Small direct expansion type solar energy heating pump

The invention discloses a small direct expansion type solar energy heating pump. The small direct expansion type solar energy heating pump comprises a heating steam engine. The heating steam engine comprises a housing. The housing is internally provided with a displacer piston and a power piston which are transversely arranged and connected with each other and a heating pipe and a cooling pipe are laid on the outside of the housing. The small direct expansion type solar energy heating pump further comprises a solar heat collection panel, a bearing and a working water tank. A heat transfer pipe of the solar heat collection panel is communicated with the heating pipe through a connecting pipe. The power piston of the heating steam engine is connected to the bearing through a connecting rod. A working piston of the working water tank is connected to the bearing through a connecting rod. A drain pipe and a pumping pipe are mounted at the bottom of the working water tank. The drain pipe is communicated with the cooling pipe. Heating space and cooling space are filled with an organic working medium of isopentane. The small direct expansion type solar energy heating pump pumps underground water by heating the organic working medium with solar energy to expand to drive the pistons to move to output mechanical energy, can continuously pump the underground water for use without using any external energy and is energy-saving, environmentally friendly and renewable.