Case Studies
Major chiller refurbishment for British multinational, York
Airmaster were presented with a unique challenge in refrigeration when tasked with the refurbishment of two chiller’s in one of York’s most stunning buildings. The chiller systems which run throughout the 6-storey building were circa 27 years old and required a number of significant repairs for future system resilience and life span longevity. With such old systems in place, parts were now obsolete and more importantly inefficient. The core focus of this project was to modernise the existing chiller systems making them more durable and efficient to compete with modern day chiller technology, all while offering a great value engineering solution beneficial to the end users budgets.
The heart of this chiller refurbishment lies in the basement where the compressors, evaporators and control panels are situated. The basement plant room is a congested area filled with mechanical equipment and associated electrical equipment. All twelve compressors had to be manoeuvred carefully out of the space safely and taken away for full refurbishment. All the refrigerant pipework, NRV’s, mufflers, vibration eliminators, ball valves, pipe insulation and pipe clamps were replaced for new in the plant room and roof top condenser area.
New Carel ExV electronic expansion valves replaced the existing dated originals. These new valves specifically focus on energy efficiency, in addition they produce high levels of precise refrigerant control passing through the evaporator.
New Airedale control panels also replaced the existing panels. The new control panels utilise a microprocessor controller taking full advantage of the latest state of the art technology.
The control system comprises of three main parts, the controller with built-in user interface, electronic expansion valve drivers and head pressure control. The display keypad is used for viewing the unit operating status and making adjustments to control parameters by allowing the operator access to a series of display pages. Visual alarm and the facility to adjust and display control settings are available at the display keypad for local operator information and control.
The chillers initially used refrigerant R22 but this was eventually phased out, MO29 (R422D) was chosen as the replacement around 10 years ago but ultimately this wasn’t a success. After diligent research, a reasonably new refrigerant to the UK market was chosen, RS70 (R453A). The focus was energy efficiency and compatibility with the systems as a whole. RS70 has a cooling capacity within 3% of R22 and has the highest efficiency rating plus the lowest GWP (1765) of all the R22 replacements currently on the market. In total, both chillers used 2,400kg of RS70.
Both chillers housed four Searle GEA condensers in total, consisting of 48 Ziehl Abegg fan motor assemblies. Twelve of the original motors were found to be faulty and were replaced with the new type Ziehl Abegg FN091. Once again, energy efficiency took president, the FN091 use EC fans and motors with maximum efficiency. The motors are controlled via pressure transmitters to the exact speed required, which in turn provide pin point operating pressures of the new refrigerant.
This was a delicate project handled with great care by the engineering team at Airmaster, who continue to grow as rising stars in the refrigeration sector. The refurbishment saved hundreds of thousands of pounds for the builder owners and provides the onsite PPM team a much more proactive way of controlling the buildings comfort conditions without the reactive issues presented by the chillers previous condition.
To download a PDF of the case study please click here.
Daikin heat recovery systems give prime office building new lease of life.
A prime office property in busy Watford has returned to the letting market after a massive facelift – including an efficient new heat recovery air conditioning installation that is configured to suit the needs of up to nine tenants. Described as a self-contained headquarters office building, 40 Clarendon Road has almost 50,000 square feet of lettable space, spread across five floors. The building, which dates from 1998, is part of an investment company’s portfolio. Refurbishment followed a previous tenant’s move to even larger premises. The new Daikin VRV IV heat recovery air conditioning system, installed by Rotherham-based Daikin D1+ Business Partner, Airmaster, as part of the Category A fit out, was designed to British Council for Offices standards.
“This means we have smaller indoor units where future tenants might want to install peripheral meeting rooms or small offices, and larger units in the central ‘general office’ areas,” says Airmaster director Gareth Campbell. Indoor units are exclusively medium static pressure concealed ceiling units. This is unusual in an exposed services environment as these units are primarily designed to offer flexibility and performance in rooms with limited space or with irregular shape (L-shaped, U-shaped, or long rooms). They also offer automatic airflow adjustment, which means they are draught-free and quickly reach the desired temperature while being whisper-quiet. Sound levels can go lower than 25 decibels.
Gareth Campbell says: "They wanted a high-end look for the pipework and ducting. We had to present a number of sample configurations and they chose a shiny, smooth aluminum cladding."
To download a PDF of this case study please click here
The Daikin indoor units are all in their ‘natural’ state – apart from in the reception area where exposed services are all sprayed matte black.
Each unit has an individual branch selector box, providing maximum flexibility to accommodate ‘cooler’ or ‘warmer’ requirements – plus facilitating isolation of units, if necessary.
At the core of the installation are 19 VRV IV heat recovery outdoor units, ranging from 8-16hp and totaling 230hp. Heat recovery units are inherently more efficient than straight heat pumps – and additionally have the ability to deliver simultaneous cooling and heating, economically using ‘waste’ heat.
The outdoor units drive nine independent systems – one for the 8,500 sq. ft ground floor, and two for each of the four upper floors which range from 8,000 to 10,000 sq. ft. As a result, the upper floors could each be let to one or two tenants.
Each of the systems is controlled at tenant level through a Daikin Intelligent Touch Manager with individual local control of 41 zones through Daikin’s elegant wall-mounted Madoka controllers. Overall, the Daikin systems are linked to building management system via a BACnet gateway.
