Technical-economical evaluation of a solar water heater with vacuum tubes collector, used in a rural area in Paran, Brazil

摘要

Solar radiation is a source of energy that can be used directly by residences and industries. In this work, the efficiency of a solar collector type all-glass installed in a rural area in Paraná, Brazil, in the winter period, was evaluated. ?Two daily showers were simulated in three different scenarios, to measure additional electrical consumption used to boost the heating of water. In the first scenario, the consumption was evaluated leaving the auxiliary heating system connected the entire day and, in the second, only in the afternoon period. This auxiliary heating system, controlled by a thermostat, was only connected when the temperature of the water in the boiler stayed below 40°C. In the third scenario, the auxiliary heating system was disconnected and the heating of the water occurred solely due to the solar heating system. These scenarios were compared with the use of the solar heating system together with an electric shower and with an electric shower alone. It was verified that the mean efficiency of the solar collector in the evaluated period was 51%. The electric shower, when used in conjunction with the solar heater, consumes 6.5 times less electrical energy than when used alone (192.55 kWh and 1240.34 kWh, respectively).