A study in Algeria looked into using a mix of solar and geothermal energy to heat homes and provide hot water. The goal was to find the best setup for a building in Batna, Algeria using a system called Solar-Assisted Ground Source Heat Pump (SAGSHP). They tested four combinations and found that a 7.7 kW heat pump with flat solar panels worked well. The system had good results with a heat pump efficiency of 3.48 to 4.55. By recharging the ground, they could reduce energy use by 30.4% compared to just using a ground source heat pump (GSHP), which helped keep the system stable and efficient.