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HEAT PUMPS & Geothermal Energy => Heat Pumps => Topic started by: MacBeagle on December 17, 2011, 06:56:52 PM



Title: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 17, 2011, 06:56:52 PM
Hi

We live south of Bristol in a 4 bedroom detached house, which we have lived in since it was built in 1986 - oil fired boiler originally as there was no gas piped to the village (there is now). It is fitted with mahogany double glazed units, suspended floors with downstairs underfloor insulation, thermal block inside wall, CWI and the loft is floored with chipboard over standard 1986 insulation and full off "stuff". Stovax 4.5Kw multi fuel inset stove for emergencies

Our hot water/heating system is a Sanyo 9.0kw CO2 Eco ASHP which was fitted in Dec 08/Jan 2009 and linked up to 13 existing radiators. The hot water side of it works fine but the heating is struggling to reach 20 even though we are getting tank temperatures of 65 - it has to be left on for a long time to get to that temperature and consequently costly. The original installers are not around anymore so I am at a loss to get any useful information - the nearest Sanyo heat pump rep is in Nottingham.

It seems from reading a lot of the posts in this section that I have a worst case scenario - inefficient rads and heat loss problems.
So, given that UFH is not an option:
a) What else can I do to improve/stop heat loss?
b) Does the floor-boarded loft and all the "stuff" constitute insulation or do I have to up the depth and raise the loft floor?
c) What constitutes a suitable radiator or is there another form of outlet that can be fitted?
d) Do I throw in the towel and fit a gas boiler?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: martin on December 17, 2011, 06:59:51 PM
If you are fortunate enough  to have mains gas, go for "d" asap!
To fit an ashp  to an existing rad system is just plain bonkers - it'll cost far more to "put it right" than get a decent gas condensing boiler


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 17, 2011, 08:02:50 PM
what size house have you
 if you are stuck with the heat pump
you could change one rad ,   to  forced convection rads and see the outcome/
try  ,solo rad  smart radiators have 15mm connections both on the one side  and need a 3 amp supply
to run fan and intergraded temperature controller, and also looks hot
also java do a basic  convector rads
 
it a good idea to ditch the heat pump if you can
if you have mains gas   
i sure their is a connection fee to consider and the cost of a a rated boiler ect
baker



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: itsnewtome on December 17, 2011, 08:08:57 PM
There are plenty of low temperature rads on the market now especially designed for heat pumps.
They have a lower water content and different designed fins etc.
Have you tried flushing the rad system?
Get the Sanyo rep to have a look he may point out something
Has it always struggled or just a recent issue?
Ther will be costs involved in getting a gas main in


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on December 17, 2011, 08:27:26 PM
It may be that all the heat is going to  hot water.  The problem with this is that with low air temperatures  the heat pump will struggle to reach that temperature and leave no heat for the radiators if DHW gets priority.      You could try setting the  DHW controller to a much lower setting and  if you have an immersion use it to bring thje water temperature up.    If  it works as expected you should start to get some heat in the radiators.   

Ideally this kind of system should be used to heat a buffer tank with off peak electricity, this would allow  heat to be used from the store when you need it  but it  probably is only capable of providing heating and very hot water when the outside temperature is warmer.   


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 17, 2011, 08:38:11 PM
Thank so much for the replies, it's a bit lonely owning a Sanyo ASHP in these parts.

We would like to hang on to the ASHP investment if possible, and I do like your suggestion of low temp rads. We are perfectly comfortable with the house at 18 if only it would get there a bit quicker and we could solve the heat loss problem, it real does drop quickly when the heating goes off. It's just weighing up the cost of 13 new rads and the hope that they will make a difference against gas conversion - we would have to have the supply moled under the back garden from the main in the road.
And yes, it has always struggled.
dhaslam - the unit has got a motorised mixing valve that should control the temperature to the radiators at every outside temperature, but the setting are so complicated (to me anyway) that nobody has been able to give me a satisfactory explanation of the optimum settings for my house - unless the rep stays for a couple of days its a case of suck it and see.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: desperate on December 17, 2011, 10:38:35 PM
Hallo MacBeagle,

you say the house cools really quickly when the heating goes off, that is your problem more than the type of heating system I believe. You have already pointed out the loft insulation is to thin, I would start there, would it be possible to bolt some 4*2 joist on top of the existing ceiling joists, this would give you room for more insulation, a cheap and worthwhile thing to do. I would bolt the new timber along the existing joists not across them, this is a stronger option. Also concentrate on draughtproofing as best you can. These sort of improvements need doing whatever you decide to do with the heating.

Desp


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on December 17, 2011, 11:25:09 PM
the unit has got a motorised mixing valve that should control the temperature to the radiators at every outside temperature, but the setting are so complicated (to me anyway) that nobody has been able to give me a satisfactory explanation of the optimum settings for my house - unless the rep stays for a couple of days its a case of suck it and see.

The idea of  the  variable  temperature mixing valve is that it raises the flow temperature when the outside temperature falls.    The problem with this is that  when it is cold  outside the  output temperature  of the heat pump also falls  so it can't reach  the set temperature  unless the load is very light. Thirteen radiators would need 13 kW  at a high flow temperature plus another  one or two kW for DHW and the output of the unit is probably something like 5 kW.  I am only guessing the output because their brochure seems very vague about the  output.     

The Co2 system is better than most heat pumps  but they all do suffer a bit from poor performance  in cold weather.     If you can turn off some of the radiators, specially the ones that can be heated with the stove  wou may be able to get the system a bit hotter.   

The Co2 heat pumps detail are near the  bottom of this document. 
http://www.oceanair.uk.net/pdf/SANYO_Heating_Brochure.pdf


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: titan on December 18, 2011, 10:33:57 AM
It is not clear from your post whether you have cavity insulation or not. Thermal blocks were the result of good lobbying by the building industry so they could continue to build poorly insulated houses the way they always have while paying lip service to improving regs. If you don't have it installing it along with at least 300mm of loft insulation will noticeable improve your heat pump  performance. You also have a stove, it it room sealed. I don't know who specified your pump but 9kW also sounds a bit small for a large detached house with 1986 insulation values.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Solal on December 18, 2011, 11:26:26 AM
Only use an air source  heat pump in the UK  when outside  temperatures  are above 7C  unless ufh is fitted  and the home is super insulated  in which case a candle should  heat it anyway.
These  things must be the greatest failures ever  brought into the uk heating market.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: tsh on December 18, 2011, 12:18:53 PM
Lots of posters here telling you that your system is wrong - not many asking if it has only recently started to cause problems or asking anything specific. There isn't necessarily any good reason not to stick with this system, although it is correct that improving your insulation will help. Look into 'space board' for the loft. It may be cheaper/easier than the timber to add more insulation.

