Development Of Solar Domestic Hot Water System Performance Prediction Methodology Based On System Test Results. 10-01-82.

Secondary Author(s)

Block, David

Report Number

FSEC PR-42-83(TL)


Solar Thermal


Solar manufacturers have a means to evaluate and certify solar domestic host water (SDHW) systems through a system test procedure. This procedure is based on ASHRAE 95-81 system test with test conditions specified by a certification organization (SRCC, ARI, TVA). One result of the SDHW system test is the ability to compare differant systems and system types. However, this comparison is only valid for the specific conditions used in the test. The experimental test procedure produces a single-day performance result. FCHART produces monthly and annual performance results. The methodology described here has used TRNSYS to bridge the gap between perscribed single-day test results and the FCHART annual performance prediction. The methodolgy is applicable to active, integral collector storage (ICS), and thermosyphon solar systems and involves the development of a detailed description of the system for input to TRNSYS. The input parameters are then adjusted to obtain agreement between the TRNSYS sumulation results and the SDHW system test results. Next, the TRSSYS input parameters are translated into a set of FCHART input parameters. FCHART can then be used be predict the annual system performance for a given system at a particular location. (ie a city in the FCHART data base). The primary output of the mehodology is the set of FCHART input prameters for each solar system which can be used by anyone with access to FCHART. It is also possible to evaluate system performance at other locations and the effect of system design changes on annual performance. Comparisons of experimental test results and TRNSYS sumulation results have achieved good Agreement in all cases. Agreement between experimental test results and simulated results also indicates that changes in environmental parameters can be simulated without additional testing.

Date Published



Solar Thermal

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