Blimey, one day away from home and this thread has become half a novel! I was going to copy and paste multiple bits and answer them one at a time but life is too short. There's an awful lot of assumptions being made here. I have absolutely no idea what the graphs posted are supposed to show, the vertical scale on the first one showing COP of between zero and 35 when the AC units I install, and the heat pump that Robert has, have a COP of around 4.5. Going on that first graph, that seems to show nothing will happen at all? I'm also not sure what the second one is supposed to be showing either. You seem to be under the impression that COP varies with external temperature, where have you got that idea from? The manufacturers data on all the units give a COP which will be the same irrespective of temperature. That is down to the design of the unit, the control measures in it and the characteristics of the refrigerant used. Warming the evaporator may stop moist air from freezing on it so it won't have to be heated to defrost, but that is all (when the system pauses to defrost, it diverts the refrigerant flow to warm up the evaporator and defrost it before resuming what it was doing). They are designed to cope with that eventuality.
My units, and I would assume that Robert's heat pump is much the same, can heat a room to between 18 and 30 degrees. It can do that when the ambient is anywhere between -15 and +24 degrees. If outside that range it will still work but it will be at that point, and only at that point, when the COP will start to drop. My test figures from last week with an ambient of 7.1 degrees, showed that when attempting to heat a room to 30 degrees, initially the condenser was at 65-70 degrees (but only until the room temperature started to get close to desired) but the evaporator temperature only dropped to 0.9 degrees. I have seen them go below zero on a really cold day, but I think the lowest I've ever seen was -1.4. So you have a temperature differential of about 7 degrees on one side but the differential of over 60 degrees on the other. OK, so my units use a fan behind the condenser to spread the heat around rather than using that heat to heat water and pump that around radiators, but the operation of the heat pump itself is exactly the same. In that respect, maximum radiator temperature, what would normally be referred to as the boiler flow temperature on a conventional gas boiler installation, will be whatever it has been set at. That will be maintained as long as the ambient temperature is within the limits the heat pump has been designed to be used in.
By adding an engine, all you are doing is possibly assisting slightly but complicating things massively. However, your idea of using a car type heater matrix with a fan behind it, would be a far better way of using an engine. In fact, rather than use a heater matrix in addition to a radiator as in a car, you could simply use the engine radiator with a fan behind it to heat a room. Or you could have a really big radiator, with a correspondingly big engine, and use that to create a ducted type system to heat multiple rooms. But remember, the amount of heat needed will depend on the volume of air you need to change the temperature of. Hence a large car having a much bigger heater matrix (and fans) than a little shopping trolley. My Range Rover has a heater matrix (with two fans) that is about 4 times the size of the heater matrix in my step-daughters Toyota Aygo because the interior of the car, and hence the volume of air that needs to have the temperature changed, is much larger. Just think what size matrix you would need for the average room size?
But at the end of the day, all your fag packet maths rely on electricity being considerably more expensive than gas. As soon as you add in a solar supply to supplement, or with the addition of battery storage, even replace, the mains electricity required so the gas to run your engine would be an additional expense. So rather than reducing running costs, you are actually increasing them.
My eco 4 heat pump fun
Re: My eco 4 heat pump fun
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare
Proud member of the YCHJCYA2PDTHFH club.
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare
Proud member of the YCHJCYA2PDTHFH club.
Re: My eco 4 heat pump fun
I'm not at the stage yet where I think it's all totally unviable but I was already saying 'concede' in my last post and you're both further convincing me it wouldn't work as a money saver. For sure far more complicated than a standard heat pump setup.
@Pinger I don't really see the relevance of the 2T engine or turbines except that you were planning on using a heat exchanger. There are water cooled marine exhaust manifolds available from suppliers stock for quite a wide range of engines for around £500 per manifold, some of these can be used as part of a pressurised cooling system. We'd still need to cool the mid section of exhaust but I imagine fabricating something for that being not too difficult, the manifold would be the difficult bit but we can buy that. Corrosion not much of a problem running on CNG, or we could make the midsection from stainless. Another difficult bit would be the evaporator sinking to the last bit of exhaust, not thought that far yet!
