newhome Posted February 25, 2018 Author Share Posted February 25, 2018 21 minutes ago, PeterW said: Now unless I am going blind ... where is the TS and Boiler on that plan ..??! Well they're not actually marked on that plan . It's called 'spot the ball' or in this case 'spot the TS' Link to comment Share on other sites More sharing options...
newhome Posted February 25, 2018 Author Share Posted February 25, 2018 33 minutes ago, SteamyTea said: But the other side of my head is only 30°C Think something is missing I'm 32°C each side. Does that make me level headed (as opposed to unhinged)? Link to comment Share on other sites More sharing options...
SteamyTea Posted February 25, 2018 Share Posted February 25, 2018 1 minute ago, newhome said: I'm 32°C each side. Does that make me level headed (as opposed to unhinged)? Just tried the 'Jeremy' method and I am 33.8°C and 34.2°C. Am I getting better. Now for an old joke. What is the difference between an oral and an anal thermometer. The taste!! 1 1 Link to comment Share on other sites More sharing options...
newhome Posted February 25, 2018 Author Share Posted February 25, 2018 8 minutes ago, SteamyTea said: Just tried the 'Jeremy' method and I am 33.8°C and 34.2°C. Am I getting better. Now for an old joke. What is the difference between an oral and an anal thermometer. The taste!! If you've been shoving this thermometer anywhere like that then I'm sure you're not getting better! Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 25, 2018 Share Posted February 25, 2018 1 hour ago, SteamyTea said: But the other side of my head is only 30°C Think something is missing No shit Sherlock. Link to comment Share on other sites More sharing options...
newhome Posted February 25, 2018 Author Share Posted February 25, 2018 @Nickfromwales I found this lying in that room. Is it a part for this or something else? Link to comment Share on other sites More sharing options...
Ferdinand Posted February 25, 2018 Share Posted February 25, 2018 (edited) 30 minutes ago, SteamyTea said: Now for an old joke. What is the difference between an oral and an anal thermometer. The taste!! I spy with my little eye something beginning with IT Person. Been there. Done that. EScaped. Now half sane. Edited February 25, 2018 by Ferdinand 1 Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 12 minutes ago, newhome said: @Nickfromwales I found this lying in that room. Is it a part for this or something else? Ha ha ha ..!! I bet that was fitted to the boiler and the last bloke removed it ..... 1 1 Link to comment Share on other sites More sharing options...
Onoff Posted February 25, 2018 Share Posted February 25, 2018 12 minutes ago, newhome said: @Nickfromwales I found this lying in that room. Is it a part for this or something else? That's a time switch..... Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 25, 2018 Share Posted February 25, 2018 32 minutes ago, PeterW said: Ha ha ha ..!! I bet that was fitted to the boiler and the last bloke removed it ..... No grasslin clock sized hole in the boiler case though? Link to comment Share on other sites More sharing options...
newhome Posted February 25, 2018 Author Share Posted February 25, 2018 1 minute ago, Nickfromwales said: No grasslin clock sized hole in the boiler case though? Nope, boiler case still intact ....... Link to comment Share on other sites More sharing options...
newhome Posted February 27, 2018 Author Share Posted February 27, 2018 Lying awake listening to the wild weather outside and a question popped into my head about the solar. If the TS is always kept at a constant temp and the boiler fires up immediately the temp drops, how is the solar ever effective as surely it’ll never kick in if the boiler is keeping everything at a fairly high temp? Back in the day when the solar was working we used to turn the boiler off and let the solar do most of the work heating up the TS and then if we needed it a bit hotter we would fire up the boiler for a little bit. Link to comment Share on other sites More sharing options...
Ferdinand Posted February 27, 2018 Share Posted February 27, 2018 (edited) 2 hours ago, newhome said: Lying awake listening to the wild weather outside and a question popped into my head about the solar. If the TS is always kept at a constant temp and the boiler fires up immediately the temp drops, how is the solar ever effective as surely it’ll never kick in if the boiler is keeping everything at a fairly high temp? Back in the day when the solar was working we used to turn the boiler off and let the solar do most of the work heating up the TS and then if we needed it a bit hotter we would fire up the boiler for a little bit. (Roughly) Because the TS has a temperature gradient ... it is hotter at the top and coldest at the bottom, and the solar heating circuit comes in at the bottom, and the boiler at the top. The thermostats and water heating circuits are arranged such that the solar water heating always operates to the max it can, and comes in to the coldest part of the tank. Ferdinand Edited February 27, 2018 by Ferdinand 1 Link to comment Share on other sites More sharing options...