Conveniently sited midway between Watford Junction and the town’s main shopping area – and an easy walk to both – the building has open and underground parking for 129 cars. The refurbishment also included new lighting, lifts and toilets.
Water-cooled VRV perfect solution for Richmond office refurbishment
A landmark 1980s ‘head office’ building in Richmond, London, has been given a new lease of life – and a fresh long-term tenant – after a £5 million refurbishment that included installation of Daikin VRV-W water- cooled air conditioning.
The 33,000 square foot four-storey building at 63 Kew Road – former UK headquarters of Pepsi Cola – is now home to the leading online marketplace for creative small businesses notonthehighstreet.com, which has taken a 10-year lease.
Owned by Low Carbon Workplace, the building has been substantially upgraded to raise its Energy Performance Certificate rating from E to B and to achieve a BREEAM Excellent rating. The improved ratings also meet the London Borough of Richmond’s target for a 40% reduction in carbon emissions.
Low Carbon Workplace is a a partnership, launched in 2010, between the Carbon Trust, fund manager Columbia Threadneedle Investments and property developer Stanhope.
The partnership acquires commercial office buildings and refurbishes them into modern, energy efficient workplaces.
In selecting the Kew Road building’s new heating and cooling system, noise criteria and line-of-sight constraints ruled out chillers and air-cooled VRV outdoor units. Water-cooled VRV, on the other hand, could be contained – out of sight and earshot – in a plant room.
VRV-W also offered the efficiency advantage of two-stage heat recovery - within each system and between systems on the water loop. This two-stage recovery substantially improves overall energy efficiency especially in situations where cooling is required even in winter.
Heat recovery was an obvious choice for a building with different aspects developing variable conditions that required simultaneous heating and cooling. The original design was also based on a Cat A selection process to ensure the system would have maximum fl exibility to accommodate the requirements of any future tenants.
There is a flexible and energy efficient control strategy to attain both the EPC and BREEAM scores required by Low Carbon Workplace. The strategy includes PIR movement sensors linked to Daikin RTD interfaces to provide the control inputs for one or more FCUs to optimise conditions when people are present, but to drift from the set point after no response from the PIR, and eventually switch off.
To allow for Individual control, one branch selector box is provided per FCU. The 20% tempered fresh air delivered to the FCUs is controlled by dampers and CO2 sensors, which further enhances efficiency. There are no local controllers, with the system controlled centrally by Daikin Intelligent Touch Managers – facilitating sub-metering of the building if it is subsequently let to multiple tenants. The system gives individual tenants the facility to control their environment through web-based access to the ITMs.
Sheffield - based Daikin D1+ Premium Partner Airmaster installed six systems totalling 13 condensers, which generate the total heating and cooling requirement for all floors and an air curtain in the lobby. Another four condensers serve the building’s two air handling units, which supply tempered air at 18oC to the rear of fan coil units (FCUs) throughout the building. The building’s total calculated load is 427kW (peak instantaneous: 348kW).
Two low-height, low-noise Guntner adiabatic dry air coolers reject heat from the water loop to the roof. A 546kW boiler generates hot water for the building and heat injection to the water loop to maintain a fixed 40oC flow to the Daikin VRV-W condensers during cold weather.
To fit the boiler and condensers into the plant room, the condensers were located using racking, one above the other. This satisfied the requirements for heating and cooling plant without compromising design – or the lettable floor area.
All FCUs are of the FXDQ type – slim concealed ceiling units, which can be mounted in ceiling voids as small as 240mm.
These medium external static pressure units can be used with flexible ducts of varying lengths. They are specially developed for small or well-insulated rooms such as hotel bedrooms and small offices – and so are ideal for ensuring future flexibility of the office layout at 63 Kew Road.
To download a PDF of this case study please click here.
Office fit out - BOC, Brinsworth
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Airmaster successfully completed the install of Air Conditioning over two floors at BOC, Brinsworth in Rotherham.
Fit-Out contractor: DL Company
Installing multiple inverter driven R32 cassette DX split systems. These cassettes were installed in the ceiling grid within the offices, training rooms & cellular spaces to provide independent heating or cooling for the area the user is working via a wall mounted remote controller.
The installation was completed with all interconnecting containment, refrigerant pipe work, thermal insulation, controls wiring and condensate drainage. The condensers for the systems were located externally at the rear ground level of the building for ease of servicing. Remote controllers were installed for each system to provide independent heating or cooling for the area the user is working.
The project was handed over with a user demonstration, O&M manual and commissioning certificates for ease of future maintenance and referencing.
The R32 systems installed offers a lower GWP (Global Warming Potential) compared to comparable R410a VRF systems. 675 compared to 2088, which means it has al lower potential to contribute to climate change making it a more sustainable choice.
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To download a full copy of the case study please click here.
“The DL company offered a professional installation to a high standard. The initial proposal helped demonstrate layout options. The level of detail for the costs allowed confidence on the proposal and final cost structures. Value was at the heart of the design, delivered on time and to budget. We would recommend DL for further schemes.”
Sally Williams, Head of Finance
BOC Limited, a Linde company
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