An innovative design and evaluation of a stratified hot water storage system - the Water Snake

Abstract

Abstract-The increase in energy prices and the demand to reduce carbon emission is attracting the attention to the implementation of diverse heating technologies such as heat pumps, solar energy, gas boilers, CHP and electric heaters. Heating applications for integrated technologies include district heating, domestic small scale applications and commercial large scale buildings. Thermal storage is likely to become key to energy efficient heating. A stratified hot water tank will play an important role in the integration of several heating technologies that operate efficiently at different level of temperatures with reduced implementation cost. This paper describes the concept and the assessment of the 'Water Snake', a novel low cost concept of a stratified hot water tank. The results show that the new concept could provide efficient stratification at a very low cost using this invention.

Assessment of a novel technology for a stratified hot water energy storage – The water snake

“…One of the novel methods proposed to improve the stratification inside the thermal energy storage is by using a thin flexible tube, named as the water snake [28]. The water snake moves up and down according to the temperature and the density of water entered into the tank placing it in the right layer where temperatures and densities are the same.…”

“…The open end is free to float within the vessel such that it will rise or drop to a position of neutral buoyancy. Thus, the end of the snake will move to the right temperature level equal to the temperature of water flowing in the snake hence reducing any mixing between different temperature levels [28]. Fig.…”

Developing a Method for the Operational Control of an Ecovat System

“…Systems with multiple or flexible inlets were found to lead to a better stratification as well. For example [62], shows that a copper tube with holes connected to the inlet inside the water improves thermal stratification by depositing the incoming water at the vertical position inside the tank with a similar temperature, while [40] indicates that the use of a flexible tube connected to the inlet of the water tank shows the same improvement. Similarly, [42] shows that having two outlets to draw water from during discharge improves thermal stratification, leading to better performance.…”