Bell and its subsidiaries own and lease buildings across Canada, with most sites located in Ontario and Quebec and a large number of sites in Manitoba and the Atlantic provinces.
Electrical load varies greatly from site to site. Approximately 600 to 700 sites are in the 100 kW to 1 MW range, while 1600 to 2000 sites are in the 30 kW to 100 kW range. Sites typically have ~60% of the total building load on 48 Volts DC power for the network equipment, with the rest on AC power (347/600V, 120/208V, 120/240V).
A significant portion of the electrical load is due to HVAC power consumption, mainly cooling. Historically, the cooling for the equipment rooms was designed to maintain the network equipment cold, with supply air temperatures (SAT) ranging from 10°C to 13°C (50°F to 55°F) and the return air temperature set to 24°C (75°F). This was done regardless of the network equipment’s operating temperature range. The cooling systems vary from site to site and may include chillers, cooling towers, computer room air handlers (CRAH), computer room air conditioners (CRAC) and other appliances. Most sites rely on direct expansion (DX) cooling systems, while larger sites typically have chillers and a chilled water loop.
Telecom / IT equipment is air-cooled. No liquid-cooled equipment is installed in Bell facilities.
In most sites, heating load is non-negligible, albeit significantly smaller than the cooling load. Most sites use electrical baseboards and / or gas or oil-fired boilers. Although most sites do not reuse waste heat from network equipment to heat the building, a few sites are better optimized and use heat pumps (which heat the building while producing chilled water for cooling).
It should also be noted that, to support its activities, Bell uses energy storage systems (48 Volts DC power plants and UPS systems). These systems are composed mainly of batteries that can support the load for a duration varying from 10 min to 8 hours, depending on the application.
The power usage effectiveness (PUE) represents the ratio between a building’s total power consumption (including HVAC, among others) and the power used by the network / IT equipment. At Bell, the average PUE ratio for buildings is 1.8, whereas the most efficient data centers from key players such as LinkedIn, Microsoft and Facebook are able to achieve a PUE below 1.1.
Bell is therefore looking for solutions to improve energy management in its buildings housing server rooms and other related equipment used to support its network and thus minimize energy consumption and carbon footprint. Bell would like to implement a more integrated approach between network / IT equipment and the buildings hosting it, in order to reduce the corresponding energy needs while ensuring the reliability of the systems.
The proposed solutions will have to take into account the current and future legislative context (in particular, at the level of refrigerants, abolition of halocarbons, alternative energy sources (natural gas, renewable, etc.). The latter must also have a favorable impact on reducing energy consumption, including fossil fuel consumption.
