Basics of the photovoltaic thermal module - Solar Energy Sciences and Engineering Applications - page 154

Figure 5.2.1 Various collector concepts: (A) sheet-and-tube PVT, (B) channel PVT, (C) free flow PVT,
(D) two-absorber PVT (insulated type) (Zondag et al., 2003).
PV application potential in the domestic sector. Apart from the said study, Chow et al.
(2009) also carried out analytical simulation to investigate the annual performance
of building-integrated photovoltaic/water-heating system for the Hong Kong climate
and found that annual thermal and cell conversion efficiencies were about 37.5% and
9.39%, respectively. Based on the results, they confirmed that PV/T systems could be
applicable even to hot-humid regions.
Though the liquid collectors have proven to be technically feasible, economic
feasibility is yet questionable. Compared to the air heating PV/T system, not many
developments are seen in the literature on liquid-heating systems due to their inherent
limitations such as: additional cost of the thermal unit pipes for the water circulation,
and the inherent freezing problem of working fluid when used in low temperature
regions, etc.
5.2.2 Air PV/T collector
The PV/T air collectors are similar to a conventional air collector with a PV laminate
functioning as the top cover of the air channel. PV/T air collectors are cheaper than the
PV/T liquid collectors because of the flexibility that conventional PV modules can be
easily converted to a PV/T system, with very few modifications. PV/T air collectors can