An experimental investigation on ground heat flow balance issue for a GCHP

For a ground-coupled heat pump (GCHP), it is vital to keep the ground heat flow balanced in order to achieve sustainable energy-saving operation. However, the importance of this issue has not been well studied. Focused on the heat flow balance issue, this paper made an exclusive experimental study using a newly installed GCHP system with the designed cooling capacity 1960 kW and heating capacity 1590 kW. The GCHP system was equipped with a data acquisition system and had temperature sensors installed in the ground-coupled heat exchanger (GCHE) field. This paper revealed the 1-year GCHP experimental data together with analyzed results. Theoretical analysis worked out that the GCHE ground had an annual energy accumulation of 1.15 × 10-super-10 kJ. With that, it predicted an annual ground temperature rise 2.1 K/a, which was close to the recorded rise 2.0 K. A conclusion was drawn that for a GCHP system, it is vital to make a balance design for the GCHE heat flows and to equip supplement heat sink/source technologies to tackle the unbalanced heat flow issue. Copyright The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com, Oxford University Press.