NetRiver Goes Green
Traditional Data Center Design:
The raised plenum floor method of cooling a data center relies on pushing air flow up through perforated tiles in front of cabinets. Given the standard raised floor clearances of 12" - 18" and the maximum raised floor tolerances (roughly 24" which allows 150 pounds per sq ft), there is a finite amount of air flow that can be pushed through the tiles due to constraints in allowable column diameter and CFM (cubic feet per minute) constraints coming through the perforated tile itself. In addition, the limited cool air that makes it in front of the cabinet does so from the bottom. With cooler air heavier than warm air, and an inadequate ability to blow air up the entire surface of the cabinet; Cold air ends up circulating in front of parts of the cabinet, leading to hot spots and uneven distribution of airflow.
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Our Design: HVAC
NetRiver has changed the distribution of air from the bottom to the top. This allows us to increase both the diameter of the ductwork column and the aperture of the opening in front of each cabinet... essentially more airflow with a more even distribution of the air as the cool air descends and is blown across the entire face of each cabinet. Thus, we are able increase the power rating of each cabinet to allow for larger ceilings in available power draw. Also, the vents themselves can be adjusted directly in front of each cabinet to allow for more or less air flow.
Next, we have adopted the hot aisle/cold aisle configuration to minimize premixing of the air. Cool air is distributed on one side and warm air is returned on the other. Overhead vents and a return ductwork plenum help isolate airflow patterns in the data center that lead to increased efficiency (we are minimizing energy consumption associated with warming and cooling the same air). VFD's (variable frequency drives) on each air handler control the air flow volume on the ductwork column in response to cooling considerations tied in with the BMS (building monitoring system).
Air handlers are horse power driven and their operational efficiency peaks occur in the middle. We operate the air handlers with VFDs in tandem with other air handler VFDs on common supply plenums to operate these systems as close to peak efficiency as possible. In addition, we utilize as much outside air as possible in our cooling techniques (free cooling) with the air handlers being able to filter and draw in outside air directly. Finally, we use Smardt Turbocor chillers for our chilled water systems. Smardt's oil-free centrifugal compressors use magnetic bearings and variable-speed drives to deliver better IPLV efficiencies than conventional oil-lubricated centrifugal, reciprocating, scroll and screw compressors. Oil-free centrifugal compressor technology boosts energy efficiency. Our BMS is designed to operate these chillers in tandem as Turbocor technology achieves the highest part-load efficiencies for chillers and chilled water systems.
Our Design: Power
At the backbone of NetRiver's power distribution system is the APC Symmetra Megawatt UPS. The UPS topology utilizes delta conversion in its AC-DC-AC conversion compared to the double conversion found traditional legacy UPSs. With an N+1 frame (two inverter sections, two control sections) it operates at 97% peak efficiency compared to 88-94% found in other UPSs. Moreover, it reaches it optimal efficiency quicker at lower utilization levels (UPSs typically run in the 60% -80% load range). This allows for a more efficient platform across all ranges and greater efficiency gains at mid operational levels compared to other UPS topology. All power to the data center floor goes through this conversion process. Not surprisingly, small percentage gains in UPS efficiency lead to huge energy and dollar savings.
Our relationship with the PUD also allows us to deliver "green power" from the utility source. Green sources of power include wind, geothermal, solar, and biomass in addition to hydroelectric power already being delivered. Companies may take advantage of carbon neutral programs consistent with their own green initiatives.
Our Design: Lighting/Ultrasonic Humidification
NetRiver's BMS also tightly controls the humidity levels necessary to maintain a high density platform. Ultrasonic humidification is used due to the low energy use. On average, this process gives us a 93% reduction in electrical usage as compared to traditional humidification alternatives. Finally, NetRiver uses compact fluorescents in its lighting scheme in conjunction with motion based lighting sensors and timers to ensure lighting is used when only necessary in the most efficient manner possible.