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  • FIRST POST
    • zeupater
    • By zeupater 21st Jul 13, 5:35 PM
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    zeupater
    Discussion ... ASHP(Air/Air) with Solar pv ....
    • #1
    • 21st Jul 13, 5:35 PM
    Discussion ... ASHP(Air/Air) with Solar pv .... 21st Jul 13 at 5:35 PM
    Hi All

    The combination of a small ASHP(Air/Air) with Solar pv seems to be a valid pairing of complementary technologies which has been raised a number of times on this forum.

    The idea of this thread is to encourage discussion of this combination in order to validate what an appropriate equipment specification would look like in order to maximise performance benefits in a typical domestic environment.

    Obviously, it is well understood that a typical domestic-scale solar pv system will not generate sufficient energy to provide winter heating, but should be considered as being a 'shoulder' months supplementary heat source for well insulated properties ... it is therefore best to concentrate on Spring & Autumn as being the target periods for heat provision, with an additional benefit of provision of cooling in heat-wave conditions such as we've been experiencing recently.

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
Page 8
    • zeupater
    • By zeupater 26th May 17, 1:12 PM
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    zeupater

    Here's my issue. The house is fairly large (4 bedrooms, 2 baths, pretty large lounge and kitchen). The most used room is the lounge but we have a log burner in there. This allows me to turn the central heating lower in the rest of the house (and obviously off altogether in the lounge). So far (in the depths of winter) I would say that the stove has added to comfort levels rather than significantly reduced the bills. I love the idea of a ASHP but were would I put it, and am I going to get much benefit/savings in the shoulder months (in addition to wonderful a/c at this time of year)
    Originally posted by Exiled Tyke
    Hi ET

    I don't know how you use the rooms, the layout of the furniture or where the property boundaries are (too close & planning restrictions could apply), but my gut feeling would be to look at the the same wall as the log-burner, but in the single storey area at the back of the house ... this would provide a heat source which isn't too close to the burner if you decide/need to run both together, which will provide a more even heat distribution.

    To give an idea ... consider a L shaped layout consisting of two rooms (similar in size to the lounge & dining room in your diagram) with double doors between the two rooms and both rooms also having double doors onto a hall - our log burner would be at the top of the vertical section of the 'L' & the ASHP in the horizontal part. We use the smaller room for TV etc and that tends to be where we sit most of the time. With doors closed, the heat-pump has no problem raising the temperature in the TV room in a few minutes even when it's very cold outside, before ramping down to draw very little power ... opening the adjoining double doors to the lounge increases the 'time-to-temperature', but the unit will still easily cope with heating the space in all conditions we've encountered so-far (remember - we have loads of insulation & high internal thermal mass) .... If you use the 'Dining Room' on the layout as a TV/entertainment area and installed the heat-pump in there (on long external wall), then you would be able to have a very similar set-up to us, but it may be a little too close to the burner when using both together (thermostat set-point cut-out) ...

    For the shoulder months we've tended to heat the 'living area' with the heat-pump during the day, then open up the doors to the hall overnight to allow the heat throughout the house ... this is just an extension of what we've done for years with the log-burner, with the doors effectively being used as baffles to control the temperature, so nothing new ... you would obviously be able to (& probably already do?) use your doors in a similar way.

    On the logs side, ASB remembers it right, we've still got about half of our usual October delivery left due to considerably shortening the burn-season ... part of this could also be due to annual temperature variations, but with last winter being similar to the previous year it looks encouraging ...

    HTH
    Z
    Last edited by zeupater; 26-05-2017 at 8:11 PM. Reason: + 's
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • zeupater
    • By zeupater 26th May 17, 1:32 PM
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    zeupater
    ... I didn't expect to get to play with the AC so soon, and I'm pretty sure it wouldn't have been needed at all last year, but ...... I really don't like being too hot, so the benefit the last 2 days has certainly been worth a lot of money to me, but hard to quantify.
    Originally posted by Martyn1981
    Hi

    It's still nice & cool in most of the house when compared to outside, but has started to become a little too warm upstairs (insulation, insulation, insu ...). For the last couple of nights we've opened bedroom windows overnight to let the heat out, before closing them again during the day to keep it out.

    At this time of year we get sun at the back of the house in the evening which often provides some unwelcome solar-gain, so yesterday our unit was run for around 15-20 minutes on a very low setting to bring the air temperature down a little ... first time this year though.


    HTH
    Z
    Last edited by zeupater; 26-05-2017 at 8:14 PM. Reason: + yesterday
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • Exiled Tyke
    • By Exiled Tyke 29th May 17, 1:59 PM
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    Exiled Tyke
    Thanks all for the great advice. Lots to think about. Currently wood is free but unlikely to stay that way forever. The log burner is in the middle section of lounge (to half of it). The very top section we currently don't use. The dining room below it is only used occasionally (actually it's music rehearsal space).

