©2013 This excerpt taken from the article of the same name which appeared in ASHRAE Journal, vol. 55, no. 4, April 2013.
By André-Benoît Allard, Eng., Member ASHRAE
About the Author
André-Benoît Allard, Eng., is director of projects at Ecosystem in Quebec. He is a member of ASHRAE’s Quebec chapter.
The Biodôme is part of Montréal Space for Life, the largest natural science museum complex in Canada, which also includes the Botanical Garden, the Insectarium and the Rio Tinto Alcan Planetarium.
The Biodôme is a unique building filled with flora and fauna from five different replicated ecosystems from the Americas. Although these ecosystems are all under one roof, they vary greatly in terms of temperature, humidity and light requirements for hundreds of animal and plant species living within the dome. Four of the ecosystems—the Laurentian Maple Forest, the Gulf of St. Lawrence, the Sub-Antarctic Islands and the Labrador Coast—must be cooled year-round while the Tropical Rainforest must be heated.
The Biodôme is deeply committed to protecting the environment and biodiversity. In addition, the building’s energy costs were consistently high because the building had some zones that required constant heating while others required the removal of excess heat. It was supplied with chilled water (yearly average 330 tons) and steam (yearly average 3,000 lb/h [0.38 kg/s]) by the neighboring building. The electric demand for the building was approximately 3,200 kW.
Finally, the electromechanical equipment used for heating, cooling, and lighting required major upgrades. Therefore, the institution decided to go forward with an ambitious energy-efficiency retrofit project aimed at significantly reducing energy consumption and greenhouse gas emissions.
An energy saving retrofit was performed on the building from 2008 to 2010.The project was carried out as an energy performance contract in partnership with a firm of energy-efficiency professionals.
Implemented in close partnership with the Biodôme’s technical services staff, the project was designed to dig deeper into the existing energy infrastructure to reduce costs, upgrade equipment and improve conditions for the collections and for the people in offices and public areas.
The $8.1 million project reduced energy costs by 52% and greenhouse gas emissions by 80%. Project costs are being repaid within a 5.2-year period by guaranteed energy savings and $1.6 million in government and utility incentives.
The project was carried out as an energy performance contract, with the energy services firm providing all services for a lump sum. All energy savings and incentives were contractually guaranteed.
The process began with the compilation and analysis of all the building’s energy bills from the last five years. One of these years, considered the most representative, was selected as the “base year.” The preliminary study and the detailed study fully met the requirements of sections 5.3 to 5.5 of Standard 100-2006, Energy Conservation in Existing Buildings, and “Level 3—Detailed analysis of capital intensive modifications.” Finally, this scope of services included a project performance monitoring phase and a guarantee by the energy services firm of financial savings over a period of five years from the provisional acceptance of the project.
Heat Recovery and Transfer Between Ecosystems
Central to the retrofit is an energy recovery and energy transfer system between the various ecosystems that is used to cool and heat other parts of the building. The heat recovery system includes four heat pumps with a total rated capacity of 1,450 tons (5100 kW). This design allows for completely secure operation, even if one of the heat pumps suffers a technical problem.
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