Comments on: Free Energy from Air Heat Pumps – is that Magic?

By: Susan Kraemer

Susan Kraemer — Tue, 01 Nov 2011 19:04:00 +0000

No they don’t pull air from basements. Typically they are on an outside wall, piping the treated air in.

By: Charles

Charles — Tue, 01 Nov 2011 15:23:00 +0000

Susan
I live in Barbados and I have been trying to find coolers that are suitable for homes. This sounds very interesting. Where can I find more information. There is a scarcity of information on the web.

By: Jeremy R

Jeremy R — Tue, 01 Nov 2011 06:11:00 +0000

If I didn’t live in NZ and also have a heat pump I would be confused by this sentence: “They extract heat from ambient air outside, filter out particles, molds and pollens and bring heated, dried air inside, using a process a bit like the refrigerator working in reverse.”

The part where you wrote: “bring heated, dried air inside,” makes it sound as though air comes from outside to the inside. I think you understand that is not the case but just wanted to clear it up.

The radon comment below should be retracted based on how impossible that there is any relationship between basements and heat pumps.

By: Susan Kraemer

Susan Kraemer — Mon, 31 Oct 2011 23:32:00 +0000

A form of green energy that seems below everyone’s radar! I knew nothing about it, despite writing (and hence reading) about such matters for the last 4 years! While ground heat exchanges are well known.

By: Susan Kraemer

Susan Kraemer — Mon, 31 Oct 2011 23:20:00 +0000

Yes, at least up around Auckland; temperatures are pretty moderate – about like the Bay Area of San Francisco. Never far too hot or freezing cold.

By: Susan Kraemer

Susan Kraemer — Mon, 31 Oct 2011 23:17:00 +0000

Thanks, Tom. So, I guess I learned something by leaving – I never knew about air heat pumps while in the US. (It did seem odd that such a good idea would be unknown in the US!)

By: NickC

NickC — Mon, 31 Oct 2011 19:09:00 +0000

Important to note how outside temperature effects efficiency. The same principle that supplies the “magic,” decreases efficiency substantially with air source units as you approach the more extreme ends of the temperature spectrum. In Arizona if its 110 outside your air source heat pump will operate at much lower efficiently than its rated at, same things if its 30 degrees or colder outside. A place like San Diego? Perfect. For most of the country though backup heat is always required.

By: Anonymous

Anonymous — Mon, 31 Oct 2011 19:01:00 +0000

Perhaps an inverter with a larger surge capacity? I picked my inverter based largely on how much surge power it could handle so that I wouldn’t have problems powering my shop tools.

Or a ‘soft start’ controller on the compressor. My submersible well pump has a soft start ability which allows me to power it with smaller gauge wire between house inverter and well. Without the low surge I would have had to spend a heck of a lot more money for copper.

By: Anonymous

Anonymous — Mon, 31 Oct 2011 18:49:00 +0000

Heat pumps have been in use for many years (decades) in the US. They probably slipped below your radar while you were visiting us here.

But, thanks for bringing the concept of “free heat”. I had never thought of heat pumps in that way, and it’s right. Heat pumps can capture heat that’s lingering around outside and move it inside for less money than what it would take to make “new heat”.

By: Anonymous

Anonymous — Mon, 31 Oct 2011 18:32:00 +0000

“It’s kind of how a fridge works:”

It’s exactly how a fridge works.

In ordinary heat engines,
High-temp thermal energy –> low-temp thermal energy + electrical energy.

Heat pumps reverse the process:
Low-temp thermal energy + electrical energy –> high-temp thermal energy.

Which is why air-source heat pumps don’t work so well in cold climes. The lower the temperature of the air, the higher the proportion of heat delivered has to come from electricity.

By: Crock48

Crock48 — Mon, 31 Oct 2011 16:50:00 +0000

I can see this being a viable option in some areas of the country but we also have to remember that Radon can exist below a dwellings basements so the air heat pump system needs to be highly evaluated depending on which area of the country you are in.

By: Dismissed

Dismissed — Mon, 31 Oct 2011 15:10:00 +0000

this is a poorly written article and difficult to read. there is so much information that is missing

By: Bob

Bob — Mon, 31 Oct 2011 14:09:00 +0000

I also live in Arizona USA like Susan who posted below. Since we have abundant sunshine, I heat my 1600 sq ft home with solar heat. I built 4×8 collector panels and force air through them into the home.
It is about as close to free heat that you can get and eliminated about 80 percent of the propane I had been using for winter..

By: Tom Garven

Tom Garven — Mon, 31 Oct 2011 14:04:00 +0000

Susan:

I live in Arizona, USA and there are literally hundreds of thousands of heat pumps in the more moderate temperature zones in the U.S.[Nevada, Utah, California, Oregon, Texas, New Mexico, etc.]. These units are usually about 3 times more efficient than electric heating and the units work well down to about 35 degrees F. Newer models with a different refrigerant gas like R410 will operate down to about 10-20 degrees F and some companies are working on experimental models using CO2 which will work far below freezing. Newer heat pumps can be purchased with super-critical water heating units so you heat or cool your home while also heating your water.

I could not imagine living without my air source heat pump.

By: Colin

Colin — Mon, 31 Oct 2011 13:53:00 +0000

I used an “air heat pump” to heat and cool my 3500 Sq Ft house for some 15 years in a Northern Canadian location. Spring, Summer and Fall it worked as advertised, however, when outside temp dropped below -5C it stopped working and the bank of 8KW radiant heaters took over and then any overall power savings evaporated. I replace it with a very effective ground source system as soon as I could afford it.

By: Bob

Bob — Mon, 31 Oct 2011 13:35:00 +0000

What I understand is that a ground source heat pump is considerably more efficient than an air source type. I am 100 percent off grid and cannot use either due to start up power required to start the compressor.

By: Anonymous

Anonymous — Mon, 31 Oct 2011 07:33:00 +0000

Heat Pump is a bit of a generic term… In Australia they’re just called reverse cycle air conditioners and it has been a standard feature for decades. It only requires a solenoid value within the unit to switch between heating and cooling modes. Perhaps the “name” has more to do with climate as I would expect (although I’ve never been there) that NZ is a fair bit cooler than Aust so heating is more in demand than cooling!

In Aust there is also a range of hot water heaters that use a small AC system on top that are referred to as “heat pump” models. They are ALOT more energy efficient than conventional electric water heater as they ‘move’ heat rather than ‘make’ heat in a resistive element.

By: Susan Kraemer

Susan Kraemer — Mon, 31 Oct 2011 06:52:00 +0000

Terminology changes: tell me about it!

In that case then, why don’t US air conditioner manufacturers use air conditioners/”heat pumps” to also move heat indoors in winter (and not just move heat outdoors in summer) if the technology is the same? Other than ground heat pumps, I am not aware of heat pump use in the US.

By: Anonymous

Anonymous — Mon, 31 Oct 2011 06:22:00 +0000

Air conditioners only cool spaces. Heat pumps are designed to work in two directions, to move heat in from the outside or heat out from the inside.

Here’s a good overview. Looks like the first heat pump was built in the 1850s.

http://en.wikipedia.org/wiki/Heat_pump#History

Part of the issue might be NZ vs. US terminology. I think of most of NZ as having a moderate climate. Just the right place for heat pumps.

Some place I’ve traveled calls air conditioners “chillers”. Took me a bit to figure out what they were talking about.

By: Susan Kraemer

Susan Kraemer — Mon, 31 Oct 2011 06:15:00 +0000

Why don’t the companies simply call them air conditioners then? It is intriguing. Maybe air conditioners are less marketable here: even average people are very green.