Remote radiators are a great solution for emergency generator installations with limited engine room space and/or insufficient air ventilation. An earlier article provided key points for specifying a remote radiator for emergency generators. This article expands on this subject by addressing one item that is often overlooked in the selection of a remote radiator: noise.
Aside from proper engine cooling, the sizing and selection of a remote radiator for an engine-generator application often has the primary goal of reducing overall physical size. A manufacturer will design a remote radiator package with a combination of elements (fan diameter, fan speed and core construction) to provide the most efficient cooling in the smallest possible package, hopefully leading to the most cost-effective solution. However, when noise level is identified as a design priority, the radiator manufacturer can take steps to achieve a balance between cooling performance, size and generated noise.
Did you know? A typical remote radiator for a 1500kW generator will generate ~60,000 scfm airflow and ~85dbA sound level (free field conditions).
Here are 3 tips to achieve a “low-noise” remote radiator assembly:
- a larger radiator core (larger face area) may be designed with a lower fin/tube density. A larger but less-dense core will reduce the airflow’s restriction, leading to a lower operating sound level. The compromise here is a larger radiator assembly to compensate for the lower heat transfer performance in the less-dense core.
- a slower-turning fan may be incorporated to reduce the air velocity across the radiator’s core. A lower air velocity means lower noise, but also less airflow, which then requires a larger radiator core (with more cooling surface area) to maintain the required cooling performance.
- a variable frequency drive (VFD) system may be incorporated to match the radiator fan’s speed with the cooling requirements of the engine. As the engine load (cooling requirement) increases, the fan speed increases, and vice-versa. This design approach would benefit installations where the generator runs at relatively low load levels. As a side note… consider that engine cooling is critical to the emergency generator system, I recommend that any variable frequency drive system be designed with a fail-safe feature to revert to full fan speed (should the electronic controls fail).
The key takeaway here is to have an understanding that radiator manufacturers can tailor the design of a remote radiator system to achieve goals related to operating noise and other environmental factors.
When faced with a special requirement for a remote cooling package, whether it be fitting the radiator in a tight space, or trying to meet strict noise requirements, please reach out for a consultation. Hurtado.cc has vast experience with the application of radiators and heat exchangers, and can be a valuable asset to your design team.