Sunamp installation

[Triassic]

9 hours ago, JSHarris said:

OK, I'm going to do  write up, with photos, on our experience with first a Sunamp PV, and since the beginning of this week with a Sunamp UniQ 9 eHW, as a blog entry this weekend. 

I’m sure I read somewhere that although you have a Eltron Sible in-line heater, it’s never been usd? Is that correct?

[Jeremy Harris]

22 minutes ago, Triassic said:

I’m sure I read somewhere that although you have a Eltron Sible in-line heater, it’s never been usd? Is that correct?

 

Yes, I fitted it as a backup, but never used it, other than to test it.  It's been removed now, and the space it occupied on the wall has been taken up by the Sunamp control box.

[Triassic]

I look forward to reading your blog entry, having read dozens (far too many) posts on here, I’ve come to the conclusion that your current set up is probably the way I’ll go. The only thing I need to finalise is the sizing of the kit, to suit a 4 bed home, with 4 bathrooms. Could you also address how cooling works in the new set up, as I’m still not sure about the plumbing layout to active this. Thanks.

Edited October 6, 2018 by Triassic

[joe90]

39 minutes ago, JSHarris said:

Yes, I fitted it as a backup, but never used it, other than to test it.  It's been removed now, and the space it occupied on the wall has been taken up by the Sunamp control box.

 

Mine is in the garage as a Backup plan to heat from ASHP DHW temp to usable temp rather than let the ASHP go into defrost mode, storing water at 40’ will have very little in the way of losses.

[Nickfromwales]

For cooling you just arrange the motorised valves so that they align the ASHP flow and return solely and directly to the UFH manifold. 

[Nickfromwales]

1 minute ago, joe90 said:

 

Mine is in the garage as a Backup plan to heat from ASHP DHW temp to usable temp rather than let the ASHP go into defrost mode, storing water at 40’ will have very little in the way of losses.

The only problem is the low flow rate ( 15mm connections ) vs the very high flow rate from the UVC that would be feeding it. 

A bit like someone standing on the garden hose and you see the drop in flow, except it would be permanently there. 

 

[joe90]

8 minutes ago, Nickfromwales said:

The only problem is the low flow rate ( 15mm connections ) vs the very high flow rate from the UVC that would be feeding it. 

A bit like someone standing on the garden hose and you see the drop in flow, except it would be permanently there. 

 

Yes but I think Jeremy didn’t notice a flow problem, might only show up if more than one shower is used at the same time!

[Nickfromwales]

7 minutes ago, joe90 said:

 

Yes but I think Jeremy didn’t notice a flow problem, might only show up if more than one shower is used at the same time!

Agreed. Just goes against the ( my ) grain to have the 15mm restriction in 22mm line.

A changeover setup to make it an ( emergency ) diversion device would be ok and I believe a lot of 24 hr fast food restaurants do so. My ex apprentice used to do that in KFCs. They accepted low flow during duress eg until the UVCs could be repaired, but meant they could keep trading.

 

I’d say for a couple without children etc it would be fine, eg no different to a decent combi. 

 

[joe90]

20 minutes ago, Nickfromwales said:

Agreed. Just goes against the ( my ) grain to have the 15mm restriction in 22mm line.

 

I agree. Yes a changeover would be good, we are normally just two adults (allegedly!) but have guests visiting regularly. I have to say our Insulated DHW tank has very little losses, (at 50’). er indoors wants the airing cupboard warmer ?.

 

 

[Jeremy Harris]

Flow restrictions from a reduction over a very short length of pipe aren't that great at normal household flow rates, the problem mainly arises when you have a narrow pipe over a long run.

 

For example, I have a deliberate flow restricting orifice on our incoming supply from the borehole pump, a 3mm diameter venturi at the ozone injector.  That flows at around 10 litres/minute, which is enough to keep the accumulators topped up at around 3 bar. 

 

Although it's good to run the largest bore pipes you can to reduce losses, there is a law of diminishing returns.  We run with an incoming pressure of between 3 and 3.5 bar, and an acceptable pressure at the taps is between 2 and 2.5 bar (anything higher than this tends to make the taps splash when fully open, unless flow restrictors are fitted).  The highest flow rate on the supply to the house we're ever likely to see is around 20 litres/min, most of the time the flow rate when using taps etc is around 6 litres/minute.

