Regenerator construction and structural design for enhanced performance in vuilleumier heat pumps

#The term “thermal energy” refers to a number of physical concepts. In thermodynamics, heat is energy transferred to or from a thermodynamic system by mechanisms other than thermodynamic work or transfer of matter. Such heat energy transfer occurs during a number of different known thermodynamic cycles. Example thermodynamic cycles in which such heat energy transfer occurs include the Vuilleumier cycle in a Vuilleumier heat pump and the Stirling cycle in a Stirling engine.

#Regenerators are a part of the common functionality in Stirling and Vuilleumier cycles. The Vuilleumier heat pump, a highly efficient thermodynamic system, relies heavily on the performance of its regenerators. These regenerators play a key role in the thermodynamic cycle by acting as “thermal capacitors” to store and deliver heat to the working fluid traveling through them. For instance, chambers of a Vuilleumier heat pump are able to maintain a temperature differential to drive a Vuilleumier cycle and a regenerator stores excess or unused thermal energy as the working fluid moves back and forth between the chambers. In playing such a critical role in the cycle, the design and fabrication of the regenerator must be very intentional to ensure optimal performance. Current regenerator designs face significant challenges that impede their efficiency and effectiveness.

#The present disclosure is directed to multiple embodiments of a regenerator that can be used in various heat engine systems and heat pump systems to perform different thermodynamic cycles. Some embodiments include a hot regenerator, while others include a cold regenerator. The regenerator embodiments can each store and deliver thermal energy to a working fluid and maintain a temperature difference between hot and cold chambers. The regenerators can each be embodied and implemented as a radially insulated regenerator having at least one of an insulation layer or a porous layer positioned between an inner liner and a bulk matrix material of the regenerator. The porous layer can have a lower porosity compared to that of the bulk matrix material to reduce flow and heat transfer near the regenerator's inner liner.

#Many aspects of the present disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, with emphasis instead being placed upon clearly illustrating the concepts of the disclosure. Moreover, repeated use of reference characters or numerals in the figures is intended to represent the same or analogous features, elements, or operations across different figures. Repeated description of such repeated reference characters or numerals is omitted for brevity.

#FIG. 1A illustrates a perspective view of an example regenerator device in accordance with various aspects and embodiments of the present disclosure.

#FIG. 1B illustrates a cross-sectional side view of the example regenerator device shown in FIG. 1A in accordance with various aspects and embodiments of the present disclosure.

#Regenerators are a part of the common functionality in Stirling and Vuilleumier thermodynamic cycles. Regenerators generally include a bulk matrix material with a large surface area to volume ratio. The bulk matrix material is typically a porous material, stacked wire mesh, or a microchannel design. The porosity of the bulk matrix material is specifically designed to optimize a low pressure drop requirement and still have enough surface area exposure to have sufficient heat transfer in the exchanger. Regenerators are considered regenerative heat exchangers where a working fluid such as gas flows through the heat exchanger in alternating directions to deposit heat or gain heat.

#The Vuilleumier heat pump, a highly efficient thermodynamic system, relies heavily on the performance of its regenerators. These regenerators play a key role in the thermodynamic cycle by acting as “thermal capacitors” to store and deliver heat to the working fluid traveling through them. For instance, hot and cold chambers of a Vuilleumier heat pump are able to maintain a temperature differential to drive a Vuilleumier cycle and a regenerator stores excess or unused thermal energy as the working fluid moves back and forth between the chambers. In playing such a critical role in the cycle, the design and fabrication of the regenerator must be very intentional to ensure optimal performance. Current regenerator designs face significant challenges that impede their efficiency and effectiveness. Among these challenges are non-uniform matrix structures, bypass issues, and thermal insulation issues.

#Non-uniform matrix structures often due to imperfections in a regenerator matrix can lead to non-uniform flow distribution. This inconsistency in flow can cause significant drops in performance, as it results in inefficient heat transfer and uneven temperature gradients.