Serving up a cool solution
at a critical city data centre.

Background

The Mary Pitt Centre is one of Ottawa’s largest municipal facilities. It houses several City departments, public programs and community services. It’s also home to an energy-intensive server room that runs some of the City’s most critical software applications.

The challenge was to improve energy efficiency and cooling capacity in the server room without impacting IT operations. But traditional heat-containment methods require too much downtime, in addition to being costly.

Background

Approach

Envari worked with the City’s energy group to conduct a feasibility study and take a data-driven approach to efficiency.

It was key to monitor cooling loads, fan energy and the temperature and humidity in the room before undertaking the project. This baseline data helped illuminate a cost-effective, control-based solution that would save energy, maintain the ideal conditions for the server equipment and avoid any major infrastructural changes.

Previously, the HVAC system was controlled via three temperature sensors, one on each of the computer room air-conditioning (CRAC) units. This led to an over-cooling of the room based on averages, rather than adjusting to the specific temperatures at the servers.

The new solution uses temperature sensors at the inlet of each server rack.

More data points provide better feedback to the cooling units. As well, each unit is now equipped with a variable frequency drive. Together, these measures result in a more targeted, precise approach to optimizing cooling, air flow and air distribution based on the actual needs of the servers.

In addition to being non-invasive, the work was completed within an already-scheduled maintenance window, ensuring no additional disruption to critical services.

Approach

Envari worked with the City’s energy group to conduct a feasibility study and take a data-driven approach to efficiency.

The new solution uses temperature sensors at the inlet of each server rack.

In addition to being non-invasive, the work was completed within an already-scheduled maintenance window, ensuring no additional disruption to critical services.

Results

Preliminary electrical metering of the three CRAC units showed a combined annual energy consumption of 697,000 kWh.

Envari monitored the energy performance for three months post-commissioning and reported a

47% reduction in the total amount of energy needed to condition the server room.

The retrofit also resulted in a better Power Usage Effectiveness (PUE) ratio. This is the benchmark that measures the energy used to condition a data centre against the energy drawn from its server equipment.

Previously, the Data Centre’s PUE was 1.48. Today, it’s 1.26, a 15% improvement.

Another benefit to the retrofit is that it was designed to be easily reversible. In an environment this critical, uptime is everything, so in the off-chance that something goes wrong with the new system, the IT staff can revert back to using the original system in a matter of minutes.

Finally, the retrofit opened up more cooling capacity, empowering the IT staff to add more server equipment in the future.

Results

Preliminary electrical metering of the three CRAC units showed a combined annual energy consumption of 697,000 kWh.

Envari monitored the energy performance for three months post-commissioning and reported a

47% reduction in the total amount of energy needed to condition the server room.

Previously, the Data Centre’s PUE was 1.48. Today, it’s 1.26, a 15% improvement.

Finally, the retrofit opened up more cooling capacity, empowering the IT staff to add more server equipment in the future.

Cooling and recapturing heat

The Mary Pitt Centre needs to cool its server room year round, but historically the waste heat was dumped outside.

Given the building has forced air heating, there was an opportunity to recover some of the waste heat during the winter months to offset the heating load for the entire building. This would help reduce natural gas consumption.

Envari worked with the City to conduct a feasibility study then implement and commission a solution. A new, smaller chiller was installed and configured to draw any rejected heat into the return air intakes of the air handlers.

In addition to cutting GHGs and utility costs, the retrofit is helping extend the life of the building’s main chillers by keeping them off for a longer period of time; the new chiller can meet short-term cooling loads during warm spells in months like March and November.

As well, the new system is providing additional cooling redundancy for the City’s mission critical IT equipment. It’s added protection for greater peace of mind.

Cooling and recapturing heat

The Mary Pitt Centre needs to cool its server room year round, but historically the waste heat was dumped outside.

As well, the new system is providing additional cooling redundancy for the City’s mission critical IT equipment. It’s added protection for greater peace of mind.