HVAC Case Studies

  • BSkyB


    Star Refrigeration has completed the installation of its revolutionary Indigochiller cooling system at BSkyB’s headquarters in London.

    BSkyB is a leading broadcaster of sports, movies, entertainment and news. The company operates the UK’s largest digital pay television platform from its headquarters at Grant Way in Isleworth. Cooling solutions specialist Star has installed a range of Indigochillers to provide chilled water for air conditioning and computer server cooling in two studio buildings on the BSkyB site. 

    Three state-of-the-art Indigochillers were installed to replace existing package chillers located in a compound between the Sky Sports and Sky News buildings. Star combined two existing independent chilled water circuits serving both buildings into a common system, boosting operating efficiency. 

    The Indigochillers provide chilled water, which is then pumped through insulated pipework to wall or ceiling mounted air handling units (AHUs). Air is circulated across the chilled water coil in each AHU to provide cooling throughout both BSkyB buildings. Broadcast facilities within the two buildings include TV studios, production suites, general offices and computer server rooms.

    A carefully phased four week installation programme ensured no disruption to broadcast operations. Temporary chillers were installed to provide supplementary cooling whilst the existing chillers were removed to make way for the new Indigochillers. 

    Star’s Indigochiller was developed in direct response to proposed F-Gas regulations. The unit’s unique design aims to eliminate refrigerant leakage and have minimal effect on the global environment. 

    All components are selected to minimise the risk of refrigerant leakage. Each unit features a welded plate and shell heat exchanger, sealed expansion valve and welded steel pipework. Leak detection requirements have been reduced to a few simple checks.

    Each Indigochiller features the revolutionary oil-free Turbocor centrifugal compressor, designed to offer reliable operation and low maintenance. The compressor operates on electromagnetic bearings and uses the synthetic refrigerant R134a. This ensures minimal vibration and noise, even when running at very high speed.

    The high efficiency, low noise Indigochiller range is ideal for medium to large-scale applications, with capacities ranging from 250kW up to 1,500kW. It features a robust PLC control system to monitor running conditions and optimise efficiency. Additional options include remote access and email alerts via a built-in modem, as well as a direct link to Star’s 24/7 call out facility. The air-cooled unit is available in two noise ranges: Standard (57 dB(A) to 61 dB(A) @ 10m) and Residential (50 dB(A) to 53 dB(A) @ 10m).

    Star’s research shows the Indigochiller uses only 60% of the energy required by a standard chiller operating on typical load and ambient profiles. This offers end users a significant saving in energy and running costs.

    Following on from the success at Isleworth, two further IA500 units have been installed at the same site and a further three have been installed at BSkyB’s offices in Dunfermline.  


  • Indigochiller for Air Conditioning


    Forward thinking operators looking for high efficiency, low maintenance air conditioning should only consider a chiller that is built to last, says cooling expert Star Refrigeration.

    Star is renowned for designing cooling solutions that provide over 20 years service. The company is currently seeing a rising number of replacement projects in which standard AC chillers have suffered early component failure or corrosion problems in less than ten years.

    Star believes that environmentally conscious building services operators should consider the chiller’s expected lifespan as a matter of priority, or be faced with a costly problem all too soon.

    Star Refrigeration sales director Rob Lamb says: “We have recently seen a number of high profile operators who have previously invested in chillers that have soon become damaged or corroded. Even if the chiller features high efficiency components, poor build quality can cause early loss of performance or even break down.”

    With growing demand to cut refrigerant leakage to meet F-Gas regulations, Star developed its Indigochiller for medium to large scale air conditioning and process cooling. Engineered to have minimal effect on the global environment, Indigochiller’s robust design aims to eliminate refrigerant leakage and offer over 20 years service.

    Star’s confidence in Indigochiller’s construction and reliability means options are available for extended warranty on both equipment and refrigerant loss.

    Rob Lamb adds: “Indigochiller stands out from the rest of the market thanks to a range of unique design features and leak-tight components. It is manufactured to ensure both long-term reliability and low life-cycle costs. These should be key considerations when selecting a chiller.”

