979, but “ammonia in those days wasn’t as common in food factories. Depending on the size of the plant, there was a break-over point on whether to use ammonia or not” , said Calum McKenzie, Star’s Regional Manager for Star’s service and maintenance branches in Aberdeen and Glasgow.

    With such a long-standing relationship, the two companies have worked together effortlessly as they both grew substantially to become leaders in their respective markets. Calum McKenzie, said, “This is one of the first systems built using the  low pressure receiver. During defrost, refrigerant flow is reversed, with hot gas flowing to the evaporator where the latent head of condensation is used to melt ice formation. This process has now been proven to be an exceptionally efficient way of defrosting and it is used in the most modern and energy-efficient refrigeration systems today.”

    Apart from replacing the cooling fluid with a drop-in refrigerant and replacing one of the evaporators, there have never been any major issues with the system or loss of cooling in almost 40 years.  Roddy McDonald confirmed that “it is basically the same plant, with all the original electrics, Star’s controls system and components. We have not even rewound the motor so it’s still working fairly efficiently”. Reliable refrigeration over the past 38 years have enabled Associated Seafoods to focus solely on what they are best at, allowing it to grow to employ over 150 people in their factory in Buckie alone. 

    Despite running for almost 40 years, Roddy MacDonald is confident Star’s system can keep going for another decade, “as long as it is kept well looked after as until now, it could keep going for another 10 years, easy.”

    The company has a lot resting on its shoulders. The reliability of the plant as well as good aftercare to ensure continuous smooth operation is critical to their business success. Associated Seafoods supplies to the UK’s leading premium food retailers and also ship their produce around the world.  Exporting to 23 countries, including the States, China and Dubai and with a turnover of £15 million per year, the company takes in around 40 tonnes a week of Scottish salmon and shellfish and has recently invested £3 million refurbishing its warehouse.

    “We are hoping to expand in the near future and continue our relation with Star Refrigeration. For me, there’s never been anybody but Star to work with”, said Stuart Gibson, Operations Director of Associated Seafoods.


  • Lunar Freezing

    Lunar Freezing and Star Refrigeration have worked together for over 25 years to develop effective and efficient Blast Freezing and Cold Storage solutions.

    Based in the fishing ports of Peterhead, Fraserburgh and Aberdeen, Lunar Freezing and Lunar Fishing are in a commanding position to supply herring, mackerel and whitefish products from catching to freezing to cold storage to final delivery worldwide.

    The Lunar facilities at Peterhead and Fraserburgh mainly process the pelagic fish species Herring, Mackerel and Blue Whiting. Pelagic fish live in the pelagic zone of the ocean being neither close to the bottom nor near the shore. The fishing is seasonal due to the fish migratory movements and the fishery management catching season and quotas. 

    A world leader in cooling and heating system innovation, Star worked with the Lunar team to design high performance blast freezing solutions for both facilities.

    Star engineered and modified the existing pumped circulation ammonia systems for Lunar installing 3 new and 2 remodelled Blast Freezers at Peterhead and 4 new Blast Freezers at Fraserburgh for freezing fish packed in cardboard boxes.

    Operational since Autumn 2015, the new freezers have expanded the capacity enabling Lunar to freeze over 1,000 tonnes of fish per day. Each blast chamber freezes around 64 tonnes of fish in 20 hours, the evaporators and refrigeration plants to achieve this are by necessity very large and must be carefully designed and installed.

    The Star blasts outperform existing blast freezers installed by others in Fraserburgh and the Star blasts have only 35% of the installed fan power of the competitor.

    Lunar Director Sinclair Banks said “These were challenging projects both carried out in the same short timeframe and both involved working on existing equipment.

    Star, Lunar and all the other contractors involved worked alongside each other to complete the work in time for the mackerel freezing season. The new freezers have shortened the freezing time allowing us to process the catch quicker and expand our business by supplying new customers”

    Star’s system ensures optimum plant performance, with PLC control and HMI touch screen interface with a range of built-in systems including pressure, temperature and gas detection monitoring.

    When it comes to designing and installing energy efficient cooling and heating systems, Star is a natural innovator.  

  • Granville Food Care

    Star Refrigeration has designed and manufactured an efficiency boosting cooling system for Granville Food Care Ltd in Northern Ireland.

    Star installed the energy saving refrigeration plant at Granville’s meat freezing and cold storage facility in Dungannon, County Tyrone. The innovative cooling system was designed to replace an existing R22 plant and increase production to meet demand from UK retailers.

    Star’s turnkey cooling solution for Granville comprised a state-of-the-art ammonia and carbon dioxide (CO2) cascade plant. Operating on natural refrigerants, the dual purpose plant provides cooling for both blast freezing and cold storage.

