Energy efficiency & what it means for the future of data centers
As society continues to grow and develop more eco-friendly and sustainable values, the pressure on data centers to become more energy efficient has greatly increased.
Recently, the data center industry has been making significant progress in developing new, energy efficient approaches in the design and manufacturing of data centers.
Basically, what we are seeing is the overall solution of deploying racks and aisle containment structures at the same time, versus the traditional model of filling a data center full of hardware and then bringing in someone to help with efficiency and containment.
Data center operators are having these conversations earlier in the design and manufacturing process, eliminating the need to make energy efficient changes in bits and pieces.
From a data center operations perspective, a key area where data centers can focus its energy efficiency efforts would the amount of energy used to cool the data center.
Whether it be the use of CRAC units, hyper CRAC units or like in Eastern Washington where the cold air outside is being used instead of cooling system, these cooling solutions will greatly improve a data center’s Power Usage Effectiveness (PUE) score.
PUE is a metric that can help data centers measure the impact of change and focus on increasing energy efficiency. Ideally, a data center will want a PUE score of one.
This can be calculated by dividing the total power used in the data center by the IT equipment power. A score of one depicts the optimal level of data center efficiency, meaning all power going into the data center is being used to power IT equipment.
Data center designers and manufacturers focus on improving a data center’s PUE score by repurposing servers that are no longer in use, powering down servers that are not being used, replacing inefficient servers and consolidating servers, to name a few. While improving a data centers PUE score is important, it is only one component and shouldn’t be the sole focus.
Another key strategy being implemented by data center designers and manufacturers is the prevention of hot and cold air mixing, through hot-aisle containment (HACS) and cold-aisle containment (CACS) structures.
Air containment increases the cooling capacity and energy efficiency of the cooling units. Both HACS and CACS will help improve the efficiency of a data center’s traditional cooling system. This can be done because an aisle containment structure facilitates higher allowable temperatures in a data center.
Higher temperature data centers save more energy due to lower fan speeds, increased temperatures in chilled water and the use of free cooling.
Unlike the rear-door cooling unit that exchanges hot air for cold air, hot and cold aisle containment structures minimize the amount of hot and cold air that mixes together. This, in turn, can increase the capacity and cooling efficiency of the cooling infrastructure.
A CACS purpose is to contain cold air, while keeping hot air out. This is done by installing either end-of-row doors, aisle ceilings or overhead vertical wall systems, which allows the cold air to be redirected into the air intakes of data servers and prevents hot air recirculation.
Cold aisle containments are also energy efficient. A cold aisle containment structure guarantees that the IT equipment is being cooled within a manufacturer’s needs. Cold aisle containment structures guarantee increased operating efficiency by creating an unchanging airflow that removes hot spots.
Due to the elimination of hot spots, more space is available throughout the data center, which provides more cabinet space.
HACS are the rows in which data servers dump their heated exhausts. Like a cold aisle containment, a hot aisle containment’s role is to prevent cold and hot air from mixing, however, hot aisles face the air conditioner ducts and send hot air through to be recycled into cold air.
This is done by having a separate path for the hot air back to the AC intake point. In some cases, hot air that hits the AC coil at the highest temperature can double the cooling tonnage. Hot aisle containment can double cooling capacity of a CRAC unit, cutting costs and increasing efficiency.
Some other simple design aspects that can help make a data center more energy efficient are:
- Power distribution – there are several different ways to distribute power in data centers. Properly distributed power would increase efficiency.
- Type of hardware – data center operators need to work hand-in-hand with the designers and manufacturers to see what kind of configurations are being used.
- Power and networking – are driving where data centers are being placed geographically. For example, in Washington a data center was built next to the Wenatchee River, which uses hydropower reduce energy costs.
As the data center industry continues to explode with the ever-increasing demand for more data, high-power density data centers will continue to grow in popularity.
Data center designers and manufacturers are now tasked with reducing power consumption and increasing efficiency.
Having a high-power density data center increases performance and output, but also having an efficient cooling system in place will greatly reduce a company’s energy bill.
Article by Erich Hamilton, director of engineering of DAMAC