The importance of panel insulation in energy bills

Panels in white lacquered steel. Polyurethane foam insulation with CFC free water, high density 45kg / m3

When purchasing or replacing refrigeration equipment, one of the key factors in the choice of appliance is the price / quality ratio .

To determine such a ratio, most consumers analyze the technical characteristics of the selected machines and compare them by applying a weighting to certain features: capacity, power, finish, ergonomics, optional extras ...

The choice of foam and thickness of the panels used for insulation is an aspect that must be taken into consideration.

Depending on the thickness and density of the polyurethane foam used, this can represent unexpected energy costs in the long run that will become substantial a few years down the line.

 

Example for retarder proving panels:

  • Panel A: thickness 50 mm, polyurethane foam density 35 kg/m3 (orange curve)
  • Hengel panel: thickness 60 mm, polyurethane foam density 43 kg/m3 (blue curve) (CFC-free water polyurethane foam)
     
  • Internal temperature of the retarder prover chamber:
    • Tint (min) = 2°C IN BLOCKING MODE
    • Tint (max) = 35°C IN PROVING MODE
       
  • External temperature: 28°C

 

Heat loss flow through a panel as a function of the temperature difference between the external and internal temperatures
Polyurethane foam insulation with CFC-free water, high density 45kg / m3
Insulating panels with metallic assembly brackets. Foam insulation, thickness 6 cm, density 43kg / m3

Chart observations:

The vertical axis represents the instantaneous heat loss in W / m² occurring through a panel having a surface area of 1m².
The horizontal axis represents the temperature difference between the interior and exterior of the chamber in ° C.

  • Δφmin for a delta T of 7 ° C: it corresponds to the loss through the walls (1m²) during the proving phase for a set-point temperature of 35 ° C
  • Δφmax for a delta T of 26 ° C: it corresponds to the loss through the walls (1m²) during the blocking phase for a set-point temperature of 2 ° C
  • Δφaverage for a delta T of 16 ° C: it corresponds to the loss through the walls (1m²) during the cold return after proving for a set-point temperature of 12 ° C

 

Nota: Data calculated with respect to thermal resistance (conductivity and thickness of the panel).
R = e/λ (m².K/W)             e = thickness (in m)        λ = lambda (W/m.K)

 

Chart Interpretation:

The orange curve is always above the blue curve. This means that regardless of the temperature difference between the interior and exterior, the heat loss is always higher with the Type-A panel.

If we observe the difference in heat loss at the points Δφmin, Δφaverage and Δφmax, we can see that the greater the difference between the external temperature and the internal temperature, the greater the heat loss.

  Energy dissipated (W) for a  1m ² panel surface area  
  Hengel panel Type-A panel Surplus energy consumed for type-A panel
Insulation Thickness 60mm, foam density 43 kg/m3 Thickness 50mm, foam density 35 kg/m3
Minimum point 3.75 5.00 33.33%
Average point  6.75 8.82 30.67%
Maximum point 10.50 13.75 30.95%

 

Conclusion

Based on these calculations, we conclude that the energy lost through insulation panels increases by more than 30% if type-A panels of a lower thickness and density are chosen compared to Hengel-type panels.

When used in combination with other equipment that has a lower quality of insulation such as a deep-freezer, freezer, refrigerator, cold room, etc., the energy bill can skyrocket after just a few years.

When you next invest, make sure you compare insulation thicknesses!

Reminder: the thickness of our panels varies according to the application:

  • 100 mm for deep freezing and negative storage
  • 60 mm for proving and positive storage

 

The density of the foam used is 43 kg / m3, regardless of the application.

To save on your energy bill, read our article on the good reflexes to adopt to reduce your electricity consumption.

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