    The cascade plant supplies cooling to three cold storage areas and seven blast freezers at the Granville facility. Star’s refrigeration system is one of the first in Northern Ireland to use CO2 technology for blast freezing.

    Star Refrigeration Sales Director Rob Lamb says: “The ammonia and CO2 cascade plant has allowed Granville to reduce energy consumption and gain a significant increase in throughput, by improving product freeze times by 23 per cent. The plant also has a very low ammonia charge, which is isolated to the plant room.”

    He adds: “Overall, the new refrigeration plant has enabled the client to expand business without further investment in building infrastructure.”

    The Granville plant has a total refrigeration capacity of 1,227kW. The system was designed with sufficient in-built compressor capacity to allow future expansion of the existing cold store.

    The new plant is located in a purpose built plant room adjacent to the main building. It comprises two low temperature CO2 compressors and surge drum. Supplying liquid CO2 to cold stores and blast freezers. It also features two ammonia compressors and evaporative condensers, as well as two ammonia to CO2 cascade heat exchangers.

    The Granville project included the removal of R22 refrigerant from the site. Some of the original plant was designed by Star over 25 years ago and had served the client well. Star worked closely with Granville throughout the 34-week project to ensure the project was completed on time and budget.

    Two further phases of the project are currently underway, to increase both cold storage and freezing capacity on site and these are due to complete over the next six months. When complete, Granville Food Care will have a blast freezing capacity of 300 tonnes per 15 hour cycle to add to their 100 tonne per day of defrosting capacity.

    Star Refrigeration is the UK’s largest 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.

    Star's technical advisory arm, Star Technical Solutions (STS), operates as an independent consultancy providing advice on refrigeration engineering issues. Star also owns food freezing and chilling equipment specialist Starfrost, as well as mechanical and electrical contractors Penec.

  • Peter's Foods

    Peter’s Food Service has boosted production capacity and cut running costs by investing in another energy efficient cooling system from Star Refrigeration.

    Established for over 30 years, Peter’s Food Service is a food manufacturing and distribution specialist. The company supplies quality chilled foods to major supermarkets, retailers and wholesalers across the UK. Its product range includes pies, pasties and sausage rolls, packaged under the Peter’s brand.

    Peter’s Food Service was looking to replace two spiral chillers and associated refrigeration plant at its manufacturing facility at Bedwas in Gwent, South Wales. The company required a modern, energy efficient chilling system that would also enable it to achieve an increase in production capacity on two lines.

    The lines affected produce a range of chilled pies in foil including minced beef, steak and kidney and chicken and mushroom, as well as Cornish pasties, cheese and onion pasties and corned beef pasties.

    Star Refrigeration was tasked to undertake the project for Peter’s Food Service. It forms the latest in a long line of projects completed by Star to meet the company’s refrigeration and air conditioning requirements. Star is a key supplier of cooling solutions for the UK food industry.

    Star worked in conjunction with freezing and chilling equipment manufacturer Starfrost on this recent project. It demonstrates another successful joint venture for the two firms, since Starfrost was acquired by Star in 2004.

    Star Refrigeration Sales Director Rob Lamb says: “This latest project for Peter’s Food Service demanded a fast track programme from system design through to delivery. Our engineering team worked closely with Starfrost to ensure minimal
    equipment downtime. We also ensured adjacent food production areas remained operational during the installation phase, completing work on time and to budget.”

    Star designed and installed a separate refrigeration system for each of the two new Starfrost Helix Spiral Chillers at Peter’s Food Service. The previous chilling system operated on the gas refrigerant R22, which is currently undergoing a phase out programme. The new plant operates on R404a, a modern gas refrigerant.

    The refrigeration plant features duplex screw compressors, Low Pressure Receiver (LPR) units and remote evaporative condensers. A reverse cycle defrost facility ensures a fast and efficient defrosting process. The system is engineered to operate with a low refrigerant charge for energy efficiency. Its simple design also helps to reduce maintenance costs.

    Star Refrigeration is the UK’s largest 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.

  • Prosper de Mulder

    Prosper de Mulder has completed the installation of an environmentally friendly and highly efficient plate freezer system. The freezers are unusual as they use carbon dioxide as the refrigerant, replacing old plant which used R22. In this application CO² is an ideal choice because it has no ozone depleting potential and will not be subject to impending “F-Gas” regulations. It is also fundamentally non-toxic and therefore is suitable for a system where the freezers are in a labour-intensive production area. Using ammonia in plate freezers is also a risk to site personnel, which is eliminated by the selection of CO². However, the greatest advantage in the use of carbon dioxide is that it enables the plant to run at lower temperatures and lower power consumption than could be achieved with R22 or ammonia. This improvement in performance results partly from greatly improved heat transfer within the plates of the freezer and partly from the reduced pressure drop in the flexible hoses and suction line from the freezer. This means that freeze times have been significantly reduced – a core temperature of –18ºC is reached in the 75mm blocks of meat in 60 minutes, compared to the time of over 2 hours which would be required in the R22 or ammonia plants.

