Shaping Tomorrow's Built Environment Today

Loft Complex Saves by Optimizing Hydronics

By Daniel Robert, P.Eng., Member ASHRAE; Stanley Katz, Member ASHRAE; Simon Kattoura, P.Eng.

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©2019 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 61, no. 4, April 2019.

About the Authors
Daniel Robert, P.Eng., is vice president sales and engineering, Stanley Katz is director general of piping, and Simon Katttoura, P.Eng., is director of energy services at Kolostat, Laval, QC, Canada.

The De Gaspe Complex (5445/5455 de Gaspe) is located in the heart of the Mile End neighborhood in Montreal, Canada, which has been known for its artistic district since the 1980s. Today, the Mile End is internationally recognized as a breeding ground for multimedia, for companies centered on artistic and creative technology. A renovation of the two-building complex resulted in a 22% reduction in energy consumption despite the demanding cooling profile of most of the new multimedia tenants and nearly doubling the occupancy.
Built in 1972 to be used as industrial condos for the clothing manufacturing industry, De Gaspe Complex was converted to loft type office spaces between 2014 and 2016. The complex has a gross area of 1,124,913 ft2 (104 508 m²) spread over 11 floors in 5445 de Gaspe and 12 floors in 5455 de Gaspe. The two adjacent buildings are physically connected on the ground floor, a sky-bridge on the 10th floor, and the basement (parking) floor that has 300 underground parking spaces. The complex is located between two subway stations and next to a new park.
Following the acquisition of the complex in 2011, the new owner implemented a major infrastructure renovation plan for the complex based on an adaptive reuse of existing industrial structures.

The loft type offices have special features such as high ceilings, abundant natural light, exposed framing, and concrete flooring. The renovation is designed so that the complex remains an essential part of the urban fabric and contributes significantly to the vibe of the community.

Before the HVAC infrastructure upgrade, the building was mainly heated by high-temperature water radiators located around the perimeter of the building and fed by three old hot water boilers installed in the mechanical penthouse on the top floor of each building. The parking garages in the basement were heated by hot water forced-flow unit heaters fed by the same boilers. The building was cooled by packaged water-cooled air conditioners connected to cooling towers in the penthouse.

As part of the HVAC infrastructure upgrade, the hot water network was kept, but the operating parameters were changed, and there are now control valves installed for all the radiators, which were replaced with larger fins to allow lower temperature operation. The original boilers were decommissioned and replaced by new condensing boilers.

A new thermal loop was created to which all new tenants are to connect packaged water source heat pumps (WSHP), as per the new owners’ building standard. (The WSHPs are to be properly zoned between perimeter and interior zones to allow for perimeter heating.) All the existing/remaining packaged water cooled units in the tenant spaces and the new WSHPs are now connected to this thermal loop. A new heat rejection system consisting of two dry coolers and two new cross flow open cooling towers with isolating plate heat exchanger were installed on the roof to evacuate the extra heat of the condensing (thermal) loop. The new condensing boilers are connected to enable the injection of heat to the condensing (thermal) loop when necessary.

The new HVAC infrastructure was upgraded to support 3,000 tons (10 551 kW) of cooling so the complex can host the most demanding multimedia tenants’ cooling loads.

The renovation of the infrastructure, which was completed in January 2016, was designed and implemented according to LEED standards without necessarily targeting certification. The complex was certified Canada BOMA BEST Silver in 2018 and won an Energia award in 2017 in the category of existing commercial buildings.


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