SUPERMARKET SYSTEMS AND EQUIPMENT
Natural refrigerants in self-contained units
The new requirements for reducing CO2 emissions due to refrigerant and
electricity consumption are making retailers consider other alternatives to traditional centralised systems. One of the preferred options is the use of plug-in and semi plug-in units, that are increasingly used worldwide in diff erent types of supermarkets, especially those of a medium size as Carel illustrates.
T
he fi rst proposals for self-contained cabinets, fi rst with HFC refrigerants such as R404A and later with HFO’s such as R448A, brought numerous advantages for the decreasing of CO2
emissions. Among them, the
reduced charge of refrigerant and the lower refrigerant leaks in comparison with centralised systems with long copper pipes.
Nowadays, a step forward has been taken, with the adaptation of this
confi guration to the use of natural refrigerants. In particular, R744 (CO2) and R290 (propane) are the refrigerants that are mostly proposed in self-contained units.
1. Plug-in and semi plug-in units The diff erence between plug-in and semi plug-in units is that the fi rst one is air condenser, whereas the second one has water-cooled condensing units. The advantage of using water-cooled condensing units is that the condensation heat is removed by the water loop, avoiding it increasing the temperature of the supermarket, and can even be used for heating and sanitary hot water production, bringing benefi ts for the unit and the whole building. On the contrary, air-cooled plug-in cabinets are more fl exible, due to the lack of plastic pipe connections, but they dissipate the heat into the supermarket. This means an extra cost of conditioning in summer, and some savings of heating in winter.
In both cases, plug-in and semi plug-in, the installation is fast because the cabinets are usually ‘ready to use’, with only the plastic pipe connections needed in the fi eld in the case of semi plug-ins. Additionally, the critical components such as compressor are already contained in the cabinet, making it easier to install and commission. This also makes their use more fl exible, having the possibility of moving the cabinets inside the supermarket at any time of their use.
The maintenance reduction with the consequent lower costs is another key feature of both plug-in and semi plug-in units. It is also important to note that these self-contained solutions free up the space typically occupied by the compressor racks in a traditional system, with the advantage of having a wider sales area and avoiding noise and vibrations usually produced in the machine
30 April 2020
rooms. Moreover, in case of air-cooled units, the roof of the supermarket has better aesthetic appearance, with no condensing unit, which becomes important especially if the shop is located in a historical city centre. As regards direct CO2 emissions, the reasons why self-contained units have a minor impact in the atmosphere than centralised systems are obvious. On the one hand, no having long copper pipes and compressor rack means a very signifi cant refrigerant charge reduction. On the other hand, the fact that there is no welding in the fi eld and the units are factory-tested reduce substantially refrigerant leaks.
2. Continuous modulation
The solution of plug-in and semi plug-in units for commercial refrigeration completes its wide range of advantages if equipped with modulating components combined with advanced control and monitoring systems. This allows you to increase effi ciency and reduce indirect CO2 emissions, among other benefi ts. Modulating components such as DC compressors and electronic expansion valves managed by an advanced electronic controllers allow the
www.acr-news.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