    I would be looking to put the o/s unit on the RHS of the lounge area but you've also raised a concern that it may be too near the boundary and upset next door. That is also the north side of the house so perhaps not the best location?

    I suppose my issue is that my major heating cost is now keeping the base temperature reasonable in the rest of the house - ok so bedrooms and bathrooms as the kitchen 'heats itself' when in use.

    I still like the idea but suspect it's not yet viable.
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    • ASavvyBuyer
    • By ASavvyBuyer 1st Jun 17, 10:12 AM
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    ASavvyBuyer
    May 2017 update for using the Toshiba Air Conditioner/Heat Pump.

    Comparing Gas & Electric use from May last year have ended up with the following figures:
    Gas use down to 12kWh compared to 97kWh last year (a saving of just over 87%) GCH got triggered to come on for a short period on a couple of cold mornings.

    Electric import the same as last year at 94kWh.

    From checking the historical records at Accuweather.com for weather, it has been very similar month to last year, except for the short heat wave last week, where the cooling from the ASHP worked a treat
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • BrianD
    • By BrianD 1st Jun 17, 4:44 PM
    • 53 Posts
    • 12 Thanks
    BrianD
    I have found this a very informative and interesting thread and am about to obtain quotes for one of the Daseikai 8 heat pumps but before doing so can I ask if either Z or ASB would still purchase the same product or is there something newer which you would choose instead?

    I have a 3.68K system of west facing panels installed in 2011 and based in Darlington
    • ASavvyBuyer
    • By ASavvyBuyer 1st Jun 17, 8:17 PM
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    ASavvyBuyer
    I have found this a very informative and interesting thread and am about to obtain quotes for one of the Daseikai 8 heat pumps but before doing so can I ask if either Z or ASB would still purchase the same product or is there something newer which you would choose instead?

    I have a 3.68K system of west facing panels installed in 2011 and based in Darlington
    Originally posted by BrianD
    Have not really be looking for later models, but have not noticed any being promoted. If we were having another one installed, would still probably go for the same unit.

    However, may be worth taking a look at some of the models listed here http://www.topten.eu/?page=monosplit-3kw as some appear to be even more efficient than the Toshiba Unit we have, but a lot depends on how controllable they are.
    Last edited by ASavvyBuyer; 01-06-2017 at 9:39 PM. Reason: added link info
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • zeupater
    • By zeupater 5th Jun 17, 12:42 PM
    • 3,577 Posts
    • 4,407 Thanks
    zeupater
    I have found this a very informative and interesting thread and am about to obtain quotes for one of the Daseikai 8 heat pumps but before doing so can I ask if either Z or ASB would still purchase the same product or is there something newer which you would choose instead?

    I have a 3.68K system of west facing panels installed in 2011 and based in Darlington
    Originally posted by BrianD
    Hi

    I'd certainly go for the same model again, here's a couple of reasons why ...

    If you look back through the thread you'll gauge that the decision for our particular model resulted from comparison of loads of different models from most of the leading manufacturers and a realisation that the specifications and functionality of whatever models we looked at were generally being subconsciously measured against the Daiseikai range.

    When looking into various alternatives I decided at an early stage that it would be better to effectively ignore the headline seasonal performance (SCOP) which manufacturers use in their specifications and concentrate more on the COP within the range of temperatures which would be likely during the daytime in the shoulder months (Spring/Autumn) when we would be using the heat-pump to utilise our own generation to provide the heat we wanted. The idea behind this was that as we intended to use the heat-pump when PV generation conditions allow, we would need to take into consideration that ... (i) the sun doesn't shine at night in the shoulder months ... and ... (ii) we had no intention to use the heat-pump as the main source of heating during the Winter ... so why would we need to consider a performance measure which took low overnight temperatures and temperatures outside the shoulder month period into account .... this effectively means that, although SCOP is a decent headline comparative measure, for what is being discussed on this thread, you need to delve a little deeper - which in itself can be pretty hard with some manufacturer published specifications, but others seem to be far more open to providing the detail you'd need ...

