Loft Complex Saves By Optimizing Hydronics

Balmoral at Great West Life Winnipeg

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 f loor 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.

New ventilation systems were designed according to ASHRAE Standard 62.1-2010. A thermal water loop was created in each building. To these loops are connected: high-efficiency VAV water to air heat pumps (WSHP) to heat and cool the spaces, cooling towers and fluid coolers to remove excess heat from the loop, and condensing boilers to add heat in the loops as needed.

Energy Efficiency

The new HVAC systems have been carefully designed to include the most proven and effective technologies to maximize comfort and energy savings. The office spaces are mainly heated and cooled by modulating WSHPs connected to the thermal loop. During the winter and mid-seasons, heat is transferred from the interior to the thermal loop and is used to heat the outdoor air, the loading docks, the basement, and the first stage of perimeter heating where WSHPs are installed. Three condensing boilers per building add heat to the loop as needed (usually when the outdoor temperature is below 0°F [– 18°C]).

The main energy-efficiency measures per building are:

Indoor Air Quality

De Gaspe’s base building was designed to meet ASHRAE Standard 62.1-2010. The newly installed energy recovery ventilators (ERVs) were designed to supply a ventilation rate that corresponds to ASHRAE Standard 62.1–2010 office requirements (5 cfm/person and 0.06 cfm/ft2 [2.5 L/s·person and 0.305 L/s·m2]) based on 125 ft2/person (11.6 m2/person). Outdoor air is distributed to the mechanical rooms at each floor (2 per floor) and is fed to every WSHP individually by a motorized damper controlled by a CO2 sensor. Outdoor air is supplied heated, cooled and dehumidified at the source at a neutral temperature (70⁰F [21°C]).

Outdoor air brought to the building is controlled and metered via DDC through outdoor air measurement stations. A demand-controlled ventilation strategy was implemented to optimize the treatment of outdoor air by using a variable frequency drive on the dedicated outdoor air systems and CO2 sensors installed in the return of each WSHP. Outdoor air systems are equipped with MERV 13 filters and MERV 8 prefilters.

A pressure control loop ensures that the building is maintained at a slightly positive pressure with respect to the exterior.

The parking ventilation system is controlled by CO/NO2 detectors to ensure good air quality in the garage at all times.

All materials, adhesives, sealants, paints, and coatings used during construction are low-emitting materials. To ensure thermal comfort, the hot water radiators heating the envelope were kept, and a “trickle heat” sequence of operation was programmed to run WSHPs as the first stage of heating and to control the hot water radiators as a second stage of modulating heating through an outdoor reset control strategy.

As part of the BOMA BEST certification, an indoor air quality (IAQ) plan was prepared and adopted by the customer. The plan was inspired from I-BEAM (IAQBuilding Education and Assessment Model) provided by the U.S. EPA. The IAQ plan is to be reviewed and updated periodically to maintain the certification.


The project’s most prominent HVAC innovations are:

All HVAC equipment is centralized on a state-of-theart energy management and control system (EMCS), which makes the operation fully automatic with no intervention required other than regular maintenance. Training on the operation and trending of the equipment was delivered to the owner’s operation team upon completion of the commissioning of the building. The equipment selection criteria included among others: easy maintenance, accessibility, and extended life expectancy.

The implemented renovation plan included:

The commissioning process and the energy monitoring allowed us to f ine tune some design parameters, which includes among others the adjustment of temperature setpoints and start/stop of the night setback strategy to maximize energy savings without affecting comfort or creating electric demand peaks.

As part of the BOMA BEST program, the preventive maintenance program of the complex was upgraded to include some IAQ, water conservation and energyefficiency procedures.

Cost Effectiveness

The building’s energy retrofit project generated 36.12% natural gas savings and 14.7% electricity savings through the prioritization of heat recovery and the installation of new energy-efficient equipment. The complex’s energy cost is reduced from $1.76/ft2 to $1.40/ft2 ($18.94/m2 to $15.07/m2) despite an increase in occupancy rate from 58% to 98% (the number of occupants almost doubled) and the demanding cooling profile of most of the new tenants (multimedia). Table 1 shows the energy consumption and cost per square foot (square meter) before and after the implementation of the project. Natural gas savings are reconciled from utility distributor’s invoices. Electrical savings are calculated using energy simulation because Hydro-Quebec’s invoices could not be used in this regard, mainly because of the centralization of all tenants’ electricity meters in a single central meter during the project and the difficulty of obtaining the tenants’ electrical bills for the reference year.

The energy management and control system in place allows for the surveillance and control of the performance of the main HVAC systems. In addition, the centralization of electrical meters was implemented along with a submetering program that allows the owner to monitor the electrical consumption of each tenant and the main HVAC equipment in common spaces. The same system is used to bill the tenants for their own electrical consumption.

Environmental Impact

The project avoided the emission of more than 952.4 tons of CO2 per year, equivalent to planting 24,421 trees or removing 201 cars from the road

In addition to avoiding greenhouse gas (GHG) emissions, the project consumes less drinking water than a conventional project, thanks to low flow plumbing fixtures and the installation of new dry coolers that operate as a first stage in the winter.

Among the several energy-efficiency and water reduction measures that reduced the environmental impact of the complex are: