Air Source Heat Pumps

albyota

Hi Muckybutt, were you advised to keep the system running once it gets cold?

muckybutt

No, just set the timer as required, as it stands at the moment water comes on 4-6am then heating 6am-4pm water again 4pm-6pm then heating 6pm-10pm

Cardew

The technical specification on the link above illustrates perfectly the how misleading the advertising is for the systems.

They talk about a COP of 5, yet the reality is very different in practical situations.

The specification sheet for the 9000i shows a COP of between 3.0 and 3.9

It also states:

General

Heatking

BWarm heat pumps are designed

to provide space heating to buildings

insulated to the latest specifications. They do
not operate at high enough water
temperatures to provide full domestic hot
water heating. The heat pump uses
refrigerants to remove heat from the outside
air at temperatures as low as –15°C and
produces up to 4 times as much heat energy
as the electrical energy put in to drive it. This
results in an efficient low cost heating
system.

Running the unit

When setting time clocks and controls allow

extra time for the heat pump to raise the
water temperature when first switching on, as
it does take longer than a traditional boiler to
reach the full operating temperature. Heat
pumps are most efficient when allowed to run
for long periods. The unit will automatically
switch on and off as required to control the
water temperature.

Radiator temperatures

Heat pumps are designed to operate with

water temperatures of about 50°C. The
radiators will feel cooler than those
associated with a gas or oil boiler traditionally
supplying water at 70°C. Radiators on a heat
pump system will be larger than a traditional
system to compensate for the lower temperature

temperature.

I am not 'knocking' ASHP's, but let us get their running costs into perspective. If you can get an overall COP of 3 that is excellent.

albyota

On the Energy Saving Trust Web site, if you drill down to ASHP's they show a table as below.



Fuel Displaced £ Saving per year CO2 saving per year
Gas £50 No saving
Electricity £700 5 tonnes
Oil £20 No saving
Solid £460 4.6 tonnes

However if you go to the MCS site you get the following,

Fuel Displaced £ Saving per year CO2 saving per year
Gas £300 830 kg
Electricity £870 6 tonnes
Oil £580 1.3 tonnes
Solid £280 5 tonnes

both are government websites, is this a case of left hand doesn't know what the right hand is doing?

tpresto3

Hi Albyota.

I see your point, and it really is a good one. However, it is always worth keeping in mind the following points.

1. Energy prices will change on a daily basis. Thus, if electricity goes up, and oil prices go down, this will change the savings substantially.

2. Different heat pumps offer different efficiencies. Thus, a system that gives you an efficiency of 1 unit in and 3 units out ( a common scenario with most heat pumps ) will not save as much money as a unit such as the Danfoss AX unit, which boasts up to 1 unit in, and 4.6 units back out. To my knowledge, this is the highest on the market, and includes domestic hot water (unlike many of the cheaper units on the market)

Thus, what you will actually save depends substantially on the type of heat pump you install, and what fuel you compare it with.

As a guide for people whom are unsure how to compare, this may help.

Oil. Costs around 40p per litre (changes regurlarly) and should give you 10kWh of energy per litre. However, if your boiler is around 80% efficient (as many are over time) then you would only get 8kWh of energy for every litre of oil, so the actual cost is around 5p per kWh.

LPG is around the same price as oil.

Gas. Prices vary, but on average, I have estimated that the average cost is around 4p per kWh. Again, the average boiler over 5 years old is only around 80% efficient, and thus you actual cost per kWh of gas is 5p.

Electric. Again, prices vary. Thus, it is worth shopping around to get the best tarrif, especially if you are installing an air source heat pump. You could look at
economy 7 or 10 packages, but check their standard daily charges. On average, I would estimate that the current cost is around 10p per kWh.

Thus, using a heat pump currently is double the price of a convential heating system. However, for every kWh of eneryg you put into a heat pump, you should get at least 3 kWh out. Thus, if you pay 10p per unit of electric, and get 3kWh units of energy out, then in reality, currently you are saving 5p per unit compared to gas or oil. Should you use a system that has an efficieny of 1-4 or higher, then you are saving over 50% on your fuel bills.

Moving forward, conventianal heating fuels are going to go up in price. This is necessery to reward people whom are using renewable energys such as heat pumps.

Thus, from April 2011, if you are using a air source heat pump, you will get paid around 6p per kWh for every unit of energy your heat pump provides. This is only an estimation currently, as the UK government is still under consultation as to the actual reward it will offer heat pump users.

I would estimate that over the next 3 years, energy prices will double.

Thus, if you are paying 10p per unit for electric now, this could rise to 20p per kWh. Thus , if you use a heat pump, and you have a 1-4 efficiency, you will get a rebate of 18p for for the energy you produce. ( 20p in, generating 3kWh of free energy, giving you a rebate of 18p) This means you will only pay 2p per unit of energy for running a heat pump. (This assumes you have installed an efficient heat pump) Compare this to gas and oil which may cost you over 10p per kWh, and the benefits of using a heat pump are clear.

The new incentive called the Renewable Heat Incentive, starts in April 2011. However, if you install accredited equipment now, you will benefit from the £900 grant funding. Plus, you will automatically qualify for the new RHI in April 2011, as if you had just installed the heat pump on that date.

I work for an independent company which sells heat pumps, and other technologies.

It really is worth looking at the RHI incentive. See the following link rhincentive.co.uk for further information, or email me [EMAIL="tpresto3@hotmail.com"]tpresto3@hotmail.com[/EMAIL]

Hope this helps.

tpresto3

Hermann wrote: »

I also like heat pumps, they have a place for some situations but definitely not all.

The RHI and getting paid for using a heat pump would mean they might make sense for a lot more situations.

