Analysis of Retrofit Solutions of a Ground Source Heat Pump System: An Italian Case Study

Abstract

Ground coupled heat pumps are a notoriously efficient system for heating and cooling buildings. Sometimes the characteristics of the building and the user’s needs are such that the amount of heat extracted from the ground during the winter season can be considerably different from the amount injected in summer. This situation can cause a progressive cooling or heating of the ground with a negative effect on the energy efficiency and correct operation of the system. In these cases, an accurate sizing has to be done. In systems already built, it could be necessary to intervene a posteriori to remedy an excessive ground thermal drift due to the energy unbalance. In this work, such a situation relating to a real office building in Italy is investigated and several solutions are examined, one of which has been then implemented. In particular, a hybrid heat pump using as heat sink both the ground and external air is compared with common solutions through computer simulations using a dedicated numerical model, which has also been compared with monitoring data. As a result, the hybrid heat pump shows better performance and limits the thermal drift of the ground temperature.

Determination of the Selected Wells Operational Power with Borehole Heat Exchangers Operating in Real Conditions, Based on Experimental Tests

“…Real measurement results are required for calculations and simulations. A number of studies [25][26][27][28][29][30][31][32][33][34] have been conducted to evaluate the performance of BHE in heat pump systems. All of these studies described the impact of BHE based on the evaluation of COP improvement in these systems.…”

Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)

“…Real measurement results are required for calculations and simulations. A series of studies [50][51][52][53][54][55][56] have been carried out to evaluate the efficiency of BHE in heat pump systems. All of these studies described the impact of BHE based on the evaluation of COP improvement in these systems.…”

“…However, if the temperature of the heat source drops consistently, it may be necessary to support regeneration, e.g., with solar collectors in the summer. The available literature, e.g., [54,[71][72][73][74][75][76][77], shows that in cold regions it seems necessary for long-term use.…”

Upgrading a District Heating System by Means of the Integration of Modular Heat Pumps, Geothermal Waters, and PVs for Resilient and Sustainable Urban Energy

“…Heat pumps were also considered as a tool for the accumulation of renewable resources generating electricity and their integration into district heating [12]. Generally, hybrid heat pumps show better performance in a system [13]. A geothermal heat pump system is found to be resilient when subjected to the major climate pathways [14].…”