@Gilbert Agreed a lot of assumptions. I think the 'theoretical values' wasn't the best example I could find, I was immediately aware of the ridiculously high scop figures (scop rather than cop because the graph is curved) but at first I thought it showed theoretical scop for an ideal heat pump when trying to bring our room up to temp. Now I think it shows theoretical values when bringing our radiators up to temp, cold temp input temp, hot temp output temp, so if it's 10C outside and we want to heat radiators to 20C the theoretical max cop is around 28 but of course having radiators at 20C wouldn't bring the room up to 20C, the radiators would need to be far warmer than 20C to bring the room up to 20C. Figure 12 seems easier to understand, I think it's supposed to be more representative of real world figures (though probably outdated and not as good as newer designs)? If we look at the 0C external temp position it shows that if we want to heat something to 30C (30C lift temp over 0c) for 30C undefloor heating the scop will be around 4.5, if we want to lift from 0C to 40C for low temp radiators the scop will be around 3.5, if we want to lift from 0C to 45C for 'medium temp' radiators (still seems cool to me) the scop will be around 2.1. If there's any truth in these figures they do at least suggest that your warm air blowing setups (which I'd think blow large volumes of air but that air isn't going to be as hot as a lower volume from a hot wire electric blow heater?) are likely to be more efficient than trying to warm the house with radiators at the same temperature.
I'm surprised you say cop is constant regardless of input temp and the temp we want to warm the house to (temp we want to warm the house to will be fairly constant while we're at home through the day but there's still 'lift temp' which is house temp minus external temp)... Most info I've seen for heat pumps describes a rising rate for cop as lift temp decreases, giving scop which is cop at specific lift temps and/or external temps, but I know a lot of info on the internet is wrong or outdated.
I'm not suggesting heat pumps need to have high cops down to below -15C, we seldom get -15C in the UK and for the odd occasion we do if the heat pump didn't work under those conditions the house owner would be better off plugging in additional hot wire heaters than buying into the more complicated and expensive system involving an engine... But I think the heat pump does need to have fairly high COP down to a little under 0C (say -5C) to be close to as good as some heat pump sellers suggest. You also suggest high constant cop figures (high flat scop) but your setups are the blown air design which Figure 12 above agrees with, we've both expressed doubts that a heat pump using water filled radiators with a heat pump isn't as efficient and Figure 12 agrees. I reckon that if heat pumps could maintain high scop regardless of lift temp there'd be no need for a house using a heat pump to have any more radiators than a house with radiators heated by a gas boiler, just use the heat pump to heat radiators to same temp as the boiler would heat them.
Regards the heater matrix idea, I don't think we'd need massive matrixes in each room if we could heat the water flowing through them to the usual engine running temp of 85C. I think average car heater matrix and fan can probably kick out more heat than we'd expect when the engine is up to 85C temp... When the engine is up to temp even in a little car if we put the heater on full and set heat to blow through dash vents the amount of heat coming from the vents is probably around a couple of kilowatts? I've imagined instead of the car heater an electric hotwire hairdryer in each vent position, each hairdryer pushing around 1kw, the car heater on full seems to be able to match that? I've also been unfortunate enough (don't ask lol!) to sleep in a car in winter with a 2kw electric fan heater running inside, the car's own heater can get the car warmer inside than the 2kw electric fan heater, which also suggests that the car heater matrix setup can blow more than 2kw. But since (if I'm right about heat pump lift temp) the heat pump is probably only going to push water at 35C to say 55C(? Fig12 would suggest 55C won't be as efficient for the heat pump, but would it?) we need bigger matrixes than if we ran the matrixs at 85C. Any heat warmer than room temp flowing out of the matrixes is going to warm the room but since body temp is 37C any temp cooler than around 37C blowing past someone in the room is going to have the wind chill effect and feel cool even if it is warming the room up, this could limit the speed of the air the matrix fan should blow and if we limit the speed the fan blows we need to increase the volume to get the same heat in the room. Not a problem for electric hot wire heaters etc as the output temp is well above 37C with those. So yes even though I think car matrixes could push a couple of kw worth of heat in the right conditions (when fitted on the car) I agree that for the matrix in the room idea the matrix's would need to be bigger than the usual car size matrix and exiting warm air speed would need to be slower.