    The plant comprises a low temperature carbon dioxide circuit of two screw compressors and a surge drum/pump set serving 16 plate freezers, each with 26 stations. The total capacity is 1000kW, capable of handling 185 tonnes of meat products per day. The high temperature circuit uses ammonia to condense the carbon dioxide, in two plate and shell heat exchangers. The ammonia system is also used to serve a cold store and some scraped surface heat exchangers, which provide a chilling option for the processing of the product. Heat is rejected from two evaporative condensers.

    Consideration was given to designing an integrated carbon dioxide system; delivering cooling not only to the plate freezers but also to the cold store and the scraped surface heat exchangers. Star had already used carbon dioxide as a refrigerant for cold store and scraped surface heat exchangers, and the results had proven very successful. However, to use carbon dioxide for the cold store would have required operating the high pressure side of the carbon dioxide system at lower conditions than was acceptable for optimised operation of the low temperature freezing plant and the client’s preferred supplier of scraped surface heat exchanger could not supply a unit suitable for operation at the pressures that would be seen with carbon dioxide.

    The main environmental benefit is the low energy consumption of this system in comparison with a more standard design. This has been achieved despite the temperature difference in the cascade heat exchanger through an integrated approach to the system design, including the use of high pressure liquid and waste heat recovery to provide hot gas for the plate freezer defrost cycle. This system means that it is not necessary to run the ammonia compressors at high head pressure in order to achieve a defrost. The nominal CoP of the freezer plant is 1.27 when running at –50ºC CO² plate evaporation and +32ºC ammonia condensation. The equivalent ammonia plant (2-stage) CoP would be 1.38, but because the CO² system can run with low head pressures in colder weather, whereas the ammonia system has to maintain head pressure to provide gas for defrosts, the CoP of the CO² plant can improve to 1.49, if the head pressure drops to 20ºC. The CO² plant configuration also allows the cold store and process load to be run from the ammonia plant; if a two stage ammonia plant was used for the freezers the additional loads would require their own plants, as the intermediate condition of the ammonia freezer plant would be too high for the cold store load.

    These power figures have been verified by site logs – but because the freezer performance is significantly better than predicted it is possible to raise the suction pressure, so that the original design freeze time of 90 minutes is maintained. The plant has not yet been run in this mode, but it is clear that the performance will be substantially better than the ammonia plant.

    One risk in entering this project was that this type of pressurised liquid defrost had not been applied to plate freezers before, However the defrosts have been quick and clean. The freezer is significantly safer than an ammonia one an less likely to rupture. A risk benefit in adopting CO² was the possibility to locate the defrost valves next to the freezers. There are two cranes traversing the freezer hall, so the common practice of raising the pipes to high level and putting the valves outside the room in the roof void was not possible.

    In comparison to the size of compressor required to run ammonia at –40ºC the CO² compressors are significantly cheaper. By running CO² at –50ºC there are also fewer plate freezers in the hall, and with narrower plate profiles for CO² each freezer station contains two more stations than could be fitted into an ammonia station. The defrost system is rather more complex than for ammonia, but this does not offset the savings made in the other areas. So, for this project the CO² system was cheaper to install and is also cheaper to run and maintain than an equivalent R22 or ammonia plant. An analysis of capital and operating costs for the CO² / NH3 cascade system assessed a 10-15% saving for the refrigeration plant and a 5% saving in energy costs.

    A cost benefit that was not realised until the plant was operational and the very fast freeze times proven, was that the clients brief, for 185 tonnes of frozen meat products per day, could have been comfortably met with four fewer plate freezers. However, as the system is designed for a future expansion of 50% more freezing capacity, the client will not be required to purchase more plate freezers to meet future growth in demand. In addition, the client presently has the ability to raise the CO² evaporating temperature and achieve significantly improved performance.

    There are significant opportunities for CO² systems like this one, not only in plate freezers but in blast freezers, spiral freezers and tunnels too. The combination of CO² with the pumped liquid defrost system would allow these other freezers to gain the benefits of more efficient running in the same way as this plate freezer installation has.

    Star Refrigeration is the UK’s largest 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 250 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 refrigeration engineering issues. Star also owns food freezing and chilling equipment specialist Starfrost, as well as mechanical and electrical contractors Penec.