You shouldn't be getting hot water at 65 degrees - this is not really necessary, although I can confirm 45 is too low (trying to get round the DHW priority and forgot to set it back to 51)

Be aware that trying to make a heat pump run Hot/off is not going to work well. Mine takes about 2 hours to get from 18 to 21 degrees - into radiators  ;D

Check that it is really switching to heating the radiators, and if you can come back with the flow/return temperatures to the heat pump. Due to the variation in efficiency, it is better to have the pump running at 35 degree output all day rather than 50 degree output for 6 hours a day (roughly - in practice it depends!) Certainly, you probably don't want to let the house drop below 17/18 degrees if you want to to be warm again in the next 12!

Edit: Just noticed that this heat pump can run up to high temps without too much trouble - although it is probably still more efficient if it's running cooler.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: martin on December 18, 2011, 12:28:04 PM
There's several good reasons not to stick with the system, most of which have already been pointed out - the heat pump would appear to be undersized for the job, there is no UFH to make the most of the low grade heat that it does produce, it would cost a small fortune to replace the pump and provide oversized rads throughout, so it would be far more pragmatic to ditch the bally thing altogether and get a decent condensing gas boiler which is suited to the existing radiators. Shame the company who supplied the system isn't in existence as I feel they let their client down badly, and should put it right (but if this is the sort of job they did, not surprised they're defunct as a company).
Obviously, whatever is done, it should be allied to insulating to the max.... I reckon that the cost of the new boiler would very soon "pay for itself" in savings on fuel costs


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Countrypaul on December 18, 2011, 01:26:51 PM
It appears that before making a decision on what to do (other than add more insulation which should always be first), gathering some more information on your usage might be helpful. For example, is it turned on 24hrs a day and if not when is it on, how much electricity do you actually use in running the HP, can you put a simple meter on to measure it? Does the heat pump cycle on and off frequently, if so then it is certainly not being utilised properly. What temperature is the feed into and out of the HP measured independantly of the pump?

If trying to use it like aGF central heating system, then the results would be disapointing.

Paul


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on December 18, 2011, 02:21:10 PM
Hi,
   It sounds like your output is undersized for your radiators/insulation levels.

If it's 9 kW system when the conditions are perfect you will be unlikely to get this in poor winter conditions
when you need it most.

I have a four bedroom detached bungalow with gas combi and good insulation. In cold weather it uses 100kWh per day to heat.
This is 4kW on average. My boiler is rated at 30 kW.

You have twice as many radiators and probably worse insulation. But your ASHP probably gives you 5 kW in winter.

After a cold night in my house with the heating off it can take 2 - 3 hours to warm up my house.

You have twice the radiators and roughly 1/6 the power input so roughly 12 times the heat up time.
i.e. 24-36 hours.(I know there are a lot of other factors involved as well)

For the hot water you have about 4kW. This compares well with an immersion heater at 3kW.
So I guess a couple of hours heating your water tank should be noticeable.

I would guess that your heat pump will just about keep your house warm once the set temperature is reached.

Also it is interesting to note in cold weather you probably need to run your pump continuously if it is
your only heat source.

Do you know your electrical consumption for the winter months ?

Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 18, 2011, 08:52:49 PM
Thank you so much for all the replies. I have just got in and wow, what a forum, so much help. Will have to read them all carefully - but in the meantime - the system is on as we speak and according to the Smartpower meter the unit is using 0.45p per hour irrespective of any change in settings. This is based on 10.30p per unit + a daily standing charge of 20.27p - nPower Sign Online 22. We use it much as we did our oil boiler i.e. twice a day and the compressor is on continuously during those times and the unit is having to defrost quite regularly. I will note down all the settings tonight and post them tomorrow to give you some more information to go on.
Again, all the advise very much appreciated.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: JonG on December 18, 2011, 08:57:31 PM
We have installed numerous systems where we are replacing gas for ASHP's and not one has failed to run cheaper than the gas alternative, even when the removed boiler was a condensing unit.

I would suggest that the start point is working out what your true heat loss is at circa minus 3 with the current insulation values and then checking it against the output of the unit at minus 3 and the flow temp that will suit your current rads.

You then have some information on which to base your decisions. It may be that by increasing the rad sizes and lowering the flow temps the output can match the load, if not then you could go bivalent and back the unit up with gas or at least be aware of what outside temperatures require you to light the stove to help the ASHP out.

Once you know the heat loss and the outputs of the heat pump, it may also be possible to design any insulation improvements iteratively to achieve a heat loss within the capacity of the unit.

Control wise we find that 24-7 operation, until the outside ambient hits 16 works best, usually with a night setback of no more than 2 degrees (air temps).

Also check simple things have you got the required flow rates through the system, if there is no flow meter a check of the differential temperature between flow and return and a comparison with the heat pumps requirements should confirm this. Usually this is between 5 and 10 degrees depending on the manufacturer but the rep should help with this. You may have a strainer that needs to be emptied too.

If you have a look through the MCS Installer data base and contact some local guys someone may take it on as a project even without full working knowledge of the unit, the principles are all fairly similar and we often pick up trouble shooting on units we don't actually install.

Don't give up with it until you have done the maths, the technology is sound, its usually the application/installation that lets it down.





Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: titan on December 18, 2011, 10:49:54 PM


Once you know the heat loss and the outputs of the heat pump, it may also be possible to design any insulation improvements iteratively to achieve a heat loss within the capacity of the unit.





This sounds like installer speak to me. A house built to 1986 insulation regs will be probably be only half as good as current regs which are not that good anyway.and then there is air leakage rates quite often found to be 5 -10 times worse than current regs when tested. Insulation and leakage improvements should always be the first priority, It sounds in this case it may be possible to reduce the maximum heat load by 25% maybe more. Fine tuning the heat pump is a bonus

   


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: martin on December 19, 2011, 12:31:35 AM
I'll stick with my previous comments, you'll be far better off to get a proper gas boiler installed, rather than faffing about with an undersized and under-radiatored system (which would probably mean you'd still need the gas boiler to make up for the thing's shortcomings when it actually gets cold.....)


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: tsh on December 19, 2011, 09:43:26 AM
I'll stick with my previous comments, you'll be far better off to get a proper gas boiler installed, rather than faffing about with an undersized and under-radiatored system (which would probably mean you'd still need the gas boiler to make up for the thing's shortcomings when it actually gets cold.....)

