dc.description | 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. | es_MX |