 

If we had a 10m run of 15mm copper pipe as the main feed, then at 20 litres/minute flow rate the pressure loss along the pipe would be 0.8933 bar.  So, for 3 bar in we would get 2.1067 bar out at 20 litres/min, which is perfectly OK for pretty much any domestic use.

 

If we had a 10m run of 22mm copper pipe as the main feed, then at 20 litres/minute flow rate the pressure loss along the pipe would be 0.1255 bar.  So, for 3 bar in we would get 2.8745 bar out at 20 litres/min, which is again perfectly OK.

 

If we look at what happens if we put a very short length of 15mm copper pipe into the system, say a 0.5m length of 15mm, with the remaining 9.5m in 22mm, then for the same 3 bar in we would get a pressure loss of 0.0447 bar along the 0.5m of 15mm pipe, plus a pressure loss of 0.1192 bar along the 9.5m of 22mm pipe, giving a total pressure loss along the whole 10m of mixed pipe of 0.1639 bar.  So, for 3 bar in we would get 2.8361 bar out at 20 litres/min, which is hardly any different to having the whole run in 22mm.

 

The above is for straight runs of pipe, and bends, particularly elbows, will likely have a greater effect on flow rate and pressure loss than a short length of smaller bore pipe. 

[joe90]

Bends in 15mm pipe cause a lot of flow resistance. I once had a job fir a customer who could not get a decent flow on a shower and wanted a pump fitted, I suggested a new pipe run in plastic which was more direct, when that was done the shower worked perfectly and the customer got his money back on the pump.

[Oz07]

Just now, joe90 said:

Bends in 15mm pipe cause a lot of flow resistance. I once had a job fir a customer who could not get a decent flow on a shower and wanted a pump fitted, I suggested a new pipe run in plastic which was more direct, when that was done the shower worked perfectly and the customer got his money back on the pump.

You mean bend as in elbow? So a "slow" bent piece of pipe restricts less?

[joe90]

Sorry yes, elbows, bent pipe has a lot less resistance. I used to be able to buy “swept bends” bigger radius but dont see them anymore.

[Jeremy Harris]

You can still get long radius elbows if you hunt around: https://www.jtmplumbing.co.uk/pipe-fittings-c433/endfeed-fittings-8mm-28mm-c117/jtm-endfeed-endfeed-long-radius-elbow-p3576

[stevethayne]

Am new to this forum, have joined because of the Sunamp content - thank you all so much for sharing your experiences, so useful.

 

Probably like many people, I became aware of Sunamp from a  Fully Charged video about them.

 

Am in the process of getting solar panels and, although I am on the gas grid and understand it is generally the cheapest fuel, looking to disconnect from the gas and "electrify everything" for sustainability and public health reasons.

 

I drive an electric car as my only car so I am on Economy 7 currently. 

 

I live by myself in a 3 bed end terrace, and am out of the house a lot for work, leisure and family reasons.

 

Am hoping to buy one or more Sunamp units to contribute or, ideally, solely supply my hot water and heating supply. I have considered Air Source heat pumps but am not convinced as yet.

 

My heating currently has been central heating. The radiators vary from room to room from single to double panel, though none with the shark fins. They are though pretty large which I understand can help with water temperatures lower than typically from a gas boiler.

 

The house was also built originally with a vented air system and the grills are still there. I understand these can work well wiith air source heat pumps. I know this is probably unlikely, but is there any possibility of them being used with the Sunamp products? So the flow of air passing over the heat exchanger instead of water?

 

I have a hot water tank with electric immersion which I intend to keep as back up. And an electric shower, likewise I intend to keep as back up.

 

I like the idea of just heating the little bits of water I need ie to wash my hands - as I need it, via the Sunamp units

 

So. Ideally I would like Sunamp unit or units - I understand they are modular? Sized to charge from economy 7 or when available solar electricity  Providing heat in the winter and hot water throughout. I am prepared to under spec initially and then expand the Sunamp capacity if needed. Note, my heating needs really will be modest. Quite happy just to heat one room for instance. Am thinking 5 kwh as a minimum - seems to be in the region of £2,000?

