Selected aspects of heat recovery simulation in houseboat installations

What is it about?

Wastewater in a houseboat facility contains a large amount of heat energy that is irretrievably lost, so it is worth considering the possibilities of its recovery. It is estimated that in a typical residential building with full sanitation, approximately 70% of the total tap water supplied is discharged as gray water and can be reused. Heat recovery from wastewater can be carried out in many ways, it is influenced by various factors, including the location of the heat collection point from wastewater. The wide range of available technologies means that the market is full of many original and interesting solutions. The subject of the work is the possibility of recovering heat from wastewater as an alternative energy source for heating domestic hot water. The article presents an overview of solutions used in practice on the market, with particular emphasis on the possibility of their application in a houseboat facility. The article practically verifies the selected recovery system on a local scale (point recovery) at the selected facility - the so-called Drain Water Heat Recovery (DWHR). In the scope of analyzes, an original simulation tool was used, allowing to verify the effectiveness of the applied solution for various design and material variants of the exchanger. The conducted analyzes and simulations show that local systems of heat recovery from gray water allow for significant savings in the scope of heating domestic hot water, and the potential rate of return depends on the purpose of the facility and the type of installation. At the same time, the research shows that the design solutions of heat exchangers and internal installations in the analyzed facility in the form of a floating house (houseboat) should be adapted to the energy parameters of the flowing medium, which are the so-called gray waters.

Featured Image

Why is it important?

This paper analyzes the solutions of local wastewater heat recovery systems, which are used in practice on the market, with particular emphasis on the possibility of their use in floating houses. This required the use of specific criteria for their selection and analysis. In the article for home use on the water, vertical spiral systems and horizontal systems in straight, spiral and sheath configurations were analyzed. Recovering heat from gray water in residential systems is one of the significant energy savings opportunities and is aimed at implementing the EU's environmental strategy. Parameters characterizing wastewater in terms of their energy potential are primarily their temperature and flow rate. Other criteria for evaluating the potential of wastewater energy recovery are their total quality, technical condition of the sewers, distance between heat sources, the technical recovery system used, as well as the type of recipients and their energy needs. The actual amount of gray water discharged from residential buildings depends on many factors such as the price of water, the quantity and quality of sanitary utensils, the habits of residents and the devices used in buildings to reduce water consumption. The amount of gray water discharged from an average household is about 60 dm3 per day. Their average temperature close to the drain system is around 30°C. A large part of the heat lost with sewage can be recovered and utilized in the place where it is generated, e.g. in the shower, washing machine or dishwasher. As local heat recovery points. This type of recovery system is based on the use of a special heat exchanger. Heat exchangers are usually installed during the construction of the sewage system in a given facility. The possibility of recovering thermal energy in this type of systems is referred to in the literature as the so-called Drain Water Heat Recovery (DWHR)

Perspectives