Economic feasibility of a system to reduce waste of water in hot water building systems: a case study in multifamily buildings
DOI:
https://doi.org/10.46421/sispred.v2i.1189Keywords:
Instantaneous gas heater, Water savings, Non-potable water storage tank, Cold water, Hot waterAbstract
ABSTRACT: In dwellings that have instantaneous gas heaters to heat water, cold water is wasted in the first seconds of using hot water fixtures. The objective of this work is to verify the economic feasibility of implementing an automated system integrated to the hot water fixtures of buildings that reduces the waste of water from the initial moments of use. A comparative economic analysis between the installation of the proposed automated system and an individual recirculation system was performed for a case study for a multifamily building. Altogether nine different economic analyses were carried out, varying the water saving potential and the type of recirculation system to obtain the Net Present Value, Internal Rate of Return and discounted payback. It was verified in all analyses that the proposed system is more viable than the traditionally used individual recirculation system. The proposed system reduces waste of water in domestic hot water systems, proving viable by providing a daily water savings potential of at least 5.6%. The use of the system depends on the existence of a heating system away from the water fixtures and the presence of an underground water tank. Costs for installation-related services must be carefully budgeted for the system to be economically feasible.
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