air source heating

[thompsk]

Hello chaps, I have today learnt that myself and family have been accepted for a government grant for a fully fitted air source heat pump system, so was just wondering if anyone knows how good these systems are and if anyone has had dealings with the grant awards ?

Just for reference we live in a medium sized two bed terraced cottage with at the moment oil fired wet heating system with 6 rads 2 double rads approx 900mm wide, 2 single rads approx 900mm wide and 2 single rads approx 600mm wide.

 

[doitall]

You have to be carefull as we really need more information, about what the plan is.

Air source works well at 30-40c an ideal temperature for underfloor heating, now for the problem, you have radiators at present and they are designed for 85c, as you can see the rads ain't gonna get very warm.

Unfortunately you/they will have to calculate the heating requirements at the much lower temperature and re-size all the radiators, or dig everything up and install underfloor heating.

What secondary heating are they giving you you.

 

[thompsk]

As a secondary source of heating we have a wood burning stove, we were going to swap our existing stove for one we have just bought with a boiler in, would you suggest we still swap the stove for the boiler stove ?

 

[doitall]

Yes you will need to supplement the heating on the coldest days, and you need to cleanse the hot water system once a month by increasing the stored water to 60c.

 

[thompsk]

and you need to cleanse the hot water system once a month by increasing the stored water to 60c.

For legionella ?

 

[Norcon]

Daikin are releasing a follow on from their air source Altherma system unto the market and uses a two stage refrigeration cycle which can heat water to 80c.

http://www.altherma.co.uk/news/items/high-temperature-altherma.jsp

 

[jon26]

Daikin are releasing a follow on from their air source Altherma system unto the market and uses a two stage refrigeration cycle which can heat water to 80c.

http://www.altherma.co.uk/news/items/high-temperature-altherma.jsp[/QUOTE]


These heat pump companies are trying to introduce models which provide higher temperatures, however they fail to say by how much the COP (efficiency) is affected.

Air source heat pumps on a good day, producing say 35degC are around 300% efficient. Producing temps of 80 degC that efficiency may be nearer 200%. Divide the cost of a unit of electic by 2 and it is very similar running cost to a using a gas boiler!

Heat pumps are best with u/f heating as the previous post says.

 

[Norcon]

Wall hung radiators can be oversized or if undersized utilise WC or a combination of both. A bi-valent heating system is another option.
The holy grail is to be able to produce higher temperatures to supply domestic hot water at a reasonable temperature...65-70c.
Daikin have just provided the holy grail IMO.

 

[doitall]

and you need to cleanse the hot water system once a month by increasing the stored water to 60c.

For legionella ?

Yes.

I like the look of the Daikin that Norcon posted the link to, must do some research.

 

[jon26]

Wall hung radiators can be oversized or if undersized utilise WC or a combination of both. A bi-valent heating system is another option.
The holy grail is to be able to produce higher temperatures to supply domestic hot water at a reasonable temperature...65-70c.
Daikin have just provided the holy grail IMO.

The unit looks like a good bit of kit. What cylinder would you use with it?

 

[Norcon]

Daikin supply a cylinder to compliment the Altherma system in three capacities.
Afaik it's an UV cylinder.
I have never fitted Altherma's but have fitted Daikin commercial equipment in the past and are highly rated in the refrigeration industry.

 

[thompsk]

Just an update really, finally got the system installed one of http://www.heatking.co.uk/bwarmi.html we have the 900i system.

Constant heat output of 54 deg when system is running, 2kw input 9kw output, 2kw standby through flow heater also installed for top up as required for cold days.

Energy meter says 48pph on start up which drops to 8pph when system has warmed up.

All new pipework fitted new rads and a new kingspan water tank, gotta say im well impressed by this system....and we got it all for free approx £6800 pounds worth.

Downside ? contractor ripped my carpet and is ignoring my letters grrrrrrrrr[/url]

 

[GeorgeBramwell]

Just an update really, finally got the system installed one of http://www.heatking.co.uk/bwarmi.html we have the 900i system.

Constant heat output of 54 deg when system is running, 2kw input 9kw output, 2kw standby through flow heater also installed for top up as required for cold days.

Energy meter says 48pph on start up which drops to 8pph when system has warmed up.

