An Experimental Study on Energy Recovery by a Pelton-Type Expander in a Domestic Refrigeration System

Abstract

A Pelton-type two-phase expander was developed to replace the throttling valve for energy recovery in a domestic vapor-compression refrigeration system. The Pelton-type expander was designed and fabricated based on thermodynamic and mathematical analysis. It consists of two Laval nozzles and one simplified twin-arc blade impeller. A combined expander-generator prototype was validated in a R-410A domestic refrigeration system and demonstrated a stable operation within a wide speed range of up to 26,500 rpm. Experimental results showed the feasibility of integrating the Pelton-type expander into a domestic refrigeration system. A maximum isentropic efficiency of 32.8% was achieved under the experimental conditions. The relationships between the recovery work, the expander efficiency, and the impeller rotational speed were investigated. The results indicated that the velocity ratio was around 0.17 when the recovery work achieved the maximum value. The results also showed that the increase in the cooling capacity by 6.5% and the coefficient of performance (COP) by 5.4% could be obtained under the testing conditions.

An inverse mean-line design method for optimizing radial outflow two-phase turbines in geothermal systems

“…The maximum efficiency was 15.8% and the output power was 32.7 kW. He et al [18] presented twin arc blade impeller for a Pelton type TPIT using R410a as the working fluid. Experimental results showed that the peak efficiency was 32.8% and the maximum rotational speed was 26500 rpm.…”

Comparison between modeling and experiments on a two-stage rotary vane expander for an HFC-410A air conditioning system

“…He et al. 10 coupled a Pelton-type expander with a centrifugal auxiliary compressor and tested the expander-compressor unit in a domestic air conditioning system using HFC-410A as working fluid and reported increases in COP and cooling capacity by 5.4% and 6.5%, respectively. Mahmoud et al.…”

“…The reported maximum turbine efficiency of the single stage turbine expander driven by HCFC-22 two-phase mixture was 52.4% at rotor speed of 1880 r/min and mass flow rate of 1.339 kg/s. He et al 10 coupled a Pelton-type expander with a centrifugal auxiliary compressor and tested the expandercompressor unit in a domestic air conditioning system using HFC-410A as working fluid and reported increases in COP and cooling capacity by 5.4% and 6.5%, respectively. Mahmoud et al 11 proposed comprehensive models regarding the frictional and internal leakage losses of a rotary vane expander in conventional vapor compression refrigeration system without estimating the cycle performance.…”

Choked Flow Characteristics of Subcritical Refrigerant Flowing Through Converging-Diverging Nozzles

“…To reduce this loss, two phase energy recovery expanders [1][2][3][4][5][6][7][8] or ejectors [9][10][11] replacing the throttling valve have been widely investigated. Flashing flow nozzles are the core part of the impulse turbo expander [12][13][14] or ejector. In the nozzles, the potential energy of the incoming high-pressure subcooled or saturated liquid flow is converted to the kinetic energy of the exiting liquid-vapor flow.…”