Conference paper

The life cycle cost of standalone solar air-water heat pumps for Australian homes

29 Jul 2016

To combat increasing electricity prices due to the high operating costs of conventional reverse cycle air-airheat pumps (RC-AA-HP), they can be powered by standalone PV systems as a radical demand side energy management solution. However, the heavy power consumption of their compressors necessitates very large and expensive standalone hotovoltaic (PV) systems. Alternatively, reversible air-water heat pumps (RCAW-HP) are integrated with thermal storage units, hence with downsized capacity RC-AW-HP but large thermal storage, the building thermal load can be handled equally. The resultant benefits of standalone PV powered RC-AW-HP, is the potential to need smaller, hence, less costly battery storage. One issue associated with using a standalone PV system is the excess power generated. However, the excess power can be utilized to power domestic heat pump water heater (D-HP-WH) which has a different load profile. Previous researches have not focused on such a system configuration, this study focuses on the techno-economic feasibility of a highly optimized component configuration for such a system to meet the entire all-year round space conditioning and domestic hot water demands of a typical Australian house in three vastly different Australian climatic conditions. The entire system is modelled and simulated in TRNSYS and coupled with GenOpt to carry out the optimization. The lifecycle cost assessment on the most optimized component configuration for 0.2% annual hours loss of load probability in generated electricity, reveal that the twenty years life cycle cost is AU$ 76,917 in Brisbane, AU$ 88,539 in Adelaide and AU$ 120,454 in Melbourne. These life cycle costs are higher than case of conventional RC-AA-HP and D-HP-WH run by grid electricity, consequently, powering RC-AW-HPs with standalone PV system is currently not cost competitive with powering them with grid electricity.
Keywords: solar air-conditioning systems, heat pumps, photovoltaic, standalone

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