The challenges of the supermarkets’ refrigeration

On the first day of 2015 the system of tariff flags became effective, which added an extra charge over the electrical energy tariff. The action was adopted due to an increase of the use of thermoelectric plants, since the hydroelectric plants have low water levels in the reservoirs. This way, the expectation for 2015 is a significant increase in the tariffs that goes beyond the adjustments of the last years. ABRAS has informed that the cost of energy represents about 1.5% of the supermarket turnover and may increase up to 1.7% in 2015.

The refrigeration systems are accounted for the majority of the energy consumption in the retail system and, thus, the automation has been one of the adopted solutions to reduce the consumption in the short term. Lucas Riga, mechanical engineer and consultant for refrigeration projects in supermarkets all over the country, reminds us that the investment of this sector in energy efficiency began with the adoption of electronic components of control. Afterwards the networks started using frequency converters to control the rotation of the compressors, as well as electronic expansion valves and electronic controllers of the refrigeration systems.

Marcellus Cerchiai, engineering manager of Walmart Brazil, stated that the network expects to reduce at least 12% of the energy consumption per square meter until 2020 with the revision of the whole refrigeration system and the implementation of new air conditioning devices in the stores.

Another action that has been adopted in the retail sector in order to save electrical energy was the implementation of doors in the counters, not only in the islands of frozen foods, but also for the counters of cooled products, dairy products, meats and even fruits and vegetables. "Without doors these areas are responsible for the consumption of over 40% of the energy total of the store", added Cerchiai. In order to reduce the consumption and to guarantee a more efficient use, Walmart Brazil intends to install doors with LED lighting in the refrigerators, which will represent a great economy in energy. "By closing the refrigerated counters, we have already reduced the store's energy consumption around 8%". Besides, Walmart Brazil has adopted compressors with capacity control, electronic expansion valves and electronic engines. 

Carrefour has also reduced the electrical energy consumption by investing in preventive maintenance and by using correctly the air conditioning and refrigeration systems. This initiative alone has already been responsible for reducing the total consumption of energy of the company by approximately 2%, between January and November of 2014. Still in 2014, an Internal Commission of Energy Conservation was founded to raise the awareness of the teams of all of the units of the network regarding the rational use of electrical energy. 

Another example is Coop which revitalized its unit in Diadema. The renovation, which includes both retrofit and the amplification of the sales area, considered the areas of cold rooms and the preparation of perishables as a priority, expanded by 300 m², to receive modern refrigeration equipment, transport and conservation of the products. It is expected that the energy economy shall reach 12% through the introduction of a set of automation controllers of the refrigeration and air conditioning systems of the store, such as the refrigeration racks, the condensers, the cold rooms, the refrigerated counters and the preparation areas. Although some of the networks invest in automation, there is still a lot to be done. Riga explained that around 80% of the supermarkets, today, still have facilities that use up a lot of energy. "Many people build new stores and opt for more financially attractive solutions. This way, they end up using equipment and components that aren't as efficient. The greatest challenge is to convince the supermarket owners that new stores should count of efficient technologies, in addition to the importance of carrying out the retrofit of the existing stores." 

Besides the energy consumption reduction, another challenge that the sector faces is controlling the harmful gas emissions to the environment. Some of those gases are being eliminated through international agreements, with the objective of promoting the consumption of refrigerating fluids that are more adequate for the environment. The process that is in-progress in Brazil is the elimination of the hydro-chlorofluorocarbons (HCFCs), known as R22 and highly implemented by the supermarket sector in the refrigeration and air conditioning systems.

International treaties, such as the Montreal protocol, predict the reduction of the use of HCFCs. The Brazilian Program for the Elimination of Hydro-chlorofluorocarbons follows the goals established to eliminate the use of HCFCs until 2040. Beginning with the reduction of 10% in 2015 and progressively in the years 2020, 2025 and 2030 (side figure). This way, the sector has revised its application and adopted new fluids and equipment.

Paulo Neulaender, vice-president of the Environment of Abrava, has pointed out that Brazil is complying with its goal within the Montreal Protocol. "The supermarkets should prepare themselves in the next five years for the change we will have after 2020, which is when Brazil will have a considerable cut in their importations of HCFCs: 35%. In practice, it means a decrease of about 400 tons per month in the national supply. Noting that the supermarkets are, today, the largest users of R22 in maintenance."

The retail sector has followed the whole process. "We have made public the need to not install new units based on R22. And regarding the existing units, the main goal is to improve the preventive maintenance to eliminate leakages", said Erlon Ortega, director of sustainability of the Paulista Association of Supermarkets (APAS). Walmart Brazil has been using secondary fluid to replace the refrigeration fluid R22 in their refrigeration systems, according to Marcellus Cerchiai, engineering manager of Walmart Brazil.

Neulaender points out that the main challenge for the supermarkets will be preparing for the new technologies in the following years, to adapt themselves. "The most important thing at the moment is that the owners of supermarkets start to apply and get to know the new technologies with natural fluids such as CO₂ and R290, as well as synthetic fluids, such as the new HFCs and the fluids for retrofit."

"A reality in Europe, the technology to use CO₂ has been installed in more than 80 stores in Brazil and is expanding to other countries of South America, such as Argentina, Columbia and Venezuela, which already have installations in sub-critical regime, the ones with better energy performance", enhances Eduardo Drigo, sales coordinator of Danfoss.