    The low charge, high performance Indigochiller features a revolutionary Turbocor compressor, which is low maintenance by design to ensure lifelong trouble free running. The oil-free compressor operates on electromagnetic bearings and uses the synthetic refrigerant R134a. The system offers reliable performance and requires minimal installation, servicing and maintenance.

    Indigochiller is manufactured from the highest quality components selected to minimise the risk of refrigerant leakage, reduce maintenance costs and enhance operating life. Standard features include ‘leak-free’ bellows seal valves, sealed expansion valves and welded steel pipework. The air-cooled Indigochiller has epoxy coated condenser fins as standard to reduce the risk of corrosion damage.

    Available as an air-cooled or water-cooled unit, Indigochiller has capacity options ranging from 250kW to 1,650kW. A robust PLC control system allows the user to monitor refrigerant charge, running conditions and optimise efficiency.

    Indigochiller is highly energy efficient using only 60% of the energy required by a standard chiller operating on typical load and ambient profiles. This offers end users a significant saving in energy and running costs.

    Star Refrigeration is the UK’s largest independent industrial refrigeration engineering company. Star focuses on the design, manufacture, installation, commissioning and aftercare of industrial refrigeration and HVAC systems.

    Star provides total cooling solutions for refrigeration, air conditioning and process cooling. The company offers a turnkey supply and support package to all users of cooling equipment. Star continues to invest in the development of new products to provide energy conscious cooling systems for the benefit of customers and the environment.


  • International Maritime Organisation


    The International Maritime Organisation building in Lambeth is headquarters to a world-renowned institution, and is the venue for many major global conferences. With the phase out of CFCs reaching its conclusion, it was necessary to replace the old R-11 chillers which provided cooling to the offices and conference suite. In making this change the efficiency of the new chillers was a key factor, because R-11 used as a refrigerant makes for an extremely efficient system. In addition, the air handling units on the building were configured to provide free cooling to the chilled water circuit in low ambient conditions. The chiller replacement project was also required to follow the Government’s policy of avoiding fluorocarbon refrigerants unless necessary. As stated in the DETR report Climate Change: The UK Programme: "HFCs should only be used where other safe, technically feasible, cost effective and more environmentally acceptable alternatives do not exist."

    Consequently, a system using ammonia as the refrigerant was specified. After careful analysis of the building and the surroundings, it was concluded that the most suitable solution was to place two chillers in an acoustic housing on the roof of the offices, close-coupled to two evaporative condensers.     

    To keep the ammonia charge to a minimum and to enable the chiller to fit within the reduced headroom space below the condensers, each unit is equipped with a low pressure receiver and plate heat exchanger. The advantages of using a low pressure receiver are:

    • The charge of ammonia is reduced, the receiver vessel normally runs empty. 
    • The full surface of the heat exchanger is used, so it runs efficiently.
    • The refrigerant flow is not dependent on height difference, as it would be in a gravity fed design.

    The two chillers are contained within separate compartments of the housing, with a total footprint of 6.5m x 6.5m and with an overall height of 3.6m. This provides ample space for safe maintenance, while keeping the installation within the roof area previously occupied by the cooling towers.

    Each chiller has a capacity of 1400kW when chilling water from 11°C to 5.5°C, with an evaporating temperature of 3.3°C on full load. To maximize efficiency the chillers are piped in series, giving a CoP on the lead unit of 6.52 and on the lag of 5.88 at design ambient conditions. The units are also configured to make best possible use of floating head pressure – a further advantage of the low pressure receiver system. Despite the series arrangement, the chillers are selected to give low pressure drop on the water side, and the total pressure difference across the units is less than 0.5 Bar. The evaporative condensers use two speed fan motors so that power consumption can be reduced to a quarter of the design load when the duty or the ambient are sufficiently low. With these features the annualised coefficient of performance was expected to be about 10, as a result of the improved efficiency achieved through allowing reduced head pressure operation.

