Sunamp container bulging

[Eileen]

In response to a couple of replies, I have pointed a director of SA at this thread.

[Jeremy Harris]

15 minutes ago, scottishjohn said:

the "amptec" boiler already has temp controls etc

simple loop with divertor valve+ pump and it will just deliver water at temp you set. 

I used one as my inline back up for solar thermal UFH  system found one very cheap compared to normal proce  --brand new on ebay 

or use an electric shower unit maybe would work the same .

from what i can see a willis heater needs a tank to fit it into  and then you back to thermal losses

 

 

Not what's needed here at all, really.  The key point is that the output flow temperature has be held within tight limits when there is a highly variable AC power input from a PV diverter. 

 

There needs to be an excess PV detect circuit (which needs to detect reliably for the whole range of excess PV diverter schemes, from simple phase control units through to zero crossing, long inter-pulse delay, pulsed power units).  This needs a timer to allow the system to remain powered up after an initial PV input, in the assumption that more heating element power will be along within 30 seconds or so (to deal with energy bucket PV diversion)

 

There needs to be a means of allowing the flow temperature to always be above the phase transition temperature, even when only a few tens of watts are available from the excess PV diverter.

 

Finally, there needs to be means to control the power to the element, independently of the pump, to deal with the case where the flow temperature is close to the upper limit with the pump on.

 

[Jeremy Harris]

28 minutes ago, Alphonsox said:

 

What is the flow detectors role in this ? I has assumed it was just there to detect cold water flow during the charging cycle and hence switch charging off. Is it performing a more complex function during charging ? Looking at its position in the water loop I assume it must be.

 

The flow sensor (not detector) is there to measure the flow rate in the charging circuit as a way to provide closed loop control of the variable speed pump, in conjunction with the temperature sensors.  This system was needed for the Sunamp PV because it shared the same hydraulic circuit for charge and discharge, separating the two by means of a cunning arrangement of non-return valves. 

 

Despite it's complexity, the Sunamp PV's design was quite elegant, as it allowed a single heat exchanger to both charge and discharge the cell, plus it coped with any type of PV diverter output, and there are a wide range of different control systems used for these, from simple phase control of power, through zero crossing modulated power, to the sub-1 Wh energy bucket system, with the latter outputting short pulses of power that may well be 30 seconds or more apart under low excess generation power conditions.

[ProDave]

2 hours ago, JSHarris said:

Worth remembering that the limited charge acceptance issue is only with one Sunamp model, the direct electrically heated eHW.  None of the other models have this issue, as far as I'm aware.

Might the resolution for you to be swap yours for a water input version, even if you don't use the water input function?

 

Then modify the marketing that the all electric version is aimed at off peak storage not solar pv?

[Jeremy Harris]

Just now, ProDave said:

Might the resolution for you to be swap yours for a water input version, even if you don't use the water input function?

 

Then modify the marketing that the all electric version is aimed at off peak storage not solar pv?

 

Mine already has the water input heating option, just needs to have the low power heat exchanger hooked up to a suitably well-controlled water heating system.  That's non-trivial, as it would involve designing and building both a water heating system and a control system, pretty much from scratch, as Sunamp don't offer a product that will do this. 

 

I've no doubt that the charge circuit from a Sunamp PV could be pretty easily modified to charge a UniQ via the low power heat exchanger, though, but it would need some adaptation, and it's likely the the control circuit may not readily be able to be adapted, so a new one might need to be designed.  Lots of plus points for having a separate "charging box", though, from being able to replace the immersion element (it's non-replaceable in the UniQ eHW) to being able to have a much better degree of control over the charge process when running from excess PV generation.

 

The latter definitely needs doing, as my energy use figures for the past week show.  I could have utilised around two or three times more of our self-generation last week had the unit been able to function as the old Sunamp PV did.

[ProDave]

Sorry miss understood you. I thought you said the water input versions used the same wet immersion heater system as the old PV version so would work properly with

PV diversion. 

[Jeremy Harris]

6 minutes ago, ProDave said:

Sorry miss understood you. I thought you said the water input versions used the same wet immersion heater system as the old PV version so would work properly with

PV diversion. 

 

Sadly not.  As far as I can tell, the water input versions use the same cell as the eHW, but without the electric element fitted in the base.  They use the low power heat exchanger to charge the unit using hot water from a boiler, heat pump, etc.

