The DOE/ORNL Heat Pump Design Model (HPDM) is one of the most widely used software products of the BTC Heating and Cooling Program. Over 300 copies of the model have been distributed to users worldwide, and it is actively used by companies representing about 30% of the U.S. unitary equipment market.
In the latest HPDM release, Mark V, capability has been included to simulate air-to-air heat pumps using R-410, R-507C, and R-404A leading near-azeotropic HFC alternatives to R-22. One natural refrigerant, propane (R-290), has also been included. Users have included Allied-Signal, which used the model to optimize heat pump systems using R-410A and was able to show an improvement in efficiency over R-22, and Purdue, which selected the HPDM over two other public domain models for use in simulating heat pump performance at extreme ambient conditions under an ASHRAE-funded research project. An interactive version of the Mark V model is available on the World Wide Web at http://www.ornl.gov/~wlj/hpdm/doehpdm.html.
ORNL and DOE are currently interviewing current and potential users of the HPDM to determine what improvements are needed to maintain and improve its usefulness to U.S. industry and researchers for future heat pump/air-conditioner product design and development. Possible improvements include
addition of a Windows-type interface with expanded coverage of state-of-the-art air- and refrigerant-side enhanced surfaces, along with more validation against high-efficiency equipment;
redeploying the HPDM in a fully modular fashion so that the user can simulate different system configurations (alternative sources/sinks, desiccant systems, alternative refrigeration cycles, manufacturer-specific algorithms, etc.);
having the model serve as an equipment module within a building simulation code to allow assessment of the energy savings impacts from engineered combination of heating/cooling equipment with ventilation/humidity control systems, heat recovery/reclaim systems, and improved heating/cooling delivery systems.