Air to Water Heat Pump

[Boris]

My daughter is thinking of buying a 2 year old house with one of these already installed.

I know nothing at all about them, but Mrs B is worried about the noise from it in the winter causing problems with the neighbours ?

Has anyone come across one of these and have any info or  helpful advice ?

Never trust an atom - they make up everything !

[Richard]

I assume that it is used to heat water for use in the house, rather than extracting heat from a water based heat source such as a pond or stream?

If so it is pretty much like any air source heat pump, I have a reversible heat pump that heats in winter and cools in summer. It is about 2 years old and so far there is no real nose other than like a refrigerator. However, they should be serviced from time to time, kept clear of muck and junk and generally looked after. Mine replaced a gas convector which was always something of a liability as it kept turning itself off and of course could only heat – useless in summer, the heat pump just cools or heats and keeps the temperature that it is set for, no fuss, no bother. It is situated in a small space between a wall and a fence. It is a bit draughty if there is any wind, but as far as I know the fence and a ‘sort of hedge’ attenuates any sounds.

[Boris]

This one is used to power the heating for a large 4 bed house.  There is an outside metal cabinet with vents in (see red X on attached) and there is a separate dedicated “plant room” indoors between the garage and house.

Never trust an atom - they make up everything !

[Richard]

If it has been in use for the past couple of years I am not sure where or why there should be an issue. I assume that he house possibly had restrictions on other options or that the builder/previous owner thought it a preferable option. Sellers are legally bound to be honest, (yes really) so if there are doubts, pass any issue via a solicitor to get valid answers. I had to answer some right off the wall questions when selling my parents old house as an executor. It was about 120 feet and three houses from a 30 foot drop to a main road;

– Is the house prone to flooding?

It would have needed a very deep flood to get its feet wet, in excess of 40 feet above that road and about 300 feet above sea level. (The river estuary was perhaps a couple of miles away and pretty much at sea level). I said not within my knowledge.

[Ed P]

My elder son has an air-source heat pump (blows warm air through under-floor ducting). He is over the moon about it, but seeing how his last house was like a draughty tent that may not be such a great recommendation.  He does however get a regular Government contribution for the installation. It would be worth checking if the property in question  is eligible and if so, will it be transferred. (some shysters buy-out/sell such incentives)

[edit] Flooding can occur from other sources than nature. A couple of homes in this area were flooded out when a water main burst.

[tadka]

Never even heard of such. So it’s like a fridge only cools the outside and warms the inside?

[Ed P]

It is like using the exchanger on the back of the fridge to heat your house.. It takes power to run the ‘system and it cools the outside air. I guess it has a downside for any nearby vegetation,, but it is a much more efficient heater than an equivalent 5-10 bar electric fire.

[Tippon]

Richard wrote:

Is the house prone to flooding? It would have needed a very deep flood to get its feet wet, in excess of 40 feet above that road and about 300 feet above sea level. (The river estuary was perhaps a couple of miles away and pretty much at sea level). I said not within my knowledge.

My mother’s house is near the top of a steep hill, and roughly 200M above sea level. She’s been flooded three or four times.

There’s an old stream that runs underground somewhere nearby, and when the local housing association refurbished the house next door, they caused some sort of problem along with putting in a completely waterproof seal under the floor. Now, if there’s an unusually heavy flow in the stream, their seal seems to stop the stream from taking any extra routes downhill, and forces it to flood my mother’s house and the neighbour’s flat that is two houses higher! ?

[Richard]

My parents house had stood there for the over 50 years they had the place and had never been flooded, the road outside fell at about 1in 50 and the house stood >6 feet above the road. We had a water main burst a few years back after a dustcart drove over the new installation. The water spout was impressive, as high as the houses but the fall on the road was more than enough to deal with the issue. Flood risk assessments do not normally require you to take account of bizarre incidents, there are risk maps produced said to be assessing the risk to areas. Their accuracy varies between crap and excellent.  However my point was that the seller has a legal responsibility to disclose salient factors, especially when asked a direct question. Ed has a good point about government subsidies. All in all I would not be too concerned about the installation though I would have a check on the quality of the components and the installation – there were some cowboys. Again it is worth asking the seller about their satisfaction and why they are selling up. With a running water water table some tens (hundreds?) of feet below my place a ground source heat pump might be a sound economic venture though could be costly and challenging to install and the payback period would be too long for my benefit. The water company has an abstraction plant some 20 fett lower than us on the bank of the river valley and 500 yards away, best not to upset the water quality then!

