ABSTRACT
The idea of using a DC pump and a photovoltaic panel to run a solar heating system is not a new one. However, the price and the lifetime of this alternative to the traditional AC pump and controller have not been sufficiently attractive to the consumers, so only very few systems of this kind are actually on the market.
The recent development of small low-flow systems have opened up new possibilities, as the nescessary power for the pump is very small, thus reducing the corresponding area of the PV panel. At the same time, reliable and relatively cheap DC pumps have been developed, and the price of PV panels has decreased. Simple calculations shows, that the system is already competitive, and if the installation and running costs of the traditional AC pump and controller are included the savings may be signinficant.
The performance of a PV powered SDHW system was tested experimentally and compared to the traditional solution. General design rules for solar heating systems with PV driven pumps are derived from the results.
