Scope
This calculation procedure deals with instantaneous DHW heat recovery using a counter-flow heat exchanger between the drain water and the incoming cold water.
The proposed procedure calculates the recovered heat, to be taken into account in the overall building energy performance calculation scheme.
This calculation procedure doesn’t cover storage heat recovery or the use of drain water as a source for a heat pump.
Purpose
In a context of reduced heating needs due to the increasing level of building insulation, the energy use for domestic hot water has an increasing role. Domestic hot water (Waste water) heat recovery is a technology that contributes to improve the energy performance of domestic hot water systems. This technology allows to cover a significant part of the domestic hot water energy needs with heat recovered from e.g. the shower drain.
Until now, this technology was taken into account in the energy performance calculation of only few EU Member states. A literature review showed that the several implementations are all different and that they often consider only part of the relevant influencing factors. Therefore, there is a need to harmonise the calculation procedures, to avoid European market fragmentation and provide more visibility to this technology.
This document is a proposal for a calculation method related to instantaneous DHW (waste water) heat recovery, whose main application is on shower drains. This procedure has been designed that it fits into the modular structure of EN-EPB standards. The calculation method can be used for hourly or monthly calculation interval.
Comment on proposal
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