Multi receiver concentrator photovoltaic testing at extreme concentrations

Kessel, Theodore van; Abduljabar, Ayman; Alyahya, Abdulaziz; Alyousef, Badr; Badahdah, Alhassan; Khonkar, Hussam; Kirchner, P. D.; Martin, Yves; Manzer, Dennis G.; Moumen, N.; Prabhakar, Aparna; Picunko, Thomas; Sandstrom, R. L.; Al-Saaedi, Yaseen; Wacaser, Brent; Guha, Supratik

doi:10.1109/pvsc.2010.5616784

Cited by 4 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Research regarding ORCs has been carried out since the late 1970's and restarted with the recent development of latent heat storage technologies [8] and new applications (i.e. HCPV systems [2]). …”

Section: Solar-driven Orc Systemsmentioning

confidence: 99%

“…This cost is particularly low for rural areas when compared to traditional power station and distribution networks. Another emerging solar energy conversion technology is to use high-concentration photovoltaics (HCPV), which make use of concentrating optics to focus the suns radiation onto a small, highly efficient photovoltaic cell and convert the energy received from the sun directly into electricity [2]. With high solar concentrations, considerable heat is generated on the photovoltaic cell.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of a Compact Organic Rankine Cycle Prototype for Low-grade Transient Solar Energy Conversion

Higgo¹,

Zhang²

2015

Energy Procedia

View full text Add to dashboard Cite

Many people in rural regions of the world do not have access to electricity although they have abundant supplies of sunlight. An off-grid system to cheaply convert this solar energy into electricity could improve the lives of millions of families. Waste heat from high-concentration photovoltaic arrays and solar energy from evacuated tube collectors are potential sources of abundant low-grade thermal energy. An Organic Rankine Cycle (ORC) is able to convert low-grade thermal energy into electricity at a relative low cost. While traditional ORCs rely on stable thermal energy inputs (i.e. geothermal energy), solar energy is not able to provide a constant supply of thermal energy. Understanding how transient solar fluctuations affect ORC performance is crucial to the development of high-performance, stable and stand-alone solar-driven ORC systems and further integration with heat storage units. In this work, an experimental ORC testbed was designed and fabricated for small-scale low-grade thermal energy utilization for transient characterization. Of particular interest in this work is the behavior of the ORC system as it approaches the operational limits. When the mass flow rate in the cycle is too high or the thermal energy input too low, the balance of the system is disturbed and strange oscillations are encountered. This work focuses on gaining a deep understanding of this abnormal behavior and its influence on ORC performance. The physical phenomena that bring about these changes in an evaporator and their effect on ORC's moving components (i.e., diaphragm pump and scroll expander) are studied and characterized. A qualitative description of the phenomena is proposed and used to describe the changes within the cycle as a result of the imbalance. Once the individual processes in the oscillations are identified, quantitative analysis is carried out to better characterize the entire cycle. This characterization may be used to predict when the heat source conditions would lead to oscillations in ORCs and the magnitude of the reactions. These oscillations hinder the ORC performance and may even cause damage to the moving components under certain circumstances. Revealing the physical mechanism of oscillations helps attain advanced design and energy-efficient operation of ORCs under transient thermal energy supplies, particularly solar. Cycle modifications such as heat storage units are also discussed to coping with transient solar energy inputs and night-time operation.

show abstract

Section: Solar-driven Orc Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of a Compact Organic Rankine Cycle Prototype for Low-grade Transient Solar Energy Conversion

Higgo¹,

Zhang²

2015

Energy Procedia

View full text Add to dashboard Cite

show abstract

“…Significant efforts have been undertaken to im prove the power production of solar CPV systems. For CPVs, high concentrations are advantageous because the open circuit voltage increases with flux, which results in higher conversion efficiencies [2]- [5]. In general, miniaturized high concentration photovoltaics allow for the replacement of a large area of expensive solar cell material by lower cost concentrating optics [4], [5]; and HCPV cells with higher solar-electric conversion efficiency could comprise a fraction of the capital investment [I].…”

mentioning

confidence: 99%

Design of a microscale organic Rankine cycle for high-concentration photovoltaics waste thermal power generation

Zhang¹,

Wang

2012

13th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

View full text Add to dashboard Cite

High-concentration photovoltaics (HCPV) is a highly promising technology to directly convert plentiful solar en ergy to electricity. However, even for the most advanced HCPVs, about 60% of the concentrated solar energy is rejected as waste heat; therefore, it is desirable to utilize the massive waste heat from HCPV modules. Considering the nature of low-grade waste thermal energy, a microscale organic Rankine cycle (MaRC) offers a promising solution. In a subcritical MaRC, subcooled refrigerant is usually pumped into a microchannel heat sink of each multi-junction photovoltaic cell. In this paper, a complete microchannel flow boiling model is developed based on distributed mass, energy and momentum conservation laws. Detailed MaRC thermal-fluid analysis is conducted to evaluate the effects of working fluid, inlet subcooling, axial fluid/cell temperature distribution and critical heat flux on cogeneration efficiency. The performance analysis indicates that the HCPV/MORC system can achieve a net 8.8% increase of power generation efficiency in comparison to liquid-cooled HCPV at ambi ent temperature. The proposed HCPV /MaRC configuration shows great promise in large-scale applications of HCPV solar power generation. A cross-sectional area (m2) Dh hydraulic diameter (m) G mass flux (kg/m2-s) h specific enthalpy (J/kg) L channel length (m) m mass flowrate (kg/s) p channel perimeter (m) P absolute pressure (Pa) Q heat load (W) r vapor core radius (m) s specific entropy (J/kg-K) T temperature (0C) V volume (m3) W work (W) z channel location (m)

show abstract