 

I hope to persuade a local plumber / electrician to install the Sunamp units based on advice given in this thread and the instructions linked to. Ideally at the same time or at least with consideration to the Solar and a wider system design.

 

Any thoughts / advice very, very welcome! 

[Nickfromwales]

Hi Steve. 

The problem you will have is generating the high grade heat that you’ll need for space heating, unless you intend to / already have seriously upgraded the insulation and airtightness of the existing fabric of your home. 

DHW ( domestic hot water ) is a no brainer so I’d try to assess what you’re going to do for heating first and then compliment that with the DHW setup. 

 

If you can improve the house enough to lend itself to say oversized lower temp radiators then you definitely would be able to go for a heat-pump, but to go to a SA ( Sunamp ) unit(s) for space heating will have its problems. It’s do-able, but the issue is getting the kW input vs the kW required, especially when it’s the depths of winter.

 

The SA units with an ‘e’ prefix have a 3kW immersion heater, and they don’t do a bigger one, so to get, for eg, 18kW of space heating via direct electric > SA you’d need 6 x ( albeit the smallest in the range will suffice ) SA units to get the conversion capacity. 

 

An option for you may be an electric boiler, fortified with the PV + battery storage system, but that would be a hell of a load to try to offset. If you’re happy to munch through electricity then without improvements I’d say electric boiler + SA for DHW.

[ProDave]

@stevethayne  It sounds like your house was originally heated with an Electricaire unit, which is a big central storage heater with a fan to blow warm air to all the rooms.   They are still made, though now targeted at commercial use https://www.dimplex.co.uk/product/electricaire-r1073

 

The smallest one has a heat storage capacity of 73KWh and typically  will run a 10KW heating element for the 7 hour off peak period to achieve that.

 

This will give you some idea of how much heating you will need for your house in order to size the system, so you will need typically three 3KW heaters just to store enough for space heating requirements

 

I would seriously consider changing to economy 10 which gives you 10 hours of cheap rate but delivered I believe in 3 off peak periods, so it is never so long until the next top up.

[Triassic]

Could someone clarify the operation of the SunampPV? Am I correct in thinking the DC current from the PV array can be wired straight into the SunampPV, I assume this saved buying an inverter?

[Jeremy Harris]

36 minutes ago, Triassic said:

Could someone clarify the operation of the SunampPV? Am I correct in thinking the DC current from the PV array can be wired straight into the SunampPV, I assume this saved buying an inverter?

 

I don't think the Sunamp PV is available now, it's been replaced by the UniQ eHW. 

 

Both are much the same, in that they have what amounts to an immersion heater element (same rating as one) that runs at 230 VAC.  This can accept either power from the grid or power from an excess PV diversion controller.  I run ours with a mix of both.  We have an excess PV diversion controller that supplies power to the Sunamp whenever we are generating more electricity than we are using, and that has an over-ride capability, either by switching it on manually or by using a time switch to provide a timed boost.  I have the time switch set to provide power (if needed) from 04:00 to 06:00, so if the Sunamp isn't charged up it will get up to 6 kWh of boost charge, if it needs it (it will only accept as much charge as it needs then shut off the power).  We also have an over-ride button that will just boost charge the Sunamp if needed at other times, plus we can switch off the boost completely for the ~9 months of the year when it's not needed.

[A_L]

1 hour ago, Triassic said:

Could someone clarify the operation of the SunampPV? Am I correct in thinking the DC current from the PV array can be wired straight into the SunampPV, I assume this saved buying an inverter?

 

Based on attached pdf the UniQ dPV  models appear to do this (fig 1.9  page 7) but it appears to be all the PV output is sent to the Sunamp. Which would be a waste in summer and not enough in winter.

 

Edit - note Sunamp have mislabelled Fig 1.9 as a UniQ ePV.

 

 

Sunamp pdf2040.pdf

Edited October 11, 2018 by A_L
as in edit

[Jeremy Harris]

24 minutes ago, A_L said:

 

Based on attached pdf the UniQ dPV  models appear to do this (fig 1.9  page 7) but it appears to be all the PV output is sent to the Sunamp. Which would be a waste in summer and not enough in winter.

