Drain waste heat recovery system that saves hot drain water by means of a helical rectangular coil heat exchanger

Abstract

Energy all over the world, is being lost in a way or another. One of the most important kinds of wasted energy is the heat energy, which is being lost in huge amounts worldwide when wasted down the drains of all buildings that use hot water for several applications. This project consists of installing a heat exchanger that uses the heat of the drain water that is going through the drain pipes by using it to transfer this heat to the surrounding cold water, which will eventually arrive to the electric heater with a remarkable gained heat energy, thus helping the electric heater to heat the water from a higher starting temperature and reach the point where it stops heating by electricity in a shorter period of time. By this process, lots of heat energy will be saved from hot water applications like showers, washing machines, kitchen sinks. Furthermore, it is obvious that hundreds of thousands of houses and public buildings are using hot water in a way or another, so saving a little energy from each building throughout the year will result in a huge save of electric consumption for the whole country. It is not profitable to pay money for hot water, and lose the hot water through the drains, it is like throwing ones own money and hard work down the drain with no return, so the model that is studied in this report will illustrate how and in what amount this heat exchanger will save, and recover heat as much as possible from the hot drain water.