Regarding the external evaporator temp, there's going to be an equal amount of cooling on that as there is heating in the house. I don't know heat pump max heat output but if it could do (say) 8kw that's 8kw of cooling for the evaporator. If external temp is (say) 5C how big does the evaporator need to be and how fast does its fan need to blow air through it to prevent its temp falling below 0C and it icing up? 2 Points here, 1. The potential for the evaporator to get below freezing and icing up and needing a defrost cycle and/or additional heating. 2. I look at both the heater matrix and the evaporator as fluid to air heat exchangers, all other aspects being the same if the evaporator can sink X heat to air for a given size our heater matrix can do similar proportionally for its size? If the heat pump heats 4 equal size rooms the heater matrix in each room would only need to be something around 1/4 as big as the evaporator? All other things are not the same, been said that the difference in temp between the evaporator and external air is less than 5C, the difference in temp between the matrix (at only 35C) and room temp (at 20C) is 15C.. could our heater matrixes be smaller than just the proportion size difference?
All these ideas do rely on gas being cheaper than electricity, and yes if you have enough solar panels and big enough battery you can heat your house for free, cook electric for free, run your entire house energy needs for free, sell electricity back to the grid. Any electric you buy from the grid still works out free if you sell enough back to the grid (with enough apparently a bit less than you buy). If gas was cheap enough we could maybe run an engine for no other purpose than to profit by selling electricity back to the grid, pity it isn't cheap enough lol.
@Pinger I don't really see the relevance of the 2T engine or turbines except that you were planning on using a heat exchanger. There are water cooled marine exhaust manifolds available from suppliers stock for quite a wide range of engines for around £500 per manifold, some of these can be used as part of a pressurised cooling system. We'd still need to cool the mid section of exhaust but I imagine fabricating something for that being not too difficult, the manifold would be the difficult bit but we can buy that. Corrosion not much of a problem running on CNG, or we could make the midsection from stainless. Another difficult bit would be the evaporator sinking to the last bit of exhaust, not thought that far yet!
@Gilbert Agreed a lot of assumptions. I think the 'theoretical values' wasn't the best example I could find, I was immediately aware of the ridiculously high scop figures (scop rather than cop because the graph is curved) but at first I thought it showed theoretical scop for an ideal heat pump when trying to bring our room up to temp. Now I think it shows theoretical values when bringing our radiators up to temp, cold temp input temp, hot temp output temp, so if it's 10C outside and we want to heat radiators to 20C the theoretical max cop is around 28 but of course having radiators at 20C wouldn't bring the room up to 20C, the radiators would need to be far warmer than 20C to bring the room up to 20C. Figure 12 seems easier to understand, I think it's supposed to be more representative of real world figures (though probably outdated and not as good as newer designs)? If we look at the 0C external temp position it shows that if we want to heat something to 30C (30C lift temp over 0c) for 30C undefloor heating the scop will be around 4.5, if we want to lift from 0C to 40C for low temp radiators the scop will be around 3.5, if we want to lift from 0C to 45C for 'medium temp' radiators (still seems cool to me) the scop will be around 2.1. If there's any truth in these figures they do at least suggest that your warm air blowing setups (which I'd think blow large volumes of air but that air isn't going to be as hot as a lower volume from a hot wire electric blow heater?) are likely to be more efficient than trying to warm the house with radiators at the same temperature.
I'm surprised you say cop is constant regardless of input temp and the temp we want to warm the house to (temp we want to warm the house to will be fairly constant while we're at home through the day but there's still 'lift temp' which is house temp minus external temp)... Most info I've seen for heat pumps describes a rising rate for cop as lift temp decreases, giving scop which is cop at specific lift temps and/or external temps, but I know a lot of info on the internet is wrong or outdated.
