Heat Pump Technology to replace central heating boilers

[Fossell]

Hi there,

I would like to introduce the topic of heat pump technology as a viable replacement of the standard gas powered boilers we all use.

For those who dont know, heat pumps are basically air conditoning units like those that cool a building space, but in reverse.
They use the temperature difference of the air outdoors and the refrigerent contained in the heat pump unit to create heat that is useable throughout the home for heating and heating water.

Its not a new technology by any means but with soaring energy prices and greater efficiency in the design of heat pumps, they are now poised to enter the domestic market and replace even the most efficient condensing boilers.

The main selling point is a ratio used that states a normal heating system will use 1kw of energy to produce less than 1kw of heat output. Where as heat pumps will use 1kw of energy and produce 3kw of heat energy. This ratio is being improved upon all the time.
Hence the potential savings for the consumer are great while also lowering ones carbon emission. (if thats something your bothered about?!)

I have been researching alternative heating sytems for some time and the main exisiting technologies that will be fighting to replace your boiler are heat pumps and MicroCHP.

Heat Pumps
Heat pumps come in to main flavours. Ground source and air source.
You may have heard of ground source heat pumps. They basically take the heat from the ground in the same way but the downside is the cost and space requirements for laying masses of pipe underground to collect this heat.
Hence 'air source' heat pumps seem the most viable option for most domestic situations.
Where previosly ground source pumps have always been considered more efficient than air source pumps, improvements in efficiency are leading to air source pumps matching and beating the efficiency of ground source pumps. Plus they offer great ease of installation compared to ground source.

MicroCHP
This is a stirling engine technology that still uses gas but at the same time as heating the home/water, will create electricity. Like a mini power station in your home. This electric can be used in the home or sold back to the national grid.
Several large boiler manufactures are readying units that will be the same size as your current combi boiler and will be fairly easy to fit.
The downside of this technology seems to be that it still uses gas, only produces electric when the heating is on and the electric produced seems to be currently limited to about 1kw which limits the amount you can 'sell' back to the energy provider.
Indeed your energy provide may well cap the amount you can sell back anyway plus there buy-back rate is open to fluctuation thus limiting any financial savings you could make.
Hence I feel that heat pump technology stands to be the best new competitor in the carbon emission cutting, money saving market of domestic heating.

Id be interested to hear comments and views from everyone on the topics.

[robin9342]

I read about heat pumps many years ago and often wondered why they are not far more widespread. I suppose they are not widely known about because its not in the energy supplier companies interests for us to use considerably less energy than we do now: Imagine the effect on their profits if every home had one installed!

Further reading for anyone interested:
Heat Pump Network Home Page

[kennythecelt]

Good post Fossell and Robin.

I am intending to put an air source heat pump into the new house I am building, combined with a couple of solar panels. I sold my last home to pay off all debts and currently live in private rented. The house will be of SIP panels- Structrural Insulation Panels- increasingly stringent thermal values will be set for all new homes and this will be difficult through traditional building methods- hence the move to European and American technologies, given limited oil reserves globally and the demand on whatever there will be in the future. The two combined methods should see annual heating and water bills as low as £200, whereas I currently pay about £2000 with oil and coal.

For information.

All Power Utility companies will operate a CERT (Carbon Emmission Reduction Target) scheme from 1/4/2008. Effectively this a government tax on their profits which the utilities must spend on reducing carbon emmissions, targeting a high percentage of fuel poor qualifying households. Apart from loft and cavity insulation, for the first time, renewable technolgies will qualify, inc solar panels, ground and air source hear pumps. This could see a big reduction in the price. A lot of this work will be in partnership with local authorities and the Warm Front scheme.

[Fossell]

Good plan combining panels with the air heat pump. After all the air pump still needs electric to run so the more of that electric coming for free from the panels the better.

Make sure to check out the latest air heat pump technologies available as some that are being marketed are nothing more than swimming pool style heaters that works on the same basis, but I believe, are noisy and less efficient.

Can provide some links if you like.

[kennythecelt]

Thanks Fossell, will do.

I would be really keen to follow up any links you might have. It would also be useful for others that might consider it at some point.

Many thanks!!

[Bigmac versus]

One thing that goes against them, COST. I have spoke to customers regarding solar and ground source heat pumps but when put in comparison to a HE condensing combi the decisions are all the same in the end.

Im sure in around 10 years these will be more affordable and will be the norm as condensing boilers are now.

[kennythecelt]

Originally Posted by Bigmac versus

One thing that goes against them, COST. I have spoke to customers regarding solar and ground source heat pumps but when put in comparison to a HE condensing combi the decisions are all the same in the end.

Im sure in around 10 years these will be more affordable and will be the norm as condensing boilers are now.

Yes, agreed Bigmac. The cost should hopefully come down as demand increases in the future.

[zilch]

If using an air source heat pump what happens in situations like today, ie freezing temperatures, and no heat in the atmosphere. You would need a back up heat source.?

[Conniff]

If anyone is interested there are some vids on youtube. This seems to be the most informative even though it is US.

YouTube - Envision Series by WaterFurnace

This is Geothermal and not air. I enquired about geothermal a while ago and was very impressed by the costs.

[robin9342]

Originally Posted by zilch

If using an air source heat pump what happens in situations like today, ie freezing temperatures, and no heat in the atmosphere. You would need a back up heat source.?

Ah, but even in low temperatures, there is still heat in the air/ground. I don't know how well current heat pumps deal with low ambient temperatures, but bear in mind that all objects above absolute zero (-273.15 celsius) contain some heat energy, albeit very difficult to extract.

[robin9342]

Originally Posted by Conniff

If anyone is interested there are some vids on youtube. This seems to be the most informative even though it is US.

YouTube - Envision Series by WaterFurnace

This is Geothermal and not air. I enquired about geothermal a while ago and was very impressed by the costs.

This is probably nit-picking, but geothermal refers to any method of extracting heat from the ground including direct heating of water and electricity generation. In the context of heat pumps, it is "ground source"

[kennythecelt]

Here is a link to the Energy Savings Trust, the page for information on renewable technologies. This gives useful background info.

Renewable energy types - solar power, wind turbines, solar heating - Energy Saving Trust

Regards, Kenny

[kennythecelt]

And a link to the Carbon Trust

Helping business and the public sector cut carbon emissions | Carbon Trust

Both sites give lots of information on renewables and rated domestic appliances. Likewise, there is information on grants, which may be useful for someone.

Regards, Kenny

[Fossell]

Originally Posted by zilch

If using an air source heat pump what happens in situations like today, ie freezing temperatures, and no heat in the atmosphere. You would need a back up heat source.?

Apparently - new technologies with heat pumps are allowing them to operate at much lower temperatures. There just has to be a difference between the air/ground temp and temp of the refrigerent in the pump for it to extract the heat.

Dont know the difference temps or minimum effective temps.
I know that older air models are known to struggle in the colder the air gets but this may be less true of newer purpose built models.

Thats where ground pumps win over as the ground temp is a constant 11-12 celsius.But who wants to dig up there whole garden or drill 50m bore holes??!!

[Conniff]

You have to think carefully before installing an air source heat pump.

They are not really pumps, but compressors just like in your fridge but bigger. The average cost of a 12kw pump is in the region of £6000, so you need to take that into consideration as well as any saving in electricity or gas.

If you pay say £50 per month for heating now, and the pump can cut that down by half £25 per month, then you need to add the cost of the pump + (6000/25 = 240) so it will in fact still cost you £50 per month for 20 years and then you will start to make an actual saving.

The only way to make any real saving is to have the pump supplied and fitted for free.