Loft Complex Saves by Optimizing Hydronics

ASHRAE TECHNOLOGY AWARD CASE STUDIES 2019 Loft Complex Saves By Optimizing Hydronics Montreal’s renovated De Gaspe Complex fits the artistic vibe of its neighborhood, housing mainly multimedia clients whose work requires a demanding cooling load. PHOTO SMITH VIGEANT ARCHITECTES; DANIEL ROBERT, P.ENG., MEMBER ASHRAE; STANLEY KATZ, MEMBER ASHRAE; SIMON KATTOURA, P.ENG. PHOTOS BY ADRIEN WILLIAMS ©ASHRAE www.ashrae.org. Used with permission from ASHRAE Journal. This article may not be copied nor distributed in either paper or digital form without ASHRAE’s 48permission.ASHRAE For more JOURNAL information aboutashrae.org ASHRAE, visitAPRIL www.ashrae.org. 2019 SECOND PLACE | 2019 ASHRAE TECHNOLOGY AWARD CASE STUDIES 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 indus- Before the HVAC infrastructure trial condos for the clothing upgrade, the building was mainly manufacturing industry, De Gaspe heated by high-temperature water Complex was converted to loft type radiators located around the perim- office spaces between 2014 and eter of the building and fed by three 2016. The complex has a gross area old hot water boilers installed in the of 1,124,913 ft2 (104 508 m²) spread mechanical penthouse on the top over 11 floors in 5445 de Gaspe and floor of each building. The park- 12 floors in 5455 de Gaspe. The two ing garages in the basement were adjacent buildings are physically heated by hot water forced-flow connected on the ground floor, a unit heaters fed by the same boilers. sky-bridge on the 10th floor, and the The building was cooled by pack- basement (parking) floor that has aged water-cooled air conditioners 300 underground parking spaces. connected to cooling towers in the The complex is located between two penthouse. subway stations and next to a new As part of the HVAC infrastructure park. upgrade, the hot water network was Following the acquisition of the kept, but the operating parameters complex in 2011, the new owner were changed, and there are now implemented a major infrastructure control valves installed for all the renovation plan for the complex radiators, which were replaced with based on an adaptive reuse of exist- larger fins to allow lower tempera- ing industrial structures. ture operation. The original boilers The loft type offices have special were decommissioned and replaced features such as high ceilings, abun- by new condensing boilers. dant natural light, exposed framing, A new thermal loop was created and concrete flooring. The renova- to which all new tenants are to con- tion is designed so that the complex nect packaged water source heat remains an essential part of the pumps (WSHP), as per the new urban fabric and contributes signif- owners’ building standard. (The icantly to the vibe of the community. WSHPs are to be properly zoned between perimeter and interior Daniel Robert, P.Eng., is vice president sales and engineer- zones to allow for perimeter heating, Stanley Katz is director general of piping, and Simon Katttoura, P.Eng., is director of energy services at Kolostat, ing.) All the existing/remaining Laval, QC, Canada. packaged water cooled units in the APRIL 2019 ashrae.org ASHRAE JOURNAL 49 ASHRAE TECHNOLOGY AWARD CASE STUDIES 2019 • A low-temperature hot water thermal loop to maximize the use of the recovered heat. The heat recovered from the interior areas of the offices and the heat generated by the heat pumps are transferred to outdoor air ventilation systems, loading docks, basement garages and the building perimeter. Excess heat is discharged outside; • Most ventilation systems and water pumps are controlled by variable frequency drives; The two adjacent buildings of Complex de Gaspe are physically connected on the ground floor, a sky-bridge on the • New modulating domestic 10th floor, and the basement (parking) floor. water booster pumping station with tenant spaces and the new WSHPs high-efficiency VAV water to air heat variable speed drives; are now connected to this thermal pumps (WSHP) to heat and cool the • Optimization of water flows in loop. A new heat rejection system spaces, cooling towers and fluid the thermal loops using unconven- consisting of two dry coolers and two coolers to remove excess heat from tional temperature differentials and new cross flow open cooling towers the loop, and condensing boilers to use of a control strategy based on with isolating plate heat exchanger add heat in the loops as needed. modulation of flows as a function of were installed on the roof to evacu- the temperature differential (DT) at ate the extra heat of the condensing Energy Efficiency the equipment level. This results in (thermal) loop. The new condensing The new HVAC systems have been a