Cool-Therm delivers ultra-quiet chillers
Cool-Therm has supplied an ultra-quiet 1.8 MW air-conditioning solution for a development of luxury apartments in Westminster. To meet a challenging limit of 51 dB(A) at 10 m specified by consultant AECOM, three additional sound-attenuation measures were applied to the conventional Turbomiser design to achieve the 12 dB(A) noise reduction required.
Following experience gained in this project Cool-Therm is developing an ultra-low-noise version of the Turbomiser chiller as a standard option.
Abell House and Cleland House are designed to meet Level 4 of the Code for Sustainable homes and included a CHP system, heat-recovery ventilation, high levels of insulation and air tightness, LED lighting — and the Turbomiser chiller.
Cool-Therm worked closely with M&E contractor Briggs & Forrester on a new design for the Turbomiser chillers to achieve the space and sound objectives. To reduce the chiller footprint, all associated equipment is accommodated on a structural frame beneath the chiller.
To reduce noise, three additional sound-attenuation measures were applied. The most substantial and visually striking is the addition of acoustic tower to both sides of each condenser fan (pictured), making an array of 16 towers per chiller.
The towers are 1.6 m high and about 1 m in diameter. They are lined with lead damping material and a perforated liner to absorb sound. Unusually, the condenser fan is positioned at the mid-point within the tower, providing attenuation at both air inlet and discharge sides.
A bull-nosed column in the tower further reduces sound. The fans themselves are sickle-bladed low-noise units, which help streamline airflow and reduce sound.
The Turbocor compressors are housed in acoustic enclosures, reducing sound from this source by 6 to 7 dB(A).
Finally, refrigerant lines from compressors to condenser are lined with lead insulation to further reduce vibration and noise.
Rob Young, Cool-Therm director, said, ‘Our calculations were that it would achieve the required 51 dB(A) at 10 m, and this was confirmed in performance tests at Geoclima’s laboratory [which made the chillers], with representatives of the contractor and consultant in attendance.’
