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Highlights • Battery state of charge profiles are affected by the suppressed demand effect. • In small rural systems the suppressed demand effect impacts directly to reliability. • Considering the suppressed effect demand lead to more sustainable systems design. Abstract Rural electrification programs usually do not consider the impact that the increment of demand has on the reliability of off-grid photovoltaic (PV)/battery systems. Based on meteorological data and electricity consumption profiles from the highlands of Bolivian Altiplano , this paper presents a modelling and simulation framework for analysing the performance and reliability of such systems. Reliability, as loss of power supply probability (LPSP), and cost were calculated using simulated PV power output and battery state of charge profiles. The effect of increasing the suppressed demand (SD) by 20% and 50% was studied to determine how reliable and resilient the system designs are. Simulations were performed for three rural application scenarios: a household, a school, and a health centre. Results for the household and school scenarios indicate that, to overcome the SD effect, it is more cost-effective to increase the PV power rather than to increase the battery capacity. However, with an increased PV-size, the battery ageing rate would be higher since the cycles are performed at high state of charge (SOC). For the health centre application, on the other hand, an increase in battery capacity prevents the risk of electricity blackouts while increasing the energy reliability of the system. These results provide important insights for the application design of off-grid PV-battery systems in rural electrification projects, enabling a more efficient and reliable source of electricity. [ABSTRACT FROM AUTHOR]

Highlights • A novel Concentrating PV/DC system is proposed for building application. • The concept of combining daylighting and PV system is presented. • Indoor experiment is conducted to validate the optical model. • The actual performance analysis of the CPV/DC system under real weather conditions is presented. • The CPV/DC system can be optimized for different building rooftop designs. Abstract A wide range of developed and commercially available daylighting systems have been reported, however, they have just a single function, so they require an extra complex component to adjust daylighting intensity to create a better visual-comfort interior environment seasonally. Thus, in this paper, a novel concentrating photovoltaic/daylighting control system based on the lens-walled compound parabolic concentrator which is made by the transparent material is proposed. It combines both PV and daylighting control for green building design. At noon, when the incidence angle is small and the solar radiation is strong, the majority of the solar radiation can be collected by the PV cell for electricity generation and the remaining solar radiation will act as the daylighting source. In the morning or evening, when the incidence angle is large and the solar radiation is weak, the majority of the solar radiation will pass into the building for daylighting while the remaining solar radiation will be collected by the PV cell for electricity generation. An optical model was built for the ray-tracing simulation by using the commercial software Lighttools®. The prototype of the lens-walled compound parabolic concentrator was manufactured and assembled for the indoor experiment to validate the optical model. To prove the feasibility of the system, the optical and electrical performance of the proposed concentrating photovoltaic/daylighting control system are derived from the simulation and experimental results, and the actual all-day daylighting performance of it is investigated through the software simulation. The simulation and experimental results indicate good electrical and daylighting performance of the concentrating photovoltaic/daylighting control system, and the proposed concentrating photovoltaic/daylighting control system suits all kinds building rooftop designs with different inclination angles, which proves it a wide scope of application. [ABSTRACT FROM AUTHOR]

This paper describes a novel type of solar concentrator – a rotationally asymmetrical compound parabolic concentrator (RACPC). The RACPC aims at addressing the following objectives: (i) to increase the electrical output of a concentrating photovoltaic (CPV) system by providing sufficient concentration gain; (ii) to minimise the usage of the PV material with the corresponding reduction of CPV system cost, and (iii) to eliminate the requirement of mechanical tracking by providing a wide field-of-view. This paper first provides a short review on variations of compound parabolic concentrator designs available to date. Next, the process of designing the RACPC is presented and the geometrical concentration gain of the concentrator is discussed. In addition, the optical concentration gain is also presented for various angles of incidence. Through simulations, it is demonstrated that the RACPC can provide significant optical concentration gains within its designed acceptance angle. An RACPC based system is an attractive alternative to conventional solar photovoltaic systems. [ABSTRACT FROM AUTHOR]

It is known that simulation of PV systems permits to study their performance helping engineers to design them. This paper deals with the dynamic simulation and modelling of stand-alone PV systems by using state variables and numerical integration methods. Two PV systems have been modelled and simulated: a PV array directly connected to a resistive load and a PV array with batteries also connected to a resistive load. A double exponential model, together with the procedure 1 for temperature and irradiance corrections of the IEC 60891 standard, has been used to model the PV array and considering the general battery model of Coppety with some modifications, the system with batteries was simulated. The obtained results from the simulations and experimental tests have been analysed and have shown that this methodology is a good option to simulate these systems. [ABSTRACT FROM AUTHOR]

China’s photovoltaic industry developed sharply, and now it is the only country whose production covers the installed. Since R&D policy and deployment policy of China’s PV industry should not increase its production, this paper focuses on impact of investment policy, regarded as subsidy, on the photovoltaic industry. Feedback model of China’s photovoltaic industry is built, and the parameters of the model were estimated. And then simulation is done based on the model. The results show that the expansion is mainly caused by overreaction to the potential of the industry, but not the investment policy. In fact, investment policy only causes price fluctuations and industry overcapacity to some extent. Therefore, China’s investment policy on PV industry investment should be reduced properly or even canceled, or at least it should be combined with deployment and R&D. [ABSTRACT FROM AUTHOR]