    The amount of time allowed for the site installation was to be kept to a minimum, due to the existing conference commitments booked by the IMO. In particular, a major international conference was due to take place on site in April, so it was imperative that all work was complete and the plant was in first class condition for this date. The units were delivered with as much pre-assembly as possible, and lifted into place on the roof in the first week of January 2002. The condenser support steels and the housings were then constructed around the chillers. The condensers were lifted into place mid February and the piping and wiring were then completed. Ammonia was charged to the units at the end of March and they were handed over, fully tested, on 10 April 2002.

    Since installation, the plant has run reliably and efficiently throughout the summers of 2002 and 2003. Data monitored by the building manager indicates that the power consumption of the ammonia chillers is significantly less than his previous system.

    The apparent risk with this approach is the use of ammonia in a heavily occupied building within a city center. In fact, this risk was minimised:

    • By locating the plant on the roof
    • By minimising the charge
    • By restricting access to the roof area
    • By ensuring that ammonia could only be released to atmosphere in a controlled manner.

    There is no significant volume of liquid outside the housing, as the high-pressure float control system automatically transfers the condensed liquid to the low pressure receiver. This means that in the event of an ammonia liquid leak, the liquid will be contained within the housing and only transferred to atmosphere in a controlled manner over a period of time. The housing is also equipped with ammonia detection equipment, so that, in the event of a leak, an alarm signal can be provided to ensure a quick and appropriate response.

    The hazard analysis conducted for the installation concluded that, with reasonable control measures in place, the only significant hazard for the installation was the risk of injury to bystanders in the event of a leak during maintenance. For this reason, the roof area in the vicinity of the chillers is administered as a "permit to work" zone.

    Although the capital costs of the chillers is high compared with standard chillers, the integrated roof top solution minimised the additional infrastructure cost so the overall project was not significantly more expensive than the building refurbishment would otherwise have been, even if standard chillers had been selected. For this building, the chillers are estimated to be over 30% more efficient than the previous installation. The project has already exceeded the expectations of the project management team who have subsequently applied similar thinking to another London refurbishment for the same client, and would very much like to do more in future.


  • Investment Bank, London


    Star Refrigeration has supplied a bespoke plant for HVAC cooling at the London offices of a global investment bank. 

    The existing refrigeration plant at the firm’s client administration centre in the City’s Square Mile was due for replacement. The plant operated on R22, an ozone-depleting HCFC refrigerant currently being phased out by EU regulations.

    Working alongside a leading building services consultancy, Star designed a new low maintenance cooling plant to improve efficiency, reduce noise and ensure the highest reliability for the building’s heating, air conditioning and ventilation system.

    The challenging aspect to the project was retaining five air handling units (AHUs) which form part of the fabric of the building. The cooling coils in these AHUs were supplied directly with R22 refrigerant.

    A detailed study was carried out into the possible use of chilled water cooling coils to remove the use of direct refrigerant. The investigation concluded that the AHUs would have to be replaced to accommodate chilled water, so a similar solution using a non ozone-depleting refrigerant was necessary.

    A world leader in cooling and heating system innovation, Star determined that a specialist flooded evaporator design was required that enabled the existing AHUs to be retained and ensured no loss of cooling capacity. Star developed a flooded evaporator coil design that could be retrofitted to the existing AHUs. This was achieved using Star’s patented Low Pressure Receiver (LPR) system design.

    Star designed, built, installed and commissioned a bespoke air cooled LPR refrigeration plant comprising four 600kW chillers operating on synthetic refrigerant R134a. The system features revolutionary Turbocor oil-free compressors to provide high efficiency, reliability and low noise operation. 

    Star’s specialist contracting team installed new R134a AHU evaporator coils in a phased installation programme to ensure adequate cooling was maintained within the building. The new cooling plant is located on the roof of the building and was designed to fit within the footprint of the previous refrigeration system.

    The project was completed within six months from order to commissioning. It was vital that there was no adverse affect on the investment bank’s business activity or interruption to HVAC supply during this period, and this was achieved. 

    When it comes to designing energy efficient cooling and heating systems, Star is a natural innovator. Star works with strategic partners across the globe to deliver low carbon, cost saving solutions.


  • John Lewis


    Star Refrigeration has installed a high efficiency cooling system at the flagship John Lewis department store in central London.

