DamonHD

The WC curve is based on (1) Octopus heat loss calcs at design temperature at the low end and (2) my observation of best fit HDD base temperature over many years at the top end. In other words I'm pretty much going by the book here. I suspect that it *is* a bit too high but we haven't been anything like cold enough to calibrate (1) yet. But in any case my own experiments (eg at Energy House) suggest that it is a silly waste of energy to heat unoccupied areas except in a very air tight modern (PH-ish) home where maintaining temperature differentials on purpose would be hard. Eg ~60% waste heating bedrooms during the day in EH1 on a 'working family' occupancy pattern, ~15% whole house in my recent paper.

IMHO (and the opinions of several plausible studies) insisting that comfort is all about very steady and uniform temperatures is overblown. I spent some years living in a farmhouse partly heated with open fires for which neither is the case and yet many people see them as some sort of comfort ideal. These things are partly a matter of (learned) personal preference, but overselling them will result in excess emissions and climate damage and ultimately will hurt us all. Because I'm working around a problem with our shiny new heat pump install I have been trying several modes of operation and was probably not doing things optimally, but continuously on, even with a flow-temperature setback at night, felt stifling and oppressive and used *double* the electricity (kWh/d) of the intermittent (OpenTRV driven) call for heat that I am now back on. Note: electricity in, not CoP or any other intermediate measure. Intermittent, albeit in a house with reasonably good fabric, is *more* comfortable and much lower footprint and cost, in this instance at least.

Note that the antifrost feature will run the circulation pump and possibly the compressor if outside temperatures are at/below 7C. I'm also seeing my Altherma eat a lot more energy that I exepct when running it open loop with a weather-comp LWT target, cf running it when needed with an external call for heat.

You could smoke something to fix that, or we could...

Our overall electricity demand curve this month up to yesterday shows some successful load shifting for DHW at least: https://www.earth.org.uk/heat-pump-16WW-control.html#2024-12-20 Load profile over 2020-12-01 to 2020-12-19 inclusive, gross and net/imported. DHW consumption spikes starting at 07:40 and 19:10 are clearly visible.

If at some point the current grid intensity is less than half its average over the last week, then I am claiming that filling my storage boots now is the same as (in CO2 emissions terms) using the heat pump with a CoP of ~2 at some random point during the last week. Similarly looking forward a couple of days. We are all aware (eg including @Ed Davies!) that there is some contention about that reading, though maybe less so now that constraining excess renewables for reasons other than transmission is becoming more of a thing. In any case I take very low relative grid carbon intensity (and no drawdown from grid storage, aka "supergreen") to be indicative of abundant low-carbon generation and minimal strain on the transmission and distribution system, so a good time also to fill boots. How should I have worded those paras better in my talk?

I gave a talk last night on how my heating system is developing... https://www.earth.org.uk/home-heat-carol.html

Might he simply be ill?

Everything seems to be working nicely. I have captured current settings/configuration. I shall do some tweaking over the next few days. Nothing major by the looks of it, certainly less than I had expected. One thing that I wanted to do does not seem possible (schedule/clock AND external call for heat) but I can live without it, as the external call is reasonably well-behaved. https://www.earth.org.uk/heat-pump-16WW-control.html

I'm a fossil - a greybeard that doesn't have long to wait for a bus pass...

Gas supply is capped, so fossil-free at home (other than me!)...

I don't know. I think that the lead may be independent and the rest employees, judging in part by the branding or lack of on their vans.

Direct link: https://www.earth.org.uk/Octopus-heat-pump-journey.html#2024-11-21

Internal prep works today including removing the existing cupboard, disconnecting the Sunamp Thermino, and threading round a new T+E from the Eddi heater 2 output for the Thermino in the new control scheme...

Modest external groundworks for the heat pump were completed on Friday morning, so it seems this is really going ahead! I have turned off (low-carbon) grid boost to the Thermino ready for the system to be rearranged...

Here is the proposed integration: https://www.earth.org.uk/Octopus-heat-pump-journey.html#2024-10-31

On Monday I had a pre-installation visit to discuss details of trenching and other prep works, for a planned install next month. We often don't put our heating on until December, so I may have already done my last space heating with gas in this house. Consumption has been tiny since April: https://www.earth.org.uk/saving-electricity-2024.html I am developing a scheme for re-integrating the Sunamp and Intasol with the heat-pump DHW which I think might work well (treating the DHW cylinder as if it is a combi in this arrangement, with the DHW cylinder being 1st priority for Eddi diversion/boost output, Sunamp 2nd),

Are you being paid a FiT? That may be at risk if you change the panels.

"earn" is not the same as "profit"

I am on the point of signing up for the next stage of an Octopus heat-pump install, enough to apply for the BUS grant, but it is a bit of a journey, and nothing is cut-n-dried yet! https://www.earth.org.uk/Octopus-heat-pump-journey.html

Fully insulating our homes and electrifying our heating *will* knock ~15% off the UK's current carbon footprint. On a slightly different note, and much smaller beer but still needs sorting and would be *very* easy to address, I'm trying to get Apple, Amazon, Spotify, etc, to do something about the the 99.9% of resources they are wasting polling RSS/podcast feeds: https://www.earth.org.uk/RSS-efficiency.htm

I am using the numbers from the original Heat Geek page / pump, a Mitsubishi Ecodan.

My model is purposely as simple as I could make it and is steady state, eg no thermal capacity, losses other than conductive, incidental gains, etc...

@sharpener"You could keep turning it down" is a bit of a straw man. 😀 My point here is mainly about tolerance (dynamic and static) of deviations from a selected preferred temperature. Yes, indeed, if you are too hot all the time then move your setpoint down. However, not all users of the same home have the same preferred setpoint or tolerance just to complicate issues, and each of us have our tolerance affected by things such as external weather, time of day, recent activity levels, ... I note that my daughter wants a set point far higher than I do, at a point where I am beginning to feel uncomfortably warm sometimes. And she is dressed sensibly! So our rooms have different set points: hard to acheive without zoning.

I have my research plan / confirmation report open right now, and I am putting "the effect that increased short-cycling on ASHP COP" in it right now... B^>