[Ed P]

As Richard says a vertical piped system can be used, but for the reasons Richard alludes to the more common method is to dig up any large back-garden and install a huge loop of pipework. link. Unfortunately for the ordinary non-farmer mortal not too many have a spare 40 metre plot of land! Although these pipes are normally buried fairly deeply I’d guess that the cooling effect on the surface vegetation would not be acceptable to keen gardeners.  For this reason Air-source heat pumps are more common and easier to maintain. (Tree roots etc could be long term problem areas for ground source systems)

[The Duke]

My FiL has been threatening for years to dig dig up his back and lay a load of pipe. It doesnt even need to be that deep to work either

If I was doing a rebuild or big revamp I’d defo be looking closely at it.

If the gov was really serious about clean energy, they would be demanding all new builds that can, should install PV and something like ground source pumps.

Also maybe insentives to install PV before a sale. Tax breaks or the like.

It would do 2 things, 1 bring down the costs of PV cells etc 2 within about 20 years, the numbers of people feeding back into the grid would really be significant. In 40 years maybe the grip may just be used as a battery to fill in spikes and nighttime use.

Anther thing my FiL is always talking about  is installing batteries at his place to harvest his PV from the day for nighttime use.

The tesla battery banks are great, but atm priced high, hopefully when solar city takes off, and we have more EV cars coming to end of life, we will have a surplus of battery banks that will be fine for running a house for many decades.

Though 20 years ago labour should of had a couple of nuclear power plants ordered coming online now to fill the next 40 years gap until we get self sufficient.

I’m sure the electric lobby will have a hand is us not getting self sufficient to quickly.

[Ed P]

In theory an EV could double up as a house battery. The only thing holding it back are the car manufactures’ concerns about potential impacts on battery warranties. Many utility companies are salivating at the thought as it could reduce their stand-by power requirements for the periods when the sun doesn’t shine and the wind does not blow, but atm it is stalled – probably needs Government action to sort out but don’t hold your breath!

[Richard]

Like all magic bullet solutions there are always more than two sides to the issue and usually more pork barrels to scrap.

1) Should batteries be owner occupied items where they pay the capex or should they be controlled by someone more central in a battery substation?

2) If owner occupiers own the batteries who should control their operating profiles?

3) Should batteries be used to fill in the peeks and troughs of supply such that they are always taking the top slice of power availability?

4) What do the batteries need to keep them healthy – might not align with anything else. Who pays if a privately owned battery fails early?

Germany has had some management issues with their network and Spain has apparently laid down many demands on Solar installations.

The green initiative insulating buildings has not always been a complete success, Grenfell is perhaps the most dramatic and worst example.

For many securing a payback or at least a recovery of investment before failure would be a key driver. The sands of my time are running out but I have never seen a scheme that would work well enough for me to take the risk. Too many dreams and not enough certainty for me.

[Ed P]

Richard you raise valid concerns. The Energy Companies are looking at a number of different options (not just tethered cars). Probably the main option under discussion is to offer solar PV owners some form of incentive to install batteries which would be centrally controlled by the companies via their smart meter system. The main use would be for peak shaving on a local basis. Use of car batteries could substantially extend such a system but raise the other issues you talk about.

The Green issues in Germany and Spain that you reference to are one side of the equation and necessitate costly gas powered standby generators that does nothing during high carbon-free generation periods (sunny, windy days) . Battery standby is an additional option to tackle the supply problems caused by dark wind-free nights.

The other additional approach is to address the demand side by using the smart metering system to give users incentives to reduce their demand e.g. take a Kwh off current demand get 2Kwh of power later. A fully automated system would be costly and probably only apply to new builds/rewiring jobs so some form of user messaging system or smart phone/IoT setup  is a more likely first approach.

