Engineering cooling technologies for data centres

Cooling technologies are crucial in data centres, requiring cost-effective and energy-efficient solutions. Liquid-based cooling, including immersion cooling, is gaining popularity for its efficiency. However, challenges remain, such as the need for server manufacturers to provide warranties for liquid cooling systems, says leading players in the industry.

Cooling is a critical aspect of data centres, accounting for a significant portion of their total power usage. High and low-temperature ranges can impact data centers’ efficiency, and cost-effective cooling solutions are necessary to handle continuous data accumulation and increasing density.

Environmental monitoring and cooling are crucial for data centers to prevent IT equipment from being damaged by high temperatures and humidity. Mechanical air cooling, refrigeration systems, and dehumidifiers are commonly used, but liquid-based solutions such as immersion cooling are becoming more popular due to their efficiency. As the data center industry grows and cloud computing drives demand for larger data centers, alternative cooling options and technologies will be required to manage the heat generated by computing servers and other systems.

Liquid cooling options for data centres
Mr. Sudhir Suryavanshi, Manager at Large Deals, West Zone of Trane India, mentioned that liquid cooling is a novel technology gaining popularity due to its various advantages. However, since it is relatively new, it must still be tested and proven in the market. Nevertheless, embracing innovative technologies that can enhance system performance is always a positive approach. As industries have progressed, new technologies have been incorporated into various business sectors, including data centers. Mr. Vaibhav Pitale, Managing Director of India and South West Asia at Belimo states that in India, the demand for data centres is still measured in megawatts. Still, globally, larger sizes are being discussed and evaluated. Although new technology must be tested, the absence of innovation doesn’t mean that businesses or companies will fail. To meet market demands, products must be adapted and innovated during the design and concept stages. With an increasing number of stacked racks, there is a rising need for an alternative medium, such as water or something else, to dissipate heat. Thus, there is a need for a thoughtful process towards liquid cooling.

Ujjwal Singh, Counsellor, Green Data Centers, CII-IGBC, added that most data centers, including new ones, clouds, and hyperscalers, are certified by IGBC. While liquid cooling is being adopted in data centers, there are still some challenges to overcome. Currently, most servers and racks operate at 10 kilowatts or below, with only 10-15% operating at densities of 10 to 15 kilowatts. Various liquid cooling technologies are available, such as rear door heat exchangers and direct-to-chip liquid cooling, which are currently crucial. However, when rack densities exceed 50 kilowatts, liquid cooling has the potential to dominate the market due to its energy efficiency. The current challenge is that server manufacturers like Dell, Intel, and Lenovo do not offer a first-party warranty for systems that use liquid cooling. Once the issue is resolved, India is expected to see a large adoption of liquid cooling technology, which could happen as early as 2025.

Liquid Cooling leverages the thermal transfer properties of the fluid to support cost-effective cooling of racks
The future of cooling technology lies in liquid cooling, which promises energy efficiency and sustainability. According to Mr. Shailesh Paradkar, Manager – National Sales HVAC & Datacenter, Energy Division, Alfa Laval, with increasing rack densities and data capacities, there may be other options than air cooling in the long run, making liquid cooling essential. However, air-cooling technologies will still be present in certain applications. Nonetheless, liquid cooling has a bright future ahead. Mr. Umesh Kale, Business Unit Manager- HCT, Munters India Humidity Control Private Ltd, thinks that, as humans, we constantly search for the best alternative solutions to enhance efficiency. Liquid immersion cooling is a viable alternative for capturing heat from its source. Still, there are challenges related to mechanical hardware, making it difficult for back providers to provide integrated systems that can remain sustainable for years. As the population continues to grow, the technology adopted in commercial buildings depends on experts in manufacturing. As an HVAC industry member, it is important to explore alternative energy-efficient options until more sustainable events are available in market without directly relying on liquid immersion cooling.

In the data center industry, there is a shift towards smaller, modularised centers located closer to end users to reduce latency. While data center density may still be a factor, the emphasis is on size and user proximity. The industry must adapt to these changes and consider the options available to stay relevant.

Standardisation of server air in the system for cooling
“Server manufacturers have taken over the responsibility of standardising server air for cooling purposes. ASHRAE has upgraded their bandwidth range from 20 to 28 and expanded its guidelines to include humidity and temperature. Therefore, any previous guidelines on a server in and out the temperature will no longer be relevant as most servers are designed to intake air between 24 to 30 degrees Celsius, by the ASHRAE standards,” says Mr. Ujjwal. In the design of data centers, issues arise from the design of servers with left or right side entry and top or bottom discharge, causing hot and cold air to mix and making it difficult to maintain temperature. This is not a fault of the air conditioning system but due to non-standard server designs causing problems for data center cooling. It is essential to establish standards for server design with front entry and backside discharge to improve system efficiency and reduce issues faced by data center coolers.

