Morning All

[Mark W]

Nice to have found this group, just saying hello to all of you self builders. I am in the early stages of planning my self build, and hopefully for next year fingers crossed. I have been in construction all of my life, I started in the early days on the civils side, road construction and concrete and progressed onto building construction and refurbishment and project management.

It has always been a dream to build my own house and the time has now come where I now have the time to look into this as an on going project.

 

I have had enough of blocks and SIP's, to be honest I like all timber construction, I have been in contact with a company in the US regarding their kit houses , I have helped construct one of their houses in Canada a few years ago and I like their design and easy of construction. The big question is how would they go down in the UK with the latest design and planning requirements

 

What do you think, would I have problems. Here is the company's website   http://www.smilingwoodsyurts.com/

 

I Looking forward to being an active member on this forum

 

Mark W 

[ragg987]

Welcome Mark and best of luck with the project.

 

That round building looks nice and package seems sensible. I guess the other obvious question would be how would you get support in the UK?

[ToughButterCup]

Hello, and welcome.

Looking back, the one thing I can say about planning a build: my taste changed over time - first we wanted a chocolate box house in a chocolate box hamlet, in a chocolate box bit of Lancashire. And we now have a passivhaus ( well nearly) under way.

[PeterW]

Nice design for the right location - it's not as hard as it sounds, I got agreement in principle from planning for a raised round house on a plot down from a grade 2 listed mill.... just pitched it as "a water wheel...."

 

Good luck with the build and welcome ..! May be worth letting people know where you are in the country too ..

[asklair]

This is a link to a guy who builds round houses, years ago I heard him give a talk, totally inspiring, the funny part was he was going to give a talk about social housing but the computer didn't work so he just talked about the round house he built. The roof design was just poles but they locked together, structural engineers could not get their heads around this concept.

 

link to his website http://www.dunbeag.org.uk/index.php

I do not know the full story, I think something happened to his first round house, so if you contact him you are aware of the situation.

[MikeSharp01]

Welcome and looks like great fun... You need to know is that self building is a lot of going round the houses so this design will make it easy,

[Nickfromwales]

4 hours ago, PeterW said:

May be worth letting people know where you are in the country too ..

I'm guessing by his accent that he's from somewhere in the south east of London . 

Welcome aboard !

[Mark W]

Hi all  and thanks for the kind welcome. Yes correct form South East London. Well to be more precise Bromley Kent, I have be spending some time reading lots of the threads on here especially the ones on renewable energy as I am a fan of this, I Still don't know what to make of this Sunamp battery ! and if it has any advantages. I have lived totally off grid while overseas, the water was catchment as well so I have a good idea what works and what is a waste of time and money. 

Anyway many thanks for the nice welcome.

 

Mark

[PeterW]

Sunamp has lots of benefits - low losses, compact unit, simple operation, multiple heat sources. It's drawback is initial outlay but if you do a true TCV over 10 years then I would expect the comparison to a Unvented Cylinder is marginal. 

 

 

So I'm having an unvented cylinder as we can't afford the Sunamp ..!

[Mark W]

PeterI have not looked at it that much yet, does the unit have a life expectancy time. and what would be the cost including all the controls and plumbing to install this unit, have not been able to find any costs I always like looking at alternatives.

[PeterW]

No idea but @Andrew Bissell - Sunamp , @TerryE Or @JSHarris may be able to answer. 

 

The controls are very simple from what I've read. Cost is based on your configuration so I think that's why you don't see a price list per se. 

[Jeremy Harris]

I can answer some questions about the Sunamp PV.  There are no controls, as such, just a four core cable, a cold water feed and hot water outlet (plus a PRV vent).  The four core cable is protective earth, neutral, line and switched line.  The line and neutral are permanently powered to run the internal controls, the switched line is normally fed with power from an excess PV energy diverter, like an Immersun or similar, but can just as easily be run from an off-peak supply, like E7.

 

The thermal batteries start charging as soon as power is supplied to the switched line, at a rate of up to 3kW.  When fully charged the charging circuit turns off.  When there is a hot water demand, the flow of water is directed through the thermal batteries, that are then triggered to start the phase change process that releases heat, that's transferred into the water at a rate of up to about 30kW.  As soon as the hot water demand stops, the thermal batteries go back to the rest state, but will accept more charge from the switched line, if it's available.

 

The only control is an internal thermostatic mixer valve in the water circuit that can be set to give a comfortable hot water output temperature.  In essence, the Sunamp PV works just like a very small thermal store heated by an immersion heater, but with very much lower losses.  The expected life of the thermal batteries is over 20 years, I believe, and all the testing so far seems to suggest that they do not degrade or lose capacity with age.

[Mark W]

Thanks for that JS I have not found that much technical information regarding the efficiency of the unit. I see it can supply 4-5 KWh worth of hot water . It would be interesting to see how many KWh of electricity  you need to put into it to get 4-5 KWh of hot water out.

