When it comes to hot aisle versus cold aisle containment, the containment in question refers to the physical barriers applied to remove opportunities for different kinds of air to mix. These structures allow for higher temperatures in data centers, and such temperatures reduce energy consumption because the speeds of fans can be reduced as well. Plus, this allows for chilled water temperatures to be elevated and free cooling to be implemented more frequently.

This blog post will take a look at how hot aisle versus cold aisle containment can not only save money, but also be a way toward reaching green energy goals.

Aisle Containment Ceiling Panel System - Aisle Containment: <br> Saving Energy and Costs According to Energy Star <br>

Aisle Containment Savings

Yes, containment units in data centers save companies money, but they also help save the environment. When it comes to money, they reduce power expenses by 5 and 10 percent. When it comes to energy consumption, these systems diminish fan energy between 20 and 25 percent. So it’s a win-win. In some experiences, companies can see the returns on this investment in two years.

In addition to these savings, there are some other costs to consider, which include modifications to the HVAC system, re-configuring power when it’s distributed to racks, and don’t forget labor, overtime, and implementation of the system.

There are two examples of ENERGY STAR companies that saved big with hot aisle containment systems: the first is BNY Mellon and the second is RagingWire. Both companies saved money on energy when they upgraded their efficiency standards with these systems. Google also performed a study that looked at small data center’s efforts to optimize their facilities and how this impacted their return on investment.

Cold Rooms Curb Costs

The data center in NetApp’s Global Dynamic Laboratory includes many amenities that contribute to saving energy, and they include enclosures known as cold rooms, that limit warm exhaust from combining with air supply at cooler temperatures.

Due to the design, the data center is able to set its temperature at a warmer setting, like 70 or 80 degrees, compared to traditional settings, which are 20 degrees lower. When you set the thermostat at a higher setting, it curtails the energy needed to temper the supply air and the run time of the chilled water. This allows it to utilize ambient air more frequently. Since warmer air weighs less and moves more swiftly, the overall fan horsepower is also lowered.

containment strip walls image 4 - Aisle Containment: <br> Saving Energy and Costs According to Energy Star <br>

Another way that a containment design can save you money is when it involves two air handlers raised in each cold room. The arrangement capitalizes on the idea that cool air falls, which conserves energy over a conventional raised floor. A traditional floor that’s raised will consume extra fan energy in order to propel the cool air skyward.

Plus, if the data center facility uses warmer chilled water temperatures, cooling the water to 55 degrees rather than 44 degrees, then this can boost efficiency up to 20 percent.

Naturally, when it comes to containment design, the savings on energy are significant. For a data center with 36 cold rooms holding 60 cabinets, which includes 2,136 rack of system equipment, this can accumulate to $36 million per year in energy bills.

What Else to Consider

When it comes to the location of aisle containment inside a data center, another thing to think about is fire detection systems. Some data centers have put forth special tiles in cold aisle containment systems that shrink and drop to the floor when the temperatures are raised, which prevents the need for fire suppression.

Another consideration is that with cold aisle containment, the temperatures are naturally warmer, which may be uncomfortable for employees, staff members, and some pieces of equipment.

In addition, “return air”, or warm air entering the CRAC for cooling, will not work in hot and cold aisle containment, because return air is more focused and is a higher temperature. And some direct CRAC units are not able to be retrofitted with speed drives of varying speeds and energy rates.

Bottom Line: Hot Aisle or Cold Aisle?

There was a recent paper that was published by the American Power Conversion (APC) that advocated for hot aisle containment more than the cold aisle option. One of the reasons it supported hot aisle is because the environment can be sustained at a temperature that’s comfortable and that the small arms in the servers are accessible to a sizeable air mass that is able to cool the servers in the situation of a cooling failure.

About Cool Shield Containment

Cool Shield provides customers with versatile, turnkey aisle containment systems for new or existing critical spaces. Call or contact us to learn more.