CSA B55.1:2020 pdf download.Test method for measuring efficiency and pressure loss of drain water heat recovery units
4.3.2 Pressure loss on the potable water side of the DWHR unit shall be determined for each test set. One of the following options shall be used depending on the location of pressure gauges:
a) Stationary on the test apparatus:
i) the pressure gauges shall be kept stationary in permanent positions on the test apparatus;
ii) a "short circuit" calibration curve for the test rig pressure loss without the existence of a DWHR unit shall be developed and reported with each test report. This calibration curve shall be based upon the series of test points described in Clause 4.2.1 and shall be included in the test report. It is understood that any difference in static pressure head is also automatically included in this calibration if the pressure gauges are to be fixed in their location, regardless of the DWHR unit being tested. If there is any change in location or pressure gauges, a new calibration curve shall be developed and subsequently reported; and
iii) for each test set, the pressure read be each pressure gauge shall be recorded. The difference between the pressure gauges, less the“calibration pressure loss" at the flow rate, shall be reported as the pressure loss at the test set.
b) At inlet and outlet of DWHR unit:
i) the pressure gauges shall be located immediately at the inlet and outlet of the DWHR unit being tested;
ii) with the system flled with potable water and under supply pressure, the pressure reading of each gauge shall be recorded. The difference between these readings is the“static pressure difference"; and
iii) the static pressure difference in Item ii) shall be subtracted from the pressure loss test results for each test set.
Note: As an alternative to testing each length of a given DWHR model as per Items a) and b) above, an interpolation method can be used to determine the DWHR unit's pressure loss in accordance with Clause 4.4.
4.4 Efficiency data point interpolation
This method shall apply to untested models with identical characteristics (e.g., diameter, tube configuration, etc.), for which only the length varies. The interpolation shall be made using a quadratic curve fit for efficiency versus length. Each curve fit shall require a minimum of four data points calculated in accordance with Clause 4.3.3 under a standard reporting condition of 9.5 L/min (2.5 usgpm). The maximum length difference between a given interpolated point and the closest data point shall be not more than 500 mm (19.68 in).CSA B55.1 pdf download.