Heat Pump Scandinavian style Central Heating

[David Morton]

Does any gt40 forum member have experience of Heat Pump systems and if so, what did it cost to install and , approximately, how much does it cost to run it? If you do have one installed, what did you have before and how does it compare.
Dave M

[Ron Earp]

You mean a regular central heat pump? About every forum member in North America will have a central heat pump installed in their house. Works great, cost depends on square footage cooled and how cool you want it.

I've a friend that does central cooling systems and is getting a used one to put in my garage. It is simply too hot here in summer to work outside and be comfortable.

Or do you mean something off the wall that cools with underground water or something like that?

[David Morton]

Ron,
This is a slightly different concept that uses the heat that is stored in the ground (typically 10c+ at about 1m deep all the year round) and uses that stored heat via a POA type of valve to generate hot water. Sort of a refridgerator in reverse. Here is a picture of what gets buried in the ground:
Ground Loops

Ground loops consist of a series of pipes buried in the garden at a depth of 1 metre. The ground temperature at this depth is fairly constant between 7 and 13°C throughout the year. The heat pump uses a ground loop (pipe) with a water and glycol mix to "capture" some of this heat.

There are two main types, and the one to use depends on the amount of land available:
Straight ground loop;
Slinky ground loop;

• More on Ground Loops

Compact Collectors

The patented compact collector allows a ground loop to be used where space is at a premium. The collectors can be buried flat to reduce the depth of the earthworks or vertically to reduce the area needed for the panels.

• More on Compact Collectors

Bore Holes

Bore holes offer a solution where very little land is available. A vertical hole is drilled to a depth of 50 to 80 metres through the rock underneath the garden.

• More on Bore Holes

Streams, Rivers and Lakes

The option also exists to bury a pipe on the bottom of a lake or river and collect heat from the stream water.

• More on lake and river collection

Need I say I no connection to any comapnies supplying this sort of technology.

[Ron Earp]

That is pretty cool, I sort of had it in the back of my mind that you were getting at something like that. Very interesting, I'll read those links since I'm bed ridden with a horrible stomach flu, thanks!

Ron

[Malcolm]

There are two schools of thought on this. First it is a great eco thing and in the long term saves you money. The other is that it is an eco thing but costs a lot to install and the people who buy your house will be the only real beneficiaries. Unless you live to 150! All the people selling will convince you it is worth doing. However I have been to seminars where university professors swear blind it is not cost effective and there are better ways to save/recycle energy. Only do it if you love the planet more than your wallet was my conclusion. You would better spend the extra money on over insulating your house so you use less energy with your current system. Change all light bulbs to low energy (look out for the mercury though and now they do make dimmable ones!) or LED replacements. Do that throughout a house and you can knock up to 75% off your lighting bill, great if you have kids who do not know what a light switch is! And if your wife was born in a barn, put a self closer on your external doors to keep the heat in. And if you are building new, don't forget to insulate the slab (even your garage if you plan to keep a 40 in it)! Heat does get sucked down as well as float up!

IMHO of course, having bought an old house with zero insulation a few years back!

[Malcolm]

To expand on Dave's post above, if you have to heat cold water say from 5 degress C to your lovely bath temp of 40 degrees C then that uses X amount of energy. If the base starting point for heating the water is 10 or 12 degrees C then you don't need so much energy to raise it to 40 degrees. The really clever bit is when the water in your system is hotter already than that water 1 metre under ground as the systems reverses the process to do the same thing. No idea on the detail of how that works though.

Another neat idea is runnig water through hollow roof tiles that all connect together. I saw that over ten years ago.

All these systems work on the principle of differing temperature areas transferring heat to each other and then harnessing it usefully.

IMHO the government should be doing more to get these zero/low energy systems out there so that one day the economies of scale for manufacture will make them propely cost effective and we will all wonder why it wasn't done years before!

[chuck smith]

liquid/ground and liguid/ lake heat pump systems are fairly prevalent around here. We used the local lake for the system at our clubhouse and it works very well and is super efficient but cost 3x as much as a liquid/ air system. air interface systems are of course poor choices for cold climates. Air interface systems cost about 2500 bucks for a garage around here with minimal ducting.

[David Morton]

There are a couple of plus points for me - firstly the current boiler is over the hill (old and outdated) and secondly my garden is being dug up with a small excavator (kubota) to install drainage pipes into a large soakaway (the garden slopes and therefore drains towards the house) so the earth that is dug up and replaced by sand does not get wasted and the kubota can excavate the system for the heat pump at the same time. The finances :the cost of installation has a one time grant grant of £1500 and the new boiler with solar additions was going to be around £3,900 or more so that is going to be 60% of the cost of the heat pump idea and that cost is if there was no other work going on in my garden such as the soakaway.
I've yet to be totally convinced but I've sent out requests for visits by two companies to tell me what they can do.
I might as well do my part as I think I mentioned it before, I feel quite responsible that I played a part in contributing to the large holes in the ozone layer and here in the UK houses have to have a 'passport' on subsequent resale which details every single item such as this sort of central heating , along with insulation, etc.

If it goes ahead and anyone is interested I'll post a few details of what happens.

[Malcolm]

Sounds like if you are to do this, now is the time with all that disruption going on anyway. I would be interested to know in due course if you feel it has lived up to the sales pitch/expectations!

[Brett James-McCall]

Dave,
Are you going to use a Thermal store when doing this? I looked at putting one in during our building work, but we didn't in the end (long story).

Anyway, as well as being able to cennect solar, ground pumps etc, it also has the ability to output wet UFH and potable hot water.

Brett

[David Morton]

Brett,
I'll ask all these questions when I get a 'field' visit from the two companies that are supposed to know all the answers. Me - I know nothing. For the moment......
N power - who have just raised their energy prices by about 20% are giving higher grants than the UK Government. (ie £1500 versus £1200) and the maximum Government grant if I did everything totally 'green' is only £2500. Totally a waste of government time obviously. Did you know that a member of the House of Lords gets £100 every time he signs in. There is a cottage industry for these guys who keep their black cabs waiting with engines running outside while they nip in to the Lords to sign in. Its worth about £16k per year to them. Not a very green thing to do...
I digress.

[Bill Musarra]

David and all,
These systems work very well. They are most cost effective if added during new or ongoing construction projects. The insulation issue is by far the most effective with isosyrine(sp?) at the top. It's not worth it just to tear out the sheet rock and add. If you have zero insulation then it is effective as they bore small holes in the sheet rock and pump it in. This is on the same idea as the expandable foam talked about in one of the threads on insulation. I think it comes in Propane style tanks. Can be added to the raters of the house to keep the attic temps down(or up). Can be done by the average guy. Google foam insulation. They have pics and video. I had a friend who built a farm house and used both in the construction of his house. Got a big energy credit for doing. His sysem tapped into the ground water(read well) and pumped it right back in with a second hole.

Bill

[TonyM]

Hi,

I'm building a new house and this was one of the options I looked at, it was very expensive and the return on investment was 10 plus years. The costs to drill was approx. $20,000 and then all the aditional equipment was another $18,000. So I decided to go with natural gas powered radiant heat instead.

Cheers,