I'm not suggesting heat pumps need to have high cops down to below -15C, we seldom get -15C in the UK and for the odd occasion we do if the heat pump didn't work under those conditions the house owner would be better off plugging in additional hot wire heaters than buying into the more complicated and expensive system involving an engine... But I think the heat pump does need to have fairly high COP down to a little under 0C (say -5C) to be close to as good as some heat pump sellers suggest. You also suggest high constant cop figures (high flat scop) but your setups are the blown air design which Figure 12 above agrees with, we've both expressed doubts that a heat pump using water filled radiators with a heat pump isn't as efficient and Figure 12 agrees. I reckon that if heat pumps could maintain high scop regardless of lift temp there'd be no need for a house using a heat pump to have any more radiators than a house with radiators heated by a gas boiler, just use the heat pump to heat radiators to same temp as the boiler would heat them.
Regards the heater matrix idea, I don't think we'd need massive matrixes in each room if we could heat the water flowing through them to the usual engine running temp of 85C. I think average car heater matrix and fan can probably kick out more heat than we'd expect when the engine is up to 85C temp... When the engine is up to temp even in a little car if we put the heater on full and set heat to blow through dash vents the amount of heat coming from the vents is probably around a couple of kilowatts? I've imagined instead of the car heater an electric hotwire hairdryer in each vent position, each hairdryer pushing around 1kw, the car heater on full seems to be able to match that? I've also been unfortunate enough (don't ask lol!) to sleep in a car in winter with a 2kw electric fan heater running inside, the car's own heater can get the car warmer inside than the 2kw electric fan heater, which also suggests that the car heater matrix setup can blow more than 2kw. But since (if I'm right about heat pump lift temp) the heat pump is probably only going to push water at 35C to say 55C(? Fig12 would suggest 55C won't be as efficient for the heat pump, but would it?) we need bigger matrixes than if we ran the matrixs at 85C. Any heat warmer than room temp flowing out of the matrixes is going to warm the room but since body temp is 37C any temp cooler than around 37C blowing past someone in the room is going to have the wind chill effect and feel cool even if it is warming the room up, this could limit the speed of the air the matrix fan should blow and if we limit the speed the fan blows we need to increase the volume to get the same heat in the room. Not a problem for electric hot wire heaters etc as the output temp is well above 37C with those. So yes even though I think car matrixes could push a couple of kw worth of heat in the right conditions (when fitted on the car) I agree that for the matrix in the room idea the matrix's would need to be bigger than the usual car size matrix and exiting warm air speed would need to be slower.
Regarding the external evaporator temp, there's going to be an equal amount of cooling on that as there is heating in the house. I don't know heat pump max heat output but if it could do (say) 8kw that's 8kw of cooling for the evaporator. If external temp is (say) 5C how big does the evaporator need to be and how fast does its fan need to blow air through it to prevent its temp falling below 0C and it icing up? 2 Points here, 1. The potential for the evaporator to get below freezing and icing up and needing a defrost cycle and/or additional heating. 2. I look at both the heater matrix and the evaporator as fluid to air heat exchangers, all other aspects being the same if the evaporator can sink X heat to air for a given size our heater matrix can do similar proportionally for its size? If the heat pump heats 4 equal size rooms the heater matrix in each room would only need to be something around 1/4 as big as the evaporator? All other things are not the same, been said that the difference in temp between the evaporator and external air is less than 5C, the difference in temp between the matrix (at only 35C) and room temp (at 20C) is 15C.. could our heater matrixes be smaller than just the proportion size difference?
All these ideas do rely on gas being cheaper than electricity, and yes if you have enough solar panels and big enough battery you can heat your house for free, cook electric for free, run your entire house energy needs for free, sell electricity back to the grid. Any electric you buy from the grid still works out free if you sell enough back to the grid (with enough apparently a bit less than you buy). If gas was cheap enough we could maybe run an engine for no other purpose than to profit by selling electricity back to the grid, pity it isn't cheap enough lol.
Last edited by LPGC on Tue Dec 17, 2024 5:41 pm, edited 1 time in total.
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Re: My eco 4 heat pump fun
this seems to suggest that simon ..
i am lucky in that my system seems to work ok at 26c -32c radiator water temps , so i am in the upper cop areas .
