DamonHD

Thanks! When I hear "Ecocent" I think of the unit that drew its heat from the house internal air, which is definitely a no-no for me. But this is clearly simply avoiding the fan unit being external. Rgds Damon

Hi, Does anyone have any views on this? https://www.groundsun.co.uk/small-home-and-apartment-heat-pumps/ Just ran across it today. Rgds Damon

FWIW, Radbot + boiler controller tries to heat burstily to let the boiler (+pump) run as hard as possible for as short a time as possible each time. Yes, circulation pumps in homes across the UK probably are >> 1GW in aggregate! Rgds Damon

It's about in line with us, 914kWh/y *imports* for a family of 4, with gross electricity consumption (backing out self-consumed PV) just under 2MWh. http://www.earth.org.uk/saving-electricity-2019.html Rgds Damon

FWIW, here is my little survey of grid-tied storage and what I went with, also not for saving money, and also not able to keep us up if the grid goes down. (The grid has only been down for 2x30m in ~15Y here!): http://www.earth.org.uk/electricity-storage-whole-household-2018.html http://www.earth.org.uk/Enphase-AC-Battery-REVIEW.html Rgds Damon

OK, given feedback here, and as soon as everything settles down from the funding round we just closed, I'll try and get this moving again. UniQ6 + CombiSol + Eddi + hub + Combimate phosphate doser plus possibly a little extra wiring to make a following phase easier plus just possibly some kind of flow meter is about the long and the short of it. Hurrah! Rgds Damon

Putting aside the moral aspect, I still wonder which is loweest carbon. Of course we do not know how fast the GB grid will continue to decarbonise, especially in winter when this really atters. Rgds Damon

Any space heat component may be a long way away yet, but I've attempted to reformulate that question as "for the last ~5 years of the life of this house would it be better to keep the current ~80% efficient gas combi for ~2.5MWh/y of space heat, or switch to low-capex direct resistance, assuming a heat-pump with CoP ~3 is not reasonably do-able?" Rgds Damon

No: I don't think that I have any meaningful way to do that... Rgds Damon

FWIW I run some low-power stuff such as my server (and occasionally my laptop and a small amount of lighting) from a 12V off-grid system with ~500Wp of panels scattered round the front and back of the house at low level. It has some storage, nominally ~2kWh though ageing and in need of replacement. I also have a fairly big (>5kWp) grid-tied solar array and now a smallish AC-coupled battery. All heavy lifting including basically anything to do with heat is done from this part. Rgds Damon

I don't know the details, but given that many people don't know how to make flat-rate gas work well, and many many people don't understand how to make anything with storage and ToU tariffs work well (eg electric storage heaters), I imagine that they ended up running everything on electric resistance heating at a punative day-time / peak rate. Rgds Damon

Only if the tenants (and landlords) understand how to use a heat-pump properly*. Close to here a heat-pump installation left at least one household with at £4k bill which required intervention of the local MP to defang. Rgds Damon *Was just at a Radbot install in a 3yo house where the tenant had asked for help getting her gas combi system set up properly and the landlord offered essentially no help at all, so HP would have been much worse.

Moving to (say) Octopus Agile and simply avoiding running the ASHP from 4pm to 7pm (eg coasting on the house thermal capacitance for space heat) your electricity would cost ~10p/kWh. Rgds Damon

My 3G has a 10Y warranty... Rgds Damon

Read all about my explosive experiences with 3G units, all replaced under warranty: http://www.earth.org.uk/triple-glazing-3G.html#Failures Outer pane failures in each case. Rgds Damon

I would suggest not heating and ventilating at the same time, but temporarily ventilating to air a room (but not to suck excessive heat out of its thermal capacity, eg plasterboard) with the heating off while generating humidity, is reasonably acheiveable. Rgds Damon

