The HRW series thermo-chiller is a high-performance device for circulating a fluid at a constant temperature (Water-cooled type). Energy saving is substantially increased by exchanging cooling water and heat directly. The HRW can achieve reduction in power consumption as it does not have a compressor, and reduction in the amount of facility water used because heat is exchanged directly with the circulating fluid which results in reduced facilities investment, space saved facility water facilities, and reduced running cost.