Division 2 METHODOLOGY FOR CALCULATING THE ENERGY EFFICIENCY INDEXF1

The methodology for calculating the energy efficiency index (EEI) for circulators is as follows:

1. 1..

   Standalone circulators with pump housing shall be measured as a complete unit;

   Standalone circulators without pump housing shall be measured with pump housing identical to the pump housing in which they are intended to be used;

   Circulators integrated in products shall be dismantled from the product and measured with a reference pump housing;

   Circulators without pump housing intended to be integrated in a product shall be measured with a reference pump housing;

   where ‘reference pump housing’ means a pump housing supplied by the manufacturer with inlet and outlet ports on the same axis and designed to be connected to the pipework of a heating system or secondary circuit of a cooling distribution system.

2. 2..

   Where a circulator has more than one setting of head and flow, measure the circulator at the maximum setting.

   ‘Head’ (H) means head (in metres) produced by the circulator at the specified point of operation.

   ‘Flow’ (Q) means the volume flow rate of water through the circulator (m ³ /hr).

3. 3..

   Find the point where Q · H is maximum and define the flow and head at this point as: Q _100 % and H _100 % .

4. 4..

   Calculate the hydraulic power P _hyd at this point.

   ‘Hydraulic power’ means an expression of the arithmetic product of the flow (Q), Head (H) and a constant.

   “P _hyd ” means hydraulic power delivered by the circulator to the fluid being pumped at the specified point of operation (in watts).

5. 5..

   Calculate the reference power as:

   P _ref = 1,7 · P _hyd + 17 · (1 – e ^{– 0,3 · P _hyd} ), 1 W ≤ P _hyd ≤ 2 500 W

   ‘Reference power’ means a relation between hydraulic power and power consumption of a circulator, taking into account the dependency between circulator efficiency and size.

   ‘P _ref ’ means the reference power (in watts) of the circulator in a given head and flow.

6. 6..

   Define the reference control curve as the straight line between the points:

   ( Q _100 % , H _100 % ) and ( Q _0 % , $\frac{H_{\mathrm{100\; \%}}}{2}$)

   

7. 7..

   Select a setting of the circulator ensuring that the circulator on the selected curve reaches Q · H = max point . For circulators integrated in products follow the reference control curve by adjusting the system curve and speed of the circulator.

   ‘System curve’ means a relationship between flow and head ( H = f( Q )) resulting from friction in the heating system or cooling distribution system, as presented in the following graph:

   

8. 8..

   Measure P ₁ and H at the flows:

   Q _100 % , 0,75 · Q _100 % , 0,5 · Q _100 % , 0,25 · Q _100 %

   ‘ P ₁ ’ means the electrical power (in watts) consumed by the circulator at the specified point of operation.

9. 9..

   Calculate P _L as follows:

   $P_L=\frac{H_{\mathrm{ref}}}{H_{\mathrm{meas}}}\times P_{\mathrm{1,meas}}$ , if H _meas ≤ H _ref

   P _L = P _1,meas , if H _meas > H _ref

   Where H _ref is the head on the reference control curve at the different flows.

10. 10..

    Using the measured values of P _L and this load profile:

    Flow [%] Time [%] 100 6 75 15 50 35 25 44

    Calculate the weighted average power P _L,avg as:

    P _L,avg = 0,06 · P _{L, 100 %} + 0,15 · P _{L, 75 %} + 0,35 · P _{L, 50 %} + 0,44 · P _{L, 25 %}

    Calculate the energy efficiency index^f1 as:

    $\mathrm{EEI}=\frac{P_{\mathrm{L,avg}}}{P_{\mathrm{ref}}}\times C_{\mathrm{20\%}}$, where C _20 % = 0,49

    Except for circulators integrated in products designed for primary circuits of thermal solar systems and for heat pumps, where the energy efficiency index is calculated as:

    $\mathrm{EEI}=\frac{P_{\mathrm{L,avg}}}{P_{\mathrm{ref}}}\times C_{\mathrm{20 \%}}\times \left(1-e^{\left(-\mathrm{3,8}\times {\left(\frac{n_s}{30}\right)}^{\mathrm{1,36}}\right)}\right)$

    where C _20 % = 0,49 and n _s is the specific speed defined as

    $n_s=\frac{n_{\mathrm{100\; \%}}}{60}\times \frac{\sqrt{Q_{\mathrm{100\; \%}}}}{H_{\mathrm{0,75}}^{\mathrm{100\; \%}}}$

    where

    n _s

11. [rpm] is specific speed of a circulator;

n _100 %

12. is rotational speed in rpm in this duty defined at Q _100 % and H _100 %.