AvaliaÃÃo econÃmica da substituiÃÃo de um chiller de compressÃo por um chiller de absorÃÃo alimentado por coletores solares com base em mediÃÃes em um prÃdio da Chesf em Recife

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The perspective of rising costs for electrical energy and fossil fuels, together with more efficient solar colectors and absorption chillers, stimulates for the retaking of the analisys towards the utilization of solar refrigeration systems, mainly in regions with good insolation characteristcs, like Northeast Brazil . Considering this context, this document presents an economic assessment where two options of water chiller are compared to substitute the existing chiller of the central air conditioning of a Chesf building in the city of Recife: the conventional one, by compression, and the solar refrigeration using absorption chillers. The capacity of the system is 200 RT. The thermal load of the building was estimated through the following mesurements in the existing chiller: electrical energy consumed during the year and the thermal power produced by the evaporator. The thermal power was determined by measuring evaporator input and output temperatures and the flow of the chilled water. These data, together with equipment catalog informations, were used to estimate the coefficient of performance (COP) of the existing chiller and the thermal load of the building during the year. To choose the new chiller, a computer model was developed, which using the historical data from insolation and temperature from the city, the building thermal load (determined as explained above), the equipment performance parameters and the control strategy of the systems, determines the electrical energy annual consumption, hourly based, of the new system. After this, considering the electrical energy tariff, the acquisition, instalation, operation and maintenance costs, the model calculates the net present value (NPV) and the internal tax of return (ITR), taking into account the whole life cicle of the system. It was performed an evaluation of NPV and ITR sensitivity to variations of several parameters values. The most important parameters observed were: solar colectors costs, electrical energy tariff, building thermal load, chillers COP and local insolation. It can be concluded that for the present conditions in the building analysed, the solar system is not economically feasible, but, the rising electrical energy tariffs, the reduction of collectors costs and greater thermal loads could make the solar systems reach the economical feasibility. Additionaly the results showed that, in the northeast semi-arid areas, the conditions are more favourable than in Recife: the solar systems could be feasible, for example, even with the present costs of the solar collectors

ASSUNTO(S)

engenharia mecÃnica absorption chiller refrigeraÃÃo por absorÃÃo engenharia mecanica energy conservation refrigeraÃÃo solar solar refrigeration

ACESSO AO ARTIGO

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