The new energy efficiency label
Do you recognize it? It seems the energy efficiency label that you can find on your new household appliance and that identifies the energy class to which your appliance belongs.
As you can see, in this label there are some slight differences from those currently in use. The reason is that the energy efficiency label is going to change.
Why? Well, the number of household appliances in the world has grown exponentially and energy consumption has proportionally increased and will continue to increase. Furthermore, industry development and competition have put on the market products even more efficient, moving up in energy classes. Most household appliances are now in the top classes (A+++, A++), but this situation generates difficulties for consumers in distinguishing the best performing products.
So, to make this scenario easier the European Commission’s Directorate for Energy decided to rescale the labelling, choosing for a more effective A to G scale, that will be effective within March 2021.
This means that every household (dishwashers, washing machines and washer-driers, refrigerators, lamps and electronic displays) will be reassessed according to specific criteria (as operating time, technology…) and will be placed in a new energy class.
Generally speaking, we can assume that A class product will be placed in G class, to be soon phased out.
As a consequence, the competition for climbing up the ladder will lead to the production of even more efficient appliances that will allow in the 2030 an annual energy saving of 38,1 TWh, according to the European Commission estimates.
Another element in the new energy efficiency label is the presence of a QR code, through which the consumers can connect to the EPREL EU database and find additional and official information, allowing greater transparency and easier market surveillance by national authorities.
What will change for domestic and commercial refrigerators market?
For refrigerators market the new energy efficiency label translates first of all in a changing of how the energy efficiency tests are performed. Criteria and tolerance thresholds will become more restrictive, and protocols stricter. On the other hand, it will increase companies’ competition for the production of more efficient refrigerators.
In order to move from one step to another of this energy efficiency ladder it is necessary to increase of 20% the level of energy efficiency of the refrigerator. To achieve this goal, important interventions have to be done on the refrigeration circuit, but sensible room for improvement can be gained also increasing the insulation efficiency (lambda) of the insulating polyurethane foam in the refrigerators.
Pros and cons of VIP
One of the most used method to improve the lambda is inserting into the refrigerators wall the VIPs, vacuum insulated panels, consisting of a gas-tight enclosure surrounding a rigid core where a vacuum has been performed. The membrane walls prevent air from entering the panel, while a rigid highly-porous material support the membrane against atmospheric pressure once the vacuum has been made. Chemicals and glass-fiber or foam cores are added to VIP to collect gases leaked through the membrane.
VIP achieves a much lower thermal conductivity than conventional insulation, so a higher thermal resistance. Good quality panels can reach a lambda of 4-5, that means about 4 times the value of insulation efficiency of a traditional pentane foam, for example.
However, VIPs are more difficult to manufacture than polyurethane foams, and require a strict quality control of membranes and sealing joins, since they have to maintain their vacuum over a long period of time.
In addition, VIPs cannot be cut to fit as with conventional insulation, but have to be produced tailor-made and require the injection of polyurethane to support them in full filling the cavities the are placed in. Polyurethane also acts as an additional protection for these panels, which have a certain degree of fragility.
A further negative aspect of the VIPs is that, being rigid and preformed, they make difficult the design and assembly of the internal refrigeration circuit of the cabinet.
For these reasons, VIP cost per unit is very much higher than common insulation. Nowadays VIPs represent an important part of refrigerator cost, and estimate to increase this expense for creating a product acceptable for the next future market. These manufacturers are therefore once again focusing on improving the insulation properties of the foams.
Polyurethane foams: how to improve the lambda
The insulation properties of the polyurethane foam strictly relate to:
- Blowing agent gas conductivity
- Foam cell size and distribution
The improvement of gas conductivity is achievable through the usage of HFO as a blowing agent.
HFO-based foams also help the reduction of typical cell size, if combined with faster reactivity formulations.
HFO costs and molar weight pushed the formulators to develop mixed HFO/C5-based solutions, in order to reach the optimal cost/performance compromise. In some cases, the blends turned out to have an azeotropic behaviour, giving even more benefits than expected.
When speaking about high reactivity foams, conventional breakers up injection from one point is not enough to properly fill the whole cabinet. To overcome this critical point, Cannon is typically proposing the following solutions:
- VAI Pascal technology: the vacuum within the refrigerator’s wall cavity during the injection of the foam and the relevant filling time, facilitates the expansion of the foam into the cabinet, obtaining a uniform density and a reduction of the polymerization time of 10-15%.
- 4 points of injection: Polyurethane is injected into the space between refrigerator’s wall through four different points located at the corners of the refrigerator’s back. This technology. guarantees a more uniform and quick distribution of the foam.
Respect to conventional C5-based foam, HFO solution can reduce the conductivity of approximately 15%, requiring sometimes a few of material overpacking, while a 50/50 C5/HFO solution can reduce the conductivity of 10% with a few points of material saving as well.
Adding VAI technology on top of the new formulation can give up to 5% of materials additional saving and a further 2% improvement on the lambda value.