Assessment of the Feasibility of Implementing Shower Heat Exchangers in Residential Buildings Based on Users’ Energy Saving Preferences

Abstract

In Poland, domestic hot water is heated mainly using fossil fuel energy sources. Such an approach results in the depletion of natural resources, pollution of the atmosphere and, consequently, irreversible changes to the climate. In response to this problem, this research identified the factors that most determine energy savings for heating water in residential buildings, as well as those that affect the choice of an alternative energy source. Additionally, the possibility of implementing shower heat exchangers in existing and newly built residential buildings was assessed, as well as society’s willingness to use such devices. The research was carried out on a sample of 462 inhabitants of the Podkarpackie Voivodeship (Poland). A questionnaire survey was used as a tool. The conducted research has shown that the perspective of environmental protection is not a sufficient motivator to save energy for heating domestic hot water. It is necessary to implement appropriate programs aimed at informing the public about the possibilities offered by the use of alternative energy sources and co-financing the purchase of appropriate devices. In the case of drain water heat recovery systems, a significant problem is also the need to develop new, highly effective designs of shower heat exchangers which can be installed under the floor linear shower drain or on the horizontal shower waste pipe.

Introducing a Calculator for the Environmental and Financial Potential of Drain Water Heat Recovery in Commercial Kitchens

“…This article focused on overcoming potential issues such as a lack of awareness by kitchen owners of the availability of heat recovery and its benefits. A lack of awareness and access to information has also been identified as an issue for the implementation of heat recovery systems for showers by domestic users [30]. From a technological perspective, the necessity to access a part of the drainpipe with an approximately 2 m vertical drop can constrain the installation of a heat exchanger, as can the existence of obstacles between the drainpipe and the boiler.…”

“…The heat recovery system considered here uses a tube-in-tube heat exchanger and hence represents a kind of direct and passive heat recovery without the need for a heat pump. This and similar kinds of heat exchangers are typically used for shower water heat recovery, for which they have been studied and installed in domestic and commercial settings across the UK and Europe [20,21,[27][28][29][30]. In 2020, the installation of a heat recovery system was completed at a case study restaurant at the Penrhyn Castle tourist attraction in Wales, UK, initiated and overseen by the authors as part of the D ŵr Uisce INTERREG project, and was proven to be effective at recovering heat from kitchen drain water [15,16,31,32].…”

“…In order to reach its maximum heat exchange effectiveness of about 60%, it needs to be installed vertically [33]. With currently available designs, vertical heat exchangers have been proven to reach higher heat exchange effectiveness and are less prone to blockage than horizontal ones, which is important for the use with kitchen wastewater carrying higher organic contaminations than shower wastewater [19,30]. In order to connect the heat exchanger to the cold-water supply and boiler, fittings, and further pipework are required, the length of which depends on site-specific conditions, and which are assumed to be insulated.…”

Peak Power of Heat Source for Domestic Hot Water Preparation (DHW) for Residential Estate in Poland as a Representative Case Study for the Climate of Central Europe

“…It should be noted that further changes in domestic hot water consumption will affect the value of peak consumption and the irregularity coefficient will increase. A survey presented in the paper [59] showed that "the perspective of environmental protection is not a sufficient motivator to save energy for heating domestic hot water" and therefore only the water and energy price model can drive further changes.…”

Financial and Social Factors Influencing the Use of Unconventional Water Systems in Single-Family Houses in Eight European Countries

“…An online questionnaire was prepared in Google Form in Polish (research conducted in Poland) and English (research conducted in other seven countries) and was sent to the respondents in 2019. A similar test method was chosen, for example, by [68,69]. The questionnaire consisted of 10 questions: 4 general and 6 concerning the possibilities of saving water and rainwater and greywater systems (Figure 2).…”