Building on the success of its Centrifugal Compressor Water Cooled Chiller, Daikin has relaunched the DWSC/DWDC range in B vintage. The next generation water cooled chiller incorporates new features, including a new Inverter drive design, unique to Daikin, and the low GWP R-513A refrigerant version.
Vienna, December 2019 – The DWSC/DWDC range in B vintage is the latest in an array of innovative products developed by Daikin to help specifiers and end users stay one step ahead of EU legislation and rising energy costs.
Available in a wide choice of cooling capacities and component combinations, the range has been developed to optimize energy efficiency and reduce operating costs. Maximizing performance at both full- and part-loads, the new chillers are available with a choice of refrigerant, R-134a or low GWP R-513a refrigerant, in single or dual compressor variants.
As part of a building system, centrifugal compressor chillers represent a significant investment. Suitable for new build or retrofit, the new chiller range delivers real benefits for the bottom line.
Daikin makes several centrifugal chiller types to meet a wide variety of project size and performance requirements, including commercial cooling, district energy plants or manufacturing processes.
The single compressor DWSC provides excellent full and part load performance with the optional unit mounted Daikin Inverter. The dual compressor DWDC chillers offers many benefits, including outstanding part-load efficiency, and system redundancy equivalent to two separate chillers, with a lower total installed cost. A dual compressor DWDC chiller can also provide installed costs savings of up to 35% compared to installing two separate chillers by reducing hardware and rigging costs and eliminating second chiller piping and pumps. See * for more information.)
‘Right-sizing’ chiller selection offers reduced installation costs from the outset: DWSC/DWDC B Vintage allows virtually infinite combinations of heat exchangers, gears, and motors to provide the exact required capacity, minimizing the need for a costly step up to a larger-size chiller package.
The flexible control logic of the Daikin inverter drive maps exact performance curves at every condition to minimize speed and still deliver the required cooling capacity. This allows the DWSC/DWDC B Vintage chillers to take advantage of off-design conditions to save energy for comfort cooling applications with variable loads - even for data centers with a constant heavy load.
The unique design of Daikin’s Inverter uses fewer internal components to create the optimal balance between cost and performance. Engineering and factory-mounting the Inverter provides significant economies of scale, ensuring low in-rush currents to the chillers, reducing the risks of overheating and wiring deterioration over time for a more dependable motor life.
Daikin’s precision-engineered gear driven design allows for lighter components, less vibration, and ability to select gear ratios that will provide the optimum impeller speed whatever the application. Older direct-drive designs must use large, heavy impellers to reach similar tip speeds, which cause more vibration and greater stress on shaft and motor during unexpected electrical interruptions.
The compact design and lighter weight components enable efficient hydrodynamic bearings to be used (079-126 compressor models). This means that during operation, the shaft is supported on a film of lubricant, with no shaft-to-bearing contact, providing theoretical infinite life bearings under normal circumstances. The design simplicity of the Daikin centrifugal compressors provides increased durability and reliable performance.
Daikin is a pioneer of the use of moveable discharge geometry to lower the surge point of centrifugal compressors which offers an outstanding unload capacity. The point at which the compressor enters a stall or surge condition generally limits compressor unloading. Chillers with a fixed discharge will experience stall or surge at low loads due to refrigerant re-entering the impeller. When in a stall condition, the refrigerant gas is unable to enter the volute due to its low velocity and remains stalled in the impeller. In a surge condition the gas rapidly reverses direction in the impeller causing excessive vibration and heat. Daikin compressors reduce the discharge area as load decreases to maintain gas velocity and greatly reduce the tendency to stall or surge.
Environmental impact reduction
The DWSC/DWDC B Vintage chiller range offers customers a choice of refrigerant: R-134a, a chlorine-free refrigerant with zero ozone depletion potential or R-513A, a refrigerant that has lower global warming potential. Both R-134a or R-513A can be used for lifetime chiller operation, eliminating the uncertainty of refrigerant availability.
R-513A is an HFO/HFC blend (R-1234yf and R-134a) refrigerant. Its Ozone Depletion Potential (ODP) is equal to zero (0) and the Global Warming Potential (GWP) is 631 (according to the EU F-gas Regulation). Meeting the ASHRAE Standard 34 and classified as an ISO-817 Class A1 non-flammable refrigerant, R-513A is compatible with all existing application standards and building codes. R-513A can also be switched in the field, offering increased flexibility and choice for retrofit applications.
DWSC/DWDC B Vintage chillers are designed and tested to ensure refrigerant stays inside the chiller. Because R-134a and R-513A operate slightly above atmospheric pressure, outside air containing non-condensable moisture cannot enter the chiller, eliminating the need for a purge unit to evacuate water vapor and refrigerant into the atmosphere.
Environmental impact reduction
Daikin has a long history of continually reducing the environmental impact of cooling, heating and refrigeration products, as well as having a unique expertise that comes from manufacturing both refrigerants and equipment. This position is a result of the company's corporate philosophy to "Be a Company that Leads in Applying Environmentally Friendly Practices".
Daikin believes in diversity of refrigerant choice to allow the best suited solution to be used in each application. Refrigerant choice is assisted by the company’s expertise in using fluorinated (HFC, HFO) as well as non-fluorinated gases (ammonia, carbon dioxide, hydrocarbons).
For a complete overview, see Daikin’s Policy and Comprehensive Actions on the Environmental Impact of Refrigerants at: www.daikin.com/csr
* DWSC/DWDC B Vintage is available in a wide range of capacities offering the widest possible choice in use. All models are fitted with a single refrigerant circuit:
Daikin DWSC B Vintage range with both R-134a and R-513A offers a choice of cooling capacity from 1050 kW (300RT) up to 4500 kW (1250RT) at nominal conditions, with single centrifugal compressor.
Daikin DWDC B Vintage range with both R-134a and R-513A offers a choice of cooling capacity from 2100 kW (600RT) up to 9000 kW (2500RT) at nominal conditions, with two centrifugal compressors.