Introduction
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Hysopt incorporates an extension of the DIN 1988-300 (2012) standard into the Hysopt software. We have extended the calculation to cope with simultaneous space heating and domestic hot water usage, and with combination of power needed in mixed systems.
In the example below, there is a shower- and a kitchen tap. When the flow rates are summed the total flow rate is 0.22 l/s, When using the simultaneous factor this becomes 0,17 l/s. For one satellite unit the difference between total and simultaneous flow rate is quite small, in case of a building with several units the simultaneous flow rate can go to 10% of the total flow rate which have a big impact on the pipe selection.
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Now the design flow rates and thermal power (SH and DHW) are known on the primary side of the satellite unit. In order to determine the design flow rate and thermal power into the common pipe sections, the SH flow rates are summed (0.33 m³/h + 0,.33 m³/h = 0.66 m³/h). The DHW simultaneous flow simultaneity flow rate is calculated as explained in the box below: the simultaneous flow simultaneity flow rate per unit is converted to liters/sec (1), then to a total flow rate in liters/second (2) using the inverse simultaneity formula, the total flow rates of the different satellite units are summed and calculated back to a simultaneity flow rate.
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. According to the standard the calculation needs to be done in liters/second.
