32 | Installation, Operating, and Maintenance Manual
Rev. 05JUL2016
Appendix G: Antifreeze Fluid Factors
The UPC-GEO controller calculates Heat of Extraction (HE) and Heat of Rejection (HR) based upon the Media
Configuration menu (Figure 14). The Media Configuration page allows setting the type and percentage of an-
tifreeze used in the ground loop system. The type choices are ethanol, methanol, glycol, and none. The Media
inputs only affect the HE/HR calculation. HE/HR is calculated as follows:
HE or HR = ∆T x Flow Rate (U.S. GPM) x Fluid Factor
where: ∆T = temperature difference between EWT and LWT
Fluid factor = adjustment for antifreeze
It is possible that the calculation shown on the controller screen is different than a hand calculation. The
reason that the calculation could be different is the use of fluid factor. The UPC-GEO calculation is based upon
the weight of the fluid, specific heat, percentage of antifreeze, and fluid temperature. Some calculations in the
geothermal heat pump industry use a fluid factor of 500 for water, and a fluid factor for all antifreezes of 485.
While this will make the calculation easier, and allow the technician to be “in the ballpark”, it may not match
the controller display, which uses calculations specific to the current conditions.
