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The purpose of an energy label is to indicate
to customers or users the energy quality of a product in order to help them
with their purchase decision. The Eurovent Energy Efficiency Labelling for
central ventilation units has become firmly established in Europe. After using
the former Eurovent Energy Label /1/ for a six-year period, the new legal
minimum energy efficiency requirements with regard to these products make an
update of the energy labelling imperative. Moreover, the requirements of the
Ecodesign Directive have been incorporated in the new Eurovent Certification
and the energy classifications. The new energy efficiency classes apply from
January 2016. Furthermore, a new Eurovent energy efficiency class A+ is being
introduced, characterising devices with the currently highest available energy
efficiency level. In the lower efficiency range, the classes “C” and “D”
correspond roughly to the legal minimum requirements for ventilation units.
In general, the Eurovent calculation process
for the definition of the energy label has not undergone significant changes.
The criteria for the calculation of the energy label are still the thermal
efficiency and the pressure drop of heat recovery, the air speed in the
cross-section area of the ventilation unit as well as the efficiency of the
fans in their operating points. The possibility of compensation between the
individual requirements as well as the consideration of different climate zones
remained unchanged. Changes have been implemented regarding the energy
requirements for the achievement of efficiency classes as demonstrated in Table 1.
Table 1. Criteria for the definition of the
Eurovent energy label classes for air handling units.
Class | max. air speed | min. efficiency HRV | max. pressure drop HRV
per airway (Pa) | min. efficiency level |
A+ | 1.4 | 83 | 250 | 64 |
A | 1.6 | 78 | 230 | 62 |
B | 1.8 | 73 | 210 | 60 |
C | 2.0 | 68 | 190 | 57 |
D | 2.2 | 63 | 170 | 52 |
E | – | – | – | – |
For ventilation units of the highest
efficiency class “A+” ambitious criteria apply. It should be noted here that
the required temperature efficiency of at least 83% can no longer be described
in economic terms with all available heat recovery processes. While it can be
realised with rotary heat exchangers and reverse flow exchangers (only in the
lower air flow range), these values cannot be depicted economically with the
heat transfer systems and cross-flow plate heat exchangers with the available
technology today.
The legal minimum efficiency for ventilation
units from 2016, equipped with a heat recovery system (HRE > 63%)
corresponds approximately to class “D”. Appliances which feature a plate or
rotary heat exchanger according to the Ecodesign Directive (HRE > 67%)
correspond approximately to class “C”. The provision for complying with the
legal minimum Ecodesign requirements is also reviewed by Eurovent during the
annual recertification process.
How can the best way to use an energy label be established for customers or users? The presentation of the energy and eventually economic differences between appliances in single efficiency classes demands a comparison of the life cycle costs, i.e. the calculation of the total operating costs of an air handling unit over a time period of e.g. 5years. Table 2 shows results of such calculations for air handling units of different energy efficiency classes. All appliances have an air supply performance of 14,500 m³/h and operate 5 days a week, 12 h daily (supply air winter = 22 °C, supply air summer = 18 °C). Electricity and thermal energy costs were estimated as follows: Electricity 13 cent/kWh, Heating 0.065 cent/kWh, Cooling 0.040 cent/kWh. The qualities of heat recovery and air supply were changed in air handling units.
Table 2. Simulated operating costs for air
handling units of the same performance from different energy efficiency
classes.
Costs | Efficiency class
according to Eurovent | |||||
A+ | A | B | C | D | ||
Eta-HRV | 83% | 78% | 73% | 68% | 63% | (--) |
PMV,ZUL | 6.98 | 7.21 | 7.44 | 7.83 | 8.56 | (kW) |
PMV,ABL | 6.04 | 6.23 | 6.43 | 6.76 | 7.4 | (kW) |
Electricity | 30 834 | 31 829 | 32 847 | 34 552 | 37 796 | (€) |
Cooling | 4 606 | 4 698 | 4 697 | 4 877 | 5 216 | (€) |
Heating | 1 879 | 5 153 | 8 383 | 11 491 | 14 325 | (€) |
Total | 37 320 | 41 660 | 45 927 | 50 920 | 57 337 | (€) |
Saving | 35% | 27% | 20% | 11% |
Table 2
shows that approximately 10% of the operating costs can be saved for air
handling units per better energy class. This means that when an appliance
belonging to energy class A is used instead of one belonging to class C, around
20% of energy costs are saved. However, this statement cannot be generalized as
the sample calculation applies only to standardized operating hours and defined
energy costs. An assessment of profitability requires that investment costs be
included too in order to arrive eventually at the right purchase decision.
Figure 1. Eurovent energy label class A+ (2016).
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