New options introduced on Screw Chillers
Daikin Europe nv (12/01/2005)
Daikin Europe has introduced a series of new optional extras to its large screw chillers: heat recovery, inverter fans and fans with high external static pressure. In addition, Daikin has fitted standard filters for both water and air cooled chillers equipped with brazed plate heat exchanger.
The first option is the heat recovery for the air cooled R-407C range from 40 to 200HP. This option aims to optimise both cooling and heat recovery capacities in order to maximise unit efficiency and generate significant energy savings.
An additional heat recovery exchanger mounted in series with the air cooled condenser allows heat that would otherwise have been rejected to atmosphere, to be used effectively for heating water up to 60°C. The use of inverter fans enables step less condensing pressure control to ensure stable operation of the unit under all conditions.
Unlike a conventional heat recovery unit, the Daikin unit accurately controls the hot water temperature. A digital input via a factory fitted hot water return sensor or a field fitted hot water tank thermostat, enables automatic changeover between cooling and heat recovery. This feature will avoid heating water to higher temperatures than are required and thereby wasting energy.
Units fitted with heat recovery are compatible with the Daikin Integrated Chiller Network (DICN). This system enables any 4 chillers of similar or different sizes, to operate simultaneously as if they were a single unit. By giving priority to the heat recovery unit, generation of hot water is reliable at part load conditions.
Extending the heat recovery potential of Daikin screw chillers is important, particularly for their use in large hotel projects. However, it also widens their appeal in many industrial and process applications where high waste heat temperatures exist alongside localised hot water requirements.
The use of inverter fans as a separate option allows control stability and steady fan speed operation. The non fluctuating sound characteristics of inverter fans provide a better “colour of sound” than standard step control. At an ambient temperature of 20°C for example, a reduction of up to 3dBa is achieved. This would equate to a 9dBa reduction in combination with the existing low noise option at these conditions. The speed of the inverter fans can be decreased by a digital input during noise sensitive periods.
The factory fitted high ESP fans (up to 150Pa) are intended for use with chillers installed in locations where restricted space might inhibit airflow across the coil or where duct connection is necessary on the air discharge side in indoor plant rooms etc. For very low noise specifications the increased ESP allows specialists acoustic treatment of the unit. Fitting of 3rd party acoustic louvers and pod attenuation on condenser intake and discharge can also be considered.
A1mm mesh filter plus Victaulic joints will be supplied on all Daikin screw chillers equipped with a brazed plate heat exchanger. This filter must be connected by the installer on the water side in front of the evaporator and is intended to obviate the possibility of incorrectly sized filters being fitted in the field.