So I agree its a good idea for people to know about these things however I just felt the website you mentioned over egged things a bit.
Investing in this technology on the basis that you will be getting paid RHI involves an element of risk, you might end up being paid but then again you may not, nothing is finalised yet.

Sadly I feel this will go the way of grants and FITs for Solar PV. To qualify you have to pay a huge premium having 'accredited' suppliiers install equipment from a specific list of 'approved equipment'. If you haven't paid over the odds to have it installed you don't get the payments.
This seriously negates the advantage of getting the payments.

As always thorough research is required before making a decision.

I'd be careful about expecting a heat pump installed now to qualify for RHI, it may or it may not.

Looking at FITs and PV, many with PV already installed will be at a disadvantage compared to a new install once FIT is introduced. I've read of people considering decommissioning their PV and then recommissioning it as a fresh installation to qualify.

Hi Hermann.

Great reply, and I do agrea with most of what you have said.

However, the Government has confirmed on July 15th 2009 that users of heat pumps WILL be paid the RHI.

Currently, they are consulting on the amounts that will be paid, and how this will be administered. They have confirmed that to ensure that heat pumps continue to be sold over the next 18months, that if you install a heat pump before April 2011, you will qualify for both incentives.

The only grey area is LCBP 2 funding. Currently, we do not know if the funding will have to be paid back after April 2011 (although the word in the work place, is that the incentive period will be reduced from 20 years to 15 years for LCBPE projects) However, this does not effect the domestic market.

Your point about MCS accredited equipment and installers is also correct.

You will need to purchase accedited equipment if you wish to qualify for the RHI. This, in many ways is a good thing. It would be easy to sell heat pumps over the counter, which would only give you a 200% efficiency, and thus would not really save you money even with the RHI.

Additionally, a heat pump which is not installed correctly will not have a good CoP. Thus, using an accredited company will have many advantages. I would also argue, not all companies are expensive. I work with a company whom sells different types of heat pumps, and some are very reasonably priced. However, as with most things in life, you get what you pay for.

Once again, I really like your thread.

Kind regards

tpresto3

tpresto3

Cardew wrote: »

The technical specification on the link above illustrates perfectly the how misleading the advertising is for the systems.

They talk about a COP of 5, yet the reality is very different in practical situations.

The specification sheet for the 9000i shows a COP of between 3.0 and 3.9

It also states:

I am not 'knocking' ASHP's, but let us get their running costs into perspective. If you can get an overall COP of 3 that is excellent.

CoP's . . . . Ignore them ! ! !! !

The CoP is a test of the compressor in factory conditions. It usually involves the air comming in at 7oC, and the water going out been at 35oC. Thus, this does not take into account cold periods, or heating water that is in excess of 35oC. Additionally, it certainly does not take into account domestic hot water, which would need to be above 42oC.

Additionally, your heating distribution system will effect your CoP. A new build using underfloor heating with 100mm centures will only need a flow temperature of around 35oC in winter. The same house using over sized radiators may need 50oC. This 15oC varience will kill your CoP ! ! ! Additinally, CoP's often do not include the circulation pumps, and defrost cycles that you need to keep your heat pump running.

Decent manufacturers will give you a SPF (Seasonal Performance Factor) This is a calculation based on your local climate data, and your heating distribution system ect. This will give you a far more valid estimation of what CoP you could expect.

I have seen CoP's range from a realistic 180% to well over 400%. It really does depend on the pump you purchase, and how you use it. I work with heat pumps, and am happy to help. tpresto3@hotmail.com

Hope this helps.

albyota

albyota wrote: »

On the Energy Saving Trust Web site, if you drill down to ASHP's they show a table as below.


Fuel Displaced £ Saving per year CO2 saving per year
Gas £50 No saving
Electricity £700 5 tonnes
Oil £20 No saving
Solid £460 4.6 tonnes

However if you go to the MCS site you get the following,

Fuel Displaced £ Saving per year CO2 saving per year
Gas £300 830 kg
Electricity £870 6 tonnes
Oil £580 1.3 tonnes
Solid £280 5 tonnes

both are government websites, is this a case of left hand doesn't know what the right hand is doing?
how can there be a difference of £560 for savings for oil....... for example?

paceinternet

tpresto3, can you review what you are saying in post #316
Oil - "the actual cost is around 5p per kWh."
Gas - "and thus you actual cost per kWh of gas is 5p."
Heat pump - "then in reality, currently you are saving 5p per unit compared to gas or oil."

Also rather confusing when you say "will not save as much money as a unit such as the Danfoss AX unit, which boasts up to 1 unit in, and 4.6 units back out".
In your later posts I think you are alluding much more to reality, whereas the Danfoss numbers should be compared with others at the same air and water conditions. And those conditions should be realistic.

Cardew

paceinternet wrote: »

tpresto3, can you review what you are saying in post #316
Oil - "the actual cost is around 5p per kWh."
Gas - "and thus you actual cost per kWh of gas is 5p."
Heat pump - "then in reality, currently you are saving 5p per unit compared to gas or oil."

Also rather confusing when you say "will not save as much money as a unit such as the Danfoss AX unit, which boasts up to 1 unit in, and 4.6 units back out".
In your later posts I think you are alluding much more to reality, whereas the Danfoss numbers should be compared with others at the same air and water conditions. And those conditions should be realistic.

"can you review what you are saying"

What a lovely phrase!!

Tpresto3,

You really do need to look at your posts again. They are full of inconsitencies, errors and unsupported assumptions.

Some of us really do understand the principle of Heat pumps both theoretically, and the practical applications.

I have no doubt that you do as well, but your posts do sound like salesmens patter. and as a salesman giving your email address is for contacts is not permissable.