PRODUCTS

Regenerators
Delivering system performance improvements.

Models and tests results show that cryocooler and Stirling engines efficiencies are increased by over 20% and in some case by over 300% when Mezzo micro-channel regenerators are used. These benefits can be utilized to improve the cooling capacity and cold head temperature of an existing cryocooler, or to replace an existing cryocooler with a smaller, lighter unit of equal performance.

Benefits:
  • High heat transfer area
  • High wall-to-gas heat transfer
  • Low axial conduction
  • Low pressure drop loss
  • High heat capacity
  • Low dead (void) volume
 

Product Description: 

Mezzo uses its advanced micro-manufacturing technology to fabricate high performance regenerators for cryocoolers and stirling engines. Our advanced regenerators offer substantial performance improvements over traditional wire mesh screens or packed beds of spheres.  

Mezzo Technologies custom designs and builds its regenerators to fit your needs. Advanced manufacturing technology allows Mezzo to fabricate regenerators with a unique micro-feature design that results in lower pressure drop, higher heat transfer, and higher thermal capacity. The increased performance and reliability of Mezzo’s regenerator will add value to your entire cooling or power system. 


The disks can be constructed from the following materials:
  • Rare-earth metals (such as Er)
  • Most metals including: Stainless steel,Ni, and lead.
  • High temperature metal alloys.

Applications & Types:
  • Cryocoolers
  • Stirling engines
   

Performance

Improving the performance of regenerators requires maximizing heat transfer from the gas to the regenerator, while at the same time minimizing the pressure drop across the regenerator. The heat transfer versus pressure drop feature of a regenerator is primarily a function of the regenerator type and the flow rate of the gas. Ruhlich and Quack have proposed the ratio of “Number of Pressure Heads pressure drop (NPH) to Number of Heat Transfer Units (NTU)” as a measure of regenerator performance where f is the friction factor and j represents heat transfer in the system.

 
Equation 1  
 
Equation 2  
 
Equation 3  

In the above equations, DP is the pressure drop across the regenerator, U the gas flow velocity, Dh the hydraulic diameter of the matrix material, L the length of the regenerator, r the gas density, Nu the Nusselt number, Re the Reynolds number, and Pr the gas Prandtl number. A plot of NPH/NTU for typical heat transfer systems is shown in the figure below. 



Increased Reliability
The monolithic construction of the micro-channel regenerators offer increased reliability and performance.  (More detail)

How It Works:
  • The building blocks of Mezzo regenerators are micro-channel discs. Which have channel and wall dimensions on the order of .0005” to .002”. The small channel passages offer high surface and heat transfer characteristics while maintaining a low pressure drop.   
  • The micro-channel disks are aligned and stack together to form a full regenerator. 
  • The individual disks are aligned to form a continuous flow path, and alignment is maintained by a pin that slips into an alignment hole built into the regenerator disks.

The building block of Mezzo regenerators is a stack of high porosity thin disks. 

Each disk is identical and can be aligned to form continuous passages through the regenerator.