[The Duke]

4. The owner. Same as the owner pays and/or maintains everything they own.

It should be a financial benefit decision. More of a life benefit. But this is where the financial benefits should increase as costs drop as manufacturing costs fall.

Your first 3 points seem non issues. 1. Both. 2 you own and operate your own if you wish.

[Richard]

Ed P wrote:

Battery standby is an additional option to tackle the supply problems caused by dark wind-free nights. The other additional approach is to address the demand side by using the smart metering system to give users incentives to reduce their demand e.g. take a Kwh off current demand get 2Kwh of power later. A fully automated system would be costly and probably only apply to new builds/rewiring jobs so some form of user messaging system or smart phone/IoT setup is a more likely first approach.

I have never believed the hot air talk about slightly less dumb meters, (smart they are not) changing the way that people use energy. If I want to heat some food, I might have a choice of methods, oven, microwave, grill and so on, all with different performance and demand profiles. What I believe very few would consider is heating the food at 3:00 am or 10:00 a.m. or some other arbitrary time to control demand profiles. So it is with almost everything most folk do. Fridges, freezers and the like consume very little power and only very intermittently, so shifting their demand would not help by anything like enough. I have not tried to monitor our use half hour by half hour, but everything is switched on when needed and off when not required. Charging a battery when the sun shines by all means and using the battery at night – (but why convert battery DC to inverter AC when LEDs prefer DC?). The washing machine on a cool wash uses marginal amounts of power, the dryer runs on gas anyway. The only KW style consumer I can think of is the kettle which runs for perhaps 3 minutes at a time a few times a day, so not a huge potential for time shifting there. The studies I saw reported related to industrial users which were then extrapolated to domestic users.

Steve, Those skilled in the issues noted as points 1~ 3 have already defined them as questions seeking answers. If I had a battery backed system then I would expect the situation in your response to 4, but would you be happy to have your resources co-opted into a cooperative that defined how it was charged and its stored power was used as some have proposed. If not how do you propose area system supply battery centres would be funded? They are not cheap. The £11 billion new meter farce is already one farce too many for some with its recycled SMETS 1 items still being fitted. Germany already had problems with unbalanced supply issues, at one point offering power at give away prices to help absorb output and as I said, Spain has severe limits on domestic deployments in an effort to stop their systems suffering .

[Ed P]

Ovens, Washing Machines and Tumbler Driers are the major consumers. As you say the rest are immaterial. The Smart Meter just allows choices – for example a text from the Energy company saying “Using your Washing Machine overnight is free – using it now will cost you £1.50”. “Over a year this could reduce your power bill by £100” With an IoT coupled Washing Machine it would be trivial to action this from work.

This is not totally a made-up example as I know such things are being actively considered.

[Spedley]

I researched Heat Pumps when I was trying to heat my pool.  It took me ages to understand how they work but I will summarise what I have learned (in my language, sorry, don’t know the proper terms)

Compressing a volume of air causes it to get hotter because it has a fixed quantity of energy in it and the smaller the space that energy occupies the hotter the gas becomes.  From this, you can see that the maximum amount of energy you can get out of a volume of air has a limit and the energy required to compress the air would become infinite.  It turns out that if you compress a very large volume of air by a very small amount you can get more energy out of it than the energy you put into it! (No, it isn’t perpetual motion, the output energy has a lower potential).
Greatest efficiency is achieved when input and output temperatures are roughly equal, i.e. when inside and outside are both the same temperature.  At this point you can get about 4KW out for every 1KW you put in.
The benefits drift off quite quickly the larger the difference between inside and outside (i.e. the potential is greater – which is how the heat pump works).

So, my summary is that heat pumps work great when it’s about 15’C outside but would just essentially be normal electric heating in the middle of winter.

i7 4790s / 8GB / 480GB SSD / GTX 980 / 34" UltraWide : i3 4170 / 8GB / 480GB SSD / GTX 770 / 24" Samsung : i3 4130 / 8GB / 500GB Spinner / GTX 1050 / 23" Acer : Q9550 / 8GB / 1TB Spinner / GTX 580 / 22" Acer : i7 720QM / 8GB / 1TB+2TB+500GB Spinners (server) : i5 4570 / 8GB / 60GB SSD / 1TB / GeForce 210 / 22" Dell It's getting warm in here!

