Thermodynamic analysis of absorption cooling system with LiBr-Al2O3/water nanofluid using solar energy

Abstract

Together with the developing nano technology, nano-fluids and nano-particles are used as working fluid in energy applications. It is foreseen that nanoparticles have high heat conduction coefficient and it will increase system performance by using as a working fluid in energy systems. Many studies in the literature show that nano fluids increase the heat transfer rate by improving heat transfer. In this study, a performance analysis of an absorption cooling system using solar energy was performed as numerically. LiBr-Al2O3/water nano-fluid has been used in the cooling system as working fluid. The thermodynamic values and calculations used in the analyses were performed with Engineering Equation Solver program. Heat load necessary for the generator is provided with a flat plate solar collector. For different operation condition, the variation of COP values was determined depend on Al2O3/water nanoparticle concentration ratio. When the Al2O3/water nanoparticle concentrations are changed as 0%, 0.5% and 0.1%, it was determined that the COP values increased. Nanoparticles added to the refrigerant at certain concentration values affects the COP values positively of cooling systems. Maximum COP value is 0.86 for 85?C generator temperature and 0.1% Al2O3/water nanoparticle concentration. The lowest COP value was obtained for the 75 oC generator temperature. When the Al2O3/water nanoparticle concentration was increased together with the generator temperature, COP values also increased. When the nanoparticle concentration of the working fluid increases, the viscosity of the nanofluid can be increases. Due to, increased viscosity increases the pressure drop in the flow channel and the pump power required for the flow. Thus, 'minimum viscosity with maximum thermal conductivity' optimisation in applications is very important.

Thermodynamic study of the effects of nanoparticles on thermal origin: A review

“…The basic element of nanomaterials are the nanoparticles, which refer to the particles with dimensions in the nanometers range. They are a novel class of materials that consist of particulate substances, with at least one dimension smaller than 100 [21][22][23]. Nanoparticles can be originated from organic, inorganic or/and combination of natural organic, for instance from living organisms, such as sear salt, pollen, dust, volcanic eruption and erosion particles; incident origin, such as emissions of diesel engine and industrial processes; and engineered particles such as metal, metal oxides, nanotubes, or fullerenes [24][25][26][27][28].…”

Compressor-Aid Absorption Chiller Working on Low Grade Temperature Heat Source: A Thermodynamic Analysis

“…They found that adding a small amount of certain additives can achieve the required improvement. Kilic and Ipek [26] combined Aluminium Oxide (Al2O3) as an additive to the LiBr-Water to flow as nanofluidic refrigerant in absorption chiller, the concentration of the oxide were 0.05% and 0.1%. The results show that the COP increased to 0.86 and The generator temperature is 85℃ at a loadng of 0.1% of the oxide.…”