substantial reduction in pumping boilers are connected to enable the carefully designed to include the power, reduced piping costs, opti- injection of heat to the condensing most proven and effective tech- mized loop diversity and maximized (thermal) loop when necessary. nologies to maximize comfort and heat recovery; The new HVAC infrastructure was energy savings. The office spaces • Heat recovery from toilets upgraded to support 3,000 tons are mainly heated and cooled by and general exhaust air to preheat (10 551 kW) of cooling so the complex modulating WSHPs connected to outdoor air with an efficiency that can host the most demanding multi- the thermal loop. During the winter can go up to 90% as a result of select- media tenants’ cooling loads. and mid-seasons, heat is transferred ing regenerative dual-core energy The renovation of the infra- from the interior to the thermal loop recovery ventilators (ERVs); structure, which was completed and is used to heat the outdoor air, • On demand ventilation in in January 2016, was designed and the loading docks, the basement, garages based on CO/NO2 sensors, implemented according to LEED and the first stage of perimeter which modulate the exhaust fans standards without necessarily tar- heating where WSHPs are installed. according to the CO/NO2 concentra- geting certification. The complex Three condensing boilers per build- tion by variable speed drives. The was certified Canada BOMA BEST ing add heat to the loop as needed envelope and ventilation heating Silver in 2018 and won an Energia (usually when the outdoor tempera- of the parking floor come mainly award in 2017 in the category of ture is below 0°F [– 18°C]). from the thermal loop with a boost existing commercial buildings. The main energy-efficiency mea- from the condensing boilers when New ventilation systems were sures per building are: required (below 0⁰F [– 18°C]); designed according to ASHRAE • High-efficiency, variable vol- • On demand ventilation using Standard 62.1-2010. A thermal water ume heat pumps with modulating new air measurement stations at loop was created in each build- compressors for spaces’ heating and every ERV, and CO2 sensors on the ing. To these loops are connected: cooling; return of the WSHPs; 50 ASHRAE JOURNAL ashrae.org APRIL 2019 ASHRAE TECHNOLOGY AWARD CASE STUDIES 2019 • Heating of domestic hot water generated by high A pressure control loop ensures that the building is efficiency natural gas condensing water heaters; maintained at a slightly positive pressure with respect to • Reduced flow water plumbing fixtures and fit- the exterior. tings as per the U.S. Environmental Protection Agency’s The parking ventilation system is controlled by (EPA’s) WaterSense guidelines; CO/NO2 detectors to ensure good air quality in the • All HVAC equipment is controlled by a new energy garage at all times. management and control system on which many trends All materials, adhesives, sealants, paints, and coatings were programmed to maximize comfort and to monitor used during construction are low-emitting materials. and optimize energy performance of main equipment; To ensure thermal comfort, the hot water radiators • Efficient lighting using T8 and T5 fluorescent light heating the envelope were kept, and a “trickle heat” fixtures with electronic ballasts and LED lamps; sequence of operation was programmed to run WSHPs • Natural lighting; as the first stage of heating and to control the hot water • Roof insulation with rigid R-30 insulation and a radiators as a second stage of modulating heating light aggregate finish to minimize heat absorption in the through an outdoor reset control strategy. summer; As part of the BOMA BEST certification, an indoor air • New efficient windows: aluminum frame with ther- quality (IAQ) plan was prepared and adopted by the mal break and double glazing with a low emissivity film customer. The plan was inspired from I-BEAM (IAQ- (Low-e) and filled with argon; and Building Education and Assessment Model) provided by • As part of the BOMA BEST certification, an energy the U.S. EPA. The IAQ plan is to be reviewed and updated management plan and a water management plan were periodically to maintain the certification. developed and adopted. Among other objectives, these plans focus on monitoring and reducing/maintaining Innovation the energy use and water use intensities of the complex. The project’s most prominent HVAC innovations are: • Optimization of the HVAC infrastructure using non- Indoor Air Quality conventional temperature setpoints, which has opti- De Gaspe’s base building was designed to meet mized pumping power and reduced the overall installa- ASHRAE Standard 62.1-2010.

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