newhome Posted February 27, 2018 Author Share Posted February 27, 2018 Thank you @Ferdinand, A couple of other questions then. What stops the water circulating so that the temperature in the TS doesn’t just even out, and if the DHW takes from the top of the tank, ie boiler heated water, then what does the solar heated water do at the bottom of the tank in summer when the solar will be most effective but only DHW is needed. Also when cock man came he said that the tank was not big enough for this house. Is that correct? It’s probably big enough for me as I only heat the rooms I use but what if the house was fully occupied? Apologies in advance for numpty questions. Link to comment Share on other sites More sharing options...
Onoff Posted February 27, 2018 Share Posted February 27, 2018 (edited) The solar controller should stop circulation in the glycol / brine loop if the ST panel temperature is lower than the tank temperature. In Summer (or any other time) the solar heated water rises. Any solar heated water is if you like pre heat to save on other fuel use. Edited February 27, 2018 by Onoff 1 Link to comment Share on other sites More sharing options...
Ferdinand Posted February 27, 2018 Share Posted February 27, 2018 (edited) 23 minutes ago, newhome said: Thank you @Ferdinand, A couple of other questions then. What stops the water circulating so that the temperature in the TS doesn’t just even out, and if the DHW takes from the top of the tank, ie boiler heated water, then what does the solar heated water do at the bottom of the tank in summer when the solar will be most effective but only DHW is needed. Also when cock man came he said that the tank was not big enough for this house. Is that correct? It’s probably big enough for me as I only heat the rooms I use but what if the house was fully occupied? Apologies in advance for numpty questions. THe tall thin shape helps prevent too much mixing. This is Stratification. The heating of the TS water all happens via heat exchangers to keep the glycol in the solar system and the water in the boiler circuit separate from the water in the tank. The boiler heats the top via one heat exchanger. THe Solar heats the bottom via another one, and because it is in the coldest part it can use its more variable / lower temperature in low sun conditions more of the time. THat is Low Quality heat because it is variable and lower temp. THe boiler ... High Quality heat ... is hotter and consistent. There are various valves and mixers and thermostats used so that the system can be most usefully .. er .. managed to give the best outputs. And if I talk about that In detail I will get something not quite right, so I won't try. Roughly the tap water is drawn off from the top, and the ufh which is lower temperature from lower down. I do not know enough to comment on size without some research. @Onoff might know, and seems to be around. J Edited February 27, 2018 by Ferdinand 1 Link to comment Share on other sites More sharing options...
Onoff Posted February 27, 2018 Share Posted February 27, 2018 14 minutes ago, Ferdinand said: I think there is a thing called Stratification which limits circulation in layers. @Onoff might know, and seems to be around, J http://www.solaruk.com/glossary/solar-energy-glossary.asp?item=2059&imagename=Stratification / de-stratification 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted February 27, 2018 Share Posted February 27, 2018 41 minutes ago, newhome said: What stops the water circulating so that the temperature in the TS doesn’t just even out, and if the DHW takes from the top of the tank, ie boiler heated water, then what does the solar heated water do at the bottom of the tank in summer when the solar will be most effective but only DHW is needed. Down to the density differences as water is heated. Without teaching my Grandmother how to suck eggs, hotter water rises to the top of of tank and stays there until it is used or cools. Cooling is generally at the interface between the water and the cylinder. Insulating the cylinder reduces this cooling over time, so there is less downwards circulation down the sides of the cylinder. This is why I dislike the word 'stratification' and much prefer using the term 'temperature gradient'. Stratification implies that there are discrete and isolated layers of water stacked one on top of another and you can access each one individually. Some cylinder manufactures have placed mechanical restrictions i.e. plates and buckets, inside cylinders to contain the natural temperature induced turbulence. But I think that is more 'marketing' driven than engineering. It might be worth just reminding readers about the Laws of Thermodynamics. Not going to show Stephanie Flanders Dad and his mate this time. 