Solar driven power unit

A power unit comprising a double acting vapour pressure actuated motor, a first pump, a mechanical coupling between the motor and first pump, a condenser, an evaporator, conduits and valves interconnecting said evaporator, motor, first pump and condenser in a closed thermodynamic circuit, and a fluoro-carbon refrigerant fluid in both liquid and vapour phases contained in the circuit, such that heating the liquid phase in the evaporator causes evaporation of the vapour at pressure which in turn applies pressure to one side of the motor and thereby actuates the motor, actuation of the motor effecting exhaustion of vapour from the other side of the motor into the condenser wherein the vapour is condensed, and then pumped as liquid by the first pump from the condenser, and through the evaporator to complete the fluid thermodynamic cycle,

• the unit also comprising a second pump being an hydraulic pump, an hydraulic motor, hydraulic conduits and valves coupling the second pump and hydraulic motor in hydraulic circuit, and a mechanical coupling between the vapour pressure actuated motor and the hydraulic pump such that operation of the vapour pressure actuated motor also causes operation of the hydraulic pump and consequential operation of the hydraulic motor.