 

I had the option of either not connecting the low power heat exchanger pipes in my unit, or connecting them in parallel with the high power heat exchanger to give a slight flow rate boost.  I chose to do the latter, but rather wish I hadn't now, as it would make experimenting with a DIY hot water charge system a bit simpler.

[Ed Davies]

I'm fairly bored with this conversation; until we know why they've limited PV charging it's all just speculation. My guess is still that it's just bone-headed software.

 

Still, if this were needed:

 

8 hours ago, Jamie998 said:

I suppose one potential workaround would be to have multiple small capacity units - not sure how they could be connected to deplete one before moving onto the next? 

 

Just connecting them in series would do it, I think. If the DHW flow is left to right then the left-hand one will discharge first and only when it's fully solid and its output temperature drops below the PCM transition temperature will the second begin to discharge (ignoring the small amount of energy stored as sensible heat once the PCM is all in one or the other phase and any tiny losses in the pipes between them). You'd want to prioritise feeding any available PV to the rightmost box which is below the required charge level (50% or whatever) and when that's full or there's more PV power available than its immersion element can take then you charge the ones to its left.

 

Thinking about it, this sort of system might work well in a (badly designed) house with multiple bathrooms/kitchens which are well separated so there are long pipe runs from any central heat source. Have a small Sunamp near each bathroom/kitchen cluster to give quick hot water most of the time and prioritise charging them where possible but have a larger unit in the utility room or where ever for the main store to tide you over dull days.

 

Is there a use for very small PCM units to go under sinks to provide immediate hot water until hot water arrives from the main source. For showers and the like which take a relatively large amount of energy once started they might not even need a separate charge circuit but could perhaps take it from the supplied hot water if their phase change temperature was a bit lower than the central source. They could be built into washing machines forming part of the weight those have for damping anyway.

[readiescards]

Apparently I'm being sent a new PCM58 which is being made to order in a week or two. I'm tempted to say delay it until Sunamp have one that both fixes the bulging and maximises excess PV only trouble is I can't have holiday cottage guests staring at a partial installation with a mass of pipes and controls for a year or two.  

 

Do we know if there is any intention by Sunamp to modify the control system to ensure excess PV can be pumped into the device even if it is only 5% discharged?

[Barney12]

21 minutes ago, readiescards said:

Do we know if there is any intention by Sunamp to modify the control system to ensure excess PV can be pumped into the device even if it is only 5% discharged?

 

My understanding is they are working on a new controller which has an integrated solar diverter. However, there is no release date. 

But, I’ve had no information that suggests this controller will deal with the 50/90% issue. Which if it doesn’t they've not really solved the fundamental problem. 

 

I do think though we need need to remind ourselves again (as as been said a number of times in this thread) that the contributors of this forum don’t necessarily represent the ‘mass market’.  

[Onoff]

Just now, Barney12 said:

 

My understanding is they are working on a new controller which has an integrated solar diverter. However, there is no release date. 

But, I’ve had no information that suggests this controller will deal with the 50/90% issue. Which if it doesn’t they've not really solved the fundamental problem. 

 

I do think though we need need to remind ourselves again (as as been said a number of times in this thread) that the contributors of this forum don’t necessarily represent the ‘mass market’.  

 

+1. There's some proper weirdos on here...

[Barney12]

I’m probably the wrong person to be pondering this, as I’m not a tech guru but why didn’t Sunamp just make a little bolt on box containing a Willis heater and pump for the ‘e’ variants? 

[Barney12]

2 minutes ago, Onoff said:

 

+1. There's some proper weirdos on here...

 

Excuse me? I resemble that remark  

[vivienz]

9 minutes ago, Onoff said:

 

+1. There's some proper weirdos on here...

 

I bought a cheap microwave in Asda at the weekend for the site cabin. It had a tricky security tag, buried in the packing tape and the cashier's manicure was in mortal danger trying to remove it. You should have seen the look I got from the man behind me at the till when I refused his offer of a bunch of keys and instead got my Swiss army knife out and made short work of slicing out the tag.

[Onoff]

Just now, vivienz said:

 

I bought a cheap microwave in Asda at the weekend for the site cabin. It had a tricky security tag, buried in the packing tape and the cashier's manicure was in mortal danger trying to remove it. You should have seen the look I got from the man behind me at the till when I refused his offer of a bunch of keys and instead got my Swiss army knife out and made short work of slicing out the tag.

 

Gerber Suspension here!

[vivienz]

Yes, but I'm a girl and highly value the fact that my red Victorinox matches my red duffle coat.

