#heatpump #buffer #lowlosheader
Today we are doing a small experiment to see if buffers or low loss headers are really needed on heat pump installations.
Today we’re trying to see if heat pumps need low loss headers we have a property that’s 3.5 KW heat loss so it’s a really well insulated house with a 5 KW THM heat pump and a low loss header and obviously another pump for the System
Scope of three for the last uh 12 months on this unit or for for the lifetime of the unit I think it is problem we have is the primary pip work is 22 mm going from the heat pump to here distance about 5 to 7 m the pipe were going for
Heating is 22 as well however on a heat loss of 3.5 KW this should work on this pip work it doesn’t matter that the heat pump is 5 KW it should never have to run at the full output because the heat loss is much lower so we can set the controls
The way that the heat pump runs at much lower flow temperature the secondary pump behind the header is set to minimum fixed speed of one so that’s a good sign that the system was operating correctly at the lowest possible setting on that pump so it’s a bit bit of an experiment
To see if when we remove header we can get the correct flow for 3.5 Kow and what I do for that I use high tools app to make my calculations quicker I just go to High tools which is going to be 3.5 KW I type my delta T which is going
To be 5 and that gives me 10 L A Minute required to provide 3.5 KW output for this property at uh dt5 which is uh 600 L per hour so once I’ve removed the header and I set my pump on the external unit if I’ve get anything above 600 L
Per hour going through the system I know I’m fine I’ve got enough flow for a heat loss of this property and the system should be more efficient than existing because we don’t have a header we don’t have a chance of uh Distortion being created one had removed one pump gone so the header’s
Removed now but in a way that we can reinstate it if we have to because it could be one big mistake what I’m doing here I don’t know what the system behaves like I don’t know what how it’s piped there’s very well I can see the
Flow rates I can see the heat loss if if Michael did his job all right and it’s R three and a half we should be fine if it’s anything bigger than three and a half we probably won’t be fine but if you don’t do you don’t learn right if
You don’t make mistake you learn nothing so I’m happy I’m happy to make some mistakes here right yeah and it’s my money and Michael’s paying for it so it’s even better and that’s the uh external unit aror plus 5 KW and that’s one of the uh early models
Cuz it’s still has a way better back cover on the PCB it has a very solid it seal here it looks looks so much better than what they have currently the current one cause problems they blow pcbs actually now I have to reprogram the unit I need to let the heat pump know
That there is no longer a header and that there is no longer a secondary pump so I have to change the system from I think diagram 10 to diagram 8 well let’s turn the heating on and let’s see what flow rates we are getting we’re getting
800 L per hour or 13.3 L per minute and it’s confirmed on both a the heat pump interface and a heat meter SX heat meter 800 L per hour or 13.3 L per minute at dt5 translate to 4.6 KW that’s 1 Kow more than the heat loss
Of this property so to me it says this should all check out this system should perform as expected with and it didn’t need a buffer at all those devices were designed for multiple pumps on the system to work together without influencing each other so pump from this
Unit will pump to this side of the vessel the water will circulate most of it at least back and back to the heat pump then on the system side there’ll be another pump this pump here that will circulate water to the system and back and they are useful when they uh pump
Inside the unit doesn’t have enough power to circulate water around the system the usual use in the industry as a free get out of jail car because if you put a header on any system the heat pump will be happy cuz it doesn’t have to uh go through the system resistance
They take space they cost money they cost efficiency the 90% of the time they not need it uh and they are used actually when some manufacturers require them because it keeps the heat pump happy heat pump can circulate through the header buffer and will not throw errors and makes manufacturers happy
Makes installers happy because they don’t have to think too much about about the system it makes uh anend users unhappy because their bills are higher and their installation bills are higher as well so from 20 hit pumps I installed in last 12 months only one had a buffer
And it really needed it not like here this one doesn’t need one so actually if you want to know how this experiment with lolos header panned out you can come to Michael’s home and have a look at the figures outside and I did not realize how cheap your house is
To run is very cheap it’s embarrassingly cheap uh the cheapest months are £8 well there’s no heating cuz that’s in the summer but cooking electrics and the most expensive month in January 2023 when we had a cold snap was 128 pounds yeah that that’s for every Everything cooking heating all the
Electric and you’re also exporting tons of energy to the GRE uh yeah yeah in the summer we export uh almost as much as we use in a whole year so all that work that I’ve done that I’m going to charge you absolute Fortune for it’s going to
Save you what a cup of four instead of three is going to save you 30 quid in a January maybe but it will make me feel good in my heart you just want to experiment see I want to understand it I want to understand what low loss headers
Do and explain it to people and uh uh make the thing a little bit better that’s awesome I would like to understand what they do as well cuz I frankly don’t [Laughter] know thank you very much and we’ll come back to this experiment soon see you in the spring thank you Michael
26 Comments
Would manufacturers void warranties if we don't fit buffers when specified?
