Estudo de um trocador de calor geotérmico para água de condensação de um sistema de ar condicionado central, nas condições de solo de Santa Maria, RS

Abstract

Commercial buildings are increasingly dependent on air conditioning systems, which impact on the cost of their energy. Condensation water systems are more energy efficient than the air condensation systems, yet require more rigorous maintenance procedures and their cooling towers have water loss by evaporation. The utilization of geothermal capacitors wil avoid these problems and brings energy efficiency, as the lower water temperature is the external heat exchanger, the lower is energy need by the compressors. Geothermal capacitors are widely used in the US, Europe and Asia, including tax incentives for its better energy efficiency. In those places there are specific air conditioning machines for geothermal systems. The simulation using geothermal system in a commercial building in Santa Maria, with heat load calculation update results in gain of 31.73% in installed capacity of air conditioners, compared to existing machines. The land area was not enough for full utilization of geothermal condensers, so for new setting is selected geothermal exchanger closed loop, with horizontal tubes and a open cycle, taking water from aquifer. Made a comparison of the existing system, using cooling tower only, configurated for new thermal load and resulted in a reduction of 2.08% in available capacity of air conditioning, 4.15% in the installed electrical power. Air conditioners operating with geothermal external heat exchanger have 11.30% reduction in electrical current in relation to the heat exchanger cooling water tower and 18.40% in relation to the air heat exchanger. For configuration with geothermal exchanger is possible to eliminate the use of treated water for replacement of losses of water through the cooling tower, using water from aquifer to it, but are required to add pumps to get water from aquifer and other for horizontal closed loop buried in the soil.