Potassium Formate Thermophysical Characterisation

Characterisation of the desiccant solution’s thermophysical properties is essential for accurate modelling of the dehumidifier and regenerator, and for experimental evaluation of the desiccant system. The density and specific heat capacity are

a Density and b specific heat capacity plots of CHKO2 solution

Fig. 3.5 a Density and b specific heat capacity plots of CHKO2 solution

a Thermal conductivity and b dynamic viscosity plots of CHKO2 solution

Fig. 3.6 a Thermal conductivity and b dynamic viscosity plots of CHKO2 solution

shown in Fig. 3.5 and the thermal conductivity and dynamic viscosity are shown in Fig. 3.6. The data presented is for a temperature of 10-50 °C and solution mass concentration of 0.2-0.8 as this is the typical working range in a liquid desiccant air conditioning system. The CHKO2 thermophysical property plots presented are linear regression curve fits to published empirical data from Melinder (2007). The coefficient of determination (r2) is provided to demonstrate the fit between the statistical model and empirical data. The linear regression curve fit functions are provided in Appendix A (A1.2).

Section 3.2 has assessed three desiccant solutions, and has justified the selection of CHKO2, based on a variety of criteria as the desiccant working fluid for the fuel cell tri-generation system. The operating conditions of the liquid desiccant solution in the dehumidifier have been selected as 20-30 °C at a solution mass concentration of 0.65-0.7, as this provides good performance over a range of climatic conditions. As highlighted in Chap. 2, there is limited published and available literature within the public domain regarding the specific physical characterisation of the CHKO2 solution for liquid desiccant air conditioning applications. The work presented in Sect. 3.2 provides a contribution to knowledge with the assimilation of various sources of data to physically characterise the CHKO2 solution in the required operating range for a liquid desiccant air conditioning application. The routines and curve fit functions can be referred to in Appendix A. Validation of the CHKO2 dehumidifier/regenerator simulations with experimental results in Sect. 6.3 demonstrates the accuracy of the physical characterisation data presented. Next, Sect. 3.3 presents the equations and modelling procedure for accessing the dehumidifier and regenerator heat and mass exchangers.

 
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