Discover the solar water heater that you did not know you had in your house

Discover the solar water heater that you did not know you had in your house

Maybe at your house they planned to buy a vacuum tube or panel solar water heater to produce hot water for domestic usebut due to its high cost, it is beyond your economic possibilities, as it is for most people in Latin America.

Starting from this problem, the Mexican researcher in eco-technology Sergio Cortés, also creator of the first ecological household detergent, proposed to direct our gaze towards a very common and inexpensive product which has been present in millions of homes for more than 30 years. . : The tinaco or tank to store drinking water.

This container whose the capacity varies between 450 and 2500 liters and is usually located on the roofs of houses where it receives the maximum sunshine, it has all the characteristics to be used usefully and economically as solar water heater to produce domestic hot water.

For example, a water tank with a capacity of 1100 liters offers a solar radiation collection surface of about 2.3 m2 taking into account the shading effect of its cylindrical shape.

In most countries of the region, there is a solar potential greater than 5 kWh per m2 per day which gives us the significant quantity of 11.5 kWh or 9888.2 kilocalories, enough to raise 494 liters of water per day to 20°C.

In areas with strong solar radiation The surface of a water tank can capture more than 4,200 kW annually, which is the equivalent of burning more than 380 kilos of LPG.

Under normal conditions, a water tank does not have a thermal insulation system allowing it to reach temperatures greater than 12°C above those of the surrounding environment, but even so it can contribute greatly to reduce energy consumption. or wood thanks to the considerable volume of preheated liquid, whose temperature, if we only consider it with a thermal gain of +10°C, it allows us to have an energy supply of 2100 kW per year.

The tinaco or tank to store drinking water, it is used to heat water

A water tank has always produced hotter water than the surrounding environment because it functions as a solar heater where solar radiation is absorbed by the surface and transmitted by conduction to the body of water contained within.

As the liquid warms throughout the day rises to the top of the container and accumulates energy there.

It is here that the traditional design of water tanks makes it impossible to use this resource usefully, because the outlet of the stored water is at the base of the water tank, so that whenever liquid is extracted, it will resort to colder water, and hot water will simply continue to float unreachably on top.

Another problem with the classic design of a water tank is that the filling mechanism by which the liquid enters at room temperature is at the top and settles on the surface of the “hot” zone, causing a loss of energy . However, despite this, one will still find a noticeable temperature gradient between the bottom and the top of up to 12°C.


A very simple and inexpensive solution.

A very simple and economical solution to heat water for free

To take advantage of this resource, it was imagined to set up a supply outlet in the area where the liquid reaches a higher temperaturethe filling mechanism has been modified so that, thanks to an extension, all the liquid settles to the bottom of the container, eliminating the heat exchange that occurs when the incoming liquid settles on the surface of the body of water .

In this way, the temperature increases in the area of ​​interestin order to manage this energy capital, the supply flow is kept at the base, which allows the supply of water at ambient temperature which, once consumed, is replaced by the deep filling system without affecting the volume and the temperature of our hot water reserve located at the top.

These simple adaptations are quite easy to make and very economical since only a flange or an adapter for the water tank and a few meters of PPR pipe are required.

This considerable volume of preheated water can be used twicesince in addition to being used to supply a boiler or a solar water heater, it can also be used to supply the cold water line which supplies the showers and sinks.

In this way, we will save even more our hot water reserves since we will need less of it to reach the desired temperature.

This simple trick can increase hot water availability by up to 40% so much so that we can do without a gas or electric based support system when using any type of commercial solar heating.

In summary, more hot water and less energy consumption.

In this way, we will have transformed our humble water tank into a solar water heater efficient enough that will save us a lot of money while significantly reducing the carbon footprint of our home.

This opens a wide range of possibilities to increase performance by implementing thermal insulation in the upper part of the water tank, or even attach a low temperature solar water heater like the plastic panels used to acclimatize swimming pools, of which there are fairly cheap and efficient models that can double the heat gain.

In the case of Mexico, from the year 1970 when the first domestic solar water heaters began to be commercialized to date, which includes a period of more than 50 years. Of the 34.7 million households that exist in the country, just over 2 million have a conventional solar water heater, which demonstrates the long way to go, and suggests that other options need to be considered. more accessible alternatives to solar energy as a viable resource for Latin. American households in the short and medium term.

Conditioning a water tank or tank is not intended to eliminate the need for a solar water heater or a gas-electric boiler, but simply proposes to use a wasted, ignored resource, which contributes in a real way to reducing energy expenditure in the production of domestic hot water at home, and which can represent the most practical and economical solution for massive access to the resource represented by solar energy.

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