Vapor Pressure of Aqueous HCOOK Solution as Working Fluids of an Absorption Heat Transformer at High Temperature

Abstract

Aqueous potassium formate solution is regarded as a potential working fluid of an absorption heat transformer (AHT) because of its noncorrosive and biodegradable characteristics. The vapor pressure of working fluids is an important property for application in an absorption cycle. However, current experimental data are mostly limited to temperature and concentration ranges that are suitable for a dehumidification system. Thus, more accurate data of vapor pressure are anticipated. In this paper, the equilibrium vapor pressures of aqueous HCOOK solution were measured with a static method in the temperature range from 323.15 to 373.15 K. The mass concentration of HCOOK varied from 10 to 70%. The measured data were compared with the estimated values of a referenced chemical engineering property database (Aspen Plus). A relatively large mean absolute relative deviation (MARD) of 13.27% was found. The data were then correlated with a modified Antoine equation, and the MARD was reduced to 0.45%. The thermodynamic performance of aqueous HCOOK solution for AHT was estimated for a typical cycle.

Experimental Research on the Vapor Pressures of CaCl2–H2O and MgCl2–H2O as Working Fluids of Absorption Heat Transformers at High Temperature

“…As shown in ref , the AARD for vapor pressures of water and NaCl solution were 0.72 and 0.74%, respectively. The maximal RD for vapor pressures of water and NaCl solution were −1.38 and 1.78%, respectively.…”

“…The validation of the apparatus was conducted in our previous work in which the relative deviation (RD) and average absolute relative deviation (AARD) were chosen to evaluate the accuracy of data for validation purpose: …”

“…According to previous studies, the air and volatile impurities dissolved in solution would lead to considerable errors in the measurement of the vapor pressure. − Therefore, it is necessary and crucial to degas the solution. A common degassing method is to freeze the solution at extremely low temperature and vacuum it. − In the experiment, aqueous solution was cooled by liquid nitrogen. When the solution was frozen completely, the valves were opened and the vacuum pump was started to remove the released gas.…”

Modelling and performance analysis of a single stage open absorption heat pump system in aspen plus using aqueous LiBr and HCOOK: A waste moist heat recovery application

“…In order to verify the properties results for HCOOK/H 2 O, results obtained by ASPEN PLUS has been compared with experimental data presented by Shaozhi et al, 45 and Pallavi et al as shown in Figure 4. A similar trend of properties results can be seen in both plots with experimental data but there is an average of 4.7% and a maximum 10.44% error with respect to Shaozhi et al 45 It can be seen that there is more deviation in ASPEN results at lower temperature as compared to higher temperature. While in comparison to the experimental data presented by Pallavi et al, 46 ASPEN results were found to be in good agreement with an average of 4.9% error and a maximum of 5.57% error.…”

“…In order to verify the properties results for HCOOK/H 2 O, results obtained by ASPEN PLUS has been compared with experimental data presented by Shaozhi et al., 45 and Pallavi et al. as shown in Figure 4.…”