Rittal Blog

The TCO of Data Center Liquid Cooling

September 16 2020 by Herb Villa


What Is the TCO of Data Center Liquid Cooling?

Every IT Facilities Manager loses sleep thinking about the amount of energy their data center is consuming, and the growing cost of that energy. With a significant portion of their budget going towards climate control and heat removal, optimizing these systems is an important mandate for most. Fortunately, the industry is continually introducing innovative solutions that help data centers reduce costs and improve overall site performance. One of those innovations is liquid cooling.

Liquid cooling systems allow data centers to increase installation densities and offer substantial savings opportunities. Higher density installations will not have an effect on the IT power,you must still plan for however many megawatts your facility will support. However, increasing installation density and deploying liquid based heat removal can have a significant impact on power supporting climate control systems. One way to identify precisely how much savings can be realized is to look at TCO, or total cost of ownership, of a system. There are several factors to consider when calculating the TCO, and in this post we will review those that go into calculating TCO of a liquid cooling system.

A quick side note: Liquid cooling systems have been around for quite some time, at least the last 15 years. Liquid to the chip has always been a favorite solution for improving processor performance, especially in the on-line gaming world. Rack and row-based systems have also been available but perhaps viewed with over-zealous caution. Bringing water into the data center space was taboo, but as with any new technology, significant improvements were made to the reliability and stability of these systems with each new product. The various liquid cooling systems available today are safe and capable and must be considered for every potential high-density deployment.

Total Cost of Ownership of a Liquid Cooling System (with Cold Air Containment)

The TCO of a liquid cooling system will vary based on the specific installation criteria, including:

  • Dimensions of the enclosure
  • Possible use of aisle containment components
  • Cooling capacities needed to support the projected per-footprint thermal loads
  • Local energy costs and pricing structures, i.e. rebates, incentives, etc.
  • Reduction of IT installation floor space

On the other hand, TCO is not affected by building infrastructure and site conditions – e.g., type of floor, slab-to-slab clearances, and infrastructure redundancy. These costs are fixed and must be considered outside the TCO analysis.

In addition - Row-based, close-coupled systems are the primary focus of the TCO analysis, preferably using closed loop airflow pathways. While all high density liquid cooling solutions will have positive effects on TCO, they should not be compared to each other. Each system - Direct to Chip, Immersion, and Rear Door must be evaluated on an individual basis and compare which could offer the optimal TCO. And select a solution based not only on the potential savings, but one that matches your requirements - projected thermal loads, space constraints, application, and budget.

Assuming a 5-year financing of a system, these costs are part of the liquid cooling system TCO calculation:

  • System Purchase. This is a one-time cost in Year One
  • (Optional) Aisle Containment Components. This is a one-time cost in Year One
  • System and Rack Installation. Installation costs can be categorized under labor, or can be capitalized as a single cost. This is a one-time cost in Year One
  • Energy Cost & Use. These figures will be the same for each year in which the system is operating
  • Lifecycle Replacement (also known as Hardware Refresh Cost). Factoring in replacement recognizes that you will have to replace the system at some point in the future (or replace components), so the cost should be included in your calculation
  • Maintenance & Support. This is the annual expense of maintaining a support contract. A good rule of thumb is that this amounts to about 20% of purchase price each year after Year One
  • Extended Service Contract. This is an optional cost, but helps mitigate potential risks, so the cost should be included in your calculation

Using these factors to calculate TCO, the cost in Year One will be higher than all subsequent years, with the total being the sum of:

  • System Purchase + Containment Components + Installation + one year’s Energy Use (at set Energy Cost) + the cost of one year of a Service Contract

In each subsequent year, the total will be the sum of:

  • Energy Use (at set Energy Cost) + Maintenance & Support + the cost of one year of a Service Contract

Additional Liquid Cooling Cost-saving Opportunities

Deploying Rittal’s LCP (liquid cooling package) in place of traditional room climate control systems (CRAC/CRAH) can provide significant cost savings, directly impacting operating expenses and providing a significant and measurable return on investment (ROI). Cost savings can be realized from, but are not limited to, some of the factors listed below:

  • Reduction in overall data center floor space
  • Reduction or elimination of construction costs to expand an existing facility
  • Reduction or elimination of air cooled components, e.g., CRAC, CRAH
  • Cost savings from improved energy efficiencies resulting from:
    • Raising server air inlet temperatures
    • Elevating chill water supply temperatures
    • Using other facility water sources – i.e. return warm water
    • Reduction in fan power consumption

The Rittal LCP product suite is built around a high efficiency air water heat exchanger designed to provide maximum heat removal capacity for high density data center installations. Two LCP configurations are available:

  • Closed Loop/In Row – All cold air is directed to rackmount server air intakes in server cabinets, with all hot air captured in the rear of server enclosures and drawn through the heat exchanger. All doors [front and rear, server enclosure(s) and LCP(s)] are solid construction; no cold or hot air escapes into cold or hot aisle spaces. Eliminating the need for any aisle containment will improve the TCO.
  • Open Loop/In Line – LCP InLine provides active room climate control or supplemental cooling and heat removal. Enclosures (server and LCP) are provided with perforated doors (front and rear); cold air is discharged into the cold aisle from the front of the LCP units, and hot air is recovered from the hot aisle and drawn over the heat exchangerRittal would be happy to provide end users with potential energy savings based on their specific operational conditions, installation details and facility system parameters. In the meantime, learn more about the options you have for saving money with liquid cooling by downloading “Data Center Cooling: 4 Effective Types of Liquid Cooling.Data Center Cooling - Liquid Cooling White paper 

Categories: Data Center Solutions, Climate Control

Herb Villa

Written by Herb Villa

Rittal Sr. Applications Engineer