CSLB C-46 Solar ContractorSolar Thermal System InstallationMedium
A solar thermal installer is determining the optimal tilt angle for a flat-plate collector array for a domestic hot water system in a residential application in California (latitude approximately 34°N). The primary goal is to maximize annual energy collection. Which of the following tilt angles is generally recommended?
- ALatitude plus 15 degrees
- BLatitude minus 15 degrees
- CFixed at 45 degrees for all locations
- DEqual to the latitude
Show answer & explanationAnswer & explanation
Correct answer: D. Equal to the latitude
For maximizing annual energy collection in solar thermal applications, especially for domestic hot water where year-round performance is desired, setting the collector tilt angle approximately equal to the local latitude is generally recommended. This balances summer and winter performance.
Why the other options are wrong
- A. Latitude plus 15 degrees would favor winter collection, reducing summer performance.
- B. Latitude minus 15 degrees would favor summer collection, reducing winter performance.
- C. A fixed 45-degree angle is a common rule of thumb but is less precise than matching local latitude for optimal annual output.
Optimal Solar Collector Tilt (Annual)
The optimal tilt angle for a solar collector to maximize annual energy collection is typically set equal to the local latitude.
- Balances summer and winter solar gain.
- Aids in maximizing overall system efficiency throughout the year.
- Adjustments may be made for specific seasonal priorities (e.g., more for winter, less for summer).
Memory trick: Latitude's the guide, for yearly solar tide.