When installing Radbots for trials we have a "damp risks" assessment with such questions as "do you open the window or use a ducted-to-outside extractor" when cooking and bathing/showering, do you dry clothes inside, do you air rooms at all, etc. I'll note that MOST people that I survey (and me too, BTW) are doing at least one problematic thing, eg leaving the bathroom door open after showering/bathing and the kitchen door open while cooking, and other ventilation issues. I think it is fair to say that social landlords report that "damp" complaints from tenants are often ventilation and condensation issues, many of which could be mitigated by behaviour changes. Maybe a quick fix/test would be to rent/borrow a dehumidifier for a few weeks and see how much that improved things, and how much moisture it captures. Rgds Damon

No, because it is usually modulating and I have no idea how efficient it is, etc. I do have hourly gas consumption readings from which I manually pick out DHW and SH use from time to time. I suspect that my SH demand is low enough that my combi is massively inefficient when satisfying it. Maybe 50%. Official efficiency ~78% (SEDBUK) though for what operation and conditions I am not clear. Rgds Damon

I don't have the abive number, but eyeballing a graph of live tempratures as measured by Radbots overnight, and ignoring the period immediately after a Rabot turns off a rad, 1C fall in 4h to 8h may be a reasonable first guess. I'd have to disturb the plumbing quite a lot to try it out, so I won't do that just yet. Rgds Damon

OK, I'm probably going straight to somewhere bad for this thought experiment, but once I have DHW sorted as per my project... 1) The council is determined to pull our place down in a few years, for redevelopment. 2) We have already greatly reduced gas consumption, from ~9MWh/y (2007) to more like 3.5MWh/y (for a family of four now) of which ~1MWh/y is DHW by my estimates. 3) Thus there is ~2.5MWh/y of space heat demand over winter. 4) It would likely be a tremendous pain getting an ASHP installed for reasons, including planning. I'd like to do a heat pump if I sensibly could for many reasons. 5) Highest mean recent gas demand was 28kWh/d over Jan 2017 with a HDD (12C base) of 248, the highest over several years. Probably 24kWh/d was space-heat. 6) I want to stop burning stuff, eg gas. I'd like to be grid friendly, eg move demand away from peak. Ignoring DHW, why shouldn't I replace the combi gas boiler with a 3kW Willis heater and circulation pump, guaranteed NOT to run 4pm to 7pm (would probably be 6am to 4pm and 7pm to 10pm ish enabled, called on demand by individual Radbots) and switch to Octupus Agile or similar? Carbon intensity probably up a bit in the short term, OPEX costs probably similar to Ecotricity (eg matching SVT locally, no gas needed any more), CAPEX costs very low. System complexity fairly low. Uses more electricity than strictly necessary, which is a clear downside. Be gentle-ish please! Rgds Damon

So what's your view on BECCS? https://en.wikipedia.org/wiki/Bio-energy_with_carbon_capture_and_storage Rgds Damon

I am not Sunamp, but I did a little review of possibilites and the Eddi looked the best for my purposes. I ranked my selection 'best' first in the "Some diverter products" part at the foot of the page: http://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html#sources Rgds Damon

Another question: ... Is there a cheap flow detector that I could insert into one or more of my water pipes (eg during my works) to monitor flow? Either yes/no or some gradation? They should not be massively expensive, nor impede flow, and ideally would be easy to monitor with (say) an RPi. (And a free unicorn with each one!) This is so that I could get an idea of DHW demand, and maybe even as clever as how much demand is satisfied by the UniQ and the residue from the combi. That might also give me a better way to predict when to pre-emptively fill the UniQ in winter if grid carbon is low or we evict the combi entirely. Rgds Damon

FYI: https://www.theregister.co.uk/2020/01/21/sonos_bricking_laudio_gear/

Small update: Sunamp has kindly allowed me (via an installer) to put up a basic schematic of theirs that covers what I'm trying to do. http://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html#Schematic Nothing mind-blowing, but does the job, I think. Rgds Damon