Plate Photovoltaic Thermal Research Articles

Thermal Performance of Single Glazing Flat Plate Photovoltaic Thermal Hybrid System with Various Air Channels

Abstract The present study attempts to investigate the thermal performance of five types of mild steel air channels in the photovoltaic thermal hybrid system. This system has been designed, fabricated, and tested in the tropical climatic condition of Chennai, India. There are five kinds of air channels studied in this work, namely, reference air channel, single-fin channel, multifin channel, fin with T baffle channel, and fin with V baffle channel. These channels are studied and compared. The experiments were accomplished with two mass flow rates, m˙: 0.00565 and 0.00847 kg/s. The photovoltaic thermal hybrid system performance was enhanced by increased air velocity, enhanced heat transfer between the absorber surface and air, and physical geometry of the channel. This optimal performance has been attained in the present study, with strong agreement with previously published findings. The photovoltaic thermal hybrid system experimentally proved to enhance thermal and photovoltaic efficiencies with increasing air mass flow rate, and the maximum electrical efficiency was found to be 13.70 % at the mass flow rate of 0.00565 kg/s and 14.27 % at the mass flow rate of 0.00847 kg/s; similarly, the thermal efficiency was 14.12 % at m˙ = 0.00565 kg/s and 20.81 % at m˙ = 0.00847 kg/s.

A novel solar cooling cycle – A ground coupled PV/T desiccant cooling (GPVTDC) system with low heat source temperatures

Abstract This study investigates the performance of a novel desiccant air dehumidification and cooling cycle that utilises ground source heat exchange and flat plate photovoltaic thermal (PV/T) collectors (the GPVTDC system) to provide conditioned air. The system was modelled in TRNSYS using verified components with a focus on three climates: (i) an oceanic climate (Cfb) (ii) a humid sub-tropical climate (Cfa), and (iii) a hot semi-arid climate (BSh). The GPVTDC system pre-cools the entry air by utilising a ground source heat exchange. This allows the desiccant regeneration process to operate at low temperatures ranging from 43 °C to 62 °C, which enables the use of glazed water type PV/T collectors as the main heat source. The collectors were sized to match both thermal and electrical energy requirements to drive the GPVTDC system. The system was simulated for a whole year in each climate to provide fresh air ventilation, dehumidification and cooling process for an office space. Evaluation of the annual cooling performance of the GPVTDC system shows that it can maintain an office space within the thermal comfort zone for up to 93% of the time, with an average system cooling coefficient of performance (COP) between 9.6 and 16.3 for the three analysed climates. In addition, electrical energy saving up to 87% is achieved in comparison to a conventional dew point air dehumidification and cooling process.

Experimental studies of rectangular tube absorber photovoltaic thermal collector with various types of nanofluids under the tropical climate conditions

The flat plate photovoltaic thermal (PVT) collectors can be classified into the type of working fluids used namely the water based PVT collectors, air based PVT collectors and combination of water/air PVT collectors. However, low thermal conductivity of the working fluids has always been the primary limitation in the development of energy-efficient heat transfer fluids, and higher collector performance. To overcome this limitation, there is a strong motivation to improve the heat transfer of fluids with higher thermal conductivity. This new generation of heat transfer fluids called nanofluids consists of suspended nanoparticles and has higher suspension stability compared to the millimeter or micrometer size nanoparticles. Thus, the heat transfer characteristics will be enhanced by using nanofluids. The PVT collector has been designed, fabricated and tested outdoor under the Malaysia tropical climate conditions. The PVT collector consists of specially designed rectangular tube absorber (stainless steel material, height of 15mm, width of 25mm and thickness of 1mm) attached under the photovoltaic module. The PVT collector was experimentally tested with different types of nanofluids (SiO2, TiO2 and SiC). The results indicated that the PVT collector with SiC nanofluid has the highest combined photovoltaic thermal (PVT) efficiency of 81.73% and PVT electrical efficiency of 13.52% with the best overall energy coefficient (COE) of 0.93 has been achieved at a flow rate of 0.170kg/s and solar irradiance levels of 1000W/m2, followed by PVT-TiO2 nanofluids, PVT-SiO2 nanofluids, and PVT-water respectively.

Efficient single glazed flat plate photovoltaic–thermal hybrid collector for domestic hot water system

► PV-T collectors convert solar energy into heat and electricity. ► We studied several configurations of glazed PV-T collector using a simple 2D model. ► We built a prototype collector based on improved materials and tested it. ► The results show a significant improvement of the thermal efficiency of our collector in comparison to previous work on PV-T collectors. This paper deals with the design of a single glazed flat plate Photovoltaic–Thermal (PV–T) solar collector. First, the thermal and electrical performances of several single glazed flat plate PV–T concepts based on water circulation are investigated, using a simple 2D thermal model, then different ways of improvement are presented. It mainly consists in focusing on the heat transfer between PV cells and fluid, and also on the optical properties of materials. Thus, the most appropriate concept configuration has been identified and suitable material properties have been selected. A prototype collector has been designed, built and tested. A high thermal efficiency was reached at zero reduced temperature. For this level of thermal efficiency, the corresponding electrical efficiency has is lower than efficiency of a standard PV panel using the same technology. However, this solar PV–T collector is reaching, in these standard conditions, the highest efficiency level reported in the literature.

Comparative study of the performances of four photovoltaic/thermal solar air collectors

An extensive investigation of the thermal, electrical, hydraulic and overall performances of flat plate photovoltaic/thermal (PV/T) air collectors has been made. Four popular designs are considered with the air flowing either over the absorber (Model I) or under it (Model II) and on both sides of the absorber in a single pass (Model III) or in a double pass fashion (Model IV). Heat balance equations are written for each model and are numerically solved, incorporating measured climate data. The effects of air specific flow rate and the selectivity of the absorber plate and PV cells on the performances have been examined. It is found that under similar operational conditions, the Model I collector has the lowest performance, while the other models exhibit comparable thermal and electrical output gains. Nevertheless, the Model III collector demands the least fan power, followed by Models IV and II. It is also shown that selective properties are inappropriate for these PV/T collectors due to the resultant reduction in the generated PV energy, especially at low flow rates. The study provides valuable information regarding the design and operation of such types of PV/T air collectors.