 

Decus et tutamen est.

[Barney12]

2 minutes ago, vivienz said:

Yes, but I'm a girl and highly value the fact that my red Victorinox matches my red duffle coat.

 

Decus et tutamen est.

 

and your Dr Martins?   

[Jeremy Harris]

12 minutes ago, Barney12 said:

I’m probably the wrong person to be pondering this, as I’m not a tech guru but why didn’t Sunamp just make a little bolt on box containing a Willis heater and pump for the ‘e’ variants? 

 

They could just adapt the heater/pump/control assembly from the top of a Sunamp PV, as that works very well at charging the PCM58.  There must be a few surplus Sunamp PV assemblies floating around in the factory and I can't see it being a major engineering challenge to reconfigure them, but the problem is that there probably isn't a significant market for such a unit. 

[joe90]

2 minutes ago, JSHarris said:

but the problem is that there probably isn't a significant market for such a unit. 

 

Then why did they bring out the eHW version (or am I barking up the wrong ?).

[Barney12]

1 minute ago, joe90 said:

 

Then why did they bring out the eHW version (or am I barking up the wrong ?).

 

Fair point!

[newhome]

8 minutes ago, vivienz said:

It had a tricky security tag, buried in the packing tape and the cashier's manicure was in mortal danger trying to remove it.

 

The other day the (male) cashier at the supermarket asked me to use my nails to scrape the label off something he was trying to scan because it was obscured. He said his weren't long enough and when I said that I would rather not as it would wreck my manicure he gave me that look that said 'you're an awkward cow', but there was no way I was digging my nails into anything less than an hour after having them done! 

I love that your knife matches your coat. Can't beat matching accessories . 

 

[vivienz]

Indeed. I was thinking it all coordinated rather well with the red flash of the underside of a pair of Louboutins rather than DMs. Not sure the budget will stretch that far once I've finished the house.

[Barney12]

3 minutes ago, vivienz said:

Indeed. I was thinking it all coordinated rather well with the red flash of the underside of a pair of Louboutins rather than DMs. Not sure the budget will stretch that far once I've finished the house.

 

Please tell me you swung your leg up onto the conveyer whilst wielding your Swiss thus revealing your red soles.

Or did you just high kick the said security tag into the veg isle thus thawting the person who bought a lowly security enabled cucumber? 

That will learn those closet Hendrix drinkers  

[Triassic]

1 hour ago, Barney12 said:

 

My understanding is they are working on a new controller which has an integrated solar diverter. However, there is no release date. 

But, I’ve had no information that suggests this controller will deal with the 50/90% issue. Which if it doesn’t they've not really solved the fundamental problem. 

 

I do think though we need need to remind ourselves again (as as been said a number of times in this thread) that the contributors of this forum don’t necessarily represent the ‘mass market’.  

If our local housing association is anything to go by, they are sticking PV on every available roof. I bet they’d not be too chuffed at the 25% utilisation of the available PV. 

 

I got the impression from the Sunamp web site that social housing was a key part of their target “mass market” !

Edited December 3, 2018 by Triassic

[Jeremy Harris]

11 hours ago, joe90 said:

 

Then why did they bring out the eHW version (or am I barking up the wrong ?).

 

Just looking at the product range, it seems that there has been a gradual shift away from a focus on making more effective use of energy from domestic scale renewable generation and towards becoming a competitor for conventional hot water storage systems.  I'll freely admit that I hadn't noticed this shift in emphasis in the time since we first fitted the Sunamp PV.

 

I think that one issue may be that product R&D may be being spread a bit thin as a result of the many different variants being brought to market at the same time.  Just from my personal observations, the old Sunamp PV was a better engineered and finished product than the newer UniQ; just a glance at the unit when it was first unpacked highlighted this.

 

The eHW may well be able to be fine tuned to overcome the shortcoming in it not being able to utilise excess PV generation charging very effectively, I don't know.  I hope that some further development of the Qontroller is able to overcome the present inability to accept charge until the unit is ~50% discharged.

 

I have wondered if the designers may have just missed the need to be able to store charge for use further ahead than the next 12 hours.  In winter, it's important to be able to store energy whenever it's available, so that it can be used 24 to 48 hours later, avoiding the need to use grid energy.  Unless you've lived with PV for a while, and seen the high degree of generation variability during the winter months, then you may not realise how important this ability to maximise energy storage for later use is, if, say, the next day is cloudy.