A Hot Shower Can Be Eco-Friendly
By Mario Osava*
Brazil, a new invention based on solar energy feeds dreams of the
pleasure of a hot shower with low economical and environmental costs.
RIO DE JANEIRO - The 27 million homes in Brazil
that use electrically heated showerheads could soon have 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 utilized by 25 million families,
according to the calculations of Augustín Woelz, inventor of the
Along with the energy savings, it would prevent
the emission of 10 million tons of carbon dioxide a year, the gas
that contributes most to global warming.
The relative savings are even greater. The
electrical showerheads are a burden to Brazil's energy production
and distribution systems because their use is concentrated at the
time of day when the country's energy demands are highest.
It is at nightfall that most household appliances
are used, 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 system would
be reduced. The electric water heaters absorb 10 percent of the
potential generated during this energy ''rush hour.''
Brazil plans to use natural gas imported from
Bolivia for its thermoelectric plants, given the difficulties of
hydroelectric dams to keep up with the country's growing energy
demands. But saving energy through other means would imply the reduced
emission of gases that contribute to the greenhouse effect.
The electrical showerheads that ''democratized
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
function with natural gas.
The ASBC, initially designed for more modest
homes, can heat 150 to 200 liters 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 generally used in Brazilian home construction,
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 homogenous temperature.
The water temperature can reach 55 degrees
centigrade, more than warm enough for a hot shower, and 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, though adding a temperature
gauge so that goes turns on automatically when the solar heat proves
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 10
years and developed it over the last two years.
He designed the apparatus with the poor sectors
of the population in mind, families that live in marginalized neighborhoods.
The inventor worked 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 (www.sunpower.com.br),
does not intend to seek patent rights, but rather to mobilize volunteers
and train technicians, builders, teachers and social workers to
promote their installation on a massive basis.
The widespread use 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,
as well as develop systems for larger buildings.
The objective is social benefit, affirms Woelz,
pointing out that each family would save nearly 150 'reais' (75
dollars) a year in energy costs, and the impact on the environment
would be greatly reduced.
* Mario Osava is an IPS correspondent