Therma-Stor Products
Manufacturer of free-standing dehumidifiers, ducted/installed dehumidifiers, commercial dehumidifiers, ventilation systems, heat recovery water heaters, restoration equipment (including dehumidifiers, air movers, meters, & instruments) & more.
http://www.thermastor.com/

Spontaneous Flow Heat Pump
Le Site de la pompe a chaleur a ecoulement spontane
http://www.new-energy-paces.com

Meterman Pump Systems, Inc.
Meterman Pump Systems customized pump systems, sales and service.
http://www.meterman.us/

Geothermal Heat Pump Energy - How It Works
Geothermal Heat Pumps by Sunteq/Enviroteq
http://www.geothermalheatpump.com/how.htm

Geothermal Heat Pump Systems
Geothermal Heat Pump Systems - How does a geothermal heat pump work, diagram of a geothermal heat pump - Everything you need to know about geothermal heat pumps.
http://www.geothermal-heat-pump-resource.org

Wikipedia: Heat Pump
Free encyclopedia article covering the technology basics. Addresses background, thermodynamic aspects for different types of heat pumps.
http://en.wikipedia.org/wiki/Heat_pumps

Water and Energy Systems Corp
Commercial and residential geothermal heating and cooling systems and water heating systems and GeoExchange heat pumps serving all of New England; Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island and Vermont
http://www.northeastgeo.com

The Engineering Page
The engineering page provides webbased calculation and information services for engineers. The calculations include pressure drop, line sizing, pump applications, centrifugal pump sizing and heat exchangers including thermal rating. The calculations can be used free of charge.
http://www.the-engineering-page.com

ICE Energy Ltd.
Ground Source Heat Pumps; Heat Pumps; geothermal;
http://www.iceenergy.co.uk/

Heatran
Korea. Specializes in design of heat transfer equipment and related systems, including heat exchangers, heat recovery steam generators, waste heat boilers, economizers, condensers, heaters, and coolers.
http://www.heatran.com/