In addition, conventional SWH systems are comparable with the SAHP systems
when solar fractions are above 50%. Besides, analysis on the sensitivity of the total equivalent warming
impact (TEWI) indicates that the towngas boosted SWH system has the greatest potential in greenhouse
gas emission reduction with various solar collector areas and the electricity boosted SWH system has the
comparative TEWI with the SAHP systems if its solar fraction is above 50%. As for SAHP systems, the solar
assisted air source heat pump (SA-ASHP) system has the least global warming impact. Based on all inves-tigation results, suggestions are given on the selection of solar thermal systems for applications in Hong
Kong.
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