Boiler themographics, a tale of their own; anatomy of a hot sunny day in late winter (or was it early spring?).
- 7:15 A dip in the middle of the boiler shows that water is drawn from it by someone taking the first shower of the day, whereby the thermocline of 20 degrees moves along the middle temperature sensor.
- 7:30 Another showering person also decreases the bottom temperature from 14 to 12 degrees.
- 7:45 coffee and tea are being made. The gas stove momentarily heats up the air in the hall.
- 8:00 The sun hits the solar sensor from the side now (a february sun) but the rays bounce off
- 9:00 Gradually more sun rays fall onto the sensor.
- 10:50 The sun enters the S/W oriented living room. To cool this room below 20°C, the door to the hall is opened and the hot air now starts gradually heating the hall.
- 11:05 The water from the panel is warmer than the water half way down the boiler and the pump starts.
- 11:05 The sensor on the tubing that comes from the panel decreases in temperature (convection of hot water from the boiler heats up this tubing when the pump is off).
- 11:30 The half way down the boiler starts to heat up; partially heated by the panel, partially heated by the water in the boiler top, which can be seen still to cool down. Also the water in the bottom of the boiler starts to heat up.
- 11:45 The sun now shines into the panel rather than being reflected off. Collected solar power sharply increases and follows a bell-shape till late-afternoon. The asymmetry of the bell is caused by the panels being oriented toward the west rather than to the south.
- 13:00. Red graph top of solar boiler is heated up from now as the water from the panel reaches temperature of over 30°C .
- 13:00-16:30 Temperatures of the boiler increase; the top heats 20 K, the middle heats 15K, the bottom heats 15K.
- 15:00- The sun now sets in the west, reducing radiation leads to lower solar power and a decline in the rise of water temperatures.
- 16:30 The pum circuit senses the temperature difference between the panel and the middle of the boiler being too small to gain anything, so the pump is switched off. Immediately the tubing temperature starts to drop.
- 16:30-17:00 Temperature at the bottom of the boiler overshoots. Probably a convection process.
- 17:00 The washing machine draws hot water, which is visible by a sharp decrease in temperature in the bottom of the boiler, caused by inflow of cold water.
- 17:30 A loss of about 0.5K/hr can be seen at the top of the boiler; considered to be 'natural losses' due to poor insulation.
- 17:45 Complete sunset.
- 18:00 The dishwasher kicks in and decreses temperatures at the bottom even further.
- 18:15 The first evening shower is taken; children's bed time; the 35° thermocline passes by the middle of the boiler.
- 19:00 The oldest child also takes a shower. The bottom of the boiler very slowly catches some heat from above.
- 22:00 Another washing is done, parents take their evening shower.
- 23:00 A thin layer of hot water starts to rapidly transfer heat to the now very cool middle and bottom of the boiler, hence the steep decline in the temperature at the top of the boiler and the slight increase of the temperature at the middle of the boiler.
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