I'll stick my neck out and suggest that you are probably not in a good position to comment on such systems, despite being an administrator on the site. Gas is an expensive short term fix, and unlikely to be any cheaper in the long run.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: martin on December 19, 2011, 10:40:20 AM
Having costed many systems, sometimes in collusion with those far more versed in heat pumps, I've never managed to make the sums add up for ASHPs (unless you're generating your own power from something like hydro), and over several years of this forum have come across reports of many underperforming and ludicrously expensive to run ones, and many people who have ripped them out in disgust - all power supplies will escalate in price - logically electricity will rise more than others, the grid is already faltering, so it is therefore sensible to use it only where no other energy source will do the job, and wherever possible not to use it for heating.

The original poster obviously has had a too small ashp installed as a straight swap for a boiler, and will therefore need to shell out for new radiators throughout, and sensibly a larger heat pump (if he's going to stick with it), AND a gas boiler to fire up when the temperature drops - which is going to cost an arm and a leg..... To make an ASHP perform at it's best you need underfloor heating, which he doesn't have, therefore my pragmatic advice is to go for gas (which whether we like it or not will be with us for some considerable time to come, way beyond the predicted life of a gas boiler) - it will be the lowest capital expenditure for him, the running costs will be reasonable, and should "do the job" for many years

To make the best of a gas system, he'd also be well advised to add solar hot water for spring-autumn use-  effectively allowing him to switch the boiler off for several months every year


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on December 19, 2011, 12:10:13 PM
A bit more detail on  heat pumps  using CO2 as the refrigerant.

http://www.annex32.net/pdf/presentations/Annex32_workshop_Kyoto_Stene.pdf

It is a bit tricky to read but basically  what it is saying is that the CO2 units  are designed for  superinsulated houses that need more than 50% of their heat for DHW rather than space heating.  They retain efficiecy at high temperatures but don't  reach very high COP at low output temperatures.  Also the pressure in the system is about ten times higher than  normal systems so the units are very expensive, around 10,000 for the Sanyo 9 kW unit (with buffer tank).

The electricity usage figure of  a little over 4 kW does seem very high but it does  seem to hold its output at 8kW or better according to the  brochure below and at  a COP  of somewhere between 1.8 for -15C/50C and  3.1 for 7C/50C, air temperature output temperature respectively,   so at  60C output a COP of 2.0 is reasonable.   This brochure does give a bit more technical information on the unit but they seem to be deliberately avoiding useful  COP graphs at various  outputs.    

http://www.airconwarehouse.com/acatalog/SANYO_CO2_ECO_Brochure.pdf

I think that what it boils down to really is  heat losses from the house seem to  be the problem.    Presumably the new system was installed because heating costs were high at that time with the old boiler.      

    


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: brackwell on December 19, 2011, 12:38:30 PM
Your worries seem to be cost and time to achieve temp.

A average house is fitted with a 30kw gas boiler and therefore is costing approx 30 x 4p = 1.20 /hr . When you compare this to your 45p/hr then whats the problem?  Also to equal the 30kw/hr of the gas boiler you need the pump on for 30/9 x 45p=1.50 so still not really a problem after considering the losses of the gas boiler.

As for time - thats what you would expect from a system that is only just big enough for the house requirements.  So what can be done?

The ASHP is at its limits to get water to 60C and whilst it is doing this it is inefficient and preventing heating taking place. In the midst of winter allow the pump to heat the DHW to say 35C and then set the immersion heater on a timer to reach somewhere between 45C-50C just before its main use.

Use the stovax but when not using it make sure you leave both controls fully off -we dont want heat rising up the chimney. Its possible you have one or more air vents for the stovax and the old gas boiler-block them up ! Generally go on a hunt for draughts when its windy outside.

You should have at least 270mm loft insulation -no excuse its so cheap

Turn the room temps down to 18C ( i manage on 17C). Every 1C reduces the heat requirement by 10% but also improve the COP of your pump by a similar amount !

You dont need the gas.

Ken



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: martin on December 19, 2011, 01:06:14 PM
Some pretty wobbly figures there - "only" 45p an hour isn't doing the job, and equates to 75 a week....... ;D


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on December 19, 2011, 03:15:57 PM
Hi,
    Martin thats 45p/hour but we do not know how many hours it is on for.

As we do not know all the factors for the house it's difficult to recommend solutions. But heres some ideas.

Making sure your loft is properly insulated is a must. It's easy to do and in the 5 houses I have done it in made a huge difference. It will pay back very quickly no matter what you decide on the heating front. Any other insulation such as draft excluders, curtains etc would also make a difference.

If you decide to keep what you have got then :-

In summer hot water from the ASHP no space heating.
In spring/autumn ASHP for hot water and space heating with the logburner used occasionally
In winter I would make the log burner the main source of heat with the ASHP used as a top up

For wood heat at 100% efficiency you would need 1 Kg for 4 kWh i.e. 25 Kg on a cold day.
This depends on your life style,enthusiasm and time available. Access to free or cheap wood is also a must. If you stove is not super efficient I would consider replacing it for a larger one(possibly with a back boiler). This would enable one firing to last a long time and probably keep it going overnight.

Converting to a gas boiler may make sense if you want reliability and cheap running costs. But this has to be balanced against the installation cost. I had a friend with oil fired heating. When the gas main was put through the village a "connection cost"  of 8,000 was quoted ! So a gas boiler would have cost 10,000 - a lot to recover in running costs and you have to pay that money up front.

So what is your annual electricity bill ? And do you know the cost of a gas connectyion ?

Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: gb484 on December 19, 2011, 04:06:58 PM
I am very interested in ASHPs, but before taking the plunge and buying one I would like to know how much they cost to run approx per day, particularly when it's 0 degrees outside as at present. You appear to be concerned about how much your system is costing to run but don't quote any figures (sorry, if I didn't see them). For comparison, during this coldish weather, I'm using around 11 cubic metres for ch and dhw in a 3 bed bungalow with 500mm of insulation in the attic, cavity wall insulation and 170mm of insulation to suspended floors, which equates costwise, I think, to around 4.40 per day, maybe a little bit more. My house is not over warm, 18 degrees in hallway, 20 in lounge and I am trying to be as frugal as I can without too many complaints from other family members. When it was warmer, 9 degrees outside, consumption was about 5-6 cubic metres. I've got a one-year old condensing gas boiler, and normal rads. A couple of things about your post that I would like to perhaps echo: as others have pointed out, your dhw doesn't need to be 65 degrees, that temp can cause scalding. What happens with the ch if you switch off the hot water for a few days? From what I've read about ASHPs, you should run them 24/7 to provide a constant low level of heat, and the lower the flow rate, the better the COP, so try turning it down to a level that is perhaps a tad too cold, then slowly nudge it back up until it's better, to find a happy medium. Upgrade your levels of attic insulation, if possible. Think about fitting convector rads, but really, 20 degrees is reasonably warm. Use the woodburner more to supplement ch when it's really cold outside.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: titan on December 19, 2011, 05:00:48 PM
This link  is on this site somewhere else but it gives live data from a Sanyo Co2  4.5 kW unit the COP does not look that impressive to me.  http://www.elisanet.fi/sanyoco2log/


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 19, 2011, 05:12:31 PM
As promised, pictures of the Settings/Display panel taken last night
https://picasaweb.google.com/107578057515193397049/SanyoCO2SettingsAndOutputs?authuser=0&authkey=Gv1sRgCIHc963EttiSEQ&feat=directlink


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 19, 2011, 07:03:21 PM
As you can see from Diagnosis Menu 2 the HP water out is 65 and the rad temp in Diagnosis Menu 1 is 40 and the tank temp is 39 - why is this and where is the 25 going?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Countrypaul on December 19, 2011, 07:19:24 PM
Have you check the temperatures independantly to ensure the readungs are correct?
How well insulated is the pipe from the HP to the rads?
Could the radiators be sludged up causing a poor flow through them?
Could the pump be operating poorly? Can you test it?

