Primary-secondary de-coupled ground source heat pump systems coefficient of performance optimization through entering water temperature control

A control technique to optimize an existing de-coupled primary-secondary ground source heat pump (GSHP) loop system using site data is presented. The proposed control algorithm improves system performance by optimizing the primary loop pump's flow of well water into the secondary loop to deliver more favorable water temperatures to downstream heat pumps. Improvements are presented on a specific installation using 15-minute interval data collected from a building automation system (BAS) for a period of one year. Energy savings are calculated to demonstrate the benefits of improved heat transfer by modulating the building heat pumps condenser/evaporator entering water temperatures to improve COP. The specifics of how to implement this control scheme with an existing de-coupled GSHP system are provided. By monitoring the building HVAC operations, and optimizing the entering secondary loop water temperature, a 3% decrease in annual heat pump energy consumption is achieved. (C) 2016 Elsevier Ltd. All rights reserved.