Figure 1
a) Access to electricity (% of population) in 2022 (IEA, 2023), b) Direct normal irradiation in Africa (Solargis, 2021).
Figure 2
SORC schematic diagram.
Figure 3
Sollar collector types (Delcea and Bitir-Istrate, 2021; Dickes et al., 2025).
Figure 4
Expander types (Alshammari et al., 2018; Quoilin et al., 2012).
Figure 5
Scroll compressor types for expander modifications (Song et al., 2015).
Figure 6
a) Before and after the removal of the check valve, b) Orbiting scroll and bearings.
Table 1
Scroll expanders converted from scroll compressors used in studies.
| STUDY | EXPANDER TYPE | WORKING FLUIDS | OVERALL EFFICIENCY (%) | ISENTROPIC EFFICIENCY (%) | ROTATIONAL SPEED (RMP) | ENERGY PRODUCED (KW) |
|---|---|---|---|---|---|---|
| Manolakos et al., (2007) | Scroll expander (Sander TRS 105) | HFC-134a | 4 | 10–65 | 2000 | 2.05 |
| Peterson et al., (2008) | Scroll expander | R123 | 7.2 | 45–50 | 600–1400 | 0.187 – 0.256 |
| Saitoh et al., (2007) | Scroll expander | R113 | 7 (based on solar radiation) | 65 | 1800 (optimal) | 0.450 |
| Galloni et al., (2015) | Scroll expander (Air Squared model E15H22N4.25L) | R245fa | 9.3 | 84.9 | 3000 | 1.17 |
| Campana et al., (2019) | Scroll expander (SANDEN TRS090) | R245fa | 3 | 45 | 200–1500 (optimal 1000–1200) | 0.450 |
| Collings et al., (2019) | Scroll expander (E15H022A-SH) | R245fa | 8.64 (regenerative); 5.37 (non-regenerative) | 74.5 (regenerative); 68.3 (non-regenerative) | – | 0.650 |
Table 2
Case study summaries.
| STUDY | CLIMATE/LOCATION | ENERGY PRODUCED | SOLAR | WORKING FLUID | EXPANDER TYPE | APPLICATION |
|---|---|---|---|---|---|---|
| Derbal-Mokrane et al., (2021) | Algeria/Mediterranean climate | 2.24 kW to 8.74 kW | PTC | enzene | Turbine | Hydrogen production |
| Piñerez et al., (2021) | Colombia/Tropical climate | Up to 5.50 kW | ETC | Toluene | Turbine | Off-grid power generation |
| Quoilin et al., (2011) | Lesotho/Temperate climate | 3 kW | PTC | R245fa | Scroll | Off-grid power generation |
| Manolakos et al., (2009) | Greece/Mediterranean climate | 2.83 (cloudy day), 5.98 kW (sunny day) | ETC | HFC-134a | Scroll | RO desalination |
| Roumpedakis et al., (2020) | South-East Mediterranean region (Athens, Thessaloniki, Istanbul, Larnaca)/Mediterranean climate | <5 kW | FPC, ETC, PTC | R245fa (several tested) | Scroll | Off-grid power generation |
| Ramos et al., (2018) | Southern European area/Mediterranean climate | 1.72 kW | FPC, ETC | R245fa, R1233zd | Turbine | Domestic solar thermal systems |
| Mavrou et al., (2015) | Greece/Mediterranean climate | 1 kW | FPC | Binary mixture | Turbine | Power generation |
| Baral et al., (2015a) | Busan, South Korea/Humid subtropical climate | 0.4–1.38 kW during the year | ETC | R245fa | Scroll | Off-grid power generation |
| Tchanche et al., (2009) | Bamako, Garoua, Bangkok/Tropical savanna climate | 2 kW | Not specified | R134a (several tested) | Micro-turbine | Not specified |
| Calise et al., (2015) | Mediterranean climate | 6 kW | ETC | n-pentane | Turbine | residential users (DHW) |
| Tchanche et al., (2010) | Greece/Mediterranean climate | Up to 2 kW | ETC | R134a, R245fa, R600 | Not specified | RO desalination |
| Facão et al., (2008) | Spain, Tunisia, Egypt/Mediterranean, hot semi-arid, hot desert climates | 5 kW | FPC, CPC, PTC | Several tested | Turbine | Residential use |
| Wang et al., (2010) | China/Temperate climate | 1.73 kW | ETC, FPC | R245fa | Rolling-Piston Expander | Off-grid power, RO desalination |
| Gilani et al., (2022) | Cyprus/Mediterranean climate | 3.92 kW | ETC | Isobutene | Turbine | Air conditioning for office building |
| Taccani et al., (2016) | Italy/Mediterranean climate | 670 W | PTC | R245fa | Scroll | Power generation |
| Fatigati et al., (2022) | Italy/Mediterranean climate | 100 – 500 W | FPC | R245fa | Scroll | DHW |
| CPC | Compound Parabolic Collectors |
| CPG | Centralised Power Generation |
| DHW | Domestic Hot Water |
| ETC | Evacuated Tube Collectors |
| EFCs | Evacuated Flat Plate Collectors |
| FPC | Flat Plate Collectors |
| GWP | Global Warming Potential |
| HVAC | Heating, Ventilation, and Air Conditioning |
| ORC | Organic Rankine Cycle |
| PTC | Parabolic Trough Collectors |
| PV | Photovoltaic |
| R&D | Research and Development |
| RO | Reverse Osmosis |
| SDG | Sustainable Development Goals |
| SORC | Solar Organic Rankine Cycle |