Micro Hydro Heat Pump project needs design resources

[microhydro]

I am designing and building a water to water heat pump to be directly driven (the runner is fixed to the end of an open drive compressor) by a turgo runner. I am looking for design resources for many aspects of this project.

A few initial questions:
1. Which open-drive or automotive compressor would be the best choice. Efficiency is a high priority.
2. My water source is a 40 degree F spring running at 5gpm. Can I capture heat below freezing?

PROJECT SPECIFICATIONS

Mechanical Input Power: 1-3 kw
RPM Range: 1000-2500 rpm
Hot water will be used for hydronic heating

 

[microhydro]

3.24" Pitch Turgo Runner, 2500 RPM.
Larger runners operate at lower RPM.