Losing almost half heat you need before the radiators suggests there is certainly scope for some changes.

Paul


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Solal on December 19, 2011, 08:12:45 PM
The hot water side of it works fine but the heating is struggling to reach 20 even though we are getting tank temperatures of 65 -

Has the compensating curve  to the heating system   been set up correctly?
Do you know  what its currently set at?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 19, 2011, 08:30:56 PM


Has the compensating curve to the heating system been set up correctly?
Do you know what its currently set at?

I don't know, nobody has given me a satisfactory answer to how it works and the explanation in the "manual" might as well be in Serbo-Croat.
The current settings are: Curve Inclination 70, curve adjust 5 - these have remained unchanged since the installation.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Solal on December 19, 2011, 09:17:56 PM
Is the flow temp  to your rads  reaching 70C. I'm trying to see it  on your images  but having no luck.

What size was your  oil boiler  you had removed?

Edit. AH I'm seeing it now. 40c.  
Which begs the question  why is it so low? The tank sensor  is reading  39C.
So it would appear the bivalent  valve is only  lifting it 1 degree!


But it shows the temperature  of   the HP water out as  65c.
It would be interesting to know  if  the outflow  temp from  the  HP  is in fact  65c by measuring  this temperature. But it very likely  is.

I'm getting the impression  the system is woefully  undersized.
  


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Panda on December 19, 2011, 10:29:07 PM
If this is the same Sanyo unit I'm thinking of it essentially consists of an inverter driven combined outdoor unit which uses CO2 as its refrigerant and an indoor thermal store (of Swedish origin, rebadged Sanyo). A low flow high head Wilo circulator pump trickle charges the thermal store to the target temperature. The flow is supposed to be very low to ensure good stratification in the thermal store. A built in anti-legionella cycle boosts the temperature every few compressor starts. There are some electric immersion heaters fitted to the thermal store which can be configured on/off/auto.The thermal store has an internal coil (a bit like a Gledhill torrent) which instantaneously heats the incoming cold water to provide domestic hot water. The space heating water flow is supplied via a motorized 4 way mixing valve and an external central heating circulation pump. The mixing valve is controlled by the software in the controller of the thermal store in accordance with the curve setting. It may choose to take water from the top of the thermal store or the middle of the store. Water from the radiators is either returned to the thermal store or recycled back through the radiators via the 4th port on the mixing valve (or somewhere in between).

If your tank is hot and your radiators are cold then that would suggest that there is either inadequate circulation or the 4 way mixing valve is not working properly. You can operate it manually via the knob on the front of it or through the control panel (can't remember how). I've attached an excel sheet which has some recommended settings for this type of heat pump (although you would have to set the curve for the desired radiator temperature - you'll want to keep this as low as you can to maintain sensible performance). I got this spreadsheet from Sanyo a couple of years ago but I know there are at least 2 different versions of firmware on the tank unit so I can't say for sure if it will be 100% representative of your system. At least there is some narrative which may help you understand the various settings.

Before abandoning all hope, I would suggest you could try contacting Sanyo directly. They may be able to help.

Good luck


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 19, 2011, 11:06:15 PM
Panda. Thank you for your reply, very informative and I am beginning to sense a glimmer of understanding. I will try those curve settings tomorrow. Would the MIN SPEED CP setting have an improving effect i.e. higher temps to the rads, as I note mine is set to 10% and the spreadsheet is set to 30%, or am I clutching straws?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Solal on December 19, 2011, 11:23:32 PM
Isn't that for service personell   to evaluate the operation? I think  the  CP  acquires  its own  run percentage  to maintain the desired  HP flow temp.
Your currently running at  21%.

What size was your previous boiler?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on December 20, 2011, 01:16:33 AM
Panda. Thank you for your reply, very informative and I am beginning to sense a glimmer of understanding. I will try those curve settings tomorrow. Would the MIN SPEED CP setting have an improving effect i.e. higher temps to the rads, as I note mine is set to 10% and the spreadsheet is set to 30%, or am I clutching straws?


The system probably  sets its own pump speed  but  it might help a little.   You need keep the compressor running but it seems to have only stopped for one hour in total in the previous twenty four and that doesn't indicate that the pump was running too slowly to circulate the full heat output.    I think that the best thing to try is cutting  thermostats down in  a number of rooms and see if the other rooms can come up to the set temperatures.   If a smaller number of rooms do come up  to the set temperature it would more or less confirm that  the heat pump  hasn't enough output to match the heat loss of the house.    You may also be expecting room temperatures that are too high, 20C is quite a high average room temperature to expect over the whole house.   


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: tsh on December 20, 2011, 12:04:33 PM
The thing that stands out to me is
HP WATER IN    41
HP WATER OUT 65

To me, this is a big red flag that you have too low a flow rate through the heat pump. It's regulating it's output temperature OK, but the flow isn't transporting much energy. Can you maybe watch the 'Compr Speed' after the unit starts up/defrosts or you drain off a lot of DHW? If the max is 80Hz, the pump is only running at 75% of it's potential.

If you have too large a radiator load (under-sized heat pump), water out will struggle to reach 65.
If you have too small a radiator set for the house, I guess it is possible that the unit is modulating the pump down. You can maybe test this by letting the system cool down (set the room stat to cold), allow WATER OUT to drop below 50, and see how the in/out temperatures track.

If you can see WATER IN=60, WATER OUT=65, then that would look more reasonable...


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: bassman on December 20, 2011, 12:50:57 PM
Hi

For true "actual" figures on ASHP running costs see my post below as I am posting links to my monthly running costs each month.  The 2 links below are graphs of power usage for the last 2 months.  Location Co Down, N Ireland.

