In Science, you want to say something nobody knew before, in words everyone can understand.

P. Dirac

Advanced Cycles

Thermal services such as refrigeration, air-conditioning, heat pumping, and gas liquefaction are essential to modern societies. Demand for these services continues to grow. Increasingly, these technologies are powered using clean electricity. Conventional heat-work conversion cycles use a fluid undergoing compression and expansion. Alternative approaches with good efficiency, reduced maintenance, and reasonable cost at smaller scales are desired. Such systems should use non-toxic, non-flammable, and environmentally benign working substances.

Calorics

Solid materials can be working substances in heat-work conversion. Solids with a reversible entropy change due to variations in applied fields such as magnetic, electric, or stress are known as caloric materials. A particular cycle is an active regenerator, where the caloric material is used as the thermal matrix. The regenerator is periodically cycled with an applied field variation and thermal regeneration due to flow of heat transfer fluid through the regenerator. With appropriate design and phasing, heat is pumped from a low temperature reservoir to a high temperature or, high temperature heat is converted to work. 

Magnetocalorics

Magneto-caloric materials display a characteristic temperature rise when the applied magnetic field is increased – known as the magnetocaloric effect (MCE). Near the ordering temperature, this temperature change can be highly reversible. Active magnetic regenerator cycles (AMRs) are being explored for use near room temperature and in the cryogenic range.  For the low temperature case, the objective is to develop new approaches to cooling for applications such as superconducting machines and liquefaction of gases such as hydrogen. Research is conducted experimentally, using active magnetic regenerator test apparatuses (AMRTA), numerically, and analytically. We have developed novel room temperature devices using permanent magnets and high-field, superconducting magnet systems.