Re the price per unit , with the agile tarrif there have even been occasions where they pay you to use power ,
however also situations like this ..where theres no solar or wind and the power is v expensive ..
i have just moved to the cosy tarrif while those sort of prices exist , and will go back to the agile in the spring .
regards
robert
i am lucky in that my system seems to work ok at 26c -32c radiator water temps , so i am in the upper cop areas .
Re the price per unit , with the agile tarrif there have even been occasions where they pay you to use power ,
however also situations like this ..where theres no solar or wind and the power is v expensive ..
- IMG_8716.PNG (330.15 KiB) Viewed 3935 times
i have just moved to the cosy tarrif while those sort of prices exist , and will go back to the agile in the spring .
regards
robert
"The Temptress" thread..... https://forum.retro-rides.org/thread/215234/temptress
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
Re: My eco 4 heat pump fun
Rob, your first image isn't working, I'm not sure what you're referring to where you say 'this seems to suggest that Simon' ?
I take it your house must be either very well insulated or you have some big radiators (compared to room sizes) if the radiators can keep the house at decent room temp regardless of external temps when rad water is only at 26 to 32C? A point Gilbert and I discussed is radiator effectiveness when radiator temps are not much above room temp, this must reduce both the convection and radiation from the radiators vastly compared to running them at usual (hotter) boiler temps?
Where you say 'i am lucky in that my system seems to work ok at 26c -32c radiator water temps , so i am in the upper cop areas', does this mean by implication you believe (like I've read) that cop does change with external temp and/or lift temp? This isn't meant as a point against Gilbert's setup, in fact it's a positive for Gilbert's setup because his setup also has relatively low condenser temp (which it can get away with because the heat is blown into the room/s rather than coming from radiators) so also achieves high cop... But it could be a negative against some air to water (to radiator) setups in some premises, especially those that don't have big enough radiators because to get the house warm enough radiators that are not big enough would need to be hotter?
I think I understand your info about the different tariffs, I suppose it doesn't matter much how much the grid charges for electricity if you're not buying from the grid because your panels are keeping the heat pump running or you don't need to run the heat pump because the weather is warm enough. If tariff buy temperature is linked to the same tariff's sell temp you'll choose the high price tariffs when selling more than you buy and vice/versa. The Agile tariff would be expensive to buy from especially at peak times. What is the Cosy tariff ?
I take it your house must be either very well insulated or you have some big radiators (compared to room sizes) if the radiators can keep the house at decent room temp regardless of external temps when rad water is only at 26 to 32C? A point Gilbert and I discussed is radiator effectiveness when radiator temps are not much above room temp, this must reduce both the convection and radiation from the radiators vastly compared to running them at usual (hotter) boiler temps?
Where you say 'i am lucky in that my system seems to work ok at 26c -32c radiator water temps , so i am in the upper cop areas', does this mean by implication you believe (like I've read) that cop does change with external temp and/or lift temp? This isn't meant as a point against Gilbert's setup, in fact it's a positive for Gilbert's setup because his setup also has relatively low condenser temp (which it can get away with because the heat is blown into the room/s rather than coming from radiators) so also achieves high cop... But it could be a negative against some air to water (to radiator) setups in some premises, especially those that don't have big enough radiators because to get the house warm enough radiators that are not big enough would need to be hotter?
I think I understand your info about the different tariffs, I suppose it doesn't matter much how much the grid charges for electricity if you're not buying from the grid because your panels are keeping the heat pump running or you don't need to run the heat pump because the weather is warm enough. If tariff buy temperature is linked to the same tariff's sell temp you'll choose the high price tariffs when selling more than you buy and vice/versa. The Agile tariff would be expensive to buy from especially at peak times. What is the Cosy tariff ?
Last edited by LPGC on Tue Dec 17, 2024 5:55 pm, edited 1 time in total.
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Re: My eco 4 heat pump fun
oh thats weird , i can see it on the forum.... heres a screen shot ..
cosy...
- 123.jpg (92.84 KiB) Viewed 3926 times
cosy...
