joth

The article is a bit misleadingly worded and doesn't cite any sources but giving it the benefit of the doubt, what it is really saying is IR panel will heat up the people in the room faster than a convection electric heater, as the later has to heat the entire [air in] the room before the occupants get its benefit, whereas IR heaters directly heat the object/person in front of them. This is a reasonable way of thinking if you accept that the whole building must remain uncomfortably cold except the exact place where a human currently happens to be at a given moment. At the other end of the scale a house with high amounts of insulation and high heat capacity (so slow to warm up, very slow to cool back down) it's more efficient to forget about the people and aim to keep every room at a comfortable temperature at all times, and for that all types of electric element heaters will be equally efficient over the long term.

Would it be inappropriate to ask who the 2 suppliers are? I'm shopping around for samples right now, one place seems impossible to get hold of let alone samples from, while another keeps chasing to see how they can help in our project. They're also less than half price of the former place..... which raises all the warning flags (for reasons others mention here)

As I'm using loxone for critical functions like lighting, my own plan is to keep the Loxone config as simple as possible - for heating, it may be very little - just relaying of the room temperature sensors to the basic heating control function (that aims to keep a constant temperature 24/7). Then add interface to Loxone (or the ASHP itself, depending on its controller) to have it expose an "Economy" energy saving mode (i.e. enable it reduces the heating set point). This will free me to use a more friendly development environment (initially Home Assistant, on an NUC or my synology box) to poke around with higher level functions like energy pricing, weather prediction, occupancy/holiday modes etc and have that just flip the "Economy mode" on of off as needed. This way I can tinker at will in the higher level system without distablizing the core automation controller. If the higher level system crashes or throws a wobbly (or, we sell up, or I'm not available to sys-admin it one day) I can very easily turn it off and have a graceful fallback to the basic mode that meets 90% of the needs. (As a general rule of thumb, I want the loxone system to have zero direct connections to internet, and strictly minimize its dependency on internal LAN). Looks like there's an initial HA integration here: https://community.home-assistant.io/t/templates-in-command-line-sensor-octopus-energy-api/96141/48 - that just pulls historical usage data but good starting point. Aside from Home-Assistant, there's more specific projects like https://openenergymonitor.org/ and www.openenergi.com and no doubt others in future... again keeping logic that plays with any of them out of my core building control system (heating and lighting in the loxone) means it will be easier to play around with the options over the years as they come and go, without risking taking the whole house offline.

It claims COP of 3.5 at 55ºC, so is it really so bad at 65ºC? The attraction of the SunAmp is lower heat loss and space saving. Sure, any system heat loss does not go "to waste" in winter, but in summer it does, and even if it is useful for space heating in winter I'd like to see if I can have sourced from ASHP (even at a COP of 2) than from a resistive element.

Slightly strangely formed question, what are the ongoing F-Gas service & maintenance costs and "hassle factor" for a typical split-system ASHP, compared to the G3 service & maintenance costs for an unvented cylinder? Reason I ask is it seems if I want ASHP to provide 100% of DHW and space heating and cooling needs I have two options: - Monobloc LT ASHP (55ºC max) with UVC (=> G3 service) - Split system LT ASHP (65ºC max) with SunAmp PCM58 (=> F-Gas service) I'd been keen to avoid the split system to avoid the added F-Gas overheads, but maybe the G3 savings (both financial and hassle-factor) sufficiently offset it. Notes: The goal here is 100% DHW from the heat pump so I'm also ignoring resistive DHW heating element for this comparison. For the purpose of comparison, I'm ignoring any short cuts around DIY or ignoring the service schedule. I'm ruling out HT monobloc ASHP as none seem to support cooling. I'm assuming the 65ºC from a Daikin Altherma 3 (for example) is sufficient to activate PCM58. If the refrigerant makes a difference, let's assume R-32 (again per the Daikin split units)

Out of interest, do you know 3ph is not possible or have you had a quote for getting 3phase installed? It took me 2 days and zero cost to get a quote, so well worth it. (Tip: when the DNO surveyor comes give the the list of things you maybe considering, and they can give a price estimate for each. They can only go away and formally quote for one job at a time, but this was super useful for comparing cost of moving existing meter vs getting a new 3ph feed (for my case this was £1k vs £3k, purely because new feed involves carriageway closure and roadworks) Having said all that, for a split E/W roof your current plan sounds solid so probably not even worth opening this can of worms.

http://www.ena-eng.org/gen-ttr/TTf1l3s/SOETC_00165_190606024212.pdf "The inverters of the SExxxH series consist of the high power models: SE4000H, SE5000H, SE6000H, SE8000H and SE10000H. All the models use the same hardware and software. The different powers are realized by software derating. " Interesting: it's just a software tweak to convert the 4kW inverter into a 10kW model.

btw I've been on a similar (but different) voyage of discovery. Got PV quotes in January, G99 approved for 8kW in August, G99 expired this month, looking to start on site in the new year so eventually need to re-apply for G99 in... May? and have it commissioned by July. In the mean time things move along (end of FiT, addition of VAT, G99 process bedding in...) I just had a look and there's a fresh wave of G99 certified ("type approved") inverters that didn't exist when I started. e.g. Solar Edge SE8000H. Which should make the whole G99 process a bit simpler at least. Also it has "HD Wave" technology which is apparently revolutionary change in inverter efficiency and reliability. ("Like flat screens replacing CRTs"). Not sure what to make of this:

Near enough. G59 was actually replaced by G99 (being the rules for >16A installs) G83 was replaced by G98 (rules for <=16A) https://33kv.com/news/the-impact-of-moving-from-g59-to-g99/ https://www.ssen.co.uk/G99G98Requirements/FAQ/

Before writing your own app, I'd first check no one already has. There's loads of apps to turn an old phone into a dashcam, most support motion activated recording so some might have the every N distance feature you need e.g. https://www.howtogeek.com/270340/how-to-turn-an-old-smartphone-into-a-dash-cam-for-your-car/ If that wasn't satisfactory, then I'd look at workflow automation apps like Tasker and Locale, see if they have plugins for movement trigger and taking a photo https://play.google.com/store/apps/details?id=com.twofortyfouram.locale&hl=en_GB https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm&hl=en_GB https://play.google.com/store/apps/details?id=com.kanetik.movement_detection&hl=en_GB If none of those work out, I'd start digging around in the Java/kotlin SDK.

