Ground Loop Heat Exchanger Design Software
GLHEPRO for Windows
GLHEPRO is used for designing ground loop heat exchangers for use with ground source heat pump systems. It is sold by the International Ground Source Heat Pump Association.
VERSION 5.0 NOW AVAILABLE - New Features
About GLHEPRO
What is GLHEPRO?
GLHEPRO was developed as an aid in the design of vertical borehole-type ground loop heat exchangers used in geothermal heat pump systems. While GLHEPRO may be used for residential system design, it is aimed at commercial systems. The heat exchanger may be composed of any number of boreholes arranged in various configurations.
GLHEPRO performs three different tasks:
Simulation (for up to 100 years) of ground loop heat exchangers to determine monthly average and peak heat pump entering and exiting fluid temperatures, as well as power consumption of the heat pump.
Determination of the required borehole depth to meet user-specified minimum and maximum heat pump entering fluid temperatures.
Sizing of hybrid ground source heat pump (HGSHP) systems by determination of the required borehole depth and necessary supplemental heat rejecter (cooling tower, fluid cooler) or heat extractor (boiler) size.
Technical Papers and Discussions:
GLHEPRO is based on the methodology developed by Eskilson at the University of Lund in Sweden, considered by Dr. Spitler to be the best currently available methodology.
A technical paper describing GLHEPRO v3.0 (pdf): most of the discussion still applies to GLHEPRO v4.1.
Xu and Spitler (2006) (pdf): discussion of the new GLHE model, which includes improved borehole thermal resistance calculations and consideration of thermal mass.
A paper was published in 2015 by Cullin et al. on the validation of GLHEPro’s results as compared to an actual system and the ASHRAE Handbook Design Method. Summary of the validation.
Input Data Requirements for GLHEPRO
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Monthly and monthly peak heating and cooling loads on the heat pumps
These are obtainable from programs such as HVAC Load Calculations for Windows, Trane Systems Analyzer, and other similar programs. GLHEPRO has an interface to the above-named programs which automates the data transfer. For other programs, the loads must be typed in manually.
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Ground thermal properties
GLHEPRO has a small database of ground thermal properties for a few different ground types. For larger jobs, an in situ test is recommended, using the in situ methodology developed at Oklahoma State University.
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Ground loop heat exchanger information
The user must select a borehole configuration and specify some related additional information - borehole diameter, borehole spacing, grout and piping properties, and fluid type and flow rate. Open and closed rectangle, line, U-shaped, L-shaped, and stacked L-shaped configurations are available; additionally, the Large Rectangle option can be purchased, which provides additional borehole configurations up to 900 boreholes.
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Heat pump information
GLHEPRO has a database of heat pump types from most manufacturers. Any models not available in the database may be added by the user using commonly available catalog data.
GLHEPRO offers an easy-to-use Windows interface. The borehole configurations are chosen from one of the following screens, depending on your version:
easy-to-use Windows interface
Regular borehole field selection
Large rectangular field selection
Heat pumps are selected from a database of heat pumps using this screen
Versions Available
GLHEPRO is now available in three different versions:
GLHEPRO 5.0-30 can size user-specified configurations of up to 30 vertical or inclined boreholes. Custom g-functions are generated using a finite line source model. It can also size horizontal ground heat exchangers – both straight and slinky type heat exchangers. It can perform hourly simulations of GSHP systems with user-specified configurations of up to 30 boreholes or of GSHP systems with standing column wells.
GLHEPRO 5.0-120 does everything that GLHEPRO 5.0-30 can do, plus it contains a library of 407 pre-defined borehole configurations.
GLHEPRO 5.0-400+ does everything that GLHEPRO 5.0-120 can do, plus it can size large rectangular borefields with vertical boreholes, up to 990 boreholes.
Validation
GLHEPro has been validated against measured data from working ground heat exchangers and compared with the ASHRAE Handbook Method. Applying the measured loads on the ground heat exchanger as the design conditions and setting the actual peak temperatures as the user-specified design temperatures, the design methods should give us back the actual design. GLHEPRO gave sizes within 5% of actual; the ASHRAE Handbook method gave designs substantially different from actual. “Why” is explained in the paper cited below that details the comparison.
Cullin, J.R., J.D. Spitler, C. Montagud, F. Ruiz-Calvo, S.J. Rees, S.S. Naicker, P. Konečný, and L.E. Southard. 2015. Validation of Vertical Ground Heat Exchanger Design Methodologies. Science and Technology for the Built Environment. 21(2):137-149.