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Department of Energy (DOE) reports produced after 1991 and a growing number of pre-1991 documents are available free via www.OSTI.gov.

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Current implementation of Immersed Coil Heat Exchangers (IHX) into Solar Domestic Hot Water (SDHW) systems use simple guidelines for dimensioning their surface area based on an intended solar collector area-or range thereof. The literature from whence these guidelines come (1970s and 80s) are based on experiments with different types of IHX (copper, flangeretrofitted) to those used today and are evaluated solely on the performance of heat transfer, thus a re-evaluation of these guidelines is considered necessary. The investigations presented attempt to combine an evaluation of the heat transfer performance and stratification together based on measurements from three IHX samples with varying material and geometrical arrangement. Preliminary analysis suggests a correlation between high convective heat transfer coefficients and low stratification efficiencies.

A new tubular cavity receiver for direct steam generation, 'SG4', has been built and tested on-sun based on integrated optical and thermal modelling. The new receiver achieved an average thermal efficiency of 97.1±2.1% across several hours of testing, and reduced the losses by more than half, compared to the modelled performance of the previous SG3 receiver and dish. Near-steady-state outlet steam temperatures up to 560°C were achieved during the tests