Photovoltaic-thermal (PV/T) technology e The future energy technology Mohd Yusof Othman * , Adnan Ibrahim, Goh Li Jin, Mohd Hafidz Ruslan, Kamaruzzaman Sopian Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia article info Article history: Available online 13 February 2012 Keywords: Double pass PV/T collector with fins Double pass PV/T collector with fin and CPC Single pass PV/T collector with V-groove absorber PV/T collector with rectangular tunnel absorber Water based PV/T collector and efficiency abstract Solar energy is one of renewable energy sources which have potential for future energy applications. New technology developments in solar energy utilization are expected to result in the improvement of the photovoltaic performance with lower production cost. This will increase the demand and viability for commercial applications. The current popular technology converts solar energy into electricity and heat separately. The photovoltaic-thermal (PV/T) hybrid system is designed to generate thermal and electrical energy simultaneously. It is well known that using a hybrid system can eliminate the need for external source of electrical energy. This paper presents research and development activity being carried out at Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia in order to realise the technology. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction There are several researches and developments had been done on solar energy field recently. This field was recognized as one of the promises of alternative energy to replace fossil fuel sources. Solar energy can generally be divided into two parts; the photovoltaic technology which derived from solar cell technology and convert into electricity, and thermal solar technology which derived from the thermal collector and convert the solar energy into heat. The component used to change solar energy to electricity is photovoltaic solar cells. Photovoltaic solar cells capable of changing some part of solar energy to electricity while the rest of the solar energy become waste. The waste is in the form of heat energy. The efficiency of the heated photovoltaic panel that exposed to sunlight will be decreased. The latest research in this field of solar energy was to gain heat energy and decrease the temperature of photovoltaic panel simultaneously. Normally, electrical energy and heat energy are collected separately. Researches on gaining electrical energy and heat energy simultaneously by using an apparatus have been developed and new hybrid systems commercially known as Photovoltaic-Thermal or PV/T collectors has been designed. Size of the solar cells can be fabricated to merge the requirement of environment while the quantity of heat collected is depend on the design of the particular solar collector. Either air or water can be used as medium and acts as heat carrier depends on the usage. In the conventional solar thermal collectors, electricity and heat gain was produced separately but this new solar collector system can provide electrical and thermal energy simultaneously. Extensive research has been done by various researches in designing a optimize hybrid solar collector before this system can be mass produce for commercialization. Florschetz [1] suggest a model proposed by Hottel-Whillier to analysis PV/T systems. Raghuraman [2] had analysis on numerical method to predict the performance of PV/T system using air or water as heat carrier. Cox & Raghuraman [3] analysed a computer simulation on PV/T system using air. Bhargava [4] and Prakash [5] reported on effect of mass flow rate, air ducting sizing and the width of collector absorber used to the performance of the PV/T system. Tonui & Tripa- nagnostopoulos [6] report on various performance of PV/T collector system with different mass flow rates. Othman [7] reported the double pass PV/T collector with fins absorber shows better performance. Othman [8] had fabricated a PV/T system with compound parabolic concentrator (CPC) and fins in their research. The objective of this paper is to show the recent research activities done by Solar Energy Research Institute, National University of Malaysia (UKM) about PV/T collector system using air and water as heat carrier. 2. Experimental conducted 2.1. Double pass PV/T collector with fins As seen in Fig. 1 , this collector consists of three main compo- nents: glass cover on the top, panel with photovoltaic cells and absorber at the bottom. The fins were fabricated using aluminium sheet to increase the capability to extract heat from PV cells. Air was * Corresponding author. E-mail address: myho@ukm.my (M.Y. Othman). Contents lists available at SciVerse ScienceDirect Renewable Energy journal homepage: www.elsevier.com/locate/renene 0960-1481/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2012.01.038 Renewable Energy 49 (2013) 171e174