Thank you for addressing this issue, sometimes too much is just that, and a buffer is also called a "CYA" cover your ass here in the US cya is just another excuse for not doing the leg work to get it designed properly.
What’s the app? Hi tools?
I recognise Michael de Podesta from his own YT channel, which is also brilliant.
We added a buffer in our system purely due to lack of volume in our system (after contacting valliant ofcourse) we have floorheating downstairs but also a aftermarket system upstairs using only 10mm tubing in stead of the 16mm downstairs, and one low temperature radiator in the attic. we added the buffer later as we had issues with the pump keep cycling to much. after adding the 40l tank it solved all our issues and halved our energy consumption. so they definitely have there benefits at some situations
Your videos are very useful for the novice customer and installers. Your idea of a buffer store is somewhat different to mine, I've worked primarily in the commercial market, to us a buffer store is a cylinder, also known as a thermal store, this allows the heat pump to run at its optimum efficiency and can incorporate other forms of heating system. We would refer to the unit that you removed as a low loss header, which you sometimes called it. These are very common commercial systems and are to protect the boiler heat exchanger from damage due to a large Delta T. I discovered ASH's in late 1988 and like the technology but have not yet been able to make the financial case for having one. Without breaching any customers privacy are you able to discuss RoI timescale. It's great that you've taken on an apprentice, especially a girl, I've employed several in the past, but primarily on maintenance, fault finding and repairs.
Nibe recommend at least 120L volume in a system to help with the defrost so a buffer is often needed when installing ufh.
See i just cant see customers actually being interested in paying for such a detailed install, to install these things perfectly is just not practical, they are only for people with lots of money AND care about their carbon emissions, so for 99% of people they just dont work.
Heat pumps are another con just like electric cars
Heat loss at what external and internal temperatures?
good video keep it going
Do you have ability for another flow rate setting for DHW heating mode or is same as set for room heating?
I bet you're booked until retirement.
I have 2 bed 71m2 property, heavily insulated, 4.7kw heat loss, all “oversized” radiators on 15mm with 22mm primaries from Combi.
Octopus have quoted to fit Daikin 6kw Monobloc, with 28mm in to the property and retain existing 22mm and all rads….but say they are fitting buffer tank…”because they always do”. Is that right or do they need correcting?
What's the lowest compressor point frequency?
On a hybrid system should antifreeze be used in a combi boiler?
As an MEP consultant, the insights and knowledge shared by experienced installers are incredibly invaluable to me. Love this channel.
Question: do you have an opinion on heat pumps manufactured by Clivet? Super cheap, which always makes me wary.
What about the defrost volume, most manufacturers wont count the rads or under floor loops as defrost for the ASHP as they could be on or off?
This looks more like a hydraulic seperator, and not a buffer. If the included pump is enough for the circuits, its pointless. Buffers are much bigger.
Can I ask, with a Vaillant Heatpump with no buffer tank (I have Kingspan Solar Tubes and cheap rate electricity at night for the immersion), only installed to heat the rads, and all of the rads have TADO's on them, then do I need to fit a bypass if all TADO's stop calling for heat, or will the AroTherm shut itself off if the flow stops ?
Reading the home owners blog recently it would seem removing the low loss header has made no difference to the COP – https://protonsforbreakfast.wordpress.com/2023/10/19/heat-pump-experiment-first-results/ Are you able to explain why this is the case?
This is a very strange video, I use LG Therma V Monobloc 9kw Heatpump but even the manufacturer clearly says a 50lt buffer tank is needed and suggest a secondary cycle pump is needed to pump the water from this buffer tank to the radiators. If what you're saying is true, then companies like LG who are spending hundreds of millions of € each year with an army of engineers is wrong (not sure I'll bet my money on this)
I’m confused – the unit removed was a low loss header, only a few litres in size. As such agree, it serves no purpose with a single pumped secondary circuit. However a low loss header is not the same as a buffer vessel, which with a heat pump of 5kw, would expect to see a buffer vessel of say 50l (15l/kw of heat pump capacity) such arrangements improve system performance by preventing short cycling of the heat pump, cheaper to run. Buffer vessels also provide a volume of buffer water to defrost the heat pump when running during high humidity low ambient conditions, heat is transferred from the buffer vessel rather than impact user comfort.
My prediction, it will make bugger all difference.
Certainly not worth the cost of the call-out.
But very keen to see the result.
The heat pumps I install in Oz all require low-loss headers.
Cheers from Oz
Wish all customers were like Michael !
I'm doing more fault finding on heat pump systems then I am installations at the moment. I'm finding that when systems do not have a buffer I'm needing to install a buffer in order to rectify the issues. I'm going to be installing a volumizer on a system on Tuesday