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 27, 2018 Share Posted February 27, 2018 2 hours ago, SteamyTea said: Down to the density differences as water is heated. Without teaching my Grandmother how to suck eggs, hotter water rises to the top of of tank and stays there until it is used or cools. Cooling is generally at the interface between the water and the cylinder. Insulating the cylinder reduces this cooling over time, so there is less downwards circulation down the sides of the cylinder. This is why I dislike the word 'stratification' and much prefer using the term 'temperature gradient'. Stratification implies that there are discrete and isolated layers of water stacked one on top of another and you can access each one individually. Some cylinder manufactures have placed mechanical restrictions i.e. plates and buckets, inside cylinders to contain the natural temperature induced turbulence. But I think that is more 'marketing' driven than engineering. One problem is when you introduce a pump into the system though, and I think the baffles that some manufacturers fit are mainly to limit the turbulence caused by the return from a pump. Because our buffer tank isn't designed as a thermal store, and has no baffles or whatever, within a minute or so of the plate heat exchanger pre-heat pump coming on cool water reaches the mid-point of the tank where the temperature sensor is and causes the heat pump to fire up. In this case that's an advantage, but it does seem to indicate that the turbulence created by pumping water from the top of the tank, cooling it through the PHE and then injecting it back at the very bottom of the tank tends to disturb the natural stratification that would otherwise occur. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 27, 2018 Share Posted February 27, 2018 1 hour ago, Ferdinand said: The heating of the TS water all happens via heat exchangers to keep the glycol in the solar system and the water in the boiler circuit separate from the water in the tank. All TS's are ( should be ) unique to each application, loaded with tappings / coils etc to suit, and most of the cylinders I buy are bespoke / made to order. This one is a one-type-suits-all and is covered in open tappings. The boiler doesn't feed this via a coil in this instance, it's direct. I thought I saw a diagram with a coil but @PeterW corrected that and I looked a bit further and, yes I'm as shocked as you are, he was right. The only coil in this TS is the ST. Good news is that the ST coil is right at the bottom, so virtually any heat produced by the TS would be useful, but the ST temp probes ultimately dictate when the ST will turn on, governed by the mid range temp. As said, the ST will only pump into the tank when it is going to be of use, eg it won't pump if it's cooler than the portion of the TS that it's temp sensors are monitoring. One key reason that stratification helps out there eg to keep the lower portion cool and take advantage of whatever ST gain is available. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted February 27, 2018 Share Posted February 27, 2018 37 minutes ago, JSHarris said: One problem is when you introduce a pump into the system though Yes, but this can be used to increase the storage capacity of a cylinder by evening out the temperature to a higher level. This could be useful when taking advantage of renewable energy. Though as soon as you turn the pump off, statistics take over and the top of the cylinder will become warmer than the bottom. Link to comment Share on other sites More sharing options...
newhome Posted February 27, 2018 Author Share Posted February 27, 2018 This forum is great! A British forum where you can post a question at 3am and have several replies by 9am Thanks all! I think I’m keeping up . A-level physics was a bloody long time ago though, and I always preferred chemistry and maths! Just one question remaining. How is the size of a TS calculated, and is this one big enough for my house? I’m not going to change it so just a theoretical question. Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 27, 2018 Share Posted February 27, 2018 1 hour ago, SteamyTea said: This could be useful when taking advantage of renewable energy. Or when looking to max out the TS prior to the electric boiler switching off for 2 hours, in line with the E2000 tariff, too. When in service, renewables ( ST in this instance ) set aside for a moment, the TS wont ever really turn off. It'll be constantly pulsing heat in, as its removed by the space heating, and then again on top of that should DHW be needed too. It could be set to DHW priority, as the last job I did was, so space heating cannot be drawn whilst DHW is, so maximising the capability of the TS to provide bulk DHW with ease. A bit of an answer about sizing, eg you can cheat a smaller TS into behaving like a bigger one with a bit of clever control, so basically make it behave like a combi boiler ( which will only do heating OR hot water never the two at the same time ). 1 Link to comment Share on other sites More sharing options...
newhome Posted February 27, 2018 Author Share Posted February 27, 2018 9 minutes ago, Nickfromwales said: It could be set to DHW priority, as the last job I did was, so space heating cannot be drawn whilst DHW is, so maximising the capability of the TS to provide bulk DHW with ease. That sounds perfect! Although the crap way my system is currently set up meaning that I have to shower / wash hair rapidly so that the water doesn’t run cold has no doubt influenced my thinking there ....... Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 27, 2018 Share Posted February 27, 2018 Just now, newhome said: That sounds perfect! Although the crap way my system is currently set up meaning that I have to shower / wash hair rapidly so that the water doesn’t run cold has no doubt influenced my thinking there ....... Once set up correctly you'll be able to run bath after bath. And an adequate shower would be able to be left running pretty much 24/7 1 Link to comment Share on other sites More sharing options...
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