Ever since beverage coolers were patented in 1979, hundreds of variations have been made to these cabinets that keep our bottles cold so we can enjoy a cool drink any time. Something that is especially pleasant these days, with maximum temperatures of 30°C in Padua, or even higher, 38°C in Madrid. So, before going into details about how efficient beverage coolers should be (also called bottle coolers, and generally included in the categories of stand-alone units or plug-in cabinets), let us thank Stanley R. Moore for his invention of the “refrigerated beverage holder” almost 40 years ago.

Why is it important to have efficient beverage coolers?

More than 20 TWh/year could be saved by decreasing the energy consumption of plug-in refrigerated cabinets with products that use the best-available-technology, according to Topten International Services (http://www.topten.eu/). This means savings of around 4 billion euros in electricity costs! In practical terms, the savings due to beverage cooler energy efficiency improvements correspond to 6.0 tonnes of CO₂ equivalents, whereas the estimated savings due to the replacement of R-134a with a green refrigerant come to 0.4 tonnes of CO₂ equivalents. Therefore, the Topten study estimates that 93% of the decrease in CO₂ emissions would be due to energy efficiency and 7% would be due to replacement of the refrigerant.

Moreover, beverage coolers are different than other refrigerators, as their objective is not to preserve food or drinks, but rather to cool them. This means that they are usually switched off when the shop is closed. In consequence, the time and effectiveness of the pull down stage is particularly important, being a crucial moment in terms of saving energy. The seasonality effect is another important factor in the efficiency of bottle coolers. On the one hand, cooling demand increases on the warmest days due to higher temperatures. On the other hand, people are thirstier and the use of the cabinets increases, meaning the doors are opened and closed more often.

The reasons described above are forcing users to think about efficiency, and not only the initial cost, when purchasing a bottle cooler. Saving money and being friendly to the environment are key factors in the market nowadays and, with available technology, beverage coolers are ready to meet these challenges! 

How efficient should a beverage cooler be in order to be sold in the European Union?

everage coolers are included in draft regulation ENER lot 12, which comprises the ecodesign requirements for refrigerated commercial display cabinets. This draft has been updated several times since the first version was distributed, and will most likely be further modified so as to be aligned with the state-of-the-art technology at the time of approval.  
According to the draft, the equation to calculate the energy efficiency of a cabinet is the same already used for professional refrigeration cabinets, included in ENTR lot 1. In both cases, the Energy efficiency index (EEI) expresses the annual energy consumption of the cabinet compared to its reference standard annual energy consumption: 

Looking at the equation, it is clear that a cabinet with an EEI higher than 100 consumes more energy than the reference standard cabinet (i.e. the cabinet in question is less efficient), whereas an EEI lower than 100 means that the cabinet consumes less energy than the equivalent standard cabinet (i.e. it is more efficient). Therefore, the lower the EEI, the more efficient the beverage cooler.

The draft regulation states that starting 1 July 2017, the EEI of refrigerated commercial display cabinets must be 110, whereas from 1 July 2020 the EEI should reach 80. When this draft was prepared, the best available technology on the market for a 520-litre beverage cooler allowed an EEI was 27, with an annual energy consumption of 511 kWh per year.

Draft regulation ENER Lot 12 goes hand in hand with the energy labelling of refrigerated commercial display cabinets, in the sense that the initial draft of the energy labelling regulations has been updated several times to be aligned with ENER Lot 12. The energy efficiency classes according to the draft energy labelling requirements are shown in the following table:
 

Energy efficiency classes of refrigerated commercial display cabinets

Accordingly, a beverage cooler with EEI= 27 (the best available technology on the market at the time the current draft regulation was prepared), would be class C.  

What are the regulations for beverage coolers in USA?

Beverage coolers are included in the Energy Conservation Standards for commercial refrigeration equipment, in force as of March 27 2017, under the category of self-contained condensing “pull-down” units. The maximum energy consumption values, as a function of the volume, are shown in the following graph:

Taking the example of a 40 ft3 unit (1.1 m3), the limit has been reduced from 8.6 to 5.2 kWh/day (-39%) with respect to the previous standard. Considering that the Max-Tech value (estimation of the minimum energy consumption with the best available technology) for this type of cabinet is 4.8 kWh/day, the units have to be designed using most of the best technology available.

In the United States, there is no compulsory labelling regulation to date, however there is a voluntary program. ENERGY STAR derives its standard levels from market data based on the performance of certain models of equipment currently available for purchase.

How can cabinet energy consumption be reduced?

Variable-speed compressors (especially those with DC technology), LED lights, smart control systems, electronic expansion valves, insulation, doors and variable-speed fans are among the key components that reduce the power consumption of cabinets. Variable-speed compressors are especially effective in the pull down stage and regarding seasonality changes, as variations in load are managed precisely with constant control of the compressor envelope.

As an example of a high-efficiency bottle cooler, the LIEBHERR FKDPv 4503 was awarded by PROCOLD at EuroShop 2017 in Düsseldorf. They stated they were very honoured to receive this recognition, and at the same time made a call for the approval of the Lot 12 regulation, which would help officially recognise the high-efficiency performance of commercial refrigeration equipment. Hopefully, it will be approved soon, so that energy use is optimised in this application too. In this way, CO₂ emissions will be reduced, the greenhouse effect will decrease, extreme temperatures will become unusual… and we will get our cool drinks because we like them, not because we need them!