Differences

This shows you the differences between two versions of the page.

--- efficiency_now:building_service:circulation [2022/12/01 07:41] – created yaling.hsiao@passiv.de
+++ efficiency_now:building_service:circulation [2022/12/02 08:08] (current) – [Circulation system] mmursi
@@ Line 12: / Line 12: @@
 installation effort for it is quite considerable ((This is one of the reasons for increased construction costs: this is often due to hidden technical improvements which make our lives easier. Hot water almost immediately in the shower - that's so convenient. However: The line length for hydraulic installation of the hot water pipe would have to be doubled for this)). Another heat-carrying pipe is routed from a point as near the point of use as possible back towards the heat source (usually a storage tank), this is called the **circulation pipe**. If we now add a pump in this pipe which brings the water in this pipe back to the storage tank, and which is constantly in operation, then all the water in this circulation loop will remain close to the temperature of the storage tank with an adequate flow rate. We will then get really hot water as soon as we open the faucet. It is undeniable that this will also save water (preliminary flow of cold water mentioned above).
-|It is often claimed that this also saves energy: but that is not necessarily correct, because if pipes are poorly insulated they will lose heat constantly due to the now higher temperatures; heat must be additionally supplied by the hot water generation system; we refer to these as **circulation losses**. In the case of really well-insulated pipes, these losses may be very high: we have therefore provided instructions here for [[https://passipedia.de/technik/leitungdaemmen|improving the thermal insulation of pipes carrying hot water.]] In principle, we could greatly reduce these losses through excellent insulation and a little attention with regard to the length of the distribution system, as was done e.g. in the case of the Passive House prototype in Darmstadt Kranichstein (picture). This is very worthwhile by the way, as the expenditure is significantly lower than the total cost of energy incurred annually for compensating such losses.|{{ :picopen:circulation_system_1.jpg |}}The four ((heating forward flow; heating return flow; hot water pipe; circulation pipe)) heat-carrying pipes here have initially been insulated individually as usual. The entire set of pipes was then enclosed in 100 mm thick insulation; the costs for this were actually very small, the losses are reduced by more than half again. However, it is clear that this must be planned for new builds, and cannot be retrofitted so easily in this perfect way in the case of existing pipes.|
+|It is often claimed that this also saves energy: but that is not necessarily correct, because if pipes are poorly insulated they will lose heat constantly due to the now higher temperatures; heat must be additionally supplied by the hot water generation system; we refer to these as **circulation losses**. In the case of really well-insulated pipes, these losses may be very high: we have therefore provided instructions here for [[efficiency_now:building_service:insulation_of_pipes|improving the thermal insulation of pipes carrying hot water.]] In principle, we could greatly reduce these losses through excellent insulation and a little attention with regard to the length of the distribution system, as was done e.g. in the case of the Passive House prototype in Darmstadt Kranichstein (picture). This is very worthwhile by the way, as the expenditure is significantly lower than the total cost of energy incurred annually for compensating such losses.|{{ :picopen:circulation_system_1.jpg |}}The four ((heating forward flow; heating return flow; hot water pipe; circulation pipe)) heat-carrying pipes here have initially been insulated individually as usual. The entire set of pipes was then enclosed in 100 mm thick insulation; the costs for this were actually very small, the losses are reduced by more than half again. However, it is clear that this must be planned for new builds, and cannot be retrofitted so easily in this perfect way in the case of existing pipes.|
 However, legislation specifies that a far lower standard of pipe insulation is legally adequate; unfortunately, often not even this standard is adhered to in practice ((especially because although the insulation is installed, it is executed extremely incompetently. Very often, the still open slits of the insulation shells are simply turned towards the back (so that they are not visible). Equall<)). Ultimately, today on average around half (!!) of the energy consumption of the central hot water generation system is attributable