For domestic solar water heaters, if you want to increase the hot water outlet, you can add a booster pump to the hot water outlet end of the water tank.
A booster pump, as the name suggests, is a pump used to increase pressure. Its main uses are increasing the pressure of water heaters, low water pressure in high-rise buildings, pressurization of saunas, baths, etc. and when the water pressure on the upper floor of an apartment is insufficient. Pressurization, automatic solar boosting, reverse osmosis water purifier boosting, etc.