Power production from low grade heat and waste heat does not only mitigate environmental impact but also improve energy efficiency and reduce energy cost. The type and design of expander for a low grade heat engine are critical and affect the performance, efficiency and cost of low grade heat and waste heat recovery system. The choice of expansion machine is strongly correlated with operating conditions, working fluid and size of the system. Low grade heat and waste heat recovery systems for electricity production are usually smaller in size. Turbines cannot be used due to their high rotational speed and high cost for waste heat and low grade heat recovery systems less than 50 kWe. Therefore, volumetric expanders are more suitable in low grade heat and waste heat engines for a smaller size. The current paper provides a comprehensive review of volumetric expanders including vane expander, screw expander, scroll expander, and piston expander applications for low grade heat and waste heat recovery using organic Rankine cycle. The operational performance, design optimizations, leakage and frictional losses, modeling techniques for each type of expander has been investigated in detail. Technical constraints and operational performance of expanders have been analyzed followed by the comparative assessment based on their performance, current market status, and economics. The comparative assessment shows that screw expander and scroll expander are most suitable having a relative score of 73.6 and 70.4 respectively on a scale of 100. The vane expanders have the lowest score of 47.2 due to low power range, leakage and frictional losses, and technical complexities.

Volumetric expanders for low grade heat and waste heat recovery applications

A comprehensive review of ejector design, performance, and applications

Advances and challenges in ORC systems modeling for low grade thermal energy recovery

A performance analysis of a novel system of a dual loop bottoming organic Rankine cycle (ORC) with a light-duty diesel engine

This paper presents a comprehensive review on research and developments on solar assisted compression heat pump systems, mostly reported during the last two decades. The first part of this paper provides a detailed description of the past efforts on various system configurations, system modeling, enhancement of system performance, modifications in compression heat pump cycles and environment friendly refrigerant options for solar assisted compression heat pump systems. The economical and environmental impacts of solar assisted compression heat pump systems are also described. Further research needs in this important field of solar assisted compression heat pump are listed. The outcomes of this review confirm that, there is a lot of research scope for improving the performance of the system and reducing its initial cost to make it competitive in the global market. The information presented in this paper is shall be highly beneficial for the active researchers working presently on solar assisted compression heat pumps.

Research and developments on solar assisted compression heat pump systems – A comprehensive review (Part A: Modeling and modifications)

Experimental verification of a rolling-piston expander that applied for low-temperature Organic Rankine Cycle

Analysis of a novel combined power and ejector-refrigeration cycle

A thermodynamic analysis of an auto-cascade heat pump cycle for heating application in cold regions

Analysis of a solar Rankine cycle powered refrigerator with zeotropic mixtures

Experimental study on two-phase separation performance of impacting T-junction

Nan Zheng

Papers

Experimental verification of a rolling-piston expander that applied for low-temperature Organic Rankine Cycle

Analysis of a novel combined power and ejector-refrigeration cycle

A thermodynamic analysis of an auto-cascade heat pump cycle for heating application in cold regions

Analysis of a solar Rankine cycle powered refrigerator with zeotropic mixtures

Experimental study on two-phase separation performance of impacting T-junction