Economic analysis of a small-scale hybrid air HDH–SSF (humidification and dehumidification–water flashing evaporation) desalination plant

The economic factor plays an important role in determining the desalination decision. The current work introduces the economic analysis of a small-scale desalination plant. The desalination plant under investigation was based on two different technologies; the first technology is air humidification–dehumidification process while the second one is the water flashing evaporation process. The economic analysis was performed and compared for two different operating modes, the hybrid mode and the separated mode to show both the economic benefits and the feasibility measurement for each mode. The TCO (total cost of ownership) concept was adopted in the analysis. The TCO concept includes different types costs like; the fixed investment costs, the production costs, the internal rate of return on investment, the operating costs, the energy costs and some other economic parameters. The two modes of desalinations; hybrid mode and separated mode, are modeled, simulated and compared against each other. This comparison is held by using the developed design simulation program. Based on the cost of energy in Egypt, the estimated cost of the generated potable water by the hybrid system was 8.6 US$/m3, while that value was reached 9.74 $/m3 for the separated system. The current study showed that, the solar water heater collecting area and the plant lifetime are considered significant factors for reducing the water production cost. Also; the produced water costs decrease with increasing both the collecting area of the solar water heater and the plant lifetime.