Feasibility of a booster for DHW circulation in apartment buildings

Development and Test: Future-Proof Substation Designs for the Low-Temperature Operation of Domestic Hot Water Systems with a Circulation Loop

“…The economic analysis results indicate that the substation in this study demonstrated overall good financial performance, primarily because of the application of the DH motivation tariff in Denmark and the lower DHW circulation loss in configurations featuring circulation loss boosters. These findings are consistent with those of Thorsen et al [27], although their substation layout differs from that used in this study, and their system includes a DHW storage tank.…”

“…other studies found that this could have an attractive payback period for end users [27]. However, even if the solution might not have a short payback for the end users in other DH markets, the DH operators could secure some financial incentives for specific users, offsetting the extra cost with the potential savings from lower heat generation costs.…”

“…One of the solutions is to redirect the return flow from the DHW system to the low-temperature SH system to cool the return temperature to below 35 • C. Another solution, involving the use of an extra heat exchanger and a micro-booster heat pump, can compensate for the circulation loss and further cool the return temperature to below 35 • C. However, the researchers theoretically investigated the potential return temperature without conducting field tests. Thorsen et al [27] noted that realizing a low DH return temperature solely by direct heat exchange is challenging; therefore, they tested the configuration using a booster heat pump to compensate for the circulation heat loss in a Danish multifamily building connected to a DH network within a one-year testing period. The test shows that the yearly average DH return temperature decreased from 47.2 • C to 21.5 • C. However, the local DH network was characterized by medium-high supply temperatures during the test.…”

Analysis of the Life Cycle Cost of a Heat Recovery System from Greywater Using a Vertical “Tube-in-Tube” Heat Exchanger: Case Study of Poland

“…As emphasized by Huber et al [21], wastewater is a source of locally available and renewable heat and can therefore make a valuable contribution to the ongoing decarbonization of energy systems, which is essential for reducing greenhouse gas emissions. With increasing pressure on district heating efficiency, Thorse et al [22] developed and tested the concept of a booster for DHW circulation in apartment buildings. The main result of these studies was the reduction in the district heating return temperature from 47.2 • C to 21.5 • C, which proves the significant efficiency of the presented concept.…”