Hybrid solar hot water A novel way to use PVs

摘要

Making hot water for domestic use here in New Zealand has had an interesting history, similar to that in Australia, I suspect. As far back as I can remember, back in the 1940s and 50s, domestic hot water in our NZ cities was almost always made using an electric element, with a thermostat set to about 60° C, and stored in a non-insulated hot water cylinder. In those days, electricity was cheap. We all had electric heaters and electric ovens (our electric stove had two large electric hobs that were on all the time-you couldn't switch them off!), and many more power hungry devices were coming onto the market. In the 1960s, electricity supply problems started to appear; transmission lines were being overloaded and the power companies weren't able to supply enough power at peak times.