    Amongst the myriad of other functional and performance information which would be relevant to the decision making process when attempting to match the capabilities of the heat-pump to those of domestic-scale PV generation is the range of operation of the heat-pump. A basic heat-pump effectively works on an on/off basis, controlled by a thermostat, therefore a small basic 3kW unit operating at a COP of around 4 will be drawing 750W, resulting in additional electricity imports when it's cloudy even with a 4kWp PV system (it's currently overcast but bright here & we're generating 489W). Moving away from the basic models we have inverter based units which generally have better comparative performance statistics, but importantly have the ability to vary their supply of heat proportionally to thermostatic set-point demand and the range of this variability becomes relevant to what we're looking to achieve ... some of the inverter heat-pumps with similar COP statistics when we were looking had a performance range which required a minimum of 400W of electricity up to their maximum, whilst others had the ability to ramp down to close to l00W .... anyone already familiar with the variability of PV generation will appreciate that being able to utilise the heat-pump to provide over 500Wt of shoulder month background heating whilst consuming close to 100W to 120W of electricity becomes very handy in dull/cloudy conditions ....

    HTH
    Z
    Last edited by zeupater; 05-06-2017 at 12:52 PM.
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • ASavvyBuyer
    • By ASavvyBuyer 5th Jun 17, 6:53 PM
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    ASavvyBuyer
    Hi

    ... some of the inverter heat-pumps with similar COP statistics when we were looking had a performance range which required a minimum of 400W of electricity up to their maximum, whilst others had the ability to ramp down to close to l00W .... anyone already familiar with the variability of PV generation will appreciate that being able to utilise the heat-pump to provide over 500Wt of shoulder month background heating whilst consuming close to 100W to 120W of electricity becomes very handy in dull/cloudy conditions ....

    HTH
    Z
    Originally posted by zeupater
    That was the main deciding point for us choosing the Toshiba Unit. It's controllability and ability to work at low power levels. Most of the time, we have found it is only using between 100 & 200 watts (apart from when starting up or on a boost).
    The link that Z provided to the Technical Manual http://www.solar-klima.com/DAISEIKAI_EN.pdf was very useful for showing the COP at various outside temperatures.
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • BrianD
    • By BrianD 6th Jun 17, 5:13 PM
    • 53 Posts
    • 12 Thanks
    BrianD
    Thank you for the comprehensive replies from Z and ASB it is most appreciated and I am starting out on the quotation stage for the same Daseikai 8 as you both have with some local suppliers one of whom came today and I await their quote.

    Does the 5% VAT rate still apply for domestic supply and install, I meant to ask the chap this morning but forgot to?
    • ASavvyBuyer
    • By ASavvyBuyer 6th Jun 17, 5:31 PM
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    ASavvyBuyer
    Does the 5% VAT rate still apply for domestic supply and install, I meant to ask the chap this morning but forgot to?
    Originally posted by BrianD
    It applied when we had ours installed and it appears to still apply according to the HMRC website https://www.gov.uk/guidance/rates-of-vat-on-different-goods-and-services#power-utilities-energy-and-energy-saving-heating

    One thing you have to make sure of, to qualify for the 5% rate, is that the installer puts the supply & install costs on the same invoice. i.e. does not charge for the supply on one invoice and the install on a seperate invoice. Also, make sure you get any electrical work needed included in the price.
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • BrianD
    • By BrianD 7th Jun 17, 6:49 AM
    • 53 Posts
    • 12 Thanks
    BrianD
    Many thanks for that excellent advice I will make sure to follow it to the letter.
    • tunnel
    • By tunnel 16th Jun 17, 5:56 PM
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    tunnel
    Also, make sure you get any electrical work needed included in the price.
    Originally posted by ASavvyBuyer
    I've decided to update my ASHP as mine sounds like an express train running through the house whilst it's on. I've plumped for the Toshiba. I've been told it needs an outside power feed so i'll have to drill the wall and wire it to an internal socket, the guy says it only pulls 10A so is perfectly safe to do so.
    How have you wired yours....the same way? New ring or something completely different?
    Interested to know if you've been advised differently.
    2 kWp SEbE , 2kWp SSW & 2.5kWp NWbW.....in sunny North Derbyshire
    • ASavvyBuyer
    • By ASavvyBuyer 16th Jun 17, 11:44 PM
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    ASavvyBuyer
    I've decided to update my ASHP as mine sounds like an express train running through the house whilst it's on. I've plumped for the Toshiba. I've been told it needs an outside power feed so i'll have to drill the wall and wire it to an internal socket, the guy says it only pulls 10A so is perfectly safe to do so.
    How have you wired yours....the same way? New ring or something completely different?
    Interested to know if you've been advised differently.
    Originally posted by tunnel
    Ours is connected via a fused spur on the lounge ring main. We live in a bungalow and the ring main wiring goes above the ceiling and drops down to the sockets (and the fused spur).

    There is no need for an outside power feed as the Toshiba unit can take the power on the inside unit and pass it through the control cable to the outside unit.

