Cálculo termodinámico, diseño y construcción de una planta piloto autónoma de 17 kw para el acondicionamiento de espacios utilizando la mezcla naoh-h2o

ABSTRACT Commercial air conditioning systems demand huge amounts of electrical energy for the operation of the compressor. This energy demand negatively affects the environment and the user, due to the economic costs associated with the operation of these systems. This thesis shows the development of an air conditioning system by solar absorption, to cover the thermal load (17.6 kW) of the case study; composed of 5 offices. ACASS (abbreviations in English Air Conditioning Absorption Solar System), is consist by a system of absorption type I and a solar plant of parabolic trough concentrators; which provides the thermal energy required by the absorption cycle. The components of the absorption cycle: Generator, Condenser, Evaporator and Absorber, were calculated considering designs of commercial heat transfer equipment, with the purpose that the air conditioning system by absorption can be reproduced whit devices that they can be found in the market. The 17 thermal kW solar plant consists of 15 parabolic trough concentrators (arranged in 3 lines), 6 safety valves, 2 track systems (automatic and manual) and 2 storage thermotank with a capacity of 300 liters each. The solar plant was evaluated experimentally during the August-December 2017 period, covering an office hours from 10:00 am to 4:00 pm. According to the results, when using water, the maximum registered temperature reached in the thermotank was 94.6 °C. By other hand, using the aqueous solution of ethylene glycol at 30%, the maximum temperature was 97.7 °C. Both temperature values satisfy the thermal energy demand required by the absorption cycle. VI A theoretical analysis was carried out under the following design conditions: TGE= 90 °C, TCO,AB= 35 °C, TEV= 10 °C and QEV= 17.6 kW. The analysis of the COP was made considered the experimental temperatures registered in the thermotanks of the solar plant, in a range of TGE= 85, 90 and 95 °C, keeping constant TEV= 10 °C and TAB,CO= 35 to 45 °C . The calculated maximum COP was 0.74 (dimensionless). During the thermodynamic cycle operation, it is very important to determine the concentration of NaOH in the working mixture (H2O-NaOH), to avoid crystallization problems; for this reason a mathematical correlation that relates the refractive index with the temperature and the concentration of NaOH in an aqueous solution was proposed and validated. The corrosion rate is an important parameter due to the wear that the components of the absorption cycle can present. The analysis was made for 316L stainless steel, in the presence of the H2O-NaOH solution at the operating conditions of ACASS. Finally, CO2 eq emissions between a commercial air conditioning system and ACASS were compared, using the Life Cycle Analysis methodology. According to Solano-Olivares, the installation of ACASS avoids 80.05% of the CO2 emissions eq that a commercial system would emit, which means to stop emitting 342.9 tons of CO2 eq.