Retrofit for IKEA
May 1, 2012
By Ken Sonmor, Antonino Lagana, M.Eng., James Wu, B.Eng., Ecovision
IKEA installed an innovative geothermal, displacement ventilation and efficient lighting system at their existing giant distribution centre in Brossard, Quebec. The home supplies retailer reduced their natural gas and electrical consumption by...
IKEA installed an innovative geothermal, displacement ventilation and efficient lighting system at their existing giant distribution centre in Brossard, Quebec. The home supplies retailer reduced their natural gas and electrical consumption by more than 80% and 30%, respectively. They increased the occupancy comfort and air quality, and provided air-conditioning in the warehouse which had never had it before.
The project won a 2012 International ASHRAE Technology Award and a first place AQME prize from the Association Québecoise pour la maîtrise de l’énergie. Ecovision experts-conseils of Montreal were the prime consultant for the HVAC design.
Situated at 5405 Place de la Couronne in Brossard, south of Montreal in Quebec, the warehouse stores goods to be distributed in an area covering a 1,000-kilometre radius. The building has a surface area of 78,110 m2, and roof varying from 11 to 15 metres in height. There is also an adjoining single-story office section with a surface area of 1,641 m2.
Chiller and Giant Hydronic Circuit
For the first time a 160-ton maglev, frictionless chiller was adapted to a geothermal system to heat a vast warehouse. (“Maglev is “magnetic levitation,” which means there are no bearings; the shaft of the impeller rotates afloat in a magnetic field, so there are no rubbing and frictional losses.) A new, building-wide hydronic circuit distributes heat from this chiller-turned-heat-pump to the numerous fancoils and air handlers in the office and warehouse.
The complete hydronic circuit and chiller (designated TP-1) are shown in the schematic, Figure 1. The fancoils are designated AT 1-15 and the air handlers UVD 1-5.
Furthermore, two 80-kW brick thermal accumulators – boilers with bricks inside (CA-1, CA-2) store heat during off-peak hours. The maglev heat pump is the primary source of heat, but a 400-kW boiler (CH-1) boosts the system’s capacity during very cold days. The original gas-fired air handlers on the roof were not removed and they augment the heating even more, but only during the coldest hours of winter.
To attain the greatest possible coefficient of performance (COP), we used more than the conventional number of wells. The wells are vertical, closed-loop wells (46 wells, 600 feet deep (183 m) that maintain a close approach with the ground temperature of 10°C. This permits the reduction of glycol concentrate which benefits the heat transfer and reduces pumping power. The system achieves unprecedented COPs of 5-7 in heating.
The manifolds for the pipes going into the geothermal wells are installed inside an accessible underground vault. This allows precise balancing of the water flow rate in each well.
The maglev heat pump does not have a change-over valve since it was designed to be a chiller. Consequently, the hydronic circuit consists of a giant loop connecting the ground to the indoor water, but that is in no way a handicap. Three-way valves send ground water into the evaporator and indoor water into the condenser during heating mode. The same valves divert ground water into the condenser and indoor water into the evaporator during cooling mode. We therefore free cool with ground water by shutting off and bypassing the heat pump, a convenient way of saving energy during the mid-season.
This geothermal heat pump requires much less maintenance than conventional heat pumps since frictionless bearings don’t wear out. The system’s operation is automated with DDC controls.
Displacement Ventilation Air
in the Office and Warehouse
Displacement ventilation in the offices consists of fancoils supplying warm or cool air at floor-level through displacement diffusers. Radiant heating panels provide supplemental heat in winter. The fancoils are designated UV 1-7 in the schematic.
Displacement ventilation is a concept that is rare in North America, although it has numerous advantages. The warm, foul air in a room rises naturally, giving way to the cool air supplied at the floor. This allows for superior air quality. It works easily during the cooling season, but for it to work in winter when heat is provided by radiant heating panels on the ceiling in the offices, relatively cool air (at about 2°C below set-point) must be supplied at floor level.
Displacement ventilation in the high-ceiling warehouse consists of custom-made air handlers blowing air through supply grills at floor-level. In summer, they allow for spot cooling of worker areas. Their cool air remains in the occupied space due to its higher density with respect to hot summer air.
In the warehouse during the heating season the air supplied by the displacement ventilation units is always warmer than set-point. We count on the Coanda effect (the adhesion of relatively fast moving air to a smooth surface like the floor) to keep warm air at floor level. The resulting warm blanket of air is comfortable. Fancoils (aerotherms) also supply heat in the warehouse at heights of about 3 metres.
Nearly 700 T12 high output (HO) fixtures were replaced with a combination of T8 and T5 HO lights. An additional 510 high-intensity discharge fixtures were replaced with T5 HO fixtures outfitted with custom-made reflectors to direct light where needed. Motion and luminosity sensors turn off lights when not needed. Other electrical measures include the use of variable-speed-drives on the main pumps of the hydronic circuit and CO2 sensors to manage fresh air.
Compared to Baseline Year
80% and 31% Savings
During the baseline year (2005), the building used 18,314 GJ or 5,08 MWh of electricity, and 13,33G J or 358,501 m3 of natural gas. The total cost of energy was $450,760 before sales taxes (at 2005 rates of 45¢/m3 for natural gas and an average of 5.7¢/kWh for electricity). Electrical costs consist of tiered rates on energy consumption plus a fixed rate on power demand. At today’s rates, that would balloon to an estimated $565,593.
The cost of the new project amounted to $1.9 million. After all the measures were implemented, natural gas and electrical consumption dropped by 80% and 31%, respectively. For the 12-month period from February 2011 to January 2012, electrical consumption amounted to 12,704 GJ or 3,529 MWh, and natural gas 2,670 GJ or 71,784 m3. The total cost of energy for that period was $288,093 (at today’s rates of 65¢/m3 for natural gas and an average of 6.8¢/kWh for electricity).
The energy savings amounted to 5,610 GJ (1,558 MWh) of electricity and 10,662 GJ (286,717 m3) of natural gas. Dollar savings were $277,500 (today’s rates). Hydro-Quebec and NRCan’s Office of Energy Efficiency offered a total of $393,741 in grants. The simple payback including grants is 5.4 years.cce
Prime consultant, HVAC engineer: Ecovision experts-conseils, Montreal (Ken Sonmor, Antonino Lagana, M.Eng.,
James Wu, B.Eng.).
Mechanical contractor: Aéro-Mech Turcotte.
Electrical contractor: Electravolt.
Supplier: IPEX (hydronic piping)