    I'll have a look for the connection diagram that shows how the power can be connected to either the inside or outside unit.
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • Martyn1981
    • By Martyn1981 17th Jun 17, 7:20 AM
    • 5,508 Posts
    • 9,471 Thanks
    Martyn1981
    I've decided to update my ASHP as mine sounds like an express train running through the house whilst it's on. I've plumped for the Toshiba. I've been told it needs an outside power feed so i'll have to drill the wall and wire it to an internal socket, the guy says it only pulls 10A so is perfectly safe to do so.
    How have you wired yours....the same way? New ring or something completely different?
    Interested to know if you've been advised differently.
    Originally posted by tunnel
    Mine came with a plug, and just plugged into a socket in the pantry which the plumbing goes via (from outside wall - pantry - conservatory wall).
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • tunnel
    • By tunnel 17th Jun 17, 8:36 AM
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    tunnel
    Cheers guys
    I was a little sceptical at first when the installer started talking electrics and part P but he assures me it's perfectly safe using a plug.
    My current(express train) system is mounted on the wall and the power cable dangles down the wall to a socket just above the floor. Now looking forward to "tidying" it up somewhat with the power cable through the wall to its own designated socket(sad I know but.....)
    2 kWp SEbE , 2kWp SSW & 2.5kWp NWbW.....in sunny North Derbyshire
    • ASavvyBuyer
    • By ASavvyBuyer 17th Jun 17, 10:39 AM
    • 395 Posts
    • 996 Thanks
    ASavvyBuyer
    Ours is connected via a fused spur on the lounge ring main. We live in a bungalow and the ring main wiring goes above the ceiling and drops down to the sockets (and the fused spur).

    There is no need for an outside power feed as the Toshiba unit can take the power on the inside unit and pass it through the control cable to the outside unit.

    I'll have a look for the connection diagram that shows how the power can be connected to either the inside or outside unit.
    Originally posted by ASavvyBuyer
    Found the connection diagram in the Toshiba Installation Manual. It recommends that power should be connected to the inside unit; connection via the outside unit is optional.
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • zeupater
    • By zeupater 17th Jun 17, 11:34 PM
    • 3,577 Posts
    • 4,407 Thanks
    zeupater
    Cheers guys
    I was a little sceptical at first when the installer started talking electrics and part P but he assures me it's perfectly safe using a plug.
    My current(express train) system is mounted on the wall and the power cable dangles down the wall to a socket just above the floor. Now looking forward to "tidying" it up somewhat with the power cable through the wall to its own designated socket(sad I know but.....)
    Originally posted by tunnel
    Hi tunnel

    Our unit takes power from a fused spur (/breaker) off the ring main almost directly behind the outdoor unit, although it's possible to wire and provide power to either unit.

    We opted to take the power to the outside unit for the very reason you've highlighted ... powering the indoor unit would involve either channelling & redecorating or surface mounting the power lead in trunking, whilst taking power through the wall shows nothing internally.

    There are details on the internal/external wiring options in the Daiseikai manual if you need to see them, but essentially To5hiba provide alternative screw terminal points to support particular site requirements.

    HTH
    Z
    Last edited by zeupater; 17-06-2017 at 11:52 PM.
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • Martyn1981
    • By Martyn1981 18th Jun 17, 7:01 PM
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    Martyn1981
    Man I lucked out this year. I'd like to say it was foresight, but after 3 years of dithering, no-one would believe me, so I'll just admit I lucked out.

    Upstairs 26C, weather station in the garden has finally dropped below 30C, living room has been 22C all day, and that's where I've been most of the day.

    And all PV powered
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • zeupater
    • By zeupater 18th Jun 17, 8:25 PM
    • 3,577 Posts
    • 4,407 Thanks
    zeupater
    Man I lucked out this year. I'd like to say it was foresight, but after 3 years of dithering, no-one would believe me, so I'll just admit I lucked out.

    Upstairs 26C, weather station in the garden has finally dropped below 30C, living room has been 22C all day, and that's where I've been most of the day.

    And all PV powered
    Originally posted by Martyn1981
    Hi

    Same here, had our running at 22C for a few hours and most of the time we were still exporting ~90% of generation.

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • tunnel
    • By tunnel 18th Jun 17, 10:59 PM
    • 2,494 Posts
    • 7,635 Thanks
    tunnel
    Upstairs 26C, weather station in the garden has finally dropped below 30C, living room has been 22C all day, and that's where I've been most of the day.
    Originally posted by Martyn1981
    Same here, had our running at 22C for a few hours and most of the time we were still exporting ~90% of generation.
    Originally posted by zeupater
    I've had the old "express train" running all day except mines in the bedroom and it cools all the upstairs as we're able to close the upstairs to the downstairs(advantages of not being open plan)......I'll leave it running all night and burn some of my hard earned FiT..........Now....if only I had batteries
    2 kWp SEbE , 2kWp SSW & 2.5kWp NWbW.....in sunny North Derbyshire
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