590
E. Fernández et al.
The operating principle of these devices is to heat water in a tank so that a certain
quantity of hot water is stored and available when needed. Unheated water then flows
into the tank to replace the used water. The thermostat controls the water temperature
in the storage tank, turning on the electrical resistance in order to maintain the desired
temperature inside the tank (Energy Education 2019; Natural Resources Canada’s
Office of Energy Efficiency 2012). DESWHs are equipped with different safety
devices such as a thermal fuse and pressure relief valve. The thermal fuse responds
to temperature, interrupting the electric current when the temperature exceeds a fixed
value. Therefore, it provides protection in case of overheating due to malfunction.
The relief valve is designed to relieve the pressure inside the tank when a fixed
limit is exceeded. The water that flows into the tank generally contains calcium and
magnesium that can precipitate and coat the heating elements and pipe surfaces,
therefore, dropping energy efficiency. We note that not only is the lifespan of the
DESWH reduced, but also it can produce bacterial contamination (Brazeau and
Edwards 2011; Lacroix 1999).
In order to minimize corrosion within the tank, a sacrificial anode rod made either
of aluminium or magnesium alloy is placed into the tank. The anode is consumed
over time so it should be checked regularly and changed when necessary. There is an
insulation between the tank and the outer case, which is usually made of polyurethane
foam or glass wool. Its function is to maintain the temperature of the interior tank,
avoiding as much as possible heat losses through the surface and therefore improving
energy efficiency. The storage tank is usually made of copper or steel. Copper is
malleable and straightforward to work, whereas stainless steel is harder to drill and
welds at higher temperatures requiring more sophisticated manufacturing processes.
Besides, copper has lower rates of corrosion (Armstrong et al. 2014). However,
copper is a much more expensive raw material than steel.
Increase in the use of home appliances in the recent decades has attracted the
attention of governments and civil organizations due to the negative impact on the
environment of discarding these types of products at their end-of-life (EoL), in addition to the shortage of landfill space (Heydari et al. 2017). Technological advances
and the search for greater comfort have caused that the amount of waste from electrical and electronic equipment (WEEE) has increased dramatically. According to
(Balde et al. 2015), the total amount of global WEEE was 47.8 million tons in 2017
and it is expected to reach 50 million tons in 2018. WEEE is the fastest growing waste
stream in many countries of the world. They have a dangerous and toxic nature, and
therefore an adequate EoL management is essential for them. It is estimated that at
least 90% of the materials on these devices can be recovered, such as copper, iron
and plastic. However, nowadays less than 20% of them are handled in a proper way
(Salhofer et al. 2015; Long et al. 2016). Uruguay is one of the countries in the region
that produces more WEEE, with an estimate of 9.5 kilos per year per capita and
only 1.5% of them are recovered (CEMPRE, Electrical and electronic devices (in
spanish). Available at: http://www.cempre.org.uy/index.php?option=com_content&
view=article&id=87&Itemid=105 [Accessed 29 Aug 2019]). In Uruguay, the legal
framework related to environmental management follows global trends in sustainable
E. Fernández et al.
The operating principle of these devices is to heat water in a tank so that a certain
quantity of hot water is stored and available when needed. Unheated water then flows
into the tank to replace the used water. The thermostat controls the water temperature
in the storage tank, turning on the electrical resistance in order to maintain the desired
temperature inside the tank (Energy Education 2019; Natural Resources Canada’s
Office of Energy Efficiency 2012). DESWHs are equipped with different safety
devices such as a thermal fuse and pressure relief valve. The thermal fuse responds
to temperature, interrupting the electric current when the temperature exceeds a fixed
value. Therefore, it provides protection in case of overheating due to malfunction.
The relief valve is designed to relieve the pressure inside the tank when a fixed
limit is exceeded. The water that flows into the tank generally contains calcium and
magnesium that can precipitate and coat the heating elements and pipe surfaces,
therefore, dropping energy efficiency. We note that not only is the lifespan of the
DESWH reduced, but also it can produce bacterial contamination (Brazeau and
Edwards 2011; Lacroix 1999).
In order to minimize corrosion within the tank, a sacrificial anode rod made either
of aluminium or magnesium alloy is placed into the tank. The anode is consumed
over time so it should be checked regularly and changed when necessary. There is an
insulation between the tank and the outer case, which is usually made of polyurethane
foam or glass wool. Its function is to maintain the temperature of the interior tank,
avoiding as much as possible heat losses through the surface and therefore improving
energy efficiency. The storage tank is usually made of copper or steel. Copper is
malleable and straightforward to work, whereas stainless steel is harder to drill and
welds at higher temperatures requiring more sophisticated manufacturing processes.
Besides, copper has lower rates of corrosion (Armstrong et al. 2014). However,
copper is a much more expensive raw material than steel.
Increase in the use of home appliances in the recent decades has attracted the
attention of governments and civil organizations due to the negative impact on the
environment of discarding these types of products at their end-of-life (EoL), in addition to the shortage of landfill space (Heydari et al. 2017). Technological advances
and the search for greater comfort have caused that the amount of waste from electrical and electronic equipment (WEEE) has increased dramatically. According to
(Balde et al. 2015), the total amount of global WEEE was 47.8 million tons in 2017
and it is expected to reach 50 million tons in 2018. WEEE is the fastest growing waste
stream in many countries of the world. They have a dangerous and toxic nature, and
therefore an adequate EoL management is essential for them. It is estimated that at
least 90% of the materials on these devices can be recovered, such as copper, iron
and plastic. However, nowadays less than 20% of them are handled in a proper way
(Salhofer et al. 2015; Long et al. 2016). Uruguay is one of the countries in the region
that produces more WEEE, with an estimate of 9.5 kilos per year per capita and
only 1.5% of them are recovered (CEMPRE, Electrical and electronic devices (in
spanish). Available at: http://www.cempre.org.uy/index.php?option=com_content&
view=article&id=87&Itemid=105 [Accessed 29 Aug 2019]). In Uruguay, the legal
framework related to environmental management follows global trends in sustainable