SteamyTea

Here is my new one, not cordless mind you. Unlike my larger ones, I can keep it switch on permanently. Much safer to use.

Not really, metal cut off saws run slower, and have a lubricant feed. Much like my latest friend.

Yes, an angle grinder is the second most useful tool in the box. I have a new one to pick up later, my cheap little one gave up the ghost (the switch went faulty). It did last 6 years though, and has more dusty usage than most.

Thanks

This is what I have/started with. 200 lt, bog standard, vented, E7 cylinder. Heating elements in the base and the top. All very standard and cheap. Had to replace cylinder after about 28 years. Small heater tank in loft. I have fitted a twin impellor shower pump to the shower/bath. This was mainly to make a decent shower, between 9 and 11 lt/minute flow rate. Pressure is irrelevant as it is flow rate. I added extra insulation inside the cupboard it sits in. This is a combination of PIR sheets and mineral wool. Works very well, reduced the standing losses by over 1 kWh/day (standing losses are a problem on E7 as some people want to bath in the evening, I don't apart from a quick shower). Initially I set the lower E7 thermostat to 65°C, but have reduced it to 50°C now. I then fitted a timer to limit the E7 heating window (nominally midnight to 7 AM) to 4 AM to 7 AM). This gives it plenty of time to heat the cylinder, settle and a reheat, before I use any (which I try to do after 7 AM so no extra reheating). This worked well and almost halved the energy usage, some of that will have been because I fitted a shower and use less water). Last year, about May I think, I decided to experiment with the top immersion heater, the thinking being is that I do not use all the 200 lt of stored water. So I fitted another timer that switched the top element on between 5 AM and off at 7 AM. I also set the temperature higher to 65°C. This worked very well in cutting energy usage, but did, on a couple of occasions, mean I had a luke warm shower after work (not so bad in the summer months, horrible when the house is a but cooler). Because I swapped my morning bath (my little luxury and seems to help my aches and pains) to a shower, that probably helped in reducing water usage, and there for energy usage (we were asked, by SW water (one of the countries largest polluters) to cut usage by 5 lt/day in return for £30 off our bill, achieved the target). This year, I may try and gauge if the saving is water usage or less standing losses. I may also try heating the water with the lower element for a day, then heating the top for a day, and then back to the lower element. The mean usage should be the same, but because of the need to have DHW at least 35°C, there may be less risk of having a cold shower. I am in a lucky position because I live alone, this mean that if there is not enough hot water, I am only shouting at myself. Energy reducing should not be down to just one person in the house making changes, it has to be everyone, then there is plenty to go around. The biggest changes will be reducing water usage, will over shadow everything else. Aunty Beed has an interesting program on about water. https://www.bbc.co.uk/sounds/play/m001k0dq

Generally I think it is a good thing, you get more energy into a smaller volume. The thermal losses may increase though, and then there are pumping losses.

Do you have an example of one, or two. I could not find one, but may be using the wrong search terms.

(expletive deleted), now you have done it, poked the sleeping Welsh dragon.

If the sentence had been longer, then we could have had kw/h as well.

Materials have a number of 'strengths'. The main thing to consider is working at the lower end of the elastic limit (material can recover), and never getting close to the yield point (material cannot recover). One of the problems is that because strength of materials is a force, and a force has a time element (f = ma, where a is acceleration m.s-2), what initially seems fine can fail in the future.

They can in a controlled environment i.e. indoors. How long would it take to shoot 1000 rats on a 100 hectare farm? If we say a good shooter managed to kill 1 in ten, and each shot takes 1 minute, then that is 10 minutes per kill. 10,000 minutes. 167 hours. Or about 1 month for someone working a 40 hour week. The only reason that farmers claim to need a gun is to massage their fragile egos. Ban guns, then, in no time, much more effective controls will be in place.

