leili garousi farshi

The growing trend of human society's need for energy consumption and the problems in energy production, leads to paying attention of researchers to recycle and improve the quality of waste heat sources. In this regard, an absorption heat transformer is one of the most attractive energy-saving technologies. Also, the loop heat pipe is a simple device that is able to transfer heat over long distances.Using the loop heat pipe as heat exchangers inside the absorption heat transformer system can lead to improving its performance. Therefore, it is necessary and important to assess the feasibility and effect of using the loop heat pipe in the absorption heat transformer system. In this study, at first, both of the mentioned systems were analyzed and validated separately from the thermodynamic point of view. Then, the thermodynamic analysis of the absorption heat transformer system integrated with the loop heat pipe was done and its performance was compared with the conventional absorption heat transformer cycle. All investigations are done in the EES software and the working fluid of the cycle is LiBr-H2O. The results show that the COP and ECOP of the combined cycle are higher than the conventional absorption heat transformer cycle.

In this article the effect of using ejector on the thermodynamic performance of the hybrid heat pump is evaluated. With simulation of the new hybrid-ejector heat pump in the EES software, first the effect of the ejector mixing section diameter on the results is analyzed and it is concluded that a diameter of about 15mm makes the primary energy ratio (PER, the ratio of useful thermal energy output to the total initial heat energy input) and second law efficiency of the heat pump to be maximum and the exit temperature of the compressor to be minimum. Next, PER, second law efficiency and the compressor exit temperature of new heat pump are compared with those of the conventional hybrid heat pump at the same amount and temperature of the input heat. The results showed that the PER and second law efficiency of the new layout is maximum 10 percent and about 18 percent higher than those of the hybrid cycle respectively. It is also observed that with considering the restriction in compressor exit temperature, in new system, it is possible to increase the temperature of input heat 35C more compared to the increase that can be occurred in the hybrid system. Finally, the analysis of the relative exergy losses in the components of the systems revealed that in the new layout, the relative exergy losses of throttling valve, desorber, compressor and absorber were reduced and improved the performance of this cycle.