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. The four-process cycle can be drawn out to provide a low demand condition by causing both displacers to remain stationary for a period of time. The four processes in which one of the displacers is commanded to move are separated by periods of inactivity in which both displacers remain stationary.
Claims16
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 within the hot cylinder;
- actuating the cold displacer to move from its central position to its remote position within the cold cylinder;
- actuating the hot displacer to move from its remote position to its central position within the hot cylinder;
- and
- actuating the cold displacer to move from its remote position to its central position within the cold cylinder wherein the actuations occur in the given order, wherein:
- the hot and cold displacers both remain stationary for a selectable dwell period between the actuating the hot displacer to move from its central position to its remote position within the hot cylinder and the actuating the cold displacer to move from its central position to its remote position within the cold cylinder;
- and
- the selectable dwell period is based on an input signal indicative of demand for one of heating and cooling.
A heat pump, comprising:
- a hot displacer disposed in a hot displacer cylinder, the hot displacer has a remote position and a central position within the hot displacer cylinder;
- a cold displacer disposed in a cold displacer cylinder, the cold displacer has a remote position and a central position within the cold displacer cylinder;
- and
- a housing in which both the hot and cold displacer cylinders are located;
- wherein:
- the hot displacer and the cold displacer 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;
- 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;
- the hot and cold displacers remain stationary between the first and second arrangements for a predetermined time.
A method to operate a heat pump, wherein:
- the heat pump has a housing having:
- a hot displacer cylinder and a cold displacer cylinder disposed therein;
- the hot displacer cylinder has a hot displacer disposed therein with the hot displacer having a central position and a remote position within the hot displacer cylinder;
- the cold displacer cylinder has a cold displacer disposed therein with the cold displacer having a central position and a remote position with the cold displacer cylinder, the method comprising:
- commanding the hot displacer to move from its central position to its remote position within the hot cylinder which comprises process one;
- commanding the cold displacer to move from its central position to its remote position within the cold cylinder which comprises process two;
- commanding the hot displacer to move from its remote position to its central position within the hot cylinder which comprises process three;
- and
- commanding the cold displacer to move from its remote position to its central position within the cold cylinder which comprises process four, wherein:
- a cycle comprises process one followed by process two followed by process three followed by process four, the method further comprising:
- commanding the hot and cold displacers to both remain stationary for a selectable dwell period between the first and second process.
Dependencies are inferred from the claim text.