- 144.jpg (65.98 KiB) Viewed 3926 times
"The Temptress" thread..... https://forum.retro-rides.org/thread/215234/temptress
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
Re: My eco 4 heat pump fun
I did my usual, posted before I should have, edited after I'd posted thinking you were unlikely to read/reply during my edit. I sometimes do that to not lose what I've written so far in case of a computer problem with potential to lose what I'd already typed. I included a couple of questions you won't have read before your reply, sorry.
With the Cosy tariff is there a potential problem of paying more than a standard electricity tariff (what 25p?) if you need to buy in electricity to run your heat pump between (say) 4pm and 7pm and electricity is 37.5p and 25.9p between 7pm and 10pm or does the solar and battery cover that or on balance over 24hours/a week/a month does it still work out cheaper?
Edit - We can see your graph now thanks. It does show scop rising for rising external temps and since the radiator temp is a constant in each of the 3 individual sets of data plotted the difference in scop must be either due to external temp or lift temp. The graph also shows a sudden change in scop for external temps between around 1C and 10C depending on which data set we refer to.
I'll risk another untimely edit... Wonder what the difference in condenser to hot water temp is with air to water (to radiator) setups, I can't see it being much more than a degree but Gilbert's hot air blowing setup will have air blowing directly through the condenser so has at least slight advantage in scop because lift temp won't need to be quite so high?
With the Cosy tariff is there a potential problem of paying more than a standard electricity tariff (what 25p?) if you need to buy in electricity to run your heat pump between (say) 4pm and 7pm and electricity is 37.5p and 25.9p between 7pm and 10pm or does the solar and battery cover that or on balance over 24hours/a week/a month does it still work out cheaper?
Edit - We can see your graph now thanks. It does show scop rising for rising external temps and since the radiator temp is a constant in each of the 3 individual sets of data plotted the difference in scop must be either due to external temp or lift temp. The graph also shows a sudden change in scop for external temps between around 1C and 10C depending on which data set we refer to.
I'll risk another untimely edit... Wonder what the difference in condenser to hot water temp is with air to water (to radiator) setups, I can't see it being much more than a degree but Gilbert's hot air blowing setup will have air blowing directly through the condenser so has at least slight advantage in scop because lift temp won't need to be quite so high?
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Re: My eco 4 heat pump fun
"With the Cosy tariff is there a potential problem of paying more than a standard electricity tariff (what 25p?) if you need to buy in electricity to run your heat pump between (say) 4pm and 7pm and electricity is 37.5p and 25.9p between 7pm and 10pm or does the solar and battery cover that or on balance over 24hours/a week/a month does it still work out cheaper?"
so far its working out ok , the battery charges over the 12 pence periods and covers the expensive times , however , i am lowering the heating to 16 in the day , so not yuor typical hs temps.
i will find out in a few days if a whole week works out cheaper , dependson what agile would have been .
"Wonder what the difference in condenser to hot water temp is with air to water (to radiator) setups,"
i am looking at an old big brass sender steam gauge wedged behind the rdiator ,and its generally showing a 4 c difference between water temp setting and rad.
ill tape a digital one on there and see .
so far its working out ok , the battery charges over the 12 pence periods and covers the expensive times , however , i am lowering the heating to 16 in the day , so not yuor typical hs temps.
i will find out in a few days if a whole week works out cheaper , dependson what agile would have been .
"Wonder what the difference in condenser to hot water temp is with air to water (to radiator) setups,"
i am looking at an old big brass sender steam gauge wedged behind the rdiator ,and its generally showing a 4 c difference between water temp setting and rad.
ill tape a digital one on there and see .
"The Temptress" thread..... https://forum.retro-rides.org/thread/215234/temptress
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
Re: My eco 4 heat pump fun
Been a while since my last post or anyone posted on this thread.
I was put off my idea of combined heat pump and engine setup, the info about electricity prices made it seem not viable in terms of running costs compared to an electric powered heat pump setup. Also as time went on I'd mistakenly got it in my head that I was waiting for some more figures that Rob said he'd be coming back with but now I realise he was only going to come back with the condenser to hot water temperature drop and that wouldn't be a figure I could hope to improve on with any setup I made.
