Solar and summer hols

sinnerboy

I would like to compare notes on CLEVER strategies to deal with solar panel installations on those occsaions when they produce more hot water than demanded

- like when you go away to Spain during August
- like when a system design for mom + pop and 3 kids - is to now serve needs of only mom + pop ( kids grown up + gone )

"Solutions" offered by installers to me include

- divert excess hot water ( via sensor valve ) - to an EXTERNAL rad
- takes lots of summer time baths
- divert into the heating system
- in case of kids grown up

• - if flat panels - tarp over part of them
• - if tubular - rotate some or all tubes away from sun

Best I have come up - which is not great I admit - is divert solar to stand alone towel rads zone - snag with that is you need a mixer / control to feed rads from primary heat source when not enough solar energy is present . May be OK to do this on a new build - may be impractical in retro fit

sydthebeat

sinnerboy wrote: »

I would like to compare notes on CLEVER strategies to deal with solar panel installations on those occsaions when they produce more hot water than demanded

- like when you go away to Spain during August
- like when a system design for mom + pop and 3 kids - is to now serve needs of only mom + pop ( kids grown up + gone )

"Solutions" offered by installers to me include

- divert excess hot water ( via sensor valve ) - to an EXTERNAL rad
- takes lots of summer time baths
- divert into the heating system

- in case of kids grown up

• - if flat panels - tarp over part of them
• - if tubular - rotate some or all tubes away from sun

Best I have come up - which is not great I admit - is divert solar to stand alone towel rads zone - snag with that is you need a mixer / control to feed rads from primary heat source when not enough solar energy is present . May be OK to do this on a new build - may be impractical in retro fit

i have always had a theory about this (not put into practise yet!)

I would divert this excess into an internal 'trombe' type wall (possible adobe or stone, or mixture of both) which has optimal decrement delay for release at night time to act as a basic 'heat dump'... thereby storing the days excess heat for release at night when you need it most.

Slates

The system is a sealed system, if the system goes into stagnation the pressure vessel takes any changes in pressure and the panels can cope with 180°C. The only time the panels will be in stagnation is when the cylinder is fully up to temperature and there is a very hot sunny day, twice this year it happened to my system where the panels got to 135°C but this is perfectly ok

What do you think ?

CJhaughey

I have a setting on my controller for holiday mode.
It heats as normal during the day but at night pumps the fluid back up to through the panels allowing the fluid to drop in temp and bring the tank back down to a lower temperature.
In effect it turns the collector into large flat radiators at night.

Juantorena

sydthebeat wrote: »

i have always had a theory about this (not put into practise yet!)

I would divert this excess into an internal 'trombe' type wall (possible adobe or stone, or mixture of both) which has optimal decrement delay for release at night time to act as a basic 'heat dump'... thereby storing the days excess heat for release at night when you need it most.

I like that idea, syd

I was going to suggest you bring the collectors to Spain with you...but of course that'd be even worse, huh :rolleyes:?

sinnerboy

Slates wrote: »

The system is a sealed system, if the system goes into stagnation the pressure vessel takes any changes in pressure and the panels can cope with 180°C. The only time the panels will be in stagnation is when the cylinder is fully up to temperature and there is a very hot sunny day, twice this year it happened to my system where the panels got to 135°C but this is perfectly ok

What do you think ?

Ok slates I suppose . Shame to waste the potential energy really . Would the arrangement work for a long term drop in demand ( kids moved out ) ?

homer911

Surely its possible to remove some of the tubes?

Invest in a swimming pool

CJ's controller is the best option (for flat panels).

bertie1

sinnerboy wrote: »

I would like to compare notes on CLEVER strategies to deal with solar panel installations on those occsaions when they produce more hot water than demanded

- like when you go away to Spain during August
- like when a system design for mom + pop and 3 kids - is to now serve needs of only mom + pop ( kids grown up + gone )

"Solutions" offered by installers to me include

- divert excess hot water ( via sensor valve ) - to an EXTERNAL rad
- takes lots of summer time baths
- divert into the heating system
- in case of kids grown up

• - if flat panels - tarp over part of them
• - if tubular - rotate some or all tubes away from sun

Best I have come up - which is not great I admit - is divert solar to stand alone towel rads zone - snag with that is you need a mixer / control to feed rads from primary heat source when not enough solar energy is present . May be OK to do this on a new build - may be impractical in retro fit

I just manually open the solenoid valve feeding back to the boiler when I am going on hoildays( with the boiler off) . That way if the water gets that hot that you need to dump it , it can travel back along the pipes to the boiler . It certainly didn't happen this year though

smooth operater

If in a semi d or a terrace you might divert it into your neighbour when your own cylinder has hit its max
Would only work on new builds though

sydthebeat

smooth operater wrote: »

If in a semi d or a terrace you might divert it into your neighbour when your own cylinder has hit its max
Would only work on new builds though

throws up huge mainanence and legal access issues though.....

fishfoodie

Deleted User wrote: »

Invest in a swimming pool

CJ's controller is the best option (for flat panels).