House has a constant temp of 20-21 degrees C

185sqm - bungalow - built 2004 - insulation level good - UFH, all floors tiled - 16kW daikin Monobloc fitted end Sept 2011


Previous average Oil usage per year over last 7 years was 3100 Litres!!

Presently saving 40% on running costs compared to oil - good insulation and no draughts are essential - nuff said


http://www.navitron.org.uk/forum/index.php/topic,14832.0.html



https://picasaweb.google.com/108455921836178416144/October262011?authuser=0&authkey=Gv1sRgCM-0qfuOjc_9ew&feat=directlink




Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: rondurrans on December 20, 2011, 03:19:55 PM
You seem to like it 'toastie' bassman - converting 3,100 l of oil into kWh = 11.85 x 3,100 = 36,735 kWh/pa = 199 kWh/m2

Do you keep the house at 20 - 21 degrees C 24/7?

Thanks,
Ron

http://www.carbontrust.co.uk/cut-carbon-reduce-costs/calculate/carbon-footprinting/pages/conversion-factors.aspx


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: bassman on December 20, 2011, 03:50:18 PM
ASHP is on for about 18 hours out of 24/7


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 20, 2011, 09:52:38 PM


Hi
just a idea
you have 0% displayed  on the mixing servo valve parameter?
is the  servo motor % pointer meter / moving  +,-  to regulate the tempature
 


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 20, 2011, 10:36:24 PM


Hijust a idea
you have 0% displayed  on the mixing servo valve parameter?
is the  servo motor % pointer meter / moving  +,-  to regulate the tempature
 

Yes, I checked that today in the MANUAL settings and it does move.
We thought we would try a new strategy for a week and leave the thermostat 24/7 to switch on if the temp falls to 12; switch it to 15 at 8am-7pm and then have it switch to 17 until 11pm then back to 12 through the night. We thought that if we didn't allow the temperature to drop too much then the system wouldn't have to work so hard to raise the temp 2 or 3 degrees. The house only seems to be losing a degree during the day - temps of a steady 6 over the last couple of days help I suppose and the real tests come when we get into minus territory. Will keep you posted.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 21, 2011, 12:13:07 AM
 Hi
compressor speed 65hz
outside air tempature 2
room tempature  14
the compressor should be runing at almost full capasity ?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: tsh on December 21, 2011, 09:09:24 AM
Hi
compressor speed 65hz
outside air tempature 2
room tempature  14
the compressor should be runing at almost full capasity ?

It can't, because the flow rate is not allowing any more heat to be taken away. Pump demand is set as a result of output temperature of the heat transport fluid.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 21, 2011, 11:22:19 AM
 

good point
getting hot


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on December 21, 2011, 02:11:19 PM
Hi MacBeagle,
             It's good to see you are experimenting with your system. Every house,heating system and inhabitants are different. Reading between the
lines you seem to have a similar insulation and heating requirements as me. I have experimented over a number of years to optimise efficiency while
maintaining comfort levels. Initially I tried just putting the heating on when required but this meant the fabric of the house was usually cold and
required a higher thermostat setting to feel comfortable(always above 20 C).

I built an extension onto my current house it is now 1/3 of the completed house. I barrowed in the cement for the new "slab" - six tons of it ! So the
whole house slab is probably 18 tons of cement. I carried in the platerboard into the house basically a pile a metre high probably another couple of
tons.The internal walls are solid brick so many more tons of thermal mass. With water pipes furniture crockery kitchen units and much more stuff. This
could easily add up to 50 tons of thermal mass to heat up.

This was brought home to me when I went on holiday for a week in March. No frosts were predicted so I turned off the heating and electricals. Coming
home on a warmish day the house was colder than the outside. The internal temperature was 12 C. Even though we put the heating on the house felt cold.
Everything we touched was chilled cutlery cups etc. It took at least a week before the house felt comfortable. Considering the tonnage of material to
heat this is no surprise. The air temperature was 20 C+ but it just felt cold and draughty.

Although the thermostat is controlled manually I keep the house continuosly between 16 C and 20 C(average 18 C). It feels comfortable and draught
free. Some years ago on the forum there was a discussion about heating continuosly versus heating when required. It was never really decided which was
best for economy. Everyone who maintained an even temperature reckoned it was cheaper.

Over the last year October 2010 to October 2011 my gas heating bill has been 504.66. I use about 40 kWh/day on average With probably the coldest
winter for 20 years included in the year. I am well pleased with this.

Strangely I run my system with a water temperture of about 50 C and maintain the house temperature all the time. This is usually recommended for heat
pumps. You seem to be setting up your system on a timer with fall back temperatures wihch is usually recommended for gas/oil boilers.

Also it is interesting to note that my 40 kWh/day usage is probably at a boiler efficiency of 75% (non condensing boiler) So the actual heat input is
30 kWh/day. If you achieve this with your system it will cost :-

Assume average COP of 2.5. electricity require = 30/2.5 per day = 12 kWh/day
Assuming a cost of 10 p/kWh this equals 12 X 0.1 = 1.20 per day (average)

This is 1.20 x 365 = 438 per year. So assuming gas at 0.035 and electric at 0.10 the heat pump is cheaper to run assuming same output is required.

Out of interest what is your yearly bill ? And do you have a cost for connecting to the gas main ?


Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Solal on December 21, 2011, 07:03:12 PM
Hi
compressor speed 65hz
outside air tempature 2
room tempature  14
the compressor should be runing at almost full capasity ?

It can't, because the flow rate is not allowing any more heat to be taken away. Pump demand is set as a result of output temperature of the heat transport fluid.


If its  say zero degrees  outside and the compensator  is asking for a discharge  flow temperature from the HP  of 65c  and a wide  differential is  between  the return and the target  temperature   then surely  the compressor   should be ramping up full  to try and narrow the differential?

As the differential  narrows  with the  return  climbing  to say  60c  then I would have thought  this is when  the compressor will start ramping down  to maintain lets say a 5 degree  f&r differential.









Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: clivejo on December 21, 2011, 08:45:25 PM
I might be missing something but all your values are nowhere near the targets in brackets.  But your ASHP is still running trying to meet the demands.  This suggests that it is undersized for the demands on it  However I have seen this in fridge/freezers where the compressor is running excessively but never reaching the desired temperature and it was because the gas level was too low.

Have you had the refrigerant gas checked?  With it being CO2 and higher pressure, it makes me think the gas will escape quicker!  Does the manual give any indication on how often the CO2 needs to be recharged or even renewed?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: JonG on December 21, 2011, 09:33:40 PM
Halcyon Richard, its an interesting debate the continuous versus timed, a thread on the Green Building Forum has examined the same thing and the consensus was that mathematically there should be no difference.

