Novel Energy Recovery Architecture for Hydraulic Elevators

Achievement date: 

Researchers at the Center for Compact and Efficient Fluid Power (CCEFP), an NSF-funded Engineering Research Center (ERC) headquartered at the University of Minnesota, have conceived a novel hydraulic system for elevators. A central element of the system is its energy recovery architecture (see figure). 


This innovative architecture offers significant improvement in the state-of-the art for efficiency of hydraulic elevators, which are supported by hydraulic-driven pistons. It also offers potential to reduce loss of market share for hydraulic elevators.   


Hydraulic elevators suffer from high inefficiencies due to fluid throttling (regulating the flow of fluid)or costly mechanical-to-electric energy conversion—both currently required for proper elevator control—and, along with continuous improvement of traction elevators (supported by cables), these problems have caused a loss of market share for the hydraulic elevator. This novel energy recapture approach would bypass the throttling issue entirely and minimize electromechanical conversion inefficiencies.


The energy recapture system uses a hydraulic transformer to bypass throttling and require minimal electromechanical energy conversion. Simulation results of the novel system show promising efficiency improvements when compared to the same operation of existing systems (manuscript in preparation); algorithms for effectively controlling the architecture have also been developed.