Heat Pump question..I know

Paul Mitchell_2

Hey guys
Just wondering if anybody has ever heard of a heat pump with some kind of propane secondary heat. I know normally electric backup or a furnace possibly. My inlaws are building a house in NC and giving me info second hand. I would assume it is a propane furnace with a heat pump.
Thanks
Paul

Jeff Lawrence_24

Dual Fuel?

Around here, it's called a dual fuel system. Most people never run the heat pump around here at temps below 45 degrees.

Jeff

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Tom_35

Dual fuel heat pumps

The back-up heat is generally gas or propane. The thermostat can be switched to "emergency heat" and the system automatically will heat with the back-up heat.

A load calculation should be run on the home to determine the proper size of the system. This will also provide the balance point of the system (the temperature at which the heat pump can no longer heat the home and will need help). This temperature will vary as most systems in Arkansas have a balance point below 30 degrees.

One of the major objections to heat pumps is the cooler air that comes from the supply air registers. Consider using a FanHandler control that will automatically slow the fan down, thereby making the air warmer. Go to www.fanhandler.com for more info.

Tom A

Paul Mitchell_2

I thought so

So the secondary "emergency heat" is a propane furnace. The guys talking to my in-laws seem to be making it sound a little complicated.

Sean Finnegan

outside reset (weather compensation)

           
I would like to know if there is any advantage in using outside reset (weather compensation) for the following system.

The system is a ground source heat pump, supplying hot water to a Radiant system in a well insulated 2000 square foot house. Piping is buried in a four inch concrete slab.

House has two floors, two zones. Each zone has eight circuits. Temperature control of each circuits is by a digital thermostat.

Flow temperature from heat pump is 95 degree Fahrenheit. Outside design conditions are 25 degree Fahrenheit.

All advice and help appreciated.

Sean Finnegan
*************************************
Renewable Energy Systems (Ireland) Ltd
74 Crossan Road
Mayobridge
Newry
Co Down
N Ireland BT34 2HY
Phone 028 308 50079
Email: sfinnegan@eircom.net
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Tom_35

Outdoor reset

Sean,

I have an ECR direct exchange heat pump system in my home and I added outdoor reset to it this year. It has done away with the floor overshooting temps during mild weather. I had used a 90% boiler previously, and now have added the heat pump and piped it where I can use either of the 2. Lots of piping, heat exchangers, wiring,---but everything runs great.

I am metering usage as well.

Tom A

imatellerslie

reset w/ geothermal

Sean,

It seems to me that if you use reset to lower the temperature to which the heat pump heats the water, that will raise the efficiency of the heat pump. That, coupled with the reduced likelihood of temperature swings with the digital control of the zones you mentioned, makes it worthwhile.