All new pipework fitted new rads and a new kingspan water tank, gotta say im well impressed by this system....and we got it all for free approx £6800 pounds worth.

Downside ? contractor ripped my carpet and is ignoring my letters grrrrrrrrr[/url]

The COP. The makers always specify the peak COP, not average, which may be around 2.5 in air-sourced. Then you are in oil boiler costs territory, and oil is a fraction of the installation costs.

When a heat pump cannot raise the DHW to over 60C, expensive to run electric resistance heaters are used, which usually is not taken into the cost equation.

Currently per kWh:

• oil: 4.5p
• natural gas: 2.8p
• electricity: 10p

Installation of heat pump systems is approx £3,000 more than oil. Currently that is approx a 10 year payback.

Historically electricity has tended to be 3 to 4 time the cost of oil, which now is hovering around twice as much. If this reverts back and electricity prices rise, then payback is even longer than 10 years.

If you have a natural gas pipe to the house always go for gas. The boilers are very cheap, cheap to install, a large service base, cheap to service and cheap to run. No contest.

Anyone got any independent tests on this Daikin heat pump a link was given to?

A heat pump is only worth it if:

• There is no other alternative, maybe because of no space for an oil tank
• You need A/C, as they are reversible. But in UK homes you don't need A/C and fitting in measures to cool is not expensive: blinds, fans, insulation, etc, and cost nothing, or little to run.
• It is water sourced and then a high COP. But calcs have to be done properly.

 

[Agile]

A good posting there from George and I can support everything he has said.

I should also add that there is NO ecological advantage in running a heat pump system because the electricity in the UK comes from fossil fuels at an efficiency of only about 33%.

Only when the source of the electricity comes from nuclear or hydro sources are heat pumps ecofriendly.

Unfortunately the UK has dropped out of the nuclear generating market and instead burnt up most of our gas reserves instead. The UK population was thought to have preferred that option at the time and the governements saved all the flack from building new nuclear power stations.

Tony

 

[GeorgeBramwell]

Unfortunately the UK has dropped out of the nuclear generating market and instead burnt up most of our gas reserves instead. The UK population was thought to have preferred that option at the time and the governements saved all the flack from building new nuclear power stations.
Tony

Thatcher burnt the gas to make electricity, against advice, to make the power industry attractive to private companies. The UK has 60 year of coal underneath with this being left in the ground and the mining industry abolished for political spite. She closed down mines and started to import cheap coal from abroad which was subsided by their governments, using safety levels in mines which would not be acceptable in the UK. She was told to reserve gas for primarily domestic use.

I was reading about shale oil. The USA/Canada has more oil than all the Middle East. It is shale oil and needs high temperature heat to get the oil out, which is why it is not that widespread. Crude oil also needs heat to refine it. Shale oil is common in many parts of the world and the UKs oil pre WW2 was mainly from Scottish shale.

The version in North America only needs to be warm not very hot taking little energy to extract the oil, and those who own land in the USA with shale oil on it are prevented from extracting the shale. The figures for the likes of the UK are that only about 6 nuclear power stations are needed to provide the energy to extract the oil from shale and also refine it at the same time and then the oil would run the other power stations. Gas also extracted from the shale. The resultant oil & gas would be vastly cheaper than extracting liquid crude in the Middle East and transporting in tankers around the world. Shale can be transported in bulk carriers. Or/also the US and Canada could do the extraction and refining and refined petrol, gas and diesel transported in the normal way.

Nuclear power stations can be concentrated in the redundant massive Cheshire Salt mines, with the steam pipe running to the surface and turning turbines. Any accidents then will be contained under ground. Nuclear waste can be stored in disused mines and encased in sprayed-in concrete at the end of seams. It came from the earth and naturally over time returns to the earth.

The reason why the US and Canadian governments do not start this shale oil extraction is that the Middle East and other oil dependent regions, would be destitute and this would make the world unstable upsetting the world balance of peace. These governments know that the western world can turn to shale oil pretty easily and will not do what they did in the 1970s when they would not even sell oil.

Then there are tidal Lagoons, which 20% of the Irish Sea can provide all the power for the British Isles. Totally pollution free, making anti-flood dams and bridges as well.