SteamyTea

Long time since I had to do MCS RHI compliance, but there used to be a rule that you had to work out total heat loss and make sure the heat pump could supply that 99% of the time. Was not difficult as you have all the info anyway.

Sensors in the MVHR are useful as they give a mean house and external air temperature reading.

Or can you just follow there rules and claim to be a competent person. More probably global prices dropping.

May have been. Last evening the wind speed dropped where I am, this meant the house had lower losses through ventilation and through the external wall surfaces. A sprinkling of rain in a wall can increase losses because of evaporation, but never worked out by how much, it is rare to get those sort of shower days here.

Looking into the real differences between building methods. Do you have any permanent temperature data logging going on?

I bought a cheap, twin impeller, pump from Screwfit. Similar to this one: https://www.screwfix.com/p/salamander-pumps-ct50-xtra-regenerative-twin-shower-pump-1-5bar/20423 Just connect to a hot pipe, the F&E tank, the mains via an RCD/MCB and isolator. Been working fine for last 13 years. I do have very soft water though.

Thanks.

@NSS What is your house made of?

Not dark here yet. But it seems to heading towards parity considering that there is usually a 2° to 3°C temp difference inside a house.

Check it later as well. See if the temperature equalises once the sun goes down.

And greedy.

I think that part of the reason to use EV batteries connected to the grid is to give the impression that energy storage is cheap and versatile. Really just a method of shifting the cost to some consumers.

I read stuff, more the academic papers. I shall look at my bookshelf and see what I have. A lot of it is obvious though and then just goes into a well crafted rant. What would be good is some more basic science stuff. Thinking that showing people why CO2, and other gases, actually changes the thermodynamics of the atmosphere. Some basic statistics would help to. Too many people think that a temperature rise is just like turning the heating up. They don't grasp how a different climate regime changes the variability.

Health and Safety. I interpreted that as hen pecked with small genitalia, but kept that to myself. While you are here, how did you manage to block me from: https://forum.buildhub.org.uk/topic/10651-are-plasterers-the-worst/?do=findComment&comment=179803 by quoting me. And I still can't login from my phone. Did use the Contact Us link, but seems there was no one at home that day.

There was a long line of cars to get into my local tip. I drove past them, parked up in the layby, got my single black bag of household waste and walked into the tip. Was told in no uncertain terms that I was not allowed in. I was 5 feet from the container. When I mentioned this over at the other place, our old mate DamonHD said he had a similar problem, as he had no car. He organised, with the council, a 'pedestrian day'. A day that normal Londoners, who don't own cars, can take stuff to the tip.

You keep mentioning this, but you are saving on imports, anywhere between 12p and 24p/kWh, depending on your tariff. If you save 2 MWh on import, that is somewhere between £240 a year and £480 a year. Not to be sniffed at.

Yes, I agree, but was highlighting the problems of choosing the correct battery/storage size, and the importance of data logging.

Trouble with that is it just gives daily, weekly, monthly or annual loads, does not help much in finding out when you import and when you would export. May be worth getting an energy logger and finding out what you use in your current place. As an example, I found out recently that I import no energy 60% of the time. That is not a contiguous 60%, but a few minutes every half hour or so. Below is an example of a typical day.

Next time you chat to him, ask if he has decent weather and crop yield records. Many farmers do.

By this do you mean different scenarios, or actual climate regimes? The UK is a tricky place to model climate for, it depends so much on local weather, which can significantly vary over a few miles.

Probably partly due to the abolition of FiT and new system not up and running yet. There is also the issue that once you have installed a system, you cannot put another one in as the roof is already full. DECC spreadsheet here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/819771/Solar_photovoltaics_deployment_June_2019.xlsx

I would like to know as I can then cobble something together and monitor @joe90 Do you actually need to know the flow rates, can you just make assumptions based on the input and output temperatures? Bit like working out the efficiency of a heat exchanger.

We used to fit toughened glass doors to saunas and steamrooms. They did shatter, but not because of the heat. Usually happened when trying to fit them and they slipped onto the tiled floor. Then the fitter said 'It just exploded'. If anyone knows Swedish, a popular country for saunas, they always agreed with me about the fitters.

Right. Shame, WeatherUnderground had a historic download option, but that seems to have gone now. I think you can specify between dates in the URL, and get it to display as text. I just wish it was as simple as it was, type in dates, download the text, import into favourite data package.

If i just uses resistance heating then probably no, though there will be some parasitic losses. Not so sure if it uses stored hot water. There may be a rare scenario where it pumps warm water back though the system for too long, and if it has had a very low CoP just before, it may dip below 1. I am starting to wonder if icing is a real problem. It may just happen when trying to raise the temperature to much for too long i.e. an undersized system.