However I am fairly sure that if I drove my car at a steady speed as opposed to accelerating and breaking regularly I would use less fuel. We have customers who have researched the same issue with heating in the lead up to a heat pump install and generally their feedback is that the fuel usage is lower.

Not only that but the thermal shock and cycling of a timed system cannot be good for any technology.

We always set up heat pumps to run 24-7 perhaps with some setback to preserve the compressor but inverter driven manufacturers have confused installers by suggesting that the modulation will take account of ramp down in the same way that a modern gas boiler will, but the reality is that it is usually 30-50% of output which can easily be exceeded in a zoned system or in the shoulder periods of the year.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 21, 2011, 10:32:18 PM
CLIVO
the demand is not  full on



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Panda on December 21, 2011, 10:37:01 PM
MacBeagle, I hope you are making some progress with this.

Keep in mind that there are two pumps. The one that is labelled CP Pump is the high head low flow pump that is directly underneath the thermal store. It is responsible for trickle charging the thermal store and its speed is controlled by the tank unit controller. The water coming out of the heat pump outdoor unit is at 65 degrees and the water returning to the heat pump outdoor unit is 41 degrees. This differential is a bit on the high side (I think it should be a 20 degree differential for these type of CO2 refrigerant heatpump) so it may be worth checking this pump. I think there is a manual speed selector on the actual pump (i.e. speed 1, 2 or 3) and I believe it should be on speed 3 which would allow the tank unit controller to modulate the pump speed over a proper range.

The other pump is your radiator circulation pump which will be mounted externally to the tank unit. This may be "interlocked" with a roomstat to stop it from wasting power when there is no further demand for space heating (or it may just run all the time if the installer didn't realise)

Your thermal store is at 49 degrees at the top so you ought to be able to send 49 degrees to the radiators. Are you able to confirm this? if the radiator flow pipe is significantly less then I'd say the problem is with the control of the 4 way mixing valve. You could drive it manually using the knob on the front of the mixing valve (turn the knob fully clockwise I think) and see if the radiator flow pipe gets hotter.

Finally, once you know that your radiators are being supplied with the highest temperature that your tank is at you might have to enable the electric immersion heaters within the tank unit controller in order to achieve your desired room temperature during cold weather.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: baker on December 21, 2011, 10:46:50 PM
  a other possibility may be
the working medium output flow rate is restricted  at the mixing servo valve by the set regulation parameters
increasing the output temperature


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 22, 2011, 02:27:17 PM
Thanks for all the replies.

Trying to take it all in but we have honed the 24/7 mindset to setting the thermostat/timer in the house on manual and have it set at 15 just to see how that pans out. The outside temperature at the moment is 10 so its no test at all really - we used 2.78 in the last 24 hours and we are an all electric house. We are both semi-retired so we spend a lot of time at home using multi and various electrical gadgets therefore it's a bit difficult to pin down exactly how much the ASHP is using.

I will enquire about the CO2 gas needing a top up but there is nothing in the "manual".

It would be nice if someone from Sanyo could come down, stand in front of the unit and explain in layman's language exactly what each bit does and why.

Panda. We did use the immersion in the tank to get the temps up last winter but the cost was astronomical.


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on December 22, 2011, 02:52:43 PM
Do you have the facility to just heat top up the DHW temperature with the immersion without having to heat the radiators as well.      A well set up system should  be able to have  the radiator take off point lower down on the store and a facility to heat the top separately.  Also  do you have  lower electricity at night?    If so you could top up the temperature in the early morning with the immersion but have the normal  flow temperature a bit lower.

I am not using my heat pump any more  but  in early December  last year  I was using 5 kWh each day to top up DHW temperature and that was mostly at night rate.     This week last year of course the  temperature was too low to use  the heat pump at all so electricity use got a bit out of hand.   


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on December 22, 2011, 04:33:24 PM
Hi MacBeagle,
                Thats interesting. Over time I have found out it can take up to a week to see the benefits of a stable temperature. For instance my 50 tons of thermal mass in my house would require 140 kWh to heat by 10 C. This is two days normal heating consumption.

Your figure of 2.78 should really be in kWh (at current prices/tariffs/economy 7 it can be misleading). So earlier you said you paid about
10 pence per KWh. This equates to about 28 kWh. If you are average electrical users you will be using 10 kWh on gadgets.

So 18 kWh to the heat pump at say a COP of 2.5 equates to 45 kWh out put. Say 6 kWh for hot water.

This means 39 kWh for heating. This is not unreasonable But one swallow does not make a summer. My figures are guestimates of course.

Also your temperature of 15 C seems low, you should be feeling the cold at that. Thermostats can be "out" by a few degrees. I checked mine by using
two other thermometers - they were all within 1 C of each other. Also the position of the thermostat is important height and position. If it's in
a cold spot the house average could be higher that the thermostat is set at.

It might pay to buy an energy monitor to see what your gadgets etc use. I replaced an old TV with a modern one which cosumes less than 1/3 of the old
one. It will make working out the power used for heating easier.

The national average household consumption electricity and gas is some thing like 1500 (mine is 1/2 of that). If you come under this on an all electrical house
you are doing very well.



Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 22, 2011, 08:27:08 PM
Hi HalcyonRichard

"Also your temperature of 15 C seems low, you should be feeling the cold at that."

Nah, toasty. We are old school, bought up when you only heated one room and froze going to the upstairs loo. The good old days - rickets, diptheria, scarlet fever.

It's no hardship at 15 and that leaves a good reserve to up it a bit when the temperature drops, and we always have the Stovax. Just wish a) I had found this forum earlier and b) the people who sold us the unit were as well informed


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on December 29, 2011, 09:40:11 AM
Hi,
    Thanks JonG I have had a look at the green building forum and joined ! Over christmas I found out that on permanentley certainly appears to be more efficient than on/off control

One night it felt chilly and draughty at 20 C but over the next hour it felt warm and still with no draughts at 20 C. So I thought has the house thermal mass finally reached equilibrium ? So I decided to leave the thermostat at 18 C for a week to check things out. Three days of similar weather and daily consumption is 48 kWh i.e. 25 % less with heating on "permanentley". The boiler seems to fire for 10 -15 minutes every four hours or so. Early days I know. The house now "feels" very different and seems to hold it's temperature very well. This made me think. I have to get to the bottom of this. I think I am on the right track and will post what I have found after I research the physics/thermodynamic principles to back up my thoughts. It seems that natural convection could explain a few things. I am posting on the green building forum on this thread :-

http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=8179&page=2#Item_15

Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on December 29, 2011, 06:40:16 PM
Have been persevering with the constant 15C, boosting it to 17 in the evening and using the Stovax every now and again. Works fine but, and it's a big but - during the early hours the thermostat will keep clicking on and off when it reaches 15, the pump kicks in for micro minutes and the radiators start clicking - it's driving us mad. The pump and thermostat are hardly discernible but the clicking rads are something else. Would modern rads eliminate this?

