Eco-smart hot water with heat storage

Energy must often be stored as heat to be subsequently used to heat homes as well as factories.

One problem that often occurs in this context is that the heat energy escapes through the ambient environment. This energy loss can be prevented by means of insulation but even the best insulating material loses heat. To achieve a more energy-efficient system, a key objective is to minimize energy loss.

An ingenious way to store energy

So-called phase shifting materials provide a solution to heat loss. These materials undergo phase changes, or reactions that reversibly store and release heat. For example, a material can change from solid to liquid form depending upon the heat it stores. Thermal energy is then stored efficiently until the phase shift back to a solid state occurs and the heat is returned to the environment. Phase shifting materials are already exploited in industry, and to store solar energy. As the materials improve, become cheaper and more environmentally friendly, they can also contribute to making our homes greener.

Energy savings at home

To date, energy efficiency measures have primarily focused on the heating of homes, while water heating has not received as much attention. Reducing waste heat from water tanks is a major environmental concern in Sweden. More importantly, it is in countries like Britain and Ireland, where many homes in urban areas are heated through their own water tanks, that energy savings could benefit the environment.

Recently, Dr. Michael McKeever, a researcher at the Dublin Institute of Technology, invented a device that can significantly reduce the waste heat in water tanks. The solution was to find a convenient and cheap phase-shifting material that can be utilized at home.

Stores and emits energy, if necessary

McKeever’s simple innovation coats the water tanks with a phase-shifting material, which can exist in both liquid and solid form, and can store six times the energy of 60 ° C water. When hot water tanks are used in the home, they tend to be warm during the night. It is then that vast amounts of energy are lost. However, when energy is delivered from a tank covered with McKeever’s coatings much of the energy is stored in the material. It is then the phase-shift occurs from solid to liquid form. During the day, when hot water is used to take a hot shower the temperature in the tank falls. Then the phase shifting materials emit part of the stored energy. As the phase transition to solid occurs, the stored energy heats up the water thereby reducing the need to heat up water in the traditional way.

Winners include the environment and the family budget

Soon, McKeever plans to launch his idea in the form of a tangible product.

These are small triangular deposits that can be used to cover water tanks of different sizes. The Irish Times reports that up to 10 units may be needed to maximize energy efficiency. Because the cost of each unit is around 15 Euro, the initial investment will be minimal for households. By reducing household energy consumption, the investment can be repaid in less than a year.

It remains to be seen if McKeever’s product is a success or not, but ultimately there is a good opportunity for phase-shifting materials to create more energy efficient and smart homes. One advantage of the technology is to use just the right material to automatically deliver and store heat at a suitable temperature. The smart materials are both energy-smart and energy efficient.

This article was published in August 2012