its depends on desalination capacity and lode used.

According to Wikipedia, there are two methods for solar desalination: Direct and Indirect. In the direct method, a solar collector is coupled with a distilling mechanism and the process is carried out in one simple cycle. Water production by direct method solar distillation is proportional to the area of the solar surface and incidence angle and has an average estimated value of 3–4 liters per square meter (0.074–0.098 US gal/sq ft). Because of this proportionality and the relatively high cost of property and material for construction direct method distillation tends to favor plants with production capacities less than 200 m3/d (53,000 US gal/d).

Indirect solar desalination employs two separate systems; a solar collection array, consisting of photovoltaic and/or fluid-based thermal collectors, and a separate conventional desalination plant]. Production by the indirect method is dependent on the efficiency of the plant and the cost per unit produced is generally reduced by an increase in scale. Many different plant arrangements have been theoretically analyzed, experimentally tested and in some cases installed. They include but are not limited to multiple-effect humidification (MEH), multi-stage flash distillation (MSF), multiple-effect distillation (MED), multiple-effect boiling (MEB), humidification–dehumidification (HDH), reverse osmosis (RO), and freeze-effect distillation.

Indirect solar desalination systems using photovoltaic (PV) panels and reverse osmosis (RO) have been commercially available and in use since 2009. Output by 2013 is up to 1,600 liters (420 US gal) per hour per system, and 200 liters(53 US gal) per day per square meter of PV panel. Municipal-scale systems are planned. Utirik Atoll in the Pacific Ocean has been supplied with fresh water this way since 2010.

Indirect solar desalination by a form of humidification/dehumidification is in use in the seawater greenhouse.

For more information see the paper in:

https://www.solarpaces.org/blueprint-solar-desalination

to get feasible results u can use concentrated thermal solar energy technologies with efficiencies not less than 50%

In my opinion, these factors should be considered:

1. Temperature (evaporation)

2. Existing technology, needing to be optimized (no author is attached)