Abstract: A geothermal heat exchanger having modular tube bundles is provided in a novel heat pump system. The modular tube bundles are particularly adapted to be placed within a narrow excavation in the ground, such as a trench excavated using a backhoe bucket, which trench can be V-shaped. A heat resistant soaker hose is disposed above or about the rectangular tube bundles. The soaker hose is coupled to a water source and has a number of apertures for leaching water to the soil surrounding the tube bundles for dampening the soil around the tubes and providing better thermal heat transfer and compaction. Individual tubes of the tube bundles can be made rifled or finned for better heat transfer. A scroll compressor with relatively orbiting spiral scroll fins is provided rather than a reciprocating piston compressor.