LiBrH 2O absorption heat pump for single-effect evaporation desalination process

Abstract

A new configuration is presented for the single-effect evaporation process combined with lithium bromide water (LiBrH 2O) solution absorption heat pump. Performance evaluation of the process is presented in terms of variations in the thermal performance ratio, the specific heat transfer area, the specific flow rate of cooling water, and the conversion ratio. These variations are presented as a function of the heating steam temperature, the lithium bromide mass fraction in the concentrated solution, and the temperature difference of the heating steam and the boiling brine. Results show thermal performance ratios of 2.4–2.8, which are higher by 50–70% than those for the single-effect thermal vapor compression system. Operation at higher heating steam temperatures and large temperature difference between the heating steam and the boiling brine is highly attractive due to drastic reduction in the specific heat transfer area and the specific flow rate of cooling water. Also, at these conditions slight reduction occurs in the system thermal performance ratio. In search for low-energy and low-cost production units, the superior performance of high temperature operation for the absorption heat pump single-effect system makes it extremely suitable for adoption by remote and small communities.