HH Angus conducted a study to evaluate the feasibility of exhaust air heat recovery from the Global Relay (GR) data centre facility at 22 Gostick Place in North Vancouver, BC.

Some of the key aspects of the study included:

• The location and footprint of the heat recovery system components were studied within the context of considerable site constraints. The study evaluated the design, construction, and cost considerations for the implementation of the proposed heat recovery system.
• We investigated available heat pump technologies that would be appropriate for recovering waste heat and would satisfy the LEC DES requirements.
• The energy recovered would be used by a water source heat pump to provide hot water to the local LEC District Energy System (DES).
• A water source heat pump system was proposed as the best solution to provide the ability to recover heat from the building ventilation system. The new system would recover heat from the GR facility and would transfer this recovered heat via a hot water loop to the local LEC DES.
• Heat recovery is feasible for the facility and can provide up to 1,100 kW of heating capacity to the LEC DES.
• Constraints to the design of the heat recovery system were also identified, and included:

(i) the quantity of air exhausted from the facility is not fixed and ranges at each exhaust plenum on a seasonal basis and depending on outdoor air temperature – this impacts how much heat can be recovered at a given time;

(ii) the minimum and maximum exhaust air temperatures range from 30°C to 43°C (86°F to 110°F) - the temperature of the exhaust air will influence how much heat can be recovered from the exhaust air; and,

(iii) the cross-sectional area available for the heat recovery coil - the more cross-sectional area that is available for a given amount of heat transfer, the less deep the coil must be (and less airside pressure drop penalty is incurred).

The study concluded that a purpose-built containerized heat pump system would be the most suitable solution to meet the needs of the project. This new containerized structure would be conveniently located adjacent to the GR facility and would exhibit the same architectural character as the existing facility. The proposed heat pump system would include one heat pump unit (based on Emerson Heat Pumps) and four heat recovery water pumps. Control valves, piping accessories, ventilation, lighting, and system controls would all be included in the proposed pre-fabricated containerized enclosure.

Outdoor hydronic piping would connect the heat pump enclosure to the GR facility and the proposed hydronic heat recovery coil system. The heat recovery coil system would consist of four new heat recovery coils placed within the existing facility exhaust air plenums. The existing exhaust fan motors would have to be upgraded in order to address the additional pressure drop introduced by the new heat recovery coils. This fan motor upgrade would also trigger upgrades to the existing electrical infrastructure.