# Difference between All Water Systems

**URL:** <https://community.blackspectacles.com/t/difference-between-all-water-systems/3350>\
**Category:** Project Development & Documentation\
**Created:** [July 24, 2021, 6:08pm UTC](https://community.blackspectacles.com/t/difference-between-all-water-systems/3350 "2021-07-24T18:08:43Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![alexfinolr](https://blackspectacles.com/uploads/images/3.png) [@alexfinolr](https://community.blackspectacles.com/u/alexfinolr)\
**Post date:** [July 24, 2021, 6:08pm UTC](https://community.blackspectacles.com/t/difference-between-all-water-systems/3350/1 "2021-07-24T18:08:43Z")

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I dont really understand what the difference is between closed loop heat pumps and fan coiled terminals. They sound extremely similar to me.

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**Author:** ![coachdarionziegler](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.blackspectacles.com/coachdarionziegler/32/1272_2.png) [@coachdarionziegler](https://community.blackspectacles.com/u/coachdarionziegler)\
**Post date:** [July 26, 2021, 7:23pm UTC](https://community.blackspectacles.com/t/difference-between-all-water-systems/3350/2 "2021-07-26T19:23:31Z")

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Hi @alexfinolr ,

Great question! I found a lot of these topics super tricky when I was studying because a lot of times my projects just have a couple RTU’s and individual PTACs.

The main difference between a fan coil and heat pump is that fan coils are simply blowing air across a coil to heat or cool a room. Heat pumps use the refrigeration cycle to cool or heat air, which is then blown by a fan throughout the ducts. A direct loop heat pump utilizes the ground as a more effective heat exchanger than air.

In the case of closed loop geothermal heat pumps, piping is ran in a continuous loop underground from and back to the heat pump.

Check out this handy website from [energy.gov](http://energy.gov) on heat pumps:  
[Geothermal Heat Pumps | Department of Energy](https://www.energy.gov/energysaver/heat-and-cool/heat-pump-systems/geothermal-heat-pumps)

And I re-read through the Wikipedia articles on heat pumps and fan coils to help make sure I was explaining properly:

> **[Ground source heat pump](https://en.wikipedia.org/wiki/Ground_source_heat_pump)**
>
> A ground source heat pump (also geothermal heat pump) is a heating/cooling system for buildings that uses a type of heat pump to transfer heat to or from the ground, taking advantage of the relative constancy of temperatures of the earth through the seasons. Ground source heat pumps (GSHPs) – or geothermal heat pump (GHP) as they are commonly termed in North America – are among the most energy-efficient technologies for providing HVAC and water heating using far less energy that can be achieved b...

> **[Fan coil unit](https://en.wikipedia.org/wiki/Fan_coil_unit)**
>
> A fan coil unit (FCU), also known as a Vertical Fan Coil-Unit (VFC), is a device consisting of a heat exchanger (coil) and a fan. As part of an HVAC system found in residential, commercial, and industrial buildings using ducted split air conditioning or with central plant cooling, a fan coil unit is often connected to ductwork and a thermostat to regulate the temperature of one or more spaces as well as assisting the main air handling unit for each space if used with chillers. The thermostat cont...

Of course, Black Spectacles PPD “OBJECTIVE 3.1: DETERMINE MECHANICAL, ELECTRICAL, AND PLUMBING SYSTEMS” lectures are a huge help for understanding systems better.

Hope this helps!  
-Darion