Four-process cycle for a Vuilleumier heat pump
AssigneeThermoLift, Inc.
InventorPeter Hofbauer
Life of this patent
Estimating the term…
Abstract
A four-process cycle is disclosed for a Vuilleumier heat pump that has mechatronically-controlled displacers. Vuilleumier heat pumps that use a crank to drive the displacers have been previously developed. However, mechatronic controls provides a greater degree of freedom to control the displacers. The four-process cycle provides a higher coefficient of performance than prior cycles in the crank-driven Vuilleumier heat pump and those previously disclosed for a mechatronically-driven Vuilleumier heat pump.
Claims11
A method to operate a heat pump, the heat pump having a hot displacer adapted to reciprocate within a hot cylinder and a cold displacer adapted to reciprocate within a cold cylinder wherein the hot displacer has a remote position and a central position within the hot cylinder and the cold displacer has a central position and a remote position within the cold cylinder, the method comprising:
- actuating the hot displacer to move from its central position to its remote position;
- actuating the cold displacer to move from its central position to its remote position;
- actuating the hot displacer to move from its remote position to its central position;
- and
- actuating the cold displacer to move from its remote position to its central position wherein:
- the actuations occur in the given order
- movement of the hot displacer from its central position to its remote position comprises a first period;
- movement of the cold displacer from its central position to its remote position takes a second period;
- the hot displacer remains stationary in its remote position for greater than the second period before starting to move to its central position;
- the actuating the hot displacer to move from its central position to its remote position comprises process one;
- the actuating the cold displacer to move from its central position to its remote position comprises process two;
- the actuating the hot displacer to move from its remote position to its central position comprises process three;
- the actuating the cold displacer to move from its remote position to its central position comprises process four;
- and
- a cycle comprises:
- process one followed by process two followed by process three followed by process four.
A heat pump, comprising:
- a hot displacer disposed in a hot displacer cylinder;
- a cold displacer disposed in a cold displacer cylinder;
- a hot displacer actuator which when actuated causes the hot displacer to reciprocate between remote and central positions within the hot displacer cylinder;
- and
- a cold displacer actuator which when actuated causes the cold displacer to reciprocate between remote and central positions within the cold displacer cylinder;
- an electronic control unit (ECU) coupled to the hot displacer actuator and the cold displacer actuator, wherein:
- the ECU commands the hot displacer and cold displacers to move through a series of arrangements:
- a first arrangement in which the hot displacer is at its central position within the hot displacer cylinder and the cold displacer is proximate its central position with the cold displacer cylinder;
- a second arrangement in which the hot displacer is at its remote position within the hot displacer cylinder and the cold displacer is proximate its central position with the cold displacer cylinder;
- a third arrangement in which the hot displacer within the hot displacer cylinder is at its remote position and the cold displacer is proximate its remote position within the cold displacer cylinder;
- and
- a fourth arrangement in which the hot displacer is at its central position within the hot displacer cylinder and the cold displacer is proximate its remote position within the cold displacer cylinder;
- wherein;
- the ECU commands the hot displacer to remain stationary in its remote position for a period significantly longer than it takes for the cold displacer to move from the second arrangement to the third arrangement before commanding the hot displacer to attain the fourth arrangement;
- and
- the ECU commands the hot displacer to remain stationary in its central position for a period longer than it takes for the cold displacer to move from the fourth arrangement to the first arrangement before commanding the hot displacer to attain the second arrangement.
Dependencies are inferred from the claim text.