Engineering360: "Types of geothermal heat pumps"

During summer, ambient temperature goes to +40 C and will be around this temperature for at least 6 hours during day .

is it possible to design a solar heat pump system that is not very much more costly than the electrical refrigeration system for air cooling ?

The geothermal systems you have mentioned are indirect systems. They use a closed loop of a heat transfer fluid to move the heat energy between the ground and the refrigerant. This requires a pump to move this fluid and a receiver tank or similar device to allow for volume changes.

I have seen at least one (early) maker of geothermal systems use a direct heat transfer approach, with the refrigerant fluid being sent through the ground coils directly. I believe this approach has been abandoned by now because of problems with leaks, contamination of the soil, balancing the amount of liquid-versus-gas in the large ground loop, as well as others.

In some cases, the fluid returning from the ground loops is at a temperature suitable for direct heat exchange with the air indoors, thus requiring no compressor and giving a lower operating cost.

--JMM