[Bob Williams]

Some years ago BC, (Before Cuts) our Social Landlord had oodles of funding provided by government  and decided to survey all their properties with a view to installing both ground source heat pumps and rooftop solar panels. They engaged a major national company to survey our 23 bungalows: I have no idea about other properties on their books, but they did survey ours.

The survey was very comprehensive, took over 12 months to complete and report, and turned over more stones than the landlord expected. First results were concerning building structures. The bungalows were originally built by East Lyndsey District Council between 1962 and 1965, in five different patterns. One of the resulting conclusions, was that the lintels over all windows, were incorrectly built: there was simply a concrete lintel across merely the width of the window, no internal, overlapping steel RSJ, which might explain why so many of our window mechanisms stick and seize. The surveyors then pointed to the SUDG windows, which were old and mostly no longer capable of insulating the homes efficiently. They then addressed the draughts that we all had under our floors: apparently caused by no insulation behind the fibreboard under the main lounge windows.

In 2003, the government forced ELDC to handover all their properties to a local Housing Trust, which is no longer local but the largest in the UK. ELDC received £57 million of taxpayer’s money for this and promptly invested it in Icelandic Banks. (I’m not making this up!) They may receive a final repayment by 2025…

By the time the CEO had recovered from the estimated cost of repairs and rectification, the next blows fell. First it was the fact that our part of Lincolnshire is only a few miles from the coast, sits just 24 metres above sea level, and has not actually been above sea level more than a few centuries. Consequently, the ground water is at a high level and our village actually lies upon a huge aquifer, with a village pump that was still in use until just after WWII and would work today if needed. So, cancel the ground source pump plans. Absolutely nothing was done to address the problems already mentioned, except to fit insulation beneath the lounge window, then fit fancy new UPVC front doors, a purely cosmetic measure which completely failed to address the other insulation problems. A long period of sustained prevarication saw the election of a new government and the introduction of the cuts which finally put paid to any funding for solar panels.

We fought as a community of Oldpharts for several years to have our ancient, inefficient Night Storage Heating replaced by GCH, but it took the intervention of our previous MP Sir Peter Tapsell, to achieve that. He bent the ear of the relevant Minister and, probably after another near heart attack by the CEO, we got GCH.

I repeat: I am not making any of this up.

When the Thought Police arrive at your door, think -
I'm out.

[Richard]

Ed P wrote:

Ovens, Washing Machines and Tumbler Driers are the major consumers. As you say the rest are immaterial. The Smart Meter just allows choices – for example a text from the Energy company saying “Using your Washing Machine overnight is free – using it now will cost you £1.50”. “Over a year this could reduce your power bill by £100” With an IoT coupled Washing Machine it would be trivial to action this from work. This is not totally a made-up example as I know such things are being actively considered.

Yes, Ed I know those totally theoretical but I accept data based examples; however they suffer a couple of flaws. To achieve that cost example the unit cost of power for all power consumed in the anti-socially timed machine cycle would need to be well beyond the normal level, perhaps as much as £1.8 per unit, however, the inconvenience factor of out of tune running is also likely to weigh heavily. As a side issue the text would likely not be spotted until hours after the event anyway – if signal conditions allowed for its delivery at all at home. As for the oven, running that out of phase with meal times is of no practical use to anyone. Throw in the idea of replacing everything with an IDIOTIC (Internet Directly Integration Of Threats Including Chaos) devices which would take too many years to contemplate amortising is a none starter; especially when they all go wrong because some sever in a foreign land fell over as has recently happened in several cases.

At one time we ran the washing machine and dishwasher over night  using timer functions. Then we found out the then dual rate tariff was still costing 30% more to be much less convenient, that was discovered by accident when the meter went wrong.

The gas tumbler drier now uses a tiny amount of electricity.

[Author]

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