In the fast-paced world of Data Centres, efficiency is not just a goal; it is a necessity.
As the demand for processing power surges, so does the need for effective cooling solutions that can sustain high-performance operations without excessive energy consumption. Enter aisle containment systems—an innovative strategy that not only streamlines airflow but also drastically enhances thermal management. By strategically enclosing aisles, these systems effectively manage airflow, enabling the optimisation of cooling systems that not only enhance performance, but also play a crucial role in achieving Power Usage Effectiveness (PUE) goals.
In this blog post, we will explore how implementing aisle containment systems can transform your Data Centre operations, leading to increased efficiency, reduced energy costs, and a greener footprint, all while maintaining peak performance for your critical infrastructure.
What is Aisle Containment?
Modern Data Centres use aisle containment as a highly effective cooling strategy to optimise cooling performance and energy efficiency. At its core, this strategy involves physically separating the hot exhaust air produced by servers from the cold supply air that cools them, preventing the two air streams from mixing. As a result, it creates clearly defined hot and cold aisles.
This separation is crucial for maintaining efficiency. Without it, hot exhaust air can recirculate back into the cold aisles. This recirculation elevates the intake temperature of the servers, forcing the cooling system to work significantly harder to maintain optimal operating temperatures. The increased workload on the cooling system directly leads to higher energy consumption and can potentially reduce the server lifespan due to overheating.
Data Centres typically implement one of two main types of aisle containment solutions:
- Cold Aisle Containment (CAC): focuses on enclosing the cold aisle to create a contained, cool environment. Typically, a combination of physical barriers—such as a roof over the aisle, doors at the ends of the aisle, and blanking panels to seal gaps or unused rack spaces—encloses the cold aisle. This setup ensures that servers receive only cool air, maximising the efficiency of the cooling infrastructure. CAC proves particularly effective when coupled with underfloor air distribution or in-row coolers.
- Hot Aisle Containment (HAC): captures the hot exhaust air emitted by servers by enclosing the hot aisle. HAC uses a similar structure as CAC, employing roof panels, end doors, and blanking panels. The configuration ducts the collected warm air back to the cooling units, preventing contamination of the cold air dedicated to cooling equipment. HAC proves especially beneficial when directing hot air back to specific cooling units or when the existing Data Centre infrastructure makes implementing CAC challenging.
Whether you implement Cold Aisle Containment or Hot Aisle Containment, the goal of aisle containment remains consistent: to establish a controlled thermal environment within the Data Centre. By preventing the mixing of hot and cold air, aisle containment allows cooling systems to operate at peak efficiency, delivering targeted cooling where it's needed most. This approach translates into significant energy savings, reduced operational costs, and improved overall performance and reliability of the Data Centre infrastructure. Furthermore, aisle containment provides a more stable and predictable thermal environment, which can extend the lifespan of servers and other IT equipment.
Why is Aisle Containment Important in Optimising Cooling?
- Increased Server Intake Temperatures: Servers forcefully draw in warmer air, which can lead to overheating and reduced performance.
- Higher Cooling System Load: The cooling system works harder to counteract the mixed air, consuming more energy.
- Uneven Cooling Distribution: Certain areas of the Data Centre remain cooler than others, leading to hotspots and potential equipment failures.
- Reduced Cooling Capacity: The system struggles to maintain acceptable temperatures, effectively reducing its overall cooling capacity.
- Enabling Higher Supply Air Temperatures: By preventing hot and cold air streams from mixing, aisle containment increases the supply air temperature from the Computer Room Air Conditioners (CRAC) or Computer Room Air Handlers (CRAH) units. This increased temperature difference allows the cooling units to operate more efficiently, reducing energy consumption.
- Eliminating Hotspots: Aisle containment ensures that servers and other IT equipment only intake cool air, helping to eliminate hotspots and maintain a more uniform temperature distribution throughout the Data Centre.
- Improving Cooling Capacity: With less wasted cooling, aisle containment increases the overall cooling capacity of the system, allowing for higher server densities within the Data Centre.
