Civil Engineering Reference
In-Depth Information
3 R&D Progress and Practical Application of the PV/T
Technologies
3.1 Overview of the R&D Achievements in PV/T Field
Quantitative researches have been carried out to study the performance of different
PV/T configurations, optimise their geometrical sizes and suggest the favourite
operational parameters. As a result, many achievements and conclusive remarks
have been obtained and these are selectively indicated as follows.
Hendrie (
1980
) developed a theoretical model for the flat-plate PV/T solar
collectors, and by using the model, he carried out the study in the thermal and
electrical performance of an air- and a liquid-based PV/T solar collector. He
concluded that when the PV modules were not in operation, the air- and liquid-
based collectors could achieve the peak thermal efficiencies of 42.5 and 40 %,
respectively. However, when the PV modules were in function, the air- and liquid-
based units obtained slightly lower thermal efficiencies, which are 40.4 and
32.9 %, respectively. The measured peak electrical efficiency of these units was
6.8 %.
Florschuetz (
1979
) used the well-known Hottel-Whillier (
1958
) thermal model
for the flat-plate solar collectors to analyse the performance of the combined PV/T
collector. By slightly modifying the parameters existing in the original computer
program, the model became available for analysing the dynamic performance of
the PV/T collector. Assuming that the solar PVs' electrical efficiency is linearly
reduced when the cells' temperature increases, the thermal and electrical effi-
ciencies of the combined PV/T collector were obtained and the results are further
analysed to established the correlations between the efficiencies and various
operational parameters of the collectors.
Raghuraman (
1981
) developed two one-dimensional analytical models to pre-
dict the thermal and electrical performance of both liquid- and air-based flat-plate
PV/T collectors. The analysis took into account the difference in temperature of
the primary absorber (the PV cells) and secondary absorber (a thermal absorber flat
plate), and a number of design notes were recommended to enable maximised
energy utilisation of the collectors.
Bergene and Lovvik (
1995
) developed a dedicated PV/T mathematical model
and the associated algorithms enabling quantitative predictions of the performance
of the system. The model was established on analysis of energy transfers including
conduction, convection and radiation initiated by Duffie and Beckman (
1991
), and
the results of model operation suggested that the overall efficiency of PV/T col-
lectors is in the range 60-80 %.
Sopian et al. (
1996
) developed the steady-state models to analyse the perfor-
mance of both single- and double-pass PV/T air collectors. The models yielded the
temperature profiles of the glass cover, plates and air stream, while the mean plate
temperature could be applied to evaluate the efficiency of the photovoltaic cells.
Performance analysis showed that the double-pass photovoltaic thermal solar