Just got some figures from nPower about my electricity usage from June 2010 - June 2011 which encompassed some minus temperatures and usage of the immersion heating elements - 11,846 Kwh total energy bill, which equates to 1293.14 (Sign On-Line 22). They reckon we could be spending roughly 1400 for gas alone based on an average 4 bed house. So, real food for thought.



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on January 01, 2012, 08:30:19 PM
Hi

Looking at Dimplex Smartrads as an alternative to the old slimline radiators to make the most of the ASHP.

This is a question for StationHouse really but feel free to chip in. In one of his posts he said "we went for the white glass fronted Dimplex SmartRads. Size them at the lowest fan speed to the room so they run at their quietest." How did you do that?

Cheers and a Happy New Year to you all





Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: StationHouse on January 01, 2012, 09:12:46 PM
Hi

Looking at Dimplex Smartrads as an alternative to the old slimline radiators to make the most of the ASHP.

This is a question for StationHouse really but feel free to chip in. In one of his posts he said "we went for the white glass fronted Dimplex SmartRads. Size them at the lowest fan speed to the room so they run at their quietest." How did you do that?

Cheers and a Happy New Year to you all





Hi, if you don't mind I'll get back to you shortly about sizing as I'm tucked up in bed  ;D Certainly SmartRads/fan convectors are the way to go if UFH or hughly oversized rads are out of the question. Now we have lived with the system for a while the one thing I like is the fast response of the system as each rad only holds about a litre of water whereas oversized rads would hold vastly more. UFH may hold even more water but the advantage there would be running the system using cheaper overnight electricity tarifs with the slab holding the room temps during the day with minimal topup?

Running cost wise Dec 2010 with a mix of snow, hard frost and semi mild has been just over 100 for the whole house. Not bad for an old house with 3m ceilings. Last Dec mimimal use of LPG for Dec, although colder, would have been around 300 plus electric for oil rads...

Put it this way, our bed still has the thin summer duvet  8)

Happy new year all  :)


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: StationHouse on January 01, 2012, 09:32:21 PM
Hi MacBeagle,
             It's good to see you are experimenting with your system. Every house,heating system and inhabitants are different. Reading between the
lines you seem to have a similar insulation and heating requirements as me. I have experimented over a number of years to optimise efficiency while
maintaining comfort levels. Initially I tried just putting the heating on when required but this meant the fabric of the house was usually cold and
required a higher thermostat setting to feel comfortable(always above 20 C).

I built an extension onto my current house it is now 1/3 of the completed house. I barrowed in the cement for the new "slab" - six tons of it ! So the
whole house slab is probably 18 tons of cement. I carried in the platerboard into the house basically a pile a metre high probably another couple of
tons.The internal walls are solid brick so many more tons of thermal mass. With water pipes furniture crockery kitchen units and much more stuff. This
could easily add up to 50 tons of thermal mass to heat up.

This was brought home to me when I went on holiday for a week in March. No frosts were predicted so I turned off the heating and electricals. Coming
home on a warmish day the house was colder than the outside. The internal temperature was 12 C. Even though we put the heating on the house felt cold.
Everything we touched was chilled cutlery cups etc. It took at least a week before the house felt comfortable. Considering the tonnage of material to
heat this is no surprise. The air temperature was 20 C+ but it just felt cold and draughty.

Although the thermostat is controlled manually I keep the house continuosly between 16 C and 20 C(average 18 C). It feels comfortable and draught
free. Some years ago on the forum there was a discussion about heating continuosly versus heating when required. It was never really decided which was
best for economy. Everyone who maintained an even temperature reckoned it was cheaper.

Over the last year October 2010 to October 2011 my gas heating bill has been 504.66. I use about 40 kWh/day on average With probably the coldest
winter for 20 years included in the year. I am well pleased with this.

Strangely I run my system with a water temperture of about 50 C and maintain the house temperature all the time. This is usually recommended for heat
pumps. You seem to be setting up your system on a timer with fall back temperatures wihch is usually recommended for gas/oil boilers.

Also it is interesting to note that my 40 kWh/day usage is probably at a boiler efficiency of 75% (non condensing boiler) So the actual heat input is
30 kWh/day. If you achieve this with your system it will cost :-

Assume average COP of 2.5. electricity require = 30/2.5 per day = 12 kWh/day
Assuming a cost of 10 p/kWh this equals 12 X 0.1 = 1.20 per day (average)

This is 1.20 x 365 = 438 per year. So assuming gas at 0.035 and electric at 0.10 the heat pump is cheaper to run assuming same output is required.

Out of interest what is your yearly bill ? And do you have a cost for connecting to the gas main ?


Regards Richard

Totally agree with this...^^^

Over on MSE they seem staunchly against this idea but in an older house, as long as it is insulated and draft free, it makes a lot of sense. Perhaps in a small modern box a different approach is required.

Great post  :)


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Ladysmeader on January 05, 2012, 06:02:40 PM
This has been a very useful thread for me as I'm considering the Sanyo CO2 ASHP for my property. I'd appreciate anyone's comments on my circumstances:-

A remote one off 3 bed-roomed cottage, 400 years old, thick cob walls, no chance of ever getting a mains gas supply. Loft very well insulated with 300mm + insulation, double glazing and well draught proofed. Currently have a 6 year old oil fired programmable rayburn for central heating, hot water and cooking. Also a wood burner which we use most evenings. We keep the temperature at 18 deg C and have the central heating on for 3 hours in the morning , 3 hours in the afternoon/early evening before lighting the wood burner. Have had PV panels installed at 3.96KWp for the last 18 months. We want to get away from oil altogether as eventually it will become prohibitively expensive.

We use 1500 litres of oil at say 50p/l = 750, 8 cu.m of logs at 45/cu.m = 360, and 2000 kwh electric at 14p = 280 (also consumed 1000 kwh of our own generation). This was over the last very cold winter. I think our running costs will be lower this winter as it has been so mild.

Thats a total of nearly 1400 for all heating, HW and cooking. We also made close to 1600 from the FIT in 2011.

We have had two quotes for the installation of the Sanyo ASHP plus thermal store ( not the swedish one mentioned in the thread but a Kingspan job which has been specified by the local sanyo rep to improve the overall COP of the pump. Both installers reckoned we needed 9KWH as we had the backup of the wood burner, and we will at the outset retain the rayburn for cooking which gives us some residual heat for several hours once hot.

