SPX Cooling Technologies 7013F081 - 7013J121, 7014H081

Marley / MC Fluid Cooler / Specifications: Options

Specifications

Miscellaneous Options

Sound Control

1.2Add the following paragraph under Base: The fluid cooler shall be quiet operation, and shall produce an overall level of sound not higher than _______

dB(A) measured at the critical location indicated on the plans.

Specification Value

■Sound produced by a standard MC Fluid Cooler operating in an unobstructed environment will meet all but the most restrictive noise limitations—and will react favorably to natural attenuation. Where the fluid cooler has been sized to operate within an enclosure, the enclo- sure itself will have a damping effect on sound. Sound also declines with distance—by about 5 or 6 dB(A) each time the distance doubles. Where noise at a critical point is likely to exceed an acceptable limit, you have several options—listed below in ascending order of cost impact:

•Where only a slight reduction in noise will satisfy—and the source of concern is in a particular direction—merely turning the fluid cooler may be the answer. Less sound emanates from the cased face of the fluid cooler than does from the air intake face.

•In many cases, noise concerns are limited to night time, when ambi- ent noise levels are lower and neighbors are trying to sleep. You can usually resolve these situations by using two speed motors in either full/half speed or full/ 2⁄3 speed configuration, and operating the fans at reduced speed without cycling “after hours”. (The natural night time reduction in wet-bulb temperature makes this a very feasible solution in most areas of the world, but the need to avoid cycling may cause the cold water temperature to vary significantly.)

•Variable speed drives automatically minimize the fluid cooler's noise level during periods of reduced load and/or reduced ambient with- out sacrificing the system's ability to maintain a constant cold water temperature. This is a relatively inexpensive solution, and can pay for itself quickly in reduced energy costs.

•Where noise is a concern at all times (for example, near a hospital), the best solution is to oversize the fluid cooler so it can operate con- tinuously at reduced (2⁄3 or ½) motor speed even at the highest design wet-bulb temperature. Typical sound reductions are 7 dB(A) at 2⁄3 fan speed or 10 dB(A) at ½ fan speed, but larger reductions are often pos- sible.

•The most extreme cases may require inlet and discharge sound attenuator sections—however, the static pressure loss imposed by discharge attenuators may necessitate an increase in fluid cooler size. Two stages of inlet or discharge attentuators supported by the fluid cooler and designed and tested for the most stringent requirements are available as an option. See page 13.

The advantage is yours. You now have the choices you need to bal- ance your project’s performance, space and cost requirements with your sound level needs for a win-win solution to your cooling system design. Your Marley sales representative will be able to help you meet your sound requirements.