Basically, the efficiency (CoP) of a heat pump increases the smaller the temperature difference between the outside air (OAT) and the delivered temperature. This is the power (W or kW). Depending on how long the heat pump is working, in hours, multiplied by the power it takes to run it, is the energy, the kWh. The problem is finding the right position under the curve (integral) that is most cost effective. This is especially hard if the outside temperature is variable i.e. the day starts cold then warms up, then gets cold again. The 'on' times need to coincide with this. This can be done manually i.e. switch the HP off for 6 hours during the warmer period of the day. The trouble with this is the efficiency of the HP may well be quite low as it tries to reheat everything up to operating temperature. This can cause icing up of the outside unit that takes energy out of the system to clear the frost off the fins. My view, and this is purely academic as I don't have a heat pump, is that, if you can run the unit for as long as possible, at the lowest output temperature possible, your increased CoP will counteract the longer running times. This may seem counter intuitive as the HP is using electric power for many hours. But ten hours at 1 kW is less than 4 hours at 3 kW, even if that 4 hours is spread across the day. The problems (calculations) gets compounded if, for tariff reasons, the amount of time the HP can be run on a cheaper tarif, especially if that tarif time is in the middle of the night. So summing up. Run the HP at the lowest output temperature you can get away with. Accept that the house temperature may vary during the day by 2 or 3⁰C. Learn how the weather compensation curves are set up, these are designed to deliver more power, but at a lower CoP when it is really needed then back off as the temperature increases. It is like driving up a hill, you have to put more pressure on the gas peddle, and sometimes change down a gear, then you can coast down the road for the next bit, as long as you did not loose too much speed on the up hill (or you just get in the way of everyone else).

Why should a pig farm not be able to control the distribution of animal feed. Do you really think that a gun is an effective manner to control vermin? Farmers tend to do what they have always done, look backwards to a time when there was less control on the food supply industry.

Would be easier to take away their food supply, they will soon move away. Always amazes me that farmers leave rat food all over the place. An oil storage depot would not be allowed the same tardiness. Guns, of any sort, should be banned.

@JohnMo You seem to be going down the same path that @Jeremy Harris went down a fair few years ago. Real shame that his blog is not about anymore (possible wayback machine has a copy). In the end he dumped it all and got a Sunamp for the DHW. No idea if that is still going well, he had trouble with one of them.

Building Merchant.

There is no one answer to that question. What are you trying to achieve, and what do you mean by efficiency?

Stops overheating. 300W is still pretty good.

Was wondering this. Can you tell how much power the unit is drawing when it is set to 15⁰C? Should not be as much as the proper inbuilt water heater.

I worked, briefly, for a small turbine manufacturer. They made a 5 kW turbine. It was a bit noisy if you were downwind of it. I did think up a way to significantly reduce and deflect the noise, but never got a chance to test it. Company ceased trading, then the design got bought off the receiver. Luckily I had not left my ideas with them.

That is interesting. I had a large garden to sort out when I was living in Hertfordshire. The small electric shredder (from B&Q) worked a treat on newly cut stuff, hopeless on week old stuff that had been left in the sun.

Could you do it with a Tyvek type material? It lets moisture out, but reduces air mass flow rate to virtually zero.

Would have to change my 3W Poundland bulb to a 5W one. I could live with 5W. 100W would not run the fridge. Would the kettle though, and that is important. May have to put the milk in first, then hope the fridge kicks in when the kettle is boiling. Second thoughts, that would make horrible tea, so happy to pay the import duty on 0.3 kWh a day.

Were you thinking that the Might James Dyson had fooled nature. Of cause it did nothing, the motor is tiny. There was a report about a new wind turbine on Moneybox the other day. Wind hits the vertical pipe, gets forced up to the turbine by vanes and generates power. Better than a traditional turbine. My arse it is. Why don't the BBC, who do reality checks, check with one of the many physicists they employ to show them the error of their ways.

That is really the over riding issue with storage. So half what is lost in cabling losses, and a lot less than inverter losses.