[Jeremy Harris]

It loses around 600 Wh/24 hrs, so is about 3 to 4 times more "efficient" than an equivalent thermal store.

[SteamyTea]

That is near a makes no difference 90% at the 5 kWh limit

87% at 4 kWh

 

It would be easy to get silly with efficiencies, especially if PV and a HP is incorporated in the mix (as Jeremy has).

[Mark W]

I need to do some more reading up on this.I must say that 20000 cycles is very good, I was actually saying about the efficiency as they class it as a battery, like a normal deep cycle 1.2v cell you need to put in more power than you get out.   

[SteamyTea]

A lot of it will be down to the time between charging up and discharge, a short gap between them and there are less losses.

I put a secondary timer on my E7 DHW so that it only heated up during the last 3 hours of the period, rather than the first few hours.  I then generally used the water within an hour of it reaching maximum temperature.

This reduced losses significantly, which increased efficiency.

[TerryE]

My electrician has just wired up my 240V side of off my dual SunAmp config, so I will be doing the commissioning testing next week.  Once I've done this, I will write it all up as a post. 

 

I did the plumbing myself.  None of the certification / notifiable constraints of a UVC. You can self-certify yourself as competent for your own DIY plumbing install, but you still need a sparky with the right tickets to do the 240V side.    SSRs, microcontroller, etc. cost me about £300 in total, but that includes my UFH control as well.

[Mark W]

This is very interesting I now know how it works as I have been looking into this, It works with PCM's, looking into it further you can cool with PCM's as well, I would love to hear how you get on with the Sunamp over the next few weeks, it all works in the phase change, I would be mrse interested in the cooling applications of PCM's, will need to do some more research.

 

[Jeremy Harris]

Although Sunamp refer to the phase change heat storage packs as "thermal batteries", that's really just a term of convenience to put an easily understandable name to a new product.  They do work like batteries, but with a Peukert factor of unity at the instantaneous level (so near 100% efficient, in that if discharged immediately after charge you get almost all the input energy back).

 

A better analogue is really a conventional fluid filled thermal store, with an internal heat exchange coil plus an immersion heater.  You charge a thermal store up, and it's then discharged whenever there is a hot water demand.  The difference is that a really well-insulated thermal store will have, in practice* much higher storage losses.  The Sunamp is a lot smaller than an equivalent sized thermal store (it will fit inside a 600mm wide kitchen cabinet) so saves a lot of space, as well as offering lower losses.

 

 

*Losses quoted by thermal store manufacturers are way off real world losses, because the measurement method specified assumes that they are cycled, and not held full of hot water, but heated prior to use then cooled by hot water being drawn off.  I measured the performance of our old thermal store, and the reality was that it lost over 3 kWh per 24 hours when charged by excess PV and an immersion heater.  I added an extra 50mm of PIR foam all around it and got the losses down to a bit over 2 kWh per 24 hours.  The official loss figure from the manufacturer was 1.6 kWh per 24 hours, so very, very optimistic in terms of real-world operation.

Edited May 4, 2017 by JSHarris

[SteamyTea]

You should have added another 50mm of insulation and stuffed any remaining space with rockwool, and then only heated to 50°C.

How I got my losses down to about a 1 kWh/day.

 

Two things that appeal to me about the Sunamp is that it is compact and easy to fit.

I am about due a failure of my DHW cylinder as it is now 30 years old, 3 neighbours (50%) have had them replaced, so only a matter of time for me.

A direct replacement in copper is about £400, but an Ecocent clone is probably about the same.

Now I know the downsides of the Ecocent, but can mitigate them to a certain extent with some ducting and the mild weather down here.

 

Just the seemingly high cost of the Sunamp that puts me off.

 

[Jeremy Harris]

A thermal store only heated to 50 deg C has less than half the usable energy storage of one heated to 60 deg C though, as you can only drop a thermal store down to a couple of deg C above the desired hot water temperature, and anything lower than about 40 deg C for hot water is a bit too cool for a decent shower.

[Ferdinand]

10 hours ago, Mark W said:

I need to do some more reading up on this.I must say that 20000 cycles is very good, I was actually saying about the efficiency as they class it as a battery, like a normal deep cycle 1.2v cell you need to put in more power than you get out.   

 

There has also been some sort of promotion running - 2nd unit for half price if you need two, perhaps?

 

People here who bought them would know.

 

Ferdinand

[Mark W]

Yes you can only put so much insulation around a thermal store, I remember we had a meeting with Gledhill regarding a solar thermal store while working for a hospital trust,, at the end of the day it was just not worth it . Hospitals use lots of hot water and it is stored at high temperature, most of their system worked with HTHW from the main boilers, this also ran the absorption chillers . at the end of the day we ended up putting in two large GHP units and re- used the waste heat from them.