Rationalization of water and energy consumption in shower systems of single-family dwelling houses

Reduction of costs incurred for supplying water and heating it for household purposes is possible by means of an application of systems recovering heat from drain water in combination with water flow limiters. Then, not only advantageous financial results can be obtained, but also positive effects in the form of reduced use of fossil fuels, improved air quality, and limited water consumption. This paper presents a calculation model that allows to assess the synergy of financial effects for different variants of an investment project consisting in mounting a water flow limiter and a DWHR unit in a shower system of a single-family building. This model has a large application potential that can be used as a tool facilitating the decision-making process both in the system design and modernization stage. A simulation test carried out for the case study involving different variants of modernization of a household shower system shows that profitability of such investment depends on the adopted modernization variant and system usage parameters. The best financial performance characterizes variants involving the use of a water flow limiter or both devices. The mounting of both devices becomes the most advantageous when the shower taking time is long. The obtained results additionally show that the most favorable financial effects can be achieved in buildings in which the total time of using shower facilities is the longest. The application of the presented solutions will be, therefore, particularly profitable in case of buildings characterized with significant water consumption and high rotation of users.