MONTREAL -- A Loblaw Cos. store heated entirely by a "secondary loop" refrigeration system is 46% more energy efficient than similar Loblaw stores that do not have heat reclamation systems, according to Mark Schembrie, senior director, procurement and engineering, Loblaw, Toronto.
Schembrie presented details of the system during a session at Food Marketing Institute's recent Energy and Technical Services Conference here at Le Centre Sheraton.
The store, located in Repentigny, Quebec, is one of 40 Loblaw stores that leverages a secondary loop refrigeration system, but the first of its kind in Canada to integrate refrigeration and heating, ventilation and air conditioning (HVAC) systems, Schembrie said. The Repentigny store opened with the energy configuration in spring 2004.
Typically, when heat is drawn out of a refrigerated system during the cooling process it is released into the atmosphere. In the Repentigny store, where last December the outside temperature dipped as low as 14 degrees below zero Fahrenheit, this heat is used to meet its heating and hot water needs.
"During heating season, the store uses 100% of the heat" extracted from the refrigeration system, said Schembrie at the conference, held Sept. 18 to 21. "The store has some backup electric heat, but very little. When we had our first very cold day we were pleased to learn that the [Repentigny] store maintained its temperature."
The Repentigny heating project was carried out as part of the Refrigeration Action Program for Buildings (RAPB) program launched by Natural Resources Canada (NRCan), a federal government department that specializes in the sustainable development and use of natural resources, energy, minerals and metals, forests and earth sciences.
RAPB seeks to implement efficient technologies to reduce energy consumption by 25% in supermarkets and by 50% in ice and curling rinks, and to reduce synthetic refrigerant leaks by 75%, according to NRCan.
NRCan served as the principal financier of the project, said Schembrie, adding that Loblaw received additional funding from AEE (Agence de l'efficacite energetique du Quebec) and Hydro-Quebec. The retailer's technical partners were CIMA, Hill-Phoenix, Hussmann, Keeprite, Consolidated Energy Solutions, Micro Thermo Technologies and Hydro-Quebec. The system's metrics are monitored by NRCan's CANMET Energy Technology Centre.
Loblaw chose the Repentigny store as the site for the project because of its extreme weather fluctuations as well as its proximity to the CANMET research lab, according to Schembrie. "We are doers, not studiers, so the technology lab fit was very positive," Schembrie said. "It let us go into another level of detail."
In June, NRCan announced that Loblaw signed an agreement to modify the HVAC and refrigeration systems in an existing Loblaw store in Barrhaven, Ontario. "We want to work with the government to establish a supermarket incentives program" for building this type of system, Schembrie said.
The Repentigny store, as well as the other Loblaw stores that use secondary loop refrigeration, are also able to reduce the amount of refrigerant used as well cut down on refrigerant leaks.
The refrigeration system is comprised of low-temperature and medium-temperature systems that use the hydrofluorocarbon (HFC) refrigerant R-507A.
The R-507A is used to cool potassium formate in the low-temperature system, and propylene glycol in the medium-temperature system, via a heat exchanger. Both substances have no environmental effect. The cooled substances then in turn cool the refrigerated cases on the store's floor.
Under the terms of the Kyoto Protocol, Canada will have to reduce its emissions of greenhouse gases, including HFC. "Canada must reduce its greenhouse gas emissions by 6% relative to 1990 levels by 2012," Schembrie said. The secondary loop system's design reduces the synthetic refrigerant (HFC) charge by 75%, according to NRCan.
In a typical grocery store, the R-507A refrigerant would circulate under pressure from the mechanical room to the display cases through piping that is susceptible to leaks. Since the Repentigny store's refrigerated display cases are cooled via secondary loop substances, the environmentally harmful refrigerant is confined to the store's mechanical room, reducing its potential for leaks by about 96%, according to an NRCan projection.