Having thought 'not viable' I haven't given it much thought since but thinking out loud now I might have underestimated my idea... I'd need to re-read to remind myself but I seem to think that I did the forward calculation - an engine/generator using 3kw worth of fuel would produce 2kw of heat + 1kw of power to drive the heat pump, the heat pump would shift 4kw of heat from the 1kw it used for total output of 6kw. But I didn't then do the backward calculation, instead of comparing running costs of the engine and heat pump combination making the same 4kw as the electric powered heat pump I compared the combined engine and heat pump making 6kw to the electricity driven heat pump making 4kw. The combined engine plus heat pump setup could be throttled back to only make 4kw output so would use less than 3kw of gas to shift the 4k of heat. If the engine used 2kw of gas it would produce 2/3rds of a kw (0.666kw) to turn the heat pump, the heat pump would shift 2.666kw of heat from that 0.666kw input, the engine would produce 1.333kw of heat, the 2.666 and 1.333 add up to 4kw so now we have the same 4kw output from using only 2kw of gas.
I think the combined engine and heat pump setup has the potential to be cheaper to run than an electricity GRID driven heat pump, especially in particularly cold weather when heat pump scop would likely see an improvement due to the evaporator sinked to engine exhaust heat. I'm not saying this would work out cheaper than the solar and battery storage enhanced electric heat pump but I'll be thinking about it a bit more again. I also think the potential to get higher scop and radiator temperatures from sinking the evaporator to an engine exhaust could make the difference between a barely warm house and a nicely warm house on particularly cold days or if the house isn't as well insulated as heat pump setups generally require. And for the same reasons could make the difference between a system involving a heat pump only working effectively / efficiently if the house is left at a fairly constant temperature (even when nobody is at home) and it being a good idea to turn the heating off when not required such as when everyone is out of the house like they do with conventional heating. All factors that might be good points for the engine plus heat pump idea in terms of both running cost and practicality.
A few things about the subject strike me... Due to scop heat pumps and solar panels are least effective when you most need them... If room temp is 19C like maybe in summer when the sun is shining nobody would bother running any heater but when it's -5C outside and there are only 6 hours of daylight people might leave the heating switched on 24/7. I know a fella who reckons his electricity company/tariff sometimes has a negative price, i.e. they pay him to use their electricity... I get that they know he has solar panels with battery storage and I get that at times the grid may have an excess of electricity, so I get that these firms might hope he will buy at negative cost to charge his battery and feed back in to the grid again at negative cost during peak times which might benefit them, but surely the fact he's retired so always at home and heats using a heat pump means he is unlikely to feed much into the grid at peak times anyway and even if the grid don't have their own batteries they have other ways of storing electricity potential such as pumping water uphill into hydro electric dams. I don't see why they would pay him to use their electricity now, and I can't see that continuing far into the future.
I was put off my idea of combined heat pump and engine setup, the info about electricity prices made it seem not viable in terms of running costs compared to an electric powered heat pump setup. Also as time went on I'd mistakenly got it in my head that I was waiting for some more figures that Rob said he'd be coming back with but now I realise he was only going to come back with the condenser to hot water temperature drop and that wouldn't be a figure I could hope to improve on with any setup I made.
Having thought 'not viable' I haven't given it much thought since but thinking out loud now I might have underestimated my idea... I'd need to re-read to remind myself but I seem to think that I did the forward calculation - an engine/generator using 3kw worth of fuel would produce 2kw of heat + 1kw of power to drive the heat pump, the heat pump would shift 4kw of heat from the 1kw it used for total output of 6kw. But I didn't then do the backward calculation, instead of comparing running costs of the engine and heat pump combination making the same 4kw as the electric powered heat pump I compared the combined engine and heat pump making 6kw to the electricity driven heat pump making 4kw. The combined engine plus heat pump setup could be throttled back to only make 4kw output so would use less than 3kw of gas to shift the 4k of heat. If the engine used 2kw of gas it would produce 2/3rds of a kw (0.666kw) to turn the heat pump, the heat pump would shift 2.666kw of heat from that 0.666kw input, the engine would produce 1.333kw of heat, the 2.666 and 1.333 add up to 4kw so now we have the same 4kw output from using only 2kw of gas.
