Overview

Given the intense demands of high density dedicated servers and the balmy Florida climate, ConnexHosting has designed an extensive and fully redundant HVAC system to ensure equipment is kept cool and running at its full potential. Our facility's current power specification is 900 watts per square foot at capacity. As a result, the facility is cooled to support this high level of utilization. HVAC systems are installed in commissioned space to support a full 51.3BTU per square foot per minute. We utilize Computer Rooms Air Conditioner (CRAC) units from three manufacturers: AirFlow, Liebert, and Stulz. Additionally, house air in the data center space is provided by two 90-ton Trane air handlers.

Design

Upon completion of the Phase 3 co-location space expansion, ConnexHosting's facility will feature a total of 590 TONs of CRAC cooled air in addition to the 180 TONs of house air in the data center space. With this large of an application, the industry norm is to deploy a chilled water system as the chilled water CRAC systems are cheaper and able cool a higher level of BTUs while occupying less floor space. Instead, our engineers shunned this concept in favor of larger and more expensive air cooled units. In our quest for maximum redundancy, our engineers realized that a large chilled water system would require us to depend on very rare, very large chillers. In our original design, York specified two 700-ton precision chillers. While one chiller could run the entire facility if the other failed, parts for such a system are hard to find and even more difficult to service. The failure of any combination of chiller, motor starter, electrical gear, manifold, or even a pipe could potentially completely disable our ability to cool the data center. At 51.3BTU per square foot per minute, the results would be disastrous.

Our current design allows us complete flexibility in controlling the environment of our facility. Once complete, the entire center will sport no less than four 20 ton AirFlow units, three 20 ton Liebert units, and 15 30 ton Stulz units. Each of the units has its own respective condenser and built in redundant measures. If any one or more unit fails, the other are completely unaffected. Each phase (Phase I, Phase II, Phase III) of the data center is cooled via a single plenum fed by all the units in that phase, so added cooling loaded resulting from the failure of any unit is simply covered by other units in that phase without creating hot spots. Our private room co-location suites, which have independent HVAC systems, feature automatic louvers connected to the main data center that open in the event of a failure of that suite's HVAC System. To further ensure that our data center is protected, we have installed several 13,000 CFM exhaust fans which are battery powered and can be enabled in a critical situation to exhaust the data center floor.

Air Handlers

Designing a system with redundancy that can recover from the failure of a complete unit without interruption is only the first step in ensuring our facility maintains its world class reputation. Selecting and configuring units that feature safeguards and built-in redundancy is the second and perhaps most important step. In reviewing manufactures of CRAC systems, we looked at no less than 6 different manufactures offering 18 different models. We selected the three units currently deployed for their respective features.

20 ton AirFlow Units · By far the most advanced of the CRAC systems, the AirFlow offer the type of precision analysis of air and environmental quality that until very recently was only detectable by professionals with manual instruments. The four units in the facility are strategically located to allow us to monitor over 18 environmental factors 24/7 in our Network Operations Center (NOC).
20 ton Liebert Units · Long considered the workhorse of data centers nationwide, the Lieberts support multi-fan condensers and two separate 10 ton compressors, allowing one to fail and the other to continue operating.
30 ton Stulz Units · Even though our original intent was to continue utilizing the Liebert units as the facility expanded, once we tested the Stulz 30-Ton units we switched our future plans. Each 15 foot long units features two 15 ton compressors and, most impressively, two separate 6,500 CFM blowers. Each unit also connects to two separate 3 fan condensers providing the most redundancy available in the CRAC marketplace. When coupled with the expanded "networking" feature among the Stulz Units' control boards, we feel the Stulz unit is the best product currently available.

Onsite Backup Stock

As with our electrical system, ConnexHosting believes in stocking every part that could fail in house. In our emergency reserve, we stock 2 Stulz units and one each of the Liebert and AirFlow units. Additionally, through our sister telecommunications construction company, Southeastern Engineering and Construction, which we share our headquarters with, we have access to certified HVAC engineers and service personnel 24/7. Our knowledge of HVAC and power systems is extensive and we maintain a separate 38,000 square foot facility dedicated to refurbishing and selling used data center equipment.