Weather variation captured by the LDR sensor
October and, so far, November 2024 have been months marked by drought but also significant sunshine. In practice, and according to Solar LIVE project data from last spring to the present, the solar water heater has consistently provided all the necessary hot water for a four-member household without major interruptions. Only 2–3 times during this entire period was alternative water heating required.
Water Heating Without Electricity
We are now entering the season when alternative sources of hot water will be needed more frequently. In my case, I use a wood-fired water heater as the primary backup, and an electric water heater as a secondary backup (the 3rd water heating source). This setup allows for water heating without electricity and covers 98–99% of the annual hot water needs. The remaining 1% accounts for exceptional situations, such as illness.
Around 20–30 days per year require the wood-fired heater, and perhaps only 5–6 times the electric heater is needed. This is in a mountainous area where the solar water heater receives sun exposure relatively late in the day. However, frequent fog is uncommon, which is a major advantage during winter when the solar heater can still perform even in low ambient temperatures.
Let’s look at how the transition to unfavorable weather affects the solar water heater, using Solar LIVE data.
Graph Analysis
In Case 1, we see days with strong sunshine and typical seasonal performance, with temperature gains exceeding 10°C.
In Case 2, the days are mostly cloudy, and the solar system shows reduced performance, with gains below 10°C.
In Case 3, we observe a heavily overcast day, clearly indicated by the LDR (light sensor) data, with minimal temperature increase—just 1–2 degrees.
This graph illustrates how an overcast day with virtually no solar gain is captured by the LDR sensor. It closely resembles the rare cases where the solar water heater recorded zero gain.
Cloud Cover
Image of cloud cover on that specific day
MSc in Environmental Education
Specialization in Educational Robotics and STEM
Specialization in E-learning and Educational Content Production
Certified Adult Educator
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