I think the combined engine and heat pump setup has the potential to be cheaper to run than an electricity GRID driven heat pump, especially in particularly cold weather when heat pump scop would likely see an improvement due to the evaporator sinked to engine exhaust heat. I'm not saying this would work out cheaper than the solar and battery storage enhanced electric heat pump but I'll be thinking about it a bit more again. I also think the potential to get higher scop and radiator temperatures from sinking the evaporator to an engine exhaust could make the difference between a barely warm house and a nicely warm house on particularly cold days or if the house isn't as well insulated as heat pump setups generally require. And for the same reasons could make the difference between a system involving a heat pump only working effectively / efficiently if the house is left at a fairly constant temperature (even when nobody is at home) and it being a good idea to turn the heating off when not required such as when everyone is out of the house like they do with conventional heating. All factors that might be good points for the engine plus heat pump idea in terms of both running cost and practicality.
A few things about the subject strike me... Due to scop heat pumps and solar panels are least effective when you most need them... If room temp is 19C like maybe in summer when the sun is shining nobody would bother running any heater but when it's -5C outside and there are only 6 hours of daylight people might leave the heating switched on 24/7. I know a fella who reckons his electricity company/tariff sometimes has a negative price, i.e. they pay him to use their electricity... I get that they know he has solar panels with battery storage and I get that at times the grid may have an excess of electricity, so I get that these firms might hope he will buy at negative cost to charge his battery and feed back in to the grid again at negative cost during peak times which might benefit them, but surely the fact he's retired so always at home and heats using a heat pump means he is unlikely to feed much into the grid at peak times anyway and even if the grid don't have their own batteries they have other ways of storing electricity potential such as pumping water uphill into hydro electric dams. I don't see why they would pay him to use their electricity now, and I can't see that continuing far into the future.
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240
Re: My eco 4 heat pump fun
Ignoring Simon's ideas of using an engine (the concept of turning the heating off to change the plugs, oil and filter seems a bit alien to me), I'm slightly intrigued with the charges Robert is paying for electricity. I noticed mentions of a 60p and 65.8p per day standing charges. Surely, with solar panels the amount of metered electricity used will be lower than without so I would have thought it would make sense to pay a slightly higher metered rate and a lower standing charge? I've just checked mine with Ovo Energy and my standing charge is 48.4p per day with the unit rate of 24p per kWh. Without doing the maths, I can't be sure but I would have thought a lower standing charge would be more beneficial?
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare
Proud member of the YCHJCYA2PDTHFH club.
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare
Proud member of the YCHJCYA2PDTHFH club.
Re: My eco 4 heat pump fun
thats interesting gilbert thank you . i am trying to use the 13 pence per unit rate as much as possible to ofset that .
"The Temptress" thread..... https://forum.retro-rides.org/thread/215234/temptress
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
Re: My eco 4 heat pump fun
For lowest power usage, keep your heat pump at a steady moderate temperature and use scheduled timers to match occupancy, avoiding frequent on/off cycles. The Fujitsu ASU9RLF1 service manual at https://www.acmanuals.com/fujitsu/asu9rlf1/service-manual/ explains how to navigate the LCD, set modes, adjust temperature limits, and optimize efficiency easily.
Re: My eco 4 heat pump fun
to update this , my first whole year results are in .
i payed 60 quid a month in ,i started the year 165 quid in credit , and received 150 heating contrib from hmg , and i am now 950 in credit .
so thats not too bad i think .
regards
robert
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- IMG_2798.PNG (221.34 KiB) Viewed 1639 times
i payed 60 quid a month in ,i started the year 165 quid in credit , and received 150 heating contrib from hmg , and i am now 950 in credit .
so thats not too bad i think .
regards
robert
"The Temptress" thread..... https://forum.retro-rides.org/thread/215234/temptress
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/
'Medusa" thread .....https://www.rodsnsods.co.uk/threads/medusa.206057/