    The state-of-the-art Indigochiller system forms part of an ongoing refurbishment by the leading UK retailer at its Oxford Street store. Project Beacon aims to futureproof the 50-year-old building and provide a platform for further development by the John Lewis Partnership. 

    Cooling solutions specialist Star has completed the installation of three Indigochillers on the sixth floor roof, each with a 1,000kW capacity. The air-cooled units circulate chilled water for air conditioning, providing comfort cooling throughout the building.

    The John Lewis Partnership was looking to improve the instore environment for shoppers and staff by installing a larger capacity high efficiency cooling system. It was vital that the comfort cooling system allowed year round temperature control, particularly during summer months. As well as an environmentally conscious design, low starting current, quiet operation and minimal maintenance were key requirements.

    John Lewis Partnership Development Engineer Stuart Watson says: "Star’s new roof-mounted Indigochillers are more efficient and will allow us to increase cooling capacity with no increase in electrical demand. They form part of a heating and cooling efficiency drive that will allow John Lewis to meet energy reduction targets and reduce its carbon footprint."

    Star’s Indigochiller was developed in direct response to proposed F-Gas regulations, which aim to limit fluorinated gas emissions. The unit’s unique design aims to eliminate refrigerant leakage and have minimal effect on the global environment. Star’s research shows the Indigochiller uses only 60% of the energy required by a standard chiller operating on typical load and ambient profiles. This offers end users a significant saving in energy and running costs.

    As well as Star’s new cooling system, additional work on infrastructure at the John Lewis Oxford Street store includes the installation of more efficient boilers, cabling and an electricity substation. Project Beacon also includes new retail departments, restaurant facilities and escalator banks to improve access and open up the building.

    Work on the overall 18-month refurbishment project is due to be completed in Autumn 2007, with trading continuing throughout. It is currently the largest retail project within an operating store in Europe.

    Star’s Indigochiller is a complete refrigeration package housed in one unit. Typical applications include new and retrofit air conditioning systems in the building services and process cooling industries. Ideal for medium to largescale applications, unit capacities range from 250kW up to 1,500kW. 

    Each Indigochiller features the revolutionary oil-free Turbocor centrifugal compressor, designed to offer reliable operation and low maintenance. The compressor operates on electromagnetic bearings and uses the synthetic refrigerant R134a. This ensures minimal vibration and noise, even when running at very high speed. The air-cooled unit is available in two noise ranges: Standard and Residential.

    All Indigochiller components are selected to minimise the risk of refrigerant leakage. Each unit features a welded plate and shell heat exchanger, sealed expansion valve and welded steel pipework. Leak detection requirements have been reduced to a few simple checks.

    The Indigochiller features a robust PLC control system to monitor running conditions and optimise efficiency. Additional options include remote access and email alerts via a built-in modem, as well as a direct link to Star’s 24/7 call out facility.


  • Refrigerant R-1234ze(E)


    Engineers at Star Refrigeration have teamed up with Danfoss Turbocor and Honeywell to develop and test a chiller using HFO 1234ze(E) refrigerant, which has a global warming potential of 7. 

    The chiller is based on Star’s very successful Indigochiller range and uses the new Turbocor TG310 prototype compressor.

    "Working with R-1234ze proved to be quite challenging," said Star’s Group Engineering Director, Dr. Andy Pearson. "We found particularly good performance at part load in lower ambient, where the efficiency was up to 20% better than the original predictions. Across the full range of load and ambient conditions performance was generally better than predicted."

    He added: "The development included some tricky puzzles. Some of the materials used in joints and seals did not perform well so we had to source special o-rings for some of the system components. We also learned that the lower gas density can cause increased pressure losses in some unexpected places, so care needs to be taken when assessing condensers, evaporators and control valves to make sure they are not going to cause excess pressure drop which would negatively affect the chiller efficiency."

    Star worked with Danfoss Turbocor to select R-1234ze(E) as the most promising fluid for this application and then in a three-way development team with Honeywell, who developed Solstice ze (R-1234ze)  for use as a refrigerant, foam-blowing agent and other applications.

