EXPERIMENTAL SETUP FOR ANALYSIS OF DRAIN WATER HEAT RECOVERY SYSTEM IN CIVIL BUILDINGS

Despite the low heat content, wastewater in civil buildings could be an important source of energy saving, especially for preparing warm water. Due to the energy consumption, buildings are responsible for much of the CO2 emissions. The EU has introduced in its policies for the reduction of carbon dioxide emissions a binding 20% target by 2020 and the ambitious target of reducing these emissions up to 80-90% by 2050, against a 1990 baseline. Inside the buildings, 60% of the water use is heated for tubs, sinks, showers, dishwashers and clothes washers, thus the residential wastewater is characterised by higher temperature. The drain water can be an important secondary energy source that can be recovered and capitalised inside the buildings. In order to reduce energy consumption, greenhouse gas emissions and the environmental impact, the drain water heat recovery system is an interesting technology applicable for any type of household. This paper investigates the potential of drain water resulting from shower and the technological solution for heat recovery. The paper is focused on the analysis and development of a drain water heat recovery system (DWHRS) for household shower. The experimental research results show the possibility of recovering the heat from drain water resulting from showers by using a heat exchanger. The results also demonstrate that such a DWHRS may be economically viable depending on some factors. Through the implementation of this technology, an important potential can be the reduction of energy consumption and greenhouse gas emissions at national level, as well as for the objectives of improving the energy efficiency of buildings, especially with regard to buildings with almost no energy consumption (Near-Zero Energy Buildings).