- Reducing Cooling Costs: The optimised cooling system consumes less energy, which directly translates into lower operational costs.
What is PUE and Why is it an Important Data Centre Metric?
- Provides a Benchmark for Energy Efficiency: PUE serves as a vital benchmark, enabling Data Centre Managers to objectively evaluate their energy performance. It allows them to make meaningful comparisons against industry standards, best practices, and the performance of other Data Centres. This benchmarking process helps them identify areas where the Data Centre excels and areas requiring improvement.
- Identifies Areas for Improvement: By understanding PUE, Data Centre operators can pinpoint specific aspects of the facility that contribute to energy wastage. They can ask questions like: Is the cooling system inefficient? Are there power distribution losses? Is the lighting outdated? Identifying these problem areas allows operators to adopt a targeted approach to optimisation, focusing resources on the most impactful changes.
- Reduces Operational Costs: By improving PUE, Data Centres achieve significant cost savings. Lowering energy consumption leads to reduced energy bills, a substantial component of a Data Centre's operational expenses. These cost savings can subsequently get reinvested in other areas of the business, fostering further growth and innovation.
- Enhances Sustainability: In an era of growing environmental awareness, PUE becomes a powerful tool for promoting sustainability. Lowering energy consumption reduces the Data Centre's carbon footprint and overall environmental impact. This commitment to sustainability not only benefits the planet but also enhances the Data Centre's reputation and appeal to environmentally conscious clients.
How Aisle Containment Aids PUE Goals
Aisle containment is a critical strategy for Data Centres striving to achieve optimal Power Usage Effectiveness (PUE) figures. By strategically controlling airflow and enhancing cooling efficiency, aisle containment directly contributes to a reduction in overall facility energy consumption, which is the core driver of a lower, more desirable PUE score. A lower PUE indicates a more energy-efficient Data Centre, meaning a larger proportion of the total energy used is dedicated to powering IT equipment rather than overhead infrastructure like cooling.
- Reduced Cooling Energy Consumption: As previously detailed, aisle containment fundamentally improves the effectiveness of cooling systems. This focused cooling approach reduces the overall amount of energy required to maintain optimal operating temperatures. Considering that cooling often constitutes a significant portion (typically 30-50%) of a Data Centre's total energy footprint, any efficiency gains in this area have a substantial and positive impact on the overall PUE.
- Optimised CRAC/CRAH Unit Operation: Aisle containment allows Computer Room Air Conditioning (CRAC) and Computer Room Air Handler (CRAH) units to operate at higher supply air temperatures. Without containment, lower supply air temperatures are often necessary to compensate for hot and cold air mixing, leading to inefficient operation. By maintaining separation, containment enables the CRAC/CRAH units to deliver warmer air, which is more energy-efficient to produce. Furthermore, precisely controlling airflow directs cooling only to the areas that require it, further reducing energy waste associated with over-cooling unintended zones. This optimised operation directly translates to reduced energy consumption by these critical cooling components.
- Reduced Fan Energy Consumption: In a Data Centre without aisle containment, fans within the cooling units and potentially within the server racks themselves must work harder to overcome the mixing of hot and cold air streams, so to maintain the desired temperatures. This increased workload translates to higher fan speeds and, consequently, greater energy consumption. Aisle containment creates a more predictable and efficient airflow pattern, allowing fans to operate at lower speeds while still effectively cooling the IT equipment. This reduction in fan energy consumption further contributes to the overall PUE improvement.
- Potential for Free Cooling: A significant advantage of aisle containment, particularly in regions with suitable climates, is the potential to leverage "free cooling" strategies. Free cooling involves using outside air to cool the Data Centre, significantly reducing or even eliminating the need for energy-intensive mechanical cooling during certain times of the year. Aisle containment enhances free cooling systems' effectiveness by ensuring that the cooler outside air channels to the IT equipment and effectively removes hot exhaust air. This can result in substantial energy savings and a dramatic improvement in PUE, making it a highly desirable outcome for environmentally conscious data centres.