ENVIRONMENT-BRAZIL: A Hot Shower Can Be Eco-Friendly

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Apr 10 2001 (IPS) - The 27 million households in Brazil that use electrically heated showerheads could soon obtain a low- cost solar water heater (‘aquecedor solar de baixo custo’ – ASBC), a simple system that provides hot water for bathing with minimal energy consumption.

The country would save 20.5 million kilowatt hours per year, or six to seven percent of total national consumption of electricity, if this heater were to be used by 25 million families, according to the calculations of Augustín Woelz, inventor of the system.

Along with the energy savings, he says, it would prevent the emission of 10 million tons of carbon dioxide a year, the gas scientists generally agree contributes most to global warming.

The relative savings would be even greater. The electrical showerheads that are generally used in Brazil are a burden to the nation’s energy production and distribution systems because their utilisation is concentrated at the time of day when the country’s energy demands are highest.

Most household appliances are used around nightfall, when streets and buildings are illuminated and industry and other businesses continue in action. By reducing consumption for heating water for bathing, the overall pressure on the energy system would also be diminished. Electric water heaters absorb 10 percent of the potential generated during this energy “rush hour.”

Brazil plans to import natural gas from Bolivia for its thermoelectric plants, given the difficulties hydroelectric dams have in keeping up with the country’s growing energy demands. But saving energy through other means, such as the ASBC, would imply the curbing the emission of fossil fuel-produced gases that contribute to the greenhouse effect.

The electrical showerheads that “democratised the hot shower” are a solution that is typical of Brazil, observed Woelz. In the rest of the world, it is more common that water heaters operate with natural gas.

The ASBC, initially designed for low-income households, can heat 150 to 200 litres of water per day, converting solar light into heat through black honeycombed panels, plastic tubing and other readily available construction materials.

The process can be installed taking advantage of the water tanks that are widely used in Brazilian home construction. All that would be needed is additional insulation.

In the ASBC system, water from the lower part of the tank passes through the apparatus and panels and is returned, a naturally occurring flow because warm water is lighter than cold water, so it remains in the upper layer of the volume of water until the full tank reaches a uniform temperature.

The water temperature can reach 55 degrees centigrade, more than warm enough for a hot shower, though on cloudy or rainy days it may fall to 40 degrees.

Due to these fluctuations, users might opt to keep their electrical showerhead on hand. By adding a temperature gauge, it could be rigged to turn on automatically when solar heat proves insufficient.

Anyone can install this system for a total cost of around 100 ‘reais’ (50 dollars), according to Woelz, an electrical engineer who says he pondered this invention over a decade, then developed it over the last two years.

He designed the apparatus with the poor sectors of the Brazilian population in mind, families that live in marginalized neighbourhoods. The inventor worked out the details of the device with the support of the National Council for Scientific and Technological Development and the Sao Paulo Research Foundation, two governmental agencies.

The firm created to disseminate the use of the water heater, Sunpower Engenharia, does not intend to seek patent rights, but rather to mobilise volunteers and train technicians, builders, teachers and social workers to promote their widespread installation.

Massive implementaiton of the solar water heater would lead to the expansion of the industries that manufacture its components. In the future, other companies could sell complete kits, or they could develop similar systems for larger buildings, Woelz pointed out.

The objective is to create social benefits, affirms Woelz, stressing that each family using this system would save nearly 150 ‘reais’ (75 dollars) a year in energy costs, and the negative impacts of human activity on the environment would be greatly reduced.