GES Caernarvon 18kW ASHP
Hello all,
I've just joined as I wait for my GES Caernarvon 18kW ASHP to be commissioned, hopefully next week! We previously had an oil boiler and were burning around 3000litres of heating oil a year to heat our detached, nearly 200-year old cottage just outside of Uxbridge.
After doing a lot of insulation work - secondary glazing, replacing loft insulation to modern standards and re-boarding, cavity wall insulation on those walls which have cavities (the original small cottage been extended multiple times over the years), and some internal insulation - our EPC went up to E (near miss for D, but the cost/benefit got really unappealing!). This allowed us to do away with the oil boiler entirely and replace it with the 18kW heat pump, qualifying for the Boiler Upgrade Scheme. We unfortunately missed the RHI due o a chip shortage at GES which put the project back nearly 6 months.
I'm excited and a little apprehensive about the switch to the ASHP, which will make us an all-electric house (we cook on an induction hob and have an electric car). Our next project is likely rooftop PV to complement our existing solar thermal setup, which is currently supplying all our hot water as we wait for the great Switch-On. The installation process has been... interesting, but Dave at GES has been very helpful in getting it over the line since he took over handling our account.
Hi Chris,
Welcome to the forum.
I would be interested with more details about your solar thermal system. Does it provide hot water throughout the whole year or just from Spring through to Autumn?
Posted by: @derek-mI would be interested with more details about your solar thermal system
Me too @chris-a
@derek-m and I have had a previous discussion about whether solar thermal should continue to be used as an input to a DHW cylinder, of if it's better to re-configure it as a pre-heater to a heat-pump when one gets installed. We don't (yet) have any answer on this, so feel free to chip in!
Save energy... recycle electrons!
@transparent and Derek M,
Thanks. We've had our solar thermal system for 9 years of trouble-tree (and nearly maintenance free) operation: it's a very simple and efficient system provided the sun is shining (unlike PV, it prefers direct sunlight rather than just lux). Whilst we had our oil boiler it made a lot of sense, as it gave us free hot water for most of summer, with a top up from oil on cloudy days.
To answer Derek M's question, it is mostly (though not exclusively) Spring to autumn. It actually works well on sunny winter days: the outside temperature doesn't matter. On a day like this (sunny with clouds) it has taken most of the 300 litre cylinder up to 64 degrees C (sensor at the bottom, as is the solar coil). Even on cloudy but bright days, it raises the bottom of the tank to around 40 degrees. o even if it's not doing the whole job, it's giving the heat pump/boiler less work to do.
Transparent - that's an interesting question. We're not set up for it to input to the heating circuit, so for us it will remain for hot water. The advantage to that is that it can raise the DHW temperature far hotter than would be efficient for the heat pump (we have a thermostatic mixing valve to prevent scalds, so a hotter tank just means more hot water). How the heat pump would react to having the heating circuit raised to above its flow design temperature I'm not sure! When the conditions are right, it can dump a LOT of heat into the cylinder. Sadly for heating, during winter when you need it most, it will do less. But of course one needs DHW all year round, so perhaps that's another argument in its favour.
Another question might be, does it even make sense to have solar thermal when PV diverters can be used for the same thing, and the PV also powers the heat pump? This wasn't an option when we put it in, but I wonder if it might be a better use of roof space for heat pump owners. But I think Solar thermal is more efficient, provided the sun is shining.
Thanks for the info. My research indicates that solar thermal is up to 4 times more efficient than solar PV, so you could get the same amount of energy from 1/4 the roof space. We have solar PV, which provides the vast majority of our hot water from Spring through to Autumn and also assist the gas boiler in producing hot water in the Winter. So very similar to your solar thermal, but with the added advantage that it has reduced our electrical consumption by 50% over a full year.
Since you are having a quite large 18kW heat pump installed, solar PV would be somewhat beneficial, particular in the Spring/Autumn period, but will not be able to fully power your heat pump during the heating season. But as they say, 'every little helps'.
Posted by: @chris-aHow the heat pump would react to having the heating circuit raised to above its flow design temperature I'm not sure!
Precisely!
And for this reason I've just copied your text and the response from @derek-m into a new topic in the area about Solar Thermal. I think that's where others would expect to find it in months to come.
I've also added a couple of diagrams to make it easier to see what we're discussing. Feel free to re-edit those as you wish!
Save energy... recycle electrons!
- 22 Forums
- 2,046 Topics
- 44.6 K Posts
- 74 Online
- 3,273 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Renewables & Heat Pumps in the News
No, sorry it's not. It was a press call*. Plus I think...
By Lucia , 29 minutes ago
-
@editor I had my second ‘Annual Service’ carried out by...
By Toodles , 2 hours ago
-
RE: Getting the best out of a heat pump - is Homely a possible answer?
@grahaml I cannot agree that it is a small percentage o...
By benson , 14 hours ago
-
RE: Warm weather and heat pumps.
You’re welcome @lucia - thanks for watching. I’ve alway...
By Mars , 15 hours ago
-
RE: Commencing on an ASHP Installation Process
In that case treating it as a separate space seems emin...
By JamesPa , 21 hours ago
-
For me, the Questions are here: 1) Does a Volumiser t...
By iantelescope , 1 day ago
-
RE: Yes, the "zoning with ASHP" topic again...
This aspect of control is a bit variable from manufactu...
By JamesPa , 1 day ago
-
RE: Samsung Gen6 16kW tribulations
@emceed, can you please give us an update on your syste...
By Mars , 2 days ago
-
RE: ASHP Ecodan L9 error - No Heating but Hot Water
@phoenix15 Sorry to hear that, we are all the way down ...
By ASHP-BOBBA , 2 days ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@editor Well last MAY i know was not the greatest for s...
By Andris , 3 days ago
-
What's the problem you are trying to solve. The answer...
By JamesPa , 4 days ago
-
Good luck. For what it is worth my system was very def...
By JamesPa , 4 days ago
-
RE: Massive Electricity Cost for Running My Air Source Heat Pump
I agree @mark-h The Building Regs are now very readable...
By Transparent , 5 days ago
-
RE: Help me understand my Mitsubishi Ecodan system
@carpenterstation When changing settings in the ser...
By RobS , 5 days ago
-
RE: Ecodan Legionella cycle - immersion heater problem
Thanks for letting us know @clockworks I admire your ...
By Transparent , 6 days ago
-
RE: Revised version of MCS-020 (noise standards for heat pumps)
As you say this is no change, which I personally think ...
By JamesPa , 6 days ago
-
RE: What happens when the outside temperature exceeds the upper WC point?
@editor not via the WC curve but as @old_scientist ment...
By bontwoody , 6 days ago
-
RE: MHHS and Heat Pump compatibility
@toodles to be clear I don't know if there will be a re...
By Scalextrix , 7 days ago
-
I did not know this concept, although others might. I...
By Morgan , 7 days ago