Charles Rand

Natural Resources Canada | NRCan · CanmetENERGY

Ejector-based refrigeration systems (ERS) raise a lot of interest, given their lower electrical consumption compared to conventional refrigeration systems. However, a single ejector suffers from a lack of capacity flexibility, while the commercial success of this technology often relies on its ability to handle the fluctuating heating load availabi...

Large quantities of energy are wasted in the form of heat. For a given waste energy source, when its temperature is high enough, a desirable recovery strategy is a first Organic Rankine Cycle (ORC) stage for electricity production, followed by using the remaining available energy, at lower temperature, for either building heating in winter or build...

Many authors have explored the performance of single-phase ejectors. A significant number of studies have focused on the impact of the nozzle head exit position (NXP) on the ejector performance and reported the existence of a single optimal NXP. However, few others found multiple optimal NXP for the same set of operating conditions. Using an experi...

Vapor ejectors raise interest for cooling applications given their low electrical consumption, however, a single ejector suffers from a lack of capacity flexibility. The current study explores the use of an adjustable needle to control the primary nozzle throat area (At) in view to allow variable ejector capacity. Tests were done using a large scal...

The current study explores the performance of an ejector-based refrigeration system (ERS) working with R245fa. The results of a numerical RANS model are compared to those obtained by a thermodynamic model to explain the effect of the nozzle head exit position (NXP) on the model accuracy. The NXP optimal values are determined numerically for fixed p...

The current study explores the performance of a variable geometry ejector (VGE) working with R245fa. The ejector is equipped with a needle that controls the primary nozzle throat area (A t). The nozzle head exit position (NXP) is also adjustable. Three different primary nozzle throat area values are tested: 1.00At , 0.80At , and 0.61At. The perform...

With the progressive ban of HydroFluoroCarbons (HFCs) by 2030 (Regulation No 517/2014), low GWP refrigerants such as Hydrofluoroolefins (HFOs) have gained traction. Ejector heat driven refrigeration cycles (EHDRC) are viable options to reduce carbon emissions as they can use these single-phase refrigerants and be coupled with a renewable energy sou...