Friday, July 13, 2007

Did Branz and EECA know there might be a performance problem early 2006?

You be the judge.....
"One of the biggest uncertainties in the cost/benefit analysis of solar water heating systems is the lack of reliable field data for system performances. Anecdotal evidence suggests that most existing systems fall significantly short of the calculated values used during the system design. This information gap needs to be urgently addressed by conducting a representative field study of existing solar water systems in New Zealand. "

The main conclusion from this study is that it is important to test actual systems before making any assumptions about energy savings and or economic performance. In particular it can be seen that the high cost of installed systems in NZ makes it difficult for them to achieve good economic return on capital. It is also clear that evacuated tube systems need to be taken into serious consideration as a preferred system type, especially for the cooler parts of the country.

"The performance of the flat-plate pumped circulation system has proved to be highly suspect and possibly dependant on the fact that it was a ‘retrofit’ installation to an existing domestic hot water cylinder. This is an important finding, as there are no on site performance tests for solar hot water systems undertaken and many New Zealand systems may be seriously underperforming, perhaps unbeknown to the house owner. "Go here for to read the full report.

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