Read the following statement: The installation of a solar thermal system of course has an investment of $$14\mathrm{.}545.$ The same conventional installation would have cost $$5\mathrm{.}890.$ The energy demand is $17\mathrm{.}200$ kWh$/$year and the solar fraction is $67\%.$ The cost of conventional energy is $ $0\mathrm{.}045/$ kWh the first year, with an expected increase of $6\%$ anually. Calculate amortization period, considering an annual inflation rate of $3\mathrm{.}5\%.$ So$,$ calculate the payback period assuming that for the previous year, the energy cost of the solar installation support system is $$0\mathrm{.}079/$kWh