Mr. Shailesh adds that the server temperature standards constantly evolve as technology advances. In the past, air-cooled servers required temperatures as low as 17-18 degrees Celsius, but now they can function at higher temperatures, around 26-27 degrees Celsius and may continue to rise as chip technology improves. This can reduce the cooling load on the servers and present opportunities to utilise free cooling methods. The ability of servers to withstand higher temperatures opens up the potential for incorporating free cooling methods in the future.

Evaporative cooling solutions
Evaporative cooling is highly beneficial, especially if the temperature is suitable. It is a more cost-effective option for cooling than using chillers for generating chilled water, thus making it economically beneficial. With the rising temperature of server racks, evaporative cooling is becoming a viable option, for example, in locations like Pune and Bangalore in India, where there is a significant difference between dry bulb and wet bulb temperatures. Evaporative cooling offers great benefits and is a more economical solution in such locations.

“The benefits of evaporative cooling are undeniable, as it is a well-established technology that can provide sustainable solutions to various challenges. Evaporative cooling is evolving, and better energy efficiency without the need of ultralow temperatures for server racks can be achieved. It is cost-effective and offers significant advantages over other cooling solutions. Therefore, it cannot be disregarded, as it is one of the most promising technologies available,” says Mr. Umesh Kale. Instead of relying only on traditional evaporative cooling methods, multiple hybrid solutions can be utilised, such as direct evaporative cooling or directindirect evaporative cooling. These alternatives are becoming more widely available. While water is typically used as the primary source of heat removal in evaporative cooling, there are now technologies for removing water. Although this technology is still evolving, vertical alternatives may be the most convenient solution.

Evaporative cooling is a technique that saves energy but requires water as its primary resource. The availability of water is an important consideration in using this technique. IGBC is educating people on how to conserve water to be used for evaporative cooling. This includes harvesting rainwater, recycling water using STPs, and governmentrecycled water. By monitoring and metering water usage, natural water resources can be conserved. It could harm the environment if directly potable water is used for evaporative cooling. Although using this technique may reduce energy bills, it is important to consider its environmental impact,” adds Mr. Ujjwal.

CyberSecurity
The physical security of data centers has seen the emergence of new technologies such as RFID tagging for equipment tracking and inventory control. Access control systems have also become more advanced, allowing for monitoring personnel movements and generating alerts for unauthorised entry attempts. Data centers regularly evaluate and investigate any suspicious activity. Overall, RFID tagging is a key technique for ensuring the security of data centers. “Ensuring data transparency is crucial, especially in the field device industry where we primarily operate. At the BMS level, we prioritise data transparency for data centers. Both hardware and software logs are used to ensure data stays within the domain. Some companies also offer cloud-based data solutions. However, data centers have internal regulations governing data publication outside their domain, and firewall technology has evolved to protect against cyber-attacks. Similar to UPI payments, where we have peace of mind due to firewalls, data centers also have tracking and closed-loop monitoring systems for flow of data and information, which are closed networks,” adds Mr. Vaibhav Pitale.

Cooling technologies hold critical places in data centers, and there is a need for cost-effective and energyefficient cooling solutions. Liquidbased cooling, such as immersion cooling, is gaining popularity due to its efficiency. However, there are challenges to overcome, such as server manufacturers’ need for a first-party warranty for liquid cooling systems. The shift towards smaller, modularised data centers closer to end-users drives the need for innovative and sustainable cooling technologies. The standardisation of server air in the system for cooling purposes is essential to improve system efficiency and reduce problems faced by data center coolers. Exploring alternative energy-efficient options is the need of the hour.

 

“India is expected to see a large adoption of liquid cooling technology, which could happen as early as 2025.”
Mr. Ujjwal Singh,  Counsellor, Green Data Centers, CII-IGBC.

“Data transparency is crucial, especially in the field device industry where we primarily operate.”
Mr. Vaibhav Pitale, Managing Director India and South West Asia, Belimo.

“With increasing rack densities and data capacities, there may be other options besides air cooling in the long run, making liquid cooling essential.”
Mr. Shailesh Paradkar, Manager – National Sales HVAC & Datacenter, Energy Division, Alfa Laval.

“With the rising temperature of server racks, evaporative cooling is becoming a viable option, especially in locations with a significant difference between dry bulb and wet bulb temperatures.”
Mr. Sudhir Suryavanshi, Manager – Large Deals, West Zone of Trane India.

“Evaporative cooling is a well-established technology that can provide sustainable solutions to various challenges besides being cost-effective.”
Mr. Umesh Kale, Business Unit Manager- HCT, Munters India Humidity Control Private Ltd.

“It is essential to prioritise the development of green data centers that are energy-efficient and sustainable. Additionally, such centers can help companies meet their sustainability goals.”
Mr. Ravichandran Purushothaman, India President, Danfoss.