Table of Chronological BTU's collected

Date - The data is given in chronological order which is helpful in showing the cyclical nature of cludy overcast Feb. and March days broken by cycles of arctic high pressure which are colder and windier, but with a high percentage of possible sunshine. There are gaps in the data when computer recording was disabled or down.

Low of Day/High of day- in fahrenheit.. acquired from a sensor placed outside and under the north eave of the house..giving lowest temp of the date (usually occuring in early AM) and high usually mid afternoon on a given day.

Wind Avg... this avg value is from local weather station based at an airport 15 miles south... the site wind speed could vary, but in general , windy days such as the opening of new arctic high pressure cell produces windiness at all sites in a region especially with winter lack of deciduous folaige to impede such winds.

Percent of Sun is also collected at the local weather data station and is stated as the number of sunny hours per day divided by the available hours of potential sun (daylight).. this may vary at any given site but is representative.

BTU Average is calculated from the known rate of air cycling in the installed air system ( which is 300 CFM) and the differences of Input air pulled from the lower house levels and Output air pulled from the warm apex of the roof collwctor.Standard values for the density of air and specific heat of air are used. The BTU's were pooled from 6 minute data records into hourly calculations which are then averaged for the stated Run time. The actual BTU's collected during peak hours are known and may be requested by interested designers.

Fan Run Time gives the number of hours of fan operation.The current operation was controlled by an absolute thermostat triggered by presense of about 80+ degree air in the collar tie plenum. The thermostat used tended to drift and required resetting... in ideal operation a differential thermostat would be employed.

Highest Roof Temp- gives the highest temperature in the collar tie space at the top of the south roof collector. This tended to be sustained for about 3 hour periods even though heat collection was meaningful for 5 to 6 hour periods.

Temp Difference - InOut .. this reports the average difference between intake..lower level.. house air and warm air returning from the collector via active fan circulation. This value is presented as an average over the Runtime of the fan and the specific "Diff" values in 6 minute cuts were used to calulate hourly BTU ouput.

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