    The chiller was comprehensively tested at Star’s chiller factory in Glasgow, including operating in an ambient of 40oC on Star’s 1500kW test rig. Turbocor worked closely with Star during the testing and were able to verify and adjust their control software while the compressor was in operation. This was the first time that Danfoss Turbocor had access to the prototype compressor on a live air-cooled chiller to verify their theoretical calculations and lab tests. The adjustments helped to raise the efficiency of the chiller by a few percentage points.

    Now that the tests are complete, the chiller has gone to its spiritual home – on the Honeywell site at Buffalo, NY where the HFO-1234ze(E) refrigerant was originally developed. The chiller will operate on the base load for the lab air-conditioning system, helping to keep the developers of the next generation of refrigerants comfortable at their work.

    Dr. Rob Lamb, Group Sales Director at Star, said: "This development is part of our long range plan. It allows us to give our customers confidence that we can help them transition to low GWP refrigerants moving forward. As the European F-Gas regulations develop, Star Refrigeration will be prepared to offer our customers a variety of refrigerant solutions."


  • Sky Studios, Isleworth


    BSkyB’s brand new sustainable landmark broadcast facility features a revolutionary air conditioning system from cooling and heating specialist Star Refrigeration.

    BSkyB is a leading broadcaster of sports, movies, entertainment and news. The company operates the UK’s largest digital pay TV platform from its headquarters in Isleworth, London.

    Star has supplied five of its state-of-the-art Indigochiller refrigeration plants to provide cooling within Sky’s new Sky Studios building. The ground-breaking facility will provide TV studios, technical and post production space for Sky.

    Five air-cooled Indigochiller units, each with a 1MW cooling capacity have been installed on the roof of the new building. Each Indigochiller provides chilled water, which is then pumped through insulated pipework to air handling units (AHUs). These AHUs will provide comfort cooling throughout the Sky Studios building, as well as some computer server cooling.

    Star Refrigeration Sales Manager Michael Reeve says: “A ground-breaking building such as Sky Studios required a state-of-the-art chilling system. Our Indigochillers have a strong track record at BSkyB, with the first installed at Isleworth over six years ago. They have proven efficiency benefits, are low maintenance by design and highly durable.”

    Star has worked in partnership with BSkyB on multiple building cooling projects since 2005 and has installed 36 Indigochiller units to date. Indigochillers are providing a total 18.85MW of cooling across fifteen BSkyB buildings, from Southampton to Livingston.

    Star’s energy efficient Indigochillers are just part of BSkyB’s efforts to ensure Sky Studios helps to reduce carbon footprint, minimise environmental impact and assist renewable energy generation at the Isleworth site.

    Designed for large-scale air conditioning and process cooling, Star’s Indigochiller is manufactured to ensure maximum efficiency, longterm reliability and low life-cycle costs. Each Indigochiller now comes with a three-year ‘no quibble’ guarantee covering component reliability, efficient performance and leak-tight operation.

    Engineered to have minimal effect on the global environment, Star’s Indigochiller has a robust design that aims to eliminate refrigerant leakage and offer over 20 years service.

    The low charge, high performance Indigochiller features a revolutionary Turbocor compressor, which is low maintenance by design to ensure lifelong trouble-free running. The oil-free compressor operates on electromagnetic bearings and uses the synthetic refrigerant R134a. The system offers reliable performance and requires minimal installation, servicing and maintenance.

    Indigochiller is manufactured from the highest quality components selected to minimise the risk of refrigerant leakage, reduce maintenance costs and enhance operating life. Standard features include ‘leak-free’ bellows seal valves, sealed expansion valves and welded steel pipework. The air-cooled Indigochiller has epoxy coated condenser fins as standard to reduce the risk of corrosion damage.

    Available as an air-cooled or water-cooled unit, Indigochiller has capacity options ranging from 250kW to 1,650kW. A robust PLC control system allows the user to monitor refrigerant charge, running conditions and optimise efficiency. Indigochiller is highly energy efficient using only 60% of the energy required by a standard chiller operating on typical load and ambient profiles. This offers end users a significant saving in energy and running costs.

    When it comes to designing energy efficient cooling and heating systems, Star is a natural innovator. Star works with strategic partners across the globe to deliver low carbon, cost saving solutions.