Storage heaters

[a1colly]

Hi all

The boss has put this in my lap today and not sure on the best approach.

An office building has storage heaters and as part of a carbon trust grant these need to have an occupancy sensor installed so that when the offices aren't in use the storage heaters do not activate. The units installed currently are Vent-Axia VASH12A. I have individual units in some rooms and up to 3 units in other rooms.

Personally I would have thought a 2 hour sensor (allowing for periods of inactivity within the room) would be best suited for something of this nature although I have personally never seen anything like this done before. Looking at the manufactures instructions for the units I can not see a way of wiring these to charge at off peak time and then function in the discharge of heat as and when required as standard but have thought about wiring into the neutral side of the controller on the unit to switch the supply as if the room was over temp.

Am I thinking logically at all or barking up the wrong tree? Any other suggestions or options?

Any help or ideas appreciated.

Thanks
Tony

 

[polo1]

Haven't given this much thought other than, if you use an occupancy sensor, the storage heaters are never going to work/charge, as presumably, the offices are empty at night, so the heaters would never charge???? Do the Carbon Trust not offer any advice on suitable controls to meet their requirements?
Also, heating is used when buildings are empty - we have this rather cold winter weather at times and try to avoid burst pipes!
No doubt somebody who deals with commercial controls will be along soon with some advice!

 

[7029 dave]

I would have an much simpler way, isolate then from the dp switch when not in use.

 

[SPARTYKUS]

Sounds like you have been handed a silly plan, as said above storage heaters 'operate' at night then slowly dribble heat out in the day, neither of those periods lend themselves to the use of an occupancy sensor.

 

[davesparks]

This has got to be a wind up!

Storage heaters on occupancy sensors? Why don't we put freezers on them too?

 

[Guest77]

Yes another thread which beggars belief.

 

[Plonker 3]

April the first was a long time ago.

 

[Silly Sausage]

Hi all

The boss has put this in my lap today and not sure on the best approach.

An office building has storage heaters and as part of a carbon trust grant these need to have an occupancy sensor installed so that when the offices aren't in use the storage heaters do not activate................

Is this some half baked idea from 'The Green bridgade'?
I've no idea how credible The Carbon Trust are.
I can think of a solution, which would be quite easy to implement, but I ain't typing it out on here!

 

[a1colly]

I wish guys, I've even got energy saving calcs provided by them and all they have stated is occupancy control for heating!

After a couple of pints of Stella my thinking is to use the internal wiring for over temp to cut the release of the heat. I have a wiring diagram which shows the neutral being switched, this would then allow them to still be charged over night and just control temp release during the day.

 

[Plonker 3]

How the hell does switching the neutral still "charge" the stored heat?

 

[Plonker 3]

Please post the wiring diagram you have so we can see please.

 

[davesparks]

Don't switch the neutral!

And of course the release of heat is controlled mechanically not electrically so whatever you do to the wiring won't help!

 

[7029 dave]

If they are on an contactor, maybe but otherwise NO.

 

[a1colly]

Sorry all when referring to switching the neutral I'm referring to the internal wiring of the unit and not the supply. I've attached a screen grab of the internal wiring which vent axia say would be the only way of doing it.

 

[SPARTYKUS]

Its all just a silly idea. Why would you want occupancy controlling a storage heaters length of time on, or even switching it on-off-on-off?

it just doesn't fit with storage heaters.

tell them they're muppets and their idea is cobblers. Tell them I said so.

 

[a1colly]

I wish, without putting myself in even more of a hot pot there's a 100k project built around all of this rubbish...led lighting and pv are well within my safe zone but this is a curve ball and one that it seems to all hinge on

 

[mache]

And of course the release of heat is controlled mechanically not electrically so whatever you do to the wiring won't help!

Agree with this post, I can only think that someone has got confused between storage and instantaneous systems because it makes no sense otherwise !! Unless some numbnut thinks they store electricity and not heat ?

 

[ImpededLoop]

Am I thinking logically at all or barking up the wrong tree? Any other suggestions or options?

Any help or ideas appreciated.

Thanks
Tony

I think you're barking up the wrong tree.

As others have said, you can only use a PIR for instantaneous heaters. Think about how the storage heater works... If nobody is in the office on a Sunday, the PIR won't trigger so they won't heat up for Monday.

You can get storage heater controls such as weather watchers and you could install a time clock / contactors to only charge the storage heaters 5 days a week.

Other than that, there's not much more you can do.

 

[davesparks]

Sorry all when referring to switching the neutral I'm referring to the internal wiring of the unit and not the supply. I've attached a screen grab of the internal wiring which vent axia say would be the only way of doing it.

You still don't switch the damned neutral, that's why the room and limit stats are in the live!

And all of that wiring is the off peak supply, which will only be live when the building is unoccupied and therefore the PIR will only switch on for its 5minutes startup sequence if it has one.

Isolating the heaters permanently will have the same effect and cost a lot less to do!

 

[egg67]

Think it can be done, all you have to do is have someone in room at night to make heaters work, if more than one room they will have to walk from one room to the next, then all heaters will heat up and then do wot they do as in let the storage heat out in the day to heat the room
Sorry for spelling mistake but had too much to drink and think this is a p''s take

 

[aesmith]

I think you're barking up the wrong tree.

As others have said, you can only use a PIR for instantaneous heaters. Think about how the storage heater works... If nobody is in the office on a Sunday, the PIR won't trigger so they won't heat up for Monday.

You can get storage heater controls such as weather watchers and you could install a time clock / contactors to only charge the storage heaters 5 days a week.

Other than that, there's not much more you can do.

We did controls for storage heaters for some Highland Regional Council buildings, they definitely had some active way of controlling heat output during occupancy but it's a long time ago so can't remember if this was via dampers or fans. They also had direct heating elements that would top up if the stored heat was exhausted. Your customer/consultant may have assumed that yours are similar. HRC did a lot of tuning of their storage heating systems, essentially trying to use the minimum charge they could get away with, since their tariff for direct heat was the same. This was back in the 80's before the bottom fell out of the energy saving market.

 

[gutterball]

maybe some sort of control that opens and closes the heat release flap?
has there been some confusion over the type of heating, perhaps you should confirm that you are talking about the same heaters as they are.

 

[a1colly]

maybe some sort of control that opens and closes the heat release flap?
has there been some confusion over the type of heating, perhaps you should confirm that you are talking about the same heaters as they are.

Firstly, thanks to all for making sense after a long day, the Green deal idiots thought that the storage heaters had boost options for daytime running and hence the occupancy sensor requirements. for my balls up of bleating on about switch neutrals, ill put that down to my good friend Stella.

Thanks for talking sense all :biggrin:

 

[ackbarthestar]

I think the occupancy control operates a secondary convector fan in each unit to circulate hot air when needed. It certainly makes no sense to control the heating elements to the storage bricks as they need to be hot, which takes time.