Similar to the simplicity of dry coolers, adiabatic cooling systems circulate process fluid through bundles of copper tubing and large fans pull outside air across the fins to cool that process fluid. However, when ambient temperatures get high enough to require additional cooling, the adiabatic cooling system releases a fine water spray into the air prior to the air being pulled over the copper cooling tubes. That water spray evaporates which lowers air temperature, offering a significant cooling advantage over dry coolers.
The VIRGA control system cycles individual fans or ramps up fan speed as process fluid temperature dictates and ultimately activates the fine spray of water only when required. During temperate conditions, water spray activation is not required and the unit operates as a dry cooler.
Systems are designed for the ASHRAE conditions of the specific project location. Each system optimizes dry mode fan staging and adiabatic spray staging based on real time process fluid temperature maximizing cooling capacity while leveraging the strengths of both dry and adiabatic approaches. This strategy provides consistent performance across climate zones, from arid Southwest installations to high-humidity Gulf Coast and Southeastern U.S. applications.
The hybrid adiabatic cooling technology used by VIRGA systems was born in response to regulations aimed at preventing the spread of Legionnaires’ disease by replacing traditional evaporative cooling systems, one of the most common breeding grounds for Legionella.
NIMBUS was the first company to manufacture hybrid adiabatic cooling technology in the US.
VIRGA systems arrive at the installation site pre-programmed to the customer’s specifications with the leaving fluid temperature sensors installed and wired.
VIRGA systems are engineered, designed and manufactured by NIMBUS Advanced Process Cooling in the USA.
Contact a representative today to learn which type of cooling solution is best suited for your operational requirements.
All VIRGA cooling systems feature UL/UL-C industrial control panels custom-built by NIMBUS (UL-Certified). Panels are installed either directly on the cooling system or remotely. Controls installed directly on the cooling system are fully contained, requiring only the primary power connection on site. NIMBUS’ cooling systems feature Type 3R-rated enclosures as standard, with Type 4 and Type 4X options available.
VIRGA units outfitted with AC fans include digital controls as standard. PLC (programmable logic controllers) controls and VFD (variable frequency drive) are available as upgrades or no controls can be selected if desired. Units outfitted with EC fans come standard with PLC controls. Standard EC fan packages and AC fan packages upgraded with PLC controls and VFD provide fan speed modulation, while standard AC fan packages with digital controls feature “on/off” fan staging. AC and EC packages may be swapped at any time on select VIRGA models.
AC fan packages are available with low-noise blades. This may require a motor swap to avoid potential derate of the unit capacity. Select EC fan packages offer sound attenuation modules as well.
With two types of configurations available, both VIRGA spray systems minimize fluctuations in process fluid temperature – reducing fan and spray cycles. This allows VIRGA units to reach steady-state conditions quicker than ever and achieves unparalleled water and energy conservation.
Our standard configuration activates all spray rows simultaneously when spraying begins. The staged configuration activates spray rows sequentially, starting with one and adding rows as needed until the desired cooling is reached. This approach rarely requires all rows, significantly conserving water usage.
How VIRGA III exceeded economizer cycle requirements in the face of a tight air shaft on The Ohio State University campus.
Be Blue is our conservation rallying cry.
Be Blue represents the NIMBUS philosophy of providing alternative, practical and economical cooling solutions that preserve water, energy and health.