The bonus for me is that the Sanyo unit will use up the excess PV electricity we don't use both in the winter and in the summer. In the winter it will go mainly to heating the home, but in summer will keep us topped up with hot water, so that we should not ever need solar thermal panels. We currently export to the grid around 3000KWH which would be better used running the sanyo heat pump. We currently have electric power showers and these will be replaced with a pressured supply from the thermal store.

Thats the theory - anyone have any comments please.



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: HalcyonRichard on January 05, 2012, 06:27:55 PM
Hi Ladysmeader,
                       If it's cost you are thinking about then you need to calculate how much power you use over a year. Then work out how much power the new system will use. After this you can calculate and compare costs. So using the data given (rough cut ball park figures):-

1/ 1500 litres @ 10 kWh 100 % efficiency = 15,000 kWh
2/ 8 m3 logs say at 500 Kg/m3 @ 4kWh/Kg 100% efficiency = 16,000 kWh
3/ All electricity @100 % efficiency = 3,000 kWh

So yearly heat input = 34,000 kWh (sanity check - my well insulated house last year consumed 14,400 kWh heating)

This figure seems about right to me - it looks in the ball park.

So lets replace all of it with a heat pump with an average COP of 2.5

So electrical input required = 34,000/2.5 = 12,800 kWh electricity to run pump.

Cost of 100% heat from heat pump @ 14 p/kWh = 12,800 * 0.14 = 1,792

So it looks on rough figures the cost is not a big incentive. But you can get cheaper possibly off peak electricity. You may not get all of your heating from the heat pump. You may like the ease of use of the heat pump.

Warning all figures are guesstimates.

Regards Richard


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Ladysmeader on January 05, 2012, 10:43:42 PM
Thanks Richard. The cost is not the real incentive, its getting away from oil and using as much of the pv generation as possible. Just tweaking your figures a bit. Probably 300l of the oil is used for cooking = 3000KWH and none of electricity is used for heating = 3000KWH. So I would guess 28000KWH goes on heating. We will continue to use the woodburner, perhaps not as much but we like the effect and ambience in our home, so say 8000KWH of the logs can be deducted. This leaves 20,000 KWH. We have 3000KWH PV being exported. If we could use say 2000KWH of this , it reduces the ASHP's requirement to 18,000 kwh at 2.5 COP and 14p/kwh = 1000 cost plus cost of half the logs 180 plus cost of 300 l oil for cooking = 150 Total cost 1330. The cost if the system actually works is very similar to current costs, but is weaning us off the oil . If it does work, we will remove the rayburn altogether in the future. We will never get a payback for the installation costs, but the income from the pv will easily repay both the PV and ASHP installation over 25 years (unless the govt change the FIT tariffs for existing users in the future - not impossible).





Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: dhaslam on January 06, 2012, 01:14:25 AM
Would it be possible to insulate the walls  outside and  get  the outside  finish back to the same as it was? 


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: knighty on January 06, 2012, 02:20:00 AM
Ladysmeader

if you're going to a have a thermal store, then it seams almost crazy not to have solar thermal, you'd get a hell of a lot of heat for the cost of the panels and a bit of pipe (if you're already buying the thermal store etc... then that's the big stuff already paid for)


I don't know much about there availability, only there existence, but can you install a heat pump which can run at lower power (an inverter controlled one) - I can't remember the proper name for these...

the idea being it would make better use of the power you generate if the heat pump runs at 3kw for 12hours instead of 9kw for 4hours ?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: Ladysmeader on January 06, 2012, 04:32:16 PM
Thanks for the answers so far. Our house walls are cob and as such they have to be "breathable". Any external wall insulation, or internal for that matter has to allow the walls to breathe. We have looked into this, products are available  but the cost is astronomical, like 25,000 to externally insulate our cottage.

We have space to put solar thermal panels on our roof and the thermal store will have the capability to take the heat from them as a future project.



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: StationHouse on January 09, 2012, 11:38:48 AM
Hi

Looking at Dimplex Smartrads as an alternative to the old slimline radiators to make the most of the ASHP.

This is a question for StationHouse really but feel free to chip in. In one of his posts he said "we went for the white glass fronted Dimplex SmartRads. Size them at the lowest fan speed to the room so they run at their quietest." How did you do that?

Cheers and a Happy New Year to you all





Hi,

Have you seen the sizing chart in this PDF?

If you like send me your room sizes and will compare to mine to double check?

Cheers


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: MacBeagle on January 12, 2012, 12:25:25 PM
Hi

"Have you seen the sizing chart in this PDF?" Not sure what PDF you mean. I did use the Dimplex heat loss calculator on their website to work out rad sizes - how does this correlate to fan speeds?

The relevant rooms sizes are:
Hall - 4mL x 2.9mW x 2.37mH - Dimplex suggests 1.26 kW DuoHeat Radiator
Living Room - 4.8mL x 3.8mW x 2.37H - Dimplex suggests 2.35 kW DuoHeat Radiator
Dining Room - 6.7mL x 3.8mW x 2.37H - Dimplex suggests 3.14 kW DuoHeat Radiator

I reverted back to the original installation settings and we are now getting temperatures through the rads of 54-58 without any increase in costs. A blitz on all the draughts and not letting the house fall below 15 at night has shown a big improvement, but there again outside temperatures of 7-10 degrees have helped.



Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: SpeedEvil on November 01, 2012, 11:45:30 AM

Also it is interesting to note that my 40 kWh/day usage is probably at a boiler efficiency of 75% (non condensing boiler) So the actual heat input is
30 kWh/day. If you achieve this with your system it will cost :-

Assume average COP of 2.5. electricity require = 30/2.5 per day = 12 kWh/day
Assuming a cost of 10 p/kWh this equals 12 X 0.1 = 1.20 per day (average)

This is 1.20 x 365 = 438 per year. So assuming gas at 0.035 and electric at 0.10 the heat pump is cheaper to run assuming same output is required.

Sorry to necro the thread, came across it after finding a reference to the OP's heat pump.
However, am I missing something, or is there an error above?
I agree that to provide 30kWh/day with 10p/kWh and a COP 2.5 pump would be 438/year.

But, 10/2.5 =4p/kWh, And the gas boiler will hit 4.11p, assuming 80% efficiency, And needs to hit 87% before parity.

Are you really basing the 'cheaper' claim on 12 quiddish savings a year?


Title: Re: Sanyo CO2 Eco 9kw ASHP - Help
Post by: brackwell on November 01, 2012, 02:08:54 PM
That thinking has to be based on wrong premise.

There is no way one can talk about a "average" COP as it is highly variable from say 1.0 in the depths of winter to perhaps 5.0

Further the COP can be significantly changed by output temps and usage patterns which dont really affect the gas boiler efficiency that much.

The real life efficiency of a gas boiler supplying DHW only is nearer 50%

Suggested reading http://www.heatpumps.co.uk/DHW.htm

Ken