In recent years, the depletion of c

In recent years, the depletion of conventional energy sources
and its likely adverse impact on environment have created growing
interest for the application of renewable energy sources. In Hong
Kong, there is also a growing government-led trend of applying
renewable energy and one area of interest lies in the wider use
of solar thermal energy for hot water supply. Till now, a number
of solar thermal systems using sunlight to heat water directly or
indirectly have been installed in government premises.
Meanwhile, considerable studies have been conducted on the
technology of solar thermal energy for hot water production in
Hong Kong[1–3]. Ji et al. [1]analyzed the annual performance of
facade-integrated hybrid photovoltaic/thermal collector system
for use in residential buildings of Hong Kong. Chow et al.[2]esti-mated the potential application of a centralized solar water heating
system for a high-rise residential building in Hong Kong. Chow
et al.[3]further conducted an experimental study of a centralized
photovoltaic and hot water collector wall system which can serve
as a water pre-heating system. Through modeling and experimen-tal analysis, all of these researches show that there is a good appli-cation potential of solar thermal energy for hot water production in
this territory.
On the other hand, a number of simulation and experimental
investigations [4–8]of the solar assisted heat pump (SAHP) tech-nology have been carried out around the world. Aye et al.[4]made
a comparison among three different water heating systems includ-ing a solar heat pump water heating system at various locations in
Australia. Kuang and Wang[5]analyzed the performance of a mul-ti-functional direct-expansion SAHP system under various weather
conditions in Shanghai, China. Hawlader et al.[6]developed a sim-ulation model to study the thermal performance of a SAHP water
heating system under the meteorological conditions of Singapore.
However, until now, there is limited research on the application
of the SAHP system for hot water supply in Hong Kong. Meanwhile,
little systematic research is conducted on the application of differ-ent solar thermal systems under Hong Kong weather conditions.
Therefore, the purpose of this study is to evaluate the application
potential of different kinds of solar thermal systems for hot water
production in Hong Kong, considering both economic characteris-tics and global warming impacts.