Short term performance comparisons between a solar thermosyphon water heater and two numerical models
- Colorado State Univ., Fort Collins, CO (United States). Solar Energy Applications Lab.
An experimental study of a solar thermosyphon domestic water heater was conducted in the indoor solar simulator facility at Colorado State University (Bickford, 1994). The system consisted of a closed-loop collector circuit filled with propylene glycol and water solution and a horizontal storage tank with an annular tank-in-tank heat exchanger. Short-term irradiated tests with and without timed draws were performed to assess overall performance and monitor collector flow rate, storage tank stratification, and heat exchanger temperature distribution. The measured performance was compared with the ``standard`` thermosyphon model in TRNSYS 13.1 (transient system simulation program). A revised TRNSYS model was developed by Graham Morrison at the University of New South Wales, Australia. The revised model specifically addressed the horizontal tank, closed-loop configuration. The standard TRNSYS version predicted solar gain within 17% of the measured values and differed dramatically from experimental collector temperatures, closed-loop flow rate, and tank stratification. This is not surprising since this model does not include the tank and tank heat exchanger. The revised TRNSYS model agreed more closely with experimental results. It predicted closed-loop flow at 8% lower than observed flow and collector temperature rise that was higher than the observed flow by approximately the same amount, resulting in extremely accurate prediction of collector output energy. Losses from the storage tank and piping were significantly underpredicted in both models, however.
- OSTI ID:
- 116241
- Report Number(s):
- CONF-950336-; ISBN 0-7918-1300-2; TRN: IM9545%%208
- Resource Relation:
- Conference: American Society of Mechanical Engineers/Japanese Society of Mechanical Engineers/Japan Solar Energy Society international solar energy conference, Lahaina, HI (United States), 19-24 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Solar engineering 1995: Proceedings. Volume 2; Stine, W.B. [ed.] [California Polytechnic Univ., Pomona, CA (United States)]; Tanaka, Tadayoshi [ed.] [Electrotechnical Lab., Ibaraki (Japan)]; Claridge, D.E. [ed.] [Texas A and M Univ., College Station, TX (United States)]; PB: 582 p.
- Country of Publication:
- United States
- Language:
- English
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