Rittal TopTherm chiller features improved precision and reduced depth

The temperature of chilled water for enclosure cooling is less essential than the water temperature used for process cooling. In order to guarantee the necessary processing accuracy, spindle cooling demands that the cooling medium is supplied within a tolerance of ± 0.5 K. If this is not the case, inaccuracies in the machined workpiece will occur due to the thermal expansion of the components.

Usually, chillers are governed by a two-point control system: turning the compressor on and off as the temperature of the cooling water either rises above or falls below the maximum and minimum permissible limits. This frequent switching would have a negative impact on component life, because it is not possible to control within the small hysteresis required for machine cooling using this method.

For this reason, Rittal’s new TopTherm Inverter Chiller incorporates a variable speed compressor powered by a brushless DC motor. The speed of the BLDC motor is controlled by an inverter so that it delivers the cooling medium at a temperature with the required accuracy.

Rittal’s TopTherm chillers also feature other optimised components in the refrigerant circuit, energy efficient electronically commutated fans and an electronically controlled expansion valve. This technology has culminated in Rittal offering a range of chillers with a capacity range of 2-19.5 kW, a chilled water temperature tolerance as low as ± 0.2 K and an impressively high energy efficiency ratio of up to 3.3.