Projeto de um sistema de condicionamento de ar com refrigeração por absorção utilizando energia solar como fonte térmica

Abstract

Air conditioning systems by vapor compression refrigeration have becoming increasingly accessible to more people. This fact implies a significant increase in electricity consumption of this equipment. Therefore, there is the opportunity to use alternative sources of energy for air conditioning processes. This work developed a case study related to an air conditioning project-cooled absorption, with the heat source solar energy. The project was developed following specific standards, ASHRAE and NBR 16401. To accomplish this, the building was first defined object of study and subsequently carried out the calculation on the thermal load. Then, using the psychrometric chart, the masses were calculated supply air to be distributed in each environment to achieve thermal comfort. To drive and inflate the air cooled environments has been designed in a network of pipes, accessories and fan. Meanwhile, to perform the air cooling was selected for an absorption refrigerating machine which uses binary solution of water- lithium bromide as working fluid. This equipment is supplied by a heat reservoir at a constant temperature, since any thermal energy generated in the system comes from solar collectors vacuum. This system performs the thermal storage of energy, operating according to the thermal load and the available sunlight. For the interconnection of all equipment, was designed a hydraulic system which includes the selection of pumps and pipe sizing. The project calculation memorial is presented through a spreadsheet containing all relevant calculations in order to illustrate in detail the procedures performed. The case study resulted in an HVAC project that got results in a solar factor of 1.23, featuring energy storage during the project day. It also determined the thermal load density per unit of floor area on collectors. This calculation showed that for every square meter of collector can generate 0.20 kW of cooling in the design condition. Finally, the economic viability of the project was developed through the comparison between the cooling system for absorption and conventional vapor compression system. We carried out the survey acquisition and operating costs of the two systems and found that, although there is a difference in initial investment of R$ 115,822.50, this value is refunded through electricity savings in a period of about nine and a half years.