Numerical Investigation of the Long-Term Performance of Solar-Enhanced Novel Energy Pile-Based Ground Source Heat Pump Systems for Space Conditioning Applications in Cold Climates
Date
2024-07-11
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Abstract
Integration of renewable energy technologies in building energy systems has become essential to meet the emission targets by 2050, especially with buildings being the second largest energy consumer globally. The ground source heat pump (GSHP) technology is one such technology for space conditioning that offers high performance compared to other technologies. High installation cost of the ground heat exchanger has been limiting the wide adoption of GSHPs. Energy pile technology offers a low-cost alternative to the conventional ground heat exchanger, taking advantage of the shallow installation and less land usage. However, studies on the use of energy pile-based GSHP systems in cold climate residential applications are limited. This study numerically investigates the performance of a GSHP system which utilizes a novel energy pile design in a residential application in Calgary, AB, Canada. A validated numerical model coupled with realistic building load profiles has been utilized for the analysis. The system’s long-term performance under three pile design thermal load conditions (0.3 ton, 0.4 ton, and 0.6 ton) and four installation configurations has been investigated. Results indicate that the ground temperature at a declines by 0.18 K, 0.25 K, and 0.41 K per year for the 0.3 ton, 0.4 ton, and 0.6 ton load conditions. The average heating COP of the system declines by 0.006, 0.011, and 0.021 per year. The best performance is given when the piles are installed beneath the building basement. Subsequently, a solar-assisted GSHP system (SAGSHP), which utilizes solar photovoltaic/thermal collectors, was proposed to improve system performance while mitigating ground thermal imbalance. SAGSHP was investigated under two pile design thermal load conditions and four collector sizes. The results show that solar integration improves the heat pump performance by 10.6 – 15.7%. Moreover, ground thermal balance can be achieved by thermally recharging the ground. The economic analysis shows that the payback periods of ground coupled systems are generally high without incentives compared to baseboard heaters + air conditioner and natural gas furnace + air conditioner combinations. The optimum SAGSHP systems achieve emission reductions of 88.6 – 91.8% and 82.1 – 87.2% compared to these conventional systems.
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Keywords
ground source heat pump, long-term performance, cold climate, solar-assisted ground source heat pump, energy pile
Citation
Beragama Jathunge, C. (2024). Numerical investigation of the long-term performance of solar-enhanced novel energy pile-based ground source heat pump systems for space conditioning applications in cold climates (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.