Field monitoring of solar domestic hot water systems based on simple tank temperature measurement

Conference · Mon May 01 00:00:00 EDT 1995

OSTI ID:64143

Burch, J; Xie, Yuantao ^[1]; Murley, C S ^[2]

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1. National Renewable Energy Lab., Golden, CO (United States)
2. Sacramento Municipal Utility District, CA (United States)

By dynamically measuring solar storage tank temperature(s), the solar storage tank effectively becomes a dynamic calorimeter to measure the energy flows in a solar system. The energy flows include solar loop gain, tank losses, and potentially draw extraction. With one-channel temperature loggers storing data over several days to several weeks, this approach provides low-cost, modest-accuracy performance assessment, useful for determination of savings persistence and diagnostics. Analysis is based upon the tank energy balance, identifying solar gain during the day and tank losses at night. These gains and losses can be compared to expectations based upon prior knowledge, and estimated weather conditions. Diagnostics include controller and pump operation, and excessive nighttime losses. With one point temperature logger, solar gain accuracy is expected to be 20 to 50%, depending on draw frequency and volume. Two examples are shown, a properly operating system and a system with excessive nighttime losses.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC36-83CH10093
• OSTI ID: 64143
• Report Number(s): NREL/TP-472-7854; CONF-950725-1; ON: DE95009208; TRN: 95:004379
• Resource Relation: Conference: SOLAR `95: national solar energy conference: 10,000 solutions - paths to a renewable future, Minneapolis, MN (United States), 15-20 Jul 1995; Other Information: PBD: May 1995
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
SOLAR WATER HEATERS
MONITORING
TANKS
TEMPERATURE MEASUREMENT
CALORIMETRY
ENERGY BALANCE