Project: Siegel House Case Study
Radiant Temperatures in the Sunspace:
Hypothesis, Methods, Data, and Analysis
As mentioned earlier on the hypothesis page, we believe
the sunspace will exhibit extreme radiant temperatures which will act in parallel with
high and low ambient temperatures to create uncomfortable conditions.
In order to judge the cumulative effects on comfort of both ambient temperature and
radiant temperature, we decided to record both simultaneously and compare them
graphically. We measured the extremes of the radiant temperatures in the sunspace by
placing a temperature sensor inside one of the skylights so it would receive constant
sunlight. In order for this sensor to record radiant temperatuires without being affected
by ambient temperatures, we covered its thermistor with a ping-pong ball painted gray.
This eliminates some of the airflow around the sensor, and approximates the color of human
skin to more accruately reprsent the radiation effects. We then plotted this data along
with the ambient temperature data to try to get a feel for what comfort in the sunspace
would be like.
Data and Analysis
This graph compares ambient and radiant temperatures in the sunspace
(11 k gif)
The data from the ambient temperature sensor and the radiant temperature sensor are
As expected, the radiant temperatures reach extreme levels at the high and low peaks. For
most of the day, these strong radiant temperatures, in combination with the high ambient
temperatures, produce uncomfortable conditions in the sunspace. On the high end of the
scale, the peak radiant temperatures routinely rose above 100 degrees fahrenheit during
this February week. On the low end, the radiant temperatures dropped down to around 50
degrees fahrenheit. Brrr.
The radiant temperatures in the sunspace are extreme enough to have a strong impact on
comfort in the space. This is especially true because they act in parallel with the
ambient temperature in the space. When the air temperature is high, the radiant
temperatures are also high, and when the air temperature is low, the ambient temperatures
are also low. This phenomenon causes both overly hot and cold conditions. For the Siegels
to make this sunspace into a part of their house where they can spend much of their day
will require some major modifications to mitigate the effects of all that glazing.
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