Building energy-consumption status worldwide and the state-of-the-art technologies for zero-energy buildings during the past decade

In the last four decades, greater attention has been paid to PV/T systems due to their advantages compared with PV or solar thermal systems alone. This paper aims to study various aspects of PV/T systems through the existing literature in order to highlight key points as future work in this field as well as illustrate different techniques used for such systems. In addition, PV/T systems are reviewed in terms of thermal and electrical side views. Furthermore, the analysis of solar thermal systems, various system applications such as air, water, air/water, phase change material PCM and Nanofluid systems are summarized. In light of most attempts to improve the PV/T system, more focus has been paid to the thermal rather than the electrical side. Furthermore, comparisons between PV/T systems in terms of performance parameters and efficiencies are presented. A critical review of many findings of previously conducted research is also discussed. It is found that the PV/T air heater system is promising for future preheating air applications. Moreover, it is suggested that the use of nanoparticles and water as base fluid improves the overall system efficiency. Furthermore, the PV side views require more attention in technical and cost terms. However, more research is essential to reduce the cost and, improve the effectiveness and technical design of such systems.

Photovoltaic/Thermal (PV/T) systems: Status and future prospects

Evaluation of the nanofluid and nano-PCM based photovoltaic thermal (PVT) system: An experimental study

Cooling the operating surface is a key operational factor to take into consideration to achieve higher efficiency when operating solar photovoltaic systems. Proper cooling can improve the electrical efficiency, and decrease the rate of cell degradation with time, resulting in maximisation of the life span of photovoltaic modules. The excessive heat removed by the cooling system can be used in domestic, commercial or industrial applications. This paper presents a review of various methods that can be used to minimize the negative impacts of the increased temperature while making an attempt to enhance the efficiency of photovoltaic solar panels operating beyond the recommended temperature of the Standard Test Conditions (STC). Different cooling technologies are reviewed, namely Floating tracking concentrating cooling system (FTCC); Hybrid solar Photovoltaic/Thermal system cooled by water spraying; Hybrid solar Photovoltaic/ Thermoelectric PV/TE system cooled by heat sink; Hybrid solar Photovoltaic/Thermal (PV/T) cooled by forced water circulation; Improving the performance of solar panels through the use of phase-change materials; Solar panel with water immersion cooling technique; Solar PV panel cooled by transparent coating (photonic crystal cooling); Hybrid solar Photovoltaic/Thermal system cooled by forced air circulation, and Solar panel with Thermoelectric cooling. Several research papers are reviewed and classified based on their focus, contribution and the type of technology used to achieve the cooling of photovoltaic panels. The discussion of the results has been done based on the advantages, disadvantages, area of application as well as techno-economic character of each technology reviewed. The purpose of this review is to provide an understanding for each of the above-mentioned technologies to reduce the surface temperature of the PV module. The study will focus on the surface temperature reduction array bound by each of the cooling technologies. The performance of each cooling technology will also be highlighted. In addition to this study, this review will include a discussion comparing the performance of each cooling technology. The outcomes of this study are detailed in the conclusion section. This paper has revealed that any adequate technology selected to cool photovoltaic panels should be used to keep the operating surface temperature low and stable, be simple and reliable and, if possible, enable the use of extracted thermal heat to enhance the overall conversion efficiency. The presented detailed review can be used by engineers working on theory, design and/or application of photovoltaic systems.

A review of solar photovoltaic systems cooling technologies

Combined solar photovoltaic-thermal systems (PVT) facilitate conversion of solar radiations into electricity and heat simultaneously. A significant amount of work has been carried out on these systems since 1970. Different PVT systems have been invented in the last thirty years. Several theoretical, mathematical, numerical and experimental models are introduced by many investigators across the world. The present article gives a broad classification and review of published research work on these systems. The article mostly covers the experimental work carried out on the different types of PVT systems in the last decade. The latest technology of liquid spectrum filters for PVT systems are also explored in depth.

Photovoltaic -Thermal systems (PVT): Technology review and future trends

Solar energy for net zero energy buildings – A comparison between solar thermal, PV and photovoltaic–thermal (PV/T) systems

In a hybrid photovoltaic–thermal (PV/T or PVT) module, electricity and thermal energy are generated simultaneously in the same module. By combining a PV module and a solar thermal collector, more of the solar radiation can be harvested, and the total efficiency of the module is increased. The combination of two technologies in one module also has the potential to reduce the use of materials and the required space. In order to assess and quantify these possibilities, several research groups have presented life cycle assessments (LCA) of different PV/T concepts and installations. This paper presents a review of the published results, and aims to find a common ground. In general, the payback time for both energy and greenhouse gas emissions of the PV/T systems are much shorter than their expected lifetime. However, due to the use of different methods and unclear data sources, it is difficult to make any wide-ranging conclusions about the environmental impact of PV/T modules.

Clara Good

Papers

Solar energy for net zero energy buildings – A comparison between solar thermal, PV and photovoltaic–thermal (PV/T) systems

Environmental impact assessments of hybrid photovoltaic–thermal (PV/T) systems – A review

Hybrid photovoltaic-thermal systems in buildings – a review

Embodied greenhouse gas emissions from PV systems in Norwegian residential Zero Emission Pilot Buildings

Influence of PV technology and system design on the emission balance of a net zero emission building concept