Na, Hot tub..

Nothing like stretching out in one at the end of a hard days work

Fingallion

what if you had a second thermostat mounted on your solar cylinder set to 65 or 70 degrees which would open the solenoid valve that feeds the cylinder from the boiler and in turn start the pump... This would exchange heat back into the boiler primary coil and around the system... I suppose that the problem would be that this would only be likely to happen summer only... tiz a shame to dump or not use your solar heat but what can you do? Probably a few holes in this idea, but you get the gyst.
It would be cheap and easy to do though. You would just have to make sure that the cylinder solenoid valve was not starting the boiler in this process.

SolarHome

CJ's suggestion is the best and cheapest option some controllers do not have a holiday function all Resol models from the BS4 up do carry this option. Its something that you should ask your installer about before the system is installed (that said your system should be capable of taking the extreme temperatures for short periods of time but if your controller carries the over heat option you might as well use it)

sculptor

What if you left the hot tap dripping when you went on hols, very environmentally unfriendly I know. I only just had the tubes installed so I haven't tried it out yet. And I presume the washing machine and greenhouse are plumbed in as well.

SolarHome

This could be done but it’s a bit extreme! I believe a bigger problem is when you have larger systems installed and a small number of people in the house this leads to over heating of the system over a more sustained period. The long term side effects for plates are the replacement of anti freeze more regularly and replacement of fibre washers on the system more frequently, tubes also have these problems as well as loss of efficiency of individual tubes over the medium term (medium term timeframe can vary depending on the make of the tube).
PS a high quality controller is very important with tubes to ensure that the flow rate is regulating correctly depending on temp difference between the tubes and the tank
Also make sure that the correct quality antifreeze is used with your tubes (I’ve been asked to install tubes for customers who have bought their own kits, this included the wrong antifreeze for tubes)

RKQ

SolarHome, what Anti-freeze do you recommend? (Can you PM me)
What mix ratio / strength?
Cheers

10-10-20

Connect the system up to a Sterling engine and use it to charge batteries...?

http://en.wikipedia.org/wiki/Stirling_engine

10-10-20

10-10-20 wrote: »

Connect the system up to a Sterling engine and use it to charge batteries...?

http://en.wikipedia.org/wiki/Stirling_engine

I had actually considered that idea, but the temperature difference and the need to cool the other end as well as the low power extracted goes against it.

But it will work!

I'm looking one step further, and investigating the idea of a wood/biomas burner with a stirling engine sat on top of it and using the (hot) water buffer tank as it's cooler to act as a CHP system.

10-10-20

A simple small bike radiator setup & fish-tank-pump should do it fine for the cooling I would expect, no?

10-10-20

10-10-20 wrote: »

A simple small bike radiator setup & fish-tank-pump should do it fine for the cooling I would expect, no?

Yes.

Could open up a whole new topic on renewable energy....

wazzoraybelle

my plan is to install 4m2 of evac. tubes next summer. I have slighly oversized the system so I can send a dump load to a radiator on the north wall of the house (inside of course). Last summer we didn't use our central heating for 4 months and while the temperatures were fine the humidity of the wet summer caused a lot of mould on the north wall. I'm hoping that by heating this area of the house every so often during the summer will eliminate the problem.

Were this not as problem I would use the excess heat to run a radiator in a shed I have to dry timber for the stove.

tippgaafan

I have a setting for max tank temperature on the controller. If this value is exceeded, it will turn the central heating circulation pump on and open the DHW zone valve. This way, excess heat is circulated around the central heating pipes including a towel rad in the bathroom. No heat is sent to any other radiators.

smooth operater

tippgaafan wrote: »

I have a setting for max tank temperature on the controller. If this value is exceeded, it will turn the central heating circulation pump on and open the DHW zone valve. This way, excess heat is circulated around the central heating pipes including a towel rad in the bathroom. No heat is sent to any other radiators.

That doesnt seem to make sense?
Howd's it serve the towel radiaotor only?

smooth operater

smooth operater wrote: »

That doesnt seem to make sense?
Howd's it serve the towel radiaotor only?

[assumption] he has thermostatic radiator valves fitted throught.[/assumption]

Can't see any other way for it to work....

smooth operater

Theres TRV's on every rad in the house, the hot water cylinder heats up to the max, the heating circuit pump comes on and absorbs the heat from the cylinder and only flows to the bathroom radiator as its the only room without the trv??

Interesting