For designers using the GeoXergy PlugIn:
Maximum loads and annual running time inputs are automatically calculated in the GeoXergy PlugIn in the appropriate worksheet. Simply copy the four values in the GeoXergy PlugIn and then click the excel button to paste the values into GLD.
For designers using other loads calculations programs/methodologies:
GLD needs the peak hourly heating and cooling loads for the installation. GLD also needs the annual running time (in a percentage format where 0% means the system is not running at all during the year and where 100% means the system is running at peak load 100% of the year).
There is more than one way to calculate the annual running time:
A. Sum the total cooling loads for the year. Divide the sum by the peak hourly cooling load to get a result with units in "hours." Divide the result by the number of hours in a year (8,760). The resulting percentage is the annual running time.
Example:
Total annual cooling kBtus: 18,500 kBtu
peak: 22 kBtu/hour
18,500 kBtu/ 22 kBtu/hour = 841 hours
841 hours/8,760 hours/year = 9.6% annual running time.
Repeat the same process for heating loads
B. For cooling, if the system were running at peak capacity, how many hours would it have to run for in order to take care of the cooling loads for the entire year? After determining the answer, divide it by 8,760 to get the annual running time percentage.
Repeat for the same process for heating loads.
GLD Full User Manual
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