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Domestic hot water flow rates have always been challenging to calculate, because we need to take into account the simultaneous usage of hot water tapping points. Not all tapping points (like showers) will be use at the same time, so a so we need to take into account in each part of the system, the maximum probability, or the maximum DHW flow of simultaneous tapping points. These are defined in diversity standards. Most of these methods only account for simultaneous flow rates, and not for simultaneous power, because domestic hot water networks are mostly operated as single pipe / fixed temperature systems.
When carrying over these norms standards to the central heating system (HIU’s, heat exchangers, storage tanks, ….), the propagation and aggregation of diversity becomes very important! This effect is amplified by the fact that central heating often operates at lower power but higher flow rates / smaller temperature delta and domestic hot water heat exchangers operate at higher power but lower flow rates.Hysopt incorporates diversity for DHW (DIN 1988-300, Cibse CP1, Danisdh Code of Practice 439, Swedish regulation DHA F:101, French Costic MTA 2016, French DTU 60-11, …) and diversity for central heating (Cibse CP1.2, logarithmic, …). On request we are happy to add new or additional diversity calculation methods in the Hysopt software.
We have extended the calculation to cope with diversified central heating and domestic hot water usage, and with combination of power needed in mixed systems.
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diversity is a kind of “statistic“ calculation, defining the maximum percentage of simultaneous DHW tappings
regime changing components introduce a difference in primary and secondary volume flow, and a difference in primary and secondary temperatures,
but they will not introduce a difference in primary and secondary diversity or primary and secondary power
Standards
Hysopt incorporates diversity for DHW (DIN 1988-300, Cibse CP1, Danisdh Code of Practice 439, Swedish regulation DHA F:101, French Costic MTA 2016, French DTU 60-11, …) and diversity for central heating (Cibse CP1.2, logarithmic, …). On request we are happy to add new or additional diversity calculation methods in the Hysopt software.
Overview
To explain diversity and aggregation, we use following example model of 2 HIU’s.
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