Well this one at Mr Resistor says it is plaster-in, trimless and fire-rated; worth a punt. There's also these ones that promise a retrofit option for seamless/trimless appearance. I'm skeptical it's really as simple as this video makes out https://tornado.co.uk/flush-trimless-plaster-wall-light-installation-guide-5

Nice! Thanks for sharing this. How long was it since installed? Could you explain the various numbers here? I guess 6.16kWp is max power it's ever generated, 3.87kW is current live power? Was your ASHP running at the time this image captured (or cooker on)? If so nice to have caught an unusual example of the getting over half of the space heating load from solar.

@Eileen another question I'd be curious what Daikin ASHP model/version you have, and if it is setup or supports cooling as well as heating? (i.e. is it reversible?) (I'm a bit lost in their model numbering, I currently have EBLQ-07CAV3 as a baseline for my specification/pricing comparison, I also see EDLQ-07CAV3 mentioned in their brochures... I think the EBLQ has cooling option and EDLQ is heating only, but it's really not clear. ) Also the newer "Daikin Altherma 3" also looks pretty ideal for Sunamp system, as supports cooling, heating and DHW at 65°C in a single stage LT heat pump, and with a built-in 2x3kW backup/boost immersion heater. Only snag is it's a split unit, so the maintenance savings from moving from UVC to sunamp are completely wiped out by adding a refrigerant loop around the house. (But, at least is is R32)

The other other popular system is GB sol RIS.

To be effective the electricity supplier would need to provide this as an API, so far none seem to and it'd doubtlessly be different for each provider making a new form of lock in if you did get it working. For some reason the industry standardisation is focused on hardware solutions (smart meters and auxiliary output circuits) rather than open APIs. That thinking is half a century out of date really, harking back to the original E7 meter.

If you have E7 you'd want to schedule to match that. This would be far more convenient to do once, centrally. If something in the system makes noise you might want to schedule to avoid nighttime. Again, centrally. Otherwise I see very little need for timers.

Many find inline systems more aesthetically pleasing. Also if you're thinking of selling at some point, surveyors can mark down on-roof installs for the extra complexity in maintaining/replacing the tiles under the panels, which puts some buyers off. (Surveyors always advise the roof tiles will soon need replacing)

I was just looking at these again, as it's an elegant idea in several ways, not least of which is avoiding the problem of where we would hide the main inverters with a conventional system design. Snag is the Enphase appear to cap out at 250Wp output? The SolarEdge optimizers start at 320W and go up to above 500W per panel. This is a problem for us, as we were aiming for 340W panels, not just because fewer panels means fewer optimizers (and hence cost savings) but also because fewer/bigger panels means fewer joints and a cleaner overall look (IMHO. it'll be very visible on the house so deserves a bit of consideration)

Presumably the quote is per square meter of radiant panel, not per m2 of habitable floor area? Although that seems very low compared to a conventional radiator. With a quick search I can't tell, are these zenhder panels entirely water to air, or do they have an electric element for heating?

@Oz07 This thread had some interesting points on the risks of cheap MVHR unit, especially around the noise output

This was my thought too. Adding additional fire hoods on each seems quite the faff. Are there any recommended plaster-over fittings with fire rating? Seems it should be possible. Or, clip in fittings with a similar looking flush finish would also be ok. I key advantage of this style is if you're doing anything other than white ceilings.

So have we already discussed the Grand Design drinking game? https://carina.org.uk/granddesigns.shtml Some very familiar memes there. I might start playing that game when reading buildhub posts too.

Thanks for sharing this feedback, a useful datapoint and sounds like things are improving on the service/support side. If you hadn't purchased the pcm34s, how would you plan to charge the pcm58 in winter? Direct from the immersion heater only, presumably at Economy 7 times?

This is a great point and I'll highlight it (in case it is lost under the helpful SI unit preface) To the original question, if there's no space or DNO constraint, and all panels are equally well positioned, I think the larger array of 270W panels will give more bang (annual yield) for buck then having half as many 330W. It's fairly easy to do some modeling with the PVGIS ( https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html ) tool to verify this. AFAICT that doesn't differentiate mono vs poly panels, so if they both have the same efficiency it will just be a matter of the larger array giving more output Thing here is both have the same efficiency, so the more expensive one isn't automatically better. I think we'd need to know the relative dimensions of them to estimate which requires more resources to manufacture and from that estimate which option has larger embedded carbon. But still, for a fixed cost, my gut instinct is go with the solution with highest annual yield and over its lifetime it will payback any higher carbon as well as economic capital cost. Sorry if came across as unkind, my comment was meant as gentle jesting with a small dose of self-deprecation. (in the context that nit picking usage of numerical units seems a well established tradition in this place )

Actually I think in this case the OP means W not kW, otherwise: ..this would be a 12MW generation plant, which would need maybe 50 acres of land and a 110kV supply ? (enough with the smart-arse replies already)