Heat-driven pumping system

A heat-driven pumping system comprising:

• a closed circuit for a first liquid, the closed circuit comprising the following elements arranged in the following order;
• i) a vaporization portion, ii) a first reservoir, and iii) a second reservoir, the vaporization portion being configured to receive heat from an external source and to cause vaporization of at least some first liquid within the vaporization portion to thereby increase an amount of gas in the closed circuit, wherein the closed circuit is sealed such that the increase in the amount of gas increases a pressure exerted on the first liquid, the first reservoir being arranged below the vaporization portion and below the second reservoir, the second reservoir having has an expandable volume by means of a first displaceable interface with a closed fluid system, the second reservoir being connected to the vaporisation portion by a non-return valve such that the first liquid can flow from the second reservoir to the vaporisation portion but can only flow from the vaporisation portion to the second reservoir via the first reservoir;
• a transfer means comprising the closed fluid system, the closed fluid system having a second displaceable interface with a third reservoir within a pumping vessel, the closed fluid system being configured so that displacement of the first displaceable interface causes a corresponding displacement of the second displaceable interface to convert the pressure exerted on the first liquid into a pumping force which is transferred to the pumping vessel for pumping a second liquid;
• and
• a valve enabling introduction of additional gas into the closed circuit and a valve enabling introduction of additional fluid into the closed fluid system so as to enable pre-setting of a position of a head of the second liquid in a discharge system coupled to the pumping vessel.