 

Edit - note Sunamp have mislabelled Fig 1.9 as a UniQ ePV.

 

 

 

Sunamp pdf2040.pdf

 

That's an older version of the manual, I believe, the current version is this one (although I'm pretty sure it's in the process of having some minor amendments added, as some things like the sensor cable colours have recently changed):

 

UniQ manual 180719.pdf

 

 

[Nickfromwales]

The SA dPV is now live, and is aimed exclusively for direct DC injection. The ( early ) figures showed around 13% increase in efficiency due to no inverter. 

 

38 minutes ago, A_L said:

but it appears to be all the PV output is sent to the Sunamp. Which would be a waste in summer and not enough in winter.

Yes, it’s a design which is best specified if going off grid for eg. I’ve yet to look closely at it and am apprehensive as to its appeal right now. When I now more I shall update with pros / cons. 

For now, I can’t recommend enough producing 240v AC and using it wherever it’s needed.

 

However, if you fit a DC system and go for SA plus battery storage you may lift your efficiency overall by up to 30%. As I said, it’s a design consideration with serious number crunching needing doing way in advance. 

[stevethayne]

On 11/10/2018 at 07:40, Nickfromwales said:

Hi Steve. 

The problem you will have is generating the high grade heat that you’ll need for space heating, unless you intend to / already have seriously upgraded the insulation and airtightness of the existing fabric of your home. 

DHW ( domestic hot water ) is a no brainer so I’d try to assess what you’re going to do for heating first and then compliment that with the DHW setup. 

 

If you can improve the house enough to lend itself to say oversized lower temp radiators then you definitely would be able to go for a heat-pump, but to go to a SA ( Sunamp ) unit(s) for space heating will have its problems. It’s do-able, but the issue is getting the kW input vs the kW required, especially when it’s the depths of winter.

 

The SA units with an ‘e’ prefix have a 3kW immersion heater, and they don’t do a bigger one, so to get, for eg, 18kW of space heating via direct electric > SA you’d need 6 x ( albeit the smallest in the range will suffice ) SA units to get the conversion capacity. 

 

An option for you may be an electric boiler, fortified with the PV + battery storage system, but that would be a hell of a load to try to offset. If you’re happy to munch through electricity then without improvements I’d say electric boiler + SA for DHW.

 

Really useful, thanks Nick.

 

I definitely intend to do work on the insulation of the house. It is double glazed but they need work to repair. Has good insulation in the loft. But aim for it to be as well insulated as possible.

 

So if I am understanding right, to get enough rate of flow to provide heating from Sunamp units alone via the radiators would require multiple units? It is not just about the storage capacity i.e. how long the units can provide energy for before they run out and need to be recharged? I understand as well that the temp of the water coming out of the SA units is much cooler than from the gas boiler, is that what you mean by "high grade heat"?

 

 

[stevethayne]

On 11/10/2018 at 08:33, ProDave said:

@stevethayne  It sounds like your house was originally heated with an Electricaire unit, which is a big central storage heater with a fan to blow warm air to all the rooms.   They are still made, though now targeted at commercial use https://www.dimplex.co.uk/product/electricaire-r1073

 

The smallest one has a heat storage capacity of 73KWh and typically  will run a 10KW heating element for the 7 hour off peak period to achieve that.

 

This will give you some idea of how much heating you will need for your house in order to size the system, so you will need typically three 3KW heaters just to store enough for space heating requirements

 

I would seriously consider changing to economy 10 which gives you 10 hours of cheap rate but delivered I believe in 3 off peak periods, so it is never so long until the next top up.

Thanks ProDave. Really interesting. Will look into Electricaire. Wonder why people stopped using them, was it just that North Sea Gas came along and was cheaper?

 

Will consider Economy 10. My electric car takes 4 hours to charge at 6.6 kwh though so will need to weigh that in.

 

 

[ProDave]

I wasn't suggesting you put an Electricair back in again, merely saying that might give you an idea of the heating requirements of the property (assuming the Electricair had proved adequate)

 

I know they were not popular around here. But then storage heaters in general are not popular, people prefer gas or even oil rather than electric storage heating. And it's also possible it proved inadequate in cold weather.