A model of a low flow solar domestic hot water system

The low-flow solar water heater – from 7 litres/hour to 15 litres/hour per solar collector area – is the most promising way for improving the solar water heater performance. This performance can be increased taking advantage of the low flow to obtain a better stratification in the tank. For this purpose, the most promising technology uses a mantle storage tank with injection of the collector fluid at several levels. The aim of this article is to present some numerical and test results from the storage tank of a low-flow solar water heater.