Could heating systems be improved with this idea?

[Roadyz]

Boiler stat will stop the boiler firing when it reaches temp (except that yours sounds to be faulty)

And when the room stat is satisfied it will tell the boiler to stop firing.

I don't see what the problem is that you are trying to invent a solution to.

JohnD, please bear in mind that I'm an electronics engineer not a plumbing engineer so I do expect to be corrected

I think you'd agree though that a satisfied room stat does not necessarily indicate that all rooms are satisfied. In an attempt to ensure this, it would seem to be necessary to identify the last room to reach it's desired comfort temperature before the stat is fitted in that room.

I would prefer to see a democracy where the vote of every TRV counts equally rather than be subject to the tyranny of a single dictator

you could have each rad on its own zone, but what would be the point in that,

 

[vexation]

To Vex!

Whilst its easy to have ideas, its very difficult to come up with ideas that have not been considered before and either developed or found to be of no or little advantage.

Amen. I've been in the innovation business for nigh-on 40 years and I do know my around a bit. I started this thread out of curiosity rather than any naive hope that I could revolutionise the heating industry. That's why I ended my OP by saying:

Perhaps I'm talking nonsense, perhaps this has already been done (where can I buy one?) or perhaps it will make me rich

My money was firmly on the first two possibilities - the later was a joke. The second possibility (that something better was already available) begs the question "where can I buy one?". There are several components to this question: I see nobody offering the householder anything better than what I've got (except on forums like this); having found it - it must make some sort of economic sense - and thanks to the knowledge on these forums I have found pointers to potential improvements.

You have been advised of a boiler which turns off if there is no flow round the system because all the TRVs have closed. Its not that wonderful because the pump has to be turned on every 5-10 minutes to see if any TRVs have opened since it last checked.

Simon had described a TRV which sends an RF signal to bring the boiler on when an individual TRV is open. Thats a very good system, at a cost, but sales managers in the UK think its too expensive and complicated for the UK market. In Germany there is a completely different attitude to life and they like expensive top of the range engineering and they are willing to pay for it. Here we prefer the cheapest option!

This is what makes it an interesting challenge. Although the cost of RF telemetry has dropped significantly, there is still big multiplication factor involved in the number of rooms over which it must be deployed. As it happens, I have a pile of class 1 Bluetooth transceivers that I could attach to temperature sensors to give an intelligent boiler lockout. One thing that puts me off is the upkeep of all the batteries. Even a change every other year is pain when there would be so many to do. For this reason some RF modules are now using kinetic power (e.g. a light switch that sends a signal using power harvested from the mechanical force on the switch).

Rather than have to deploy something in each room I was keen to explore the possibilities of a single point of contact with the system. A constant 10Watts costs about £10 per year - an amount I would gladly pay for not having to maintain electronics and batteries in every room - if for no other gains. If this sort of power was sufficient to determine the demand by testing the circulation, then it would seem like a reasonable solution to me.

 

[JohnD]

OOI, I haven't grasped the advantages

If I compare this to the method of using TRVs in every room except the one with the Room Stat, and having a modulating boiler and a modulating pump, what benefits would your proposal give me?

note: complexity is not a benefit

 

[vexation]

It's getting a bit complicated now! I guess the smart pump wouldn't work very well with an automatic bypass.

If you want it doing properly read what I write.

Sorry BigBurner, I could have made my reply clearer. I was very taken with the prospect of a "smart pump". Fixing on this, I was thinking about how it would fare if dropped into my existing system. The question then arises about a bypass - which you'd already addressed with the heat exchanger plate. That sounded a bit too radical although I do understand the benefits you have described.

 

[vexation]

OOI, I haven't grasped the advantages

If I compare this to the method of using TRVs in every room except the one with the Room Stat, and having a modulating boiler and a modulating pump, what benefits would your proposal give me?

note: complexity is not a benefit

Having global demand dictated by a local sensor is a non-optimal solution. The Honeywell distributed sensor system is an attempt to improve on this. Now that particular system, I agree, may introduce a level of complexity that outweighs its benefits.

If, on the other hand, all rooms can be made to have unhindered closed-loop temperature regulation (in the form of standard TRV's) - and global demand can be transduced from a single sensor with global access to the system's state - then I personally see this as offering a distinct advantage.

I really don't see why we should defend the "standard" solution when the principle behind it can be seen to be flawed. Apart from the principle of not relying on "dead reckoning" (aka careful balancing) I can see several instances where a single thermostat in a room with otherwise unregulated heat source(s) is not fit for determining boiler demand. An obvious one is solar radiation that can have a significant effect in this one "special room". In other rooms, conditions may change leading to heat loss through the opening of an outside door. Our "special room" knows nothing of these transient events in other areas of the house.[/i]

 

[BigBurner]

It's getting a bit complicated now! I guess the smart pump wouldn't work very well with an automatic bypass.

If you want it doing properly read what I write.

Sorry BigBurner, I could have made my reply clearer. I was very taken with the prospect of a "smart pump". Fixing on this, I was thinking about how it would fare if dropped into my existing system. The question then arises about a bypass - which you'd already addressed with the heat exchanger plate. That sounded a bit too radical although I do understand the benefits you have described.

You have a remote pump. Is it switched from the boiler? If so, it does have to be. The best is probably a Grundfos Alpha Smart pump. After an auto by-pass valve. You link to how you set it has been given. Then after the tee to the by-pass on the flow, a flow switch. The flow switch switches the burner (boiler) out using the room stat circuitry. The Smart pump is switched on and off by a remote time clock (not integral to the boiler).

Operation:
When all TRVs are open the Smart pump is at full revs and flow.
When the TRVs close up, it revs down.
When the TRVs are all off the flow switch cuts out the burner
The Smart pump opens the auto by-pass and circulation through the boiler. When a TRV opens the Smart pump detects a low pressure resistance and revs up.
The flow switch closes and brings in the burner.

Smart pumps use less electricity and are far quieter when TRVs are nearly all closed up.

Or:
Keep the fixed speed pump.
Insert a by-pass and have a 2-port zone valve in it. After the tee to the by-pass on the flow, install a flow switch. The flow switch switches the burner (boiler) out using the room stat circuitry. The pump is switched on and off by a remote time clock (not integral to the boiler).
You have a simple timer.
When the flow switch switches off it activates the timer that opens the zone valve for 2 to 5 minutes.. The end switch on the zone valve energises the pump too, if a pump over-run is needed.

Cost?
a timer, a cheap 2-port zone valve, flow switch and a TRV.

When all TRVs are closed the flow switch switches out the burner.
The timer operates and opens the zone valve
If the pump is switched via the boiler (needs pump over-run) leave it as it is.
If the pump is not switched via the boiler and by the time clock, also switch the pump via the z0ne valve end switch too.

With this you get fill flow through the zone valve to dissipate heat.

BTW, The plate heat exchanger is passive (no moving parts. It gives great protection to the boiler by isolating it from the system. I have done this when changing a boiler and the system is old with sludge in it - difficult to to get out.

 

[vexation]

You have a remote pump. Is it switched from the boiler? If so, it does have to be.

It is switched by the boiler which controls an over-run, but I think I can see how to modify your first suggestion to get around this...

The best is probably a Grundfos Alpha Smart pump. After an auto by-pass valve. You link to how you set it has been given. Then after the tee to the by-pass on the flow, a flow switch. The flow switch switches the burner (boiler) out using the room stat circuitry. The Smart pump is switched on and off by a remote time clock (not integral to the boiler).

Operation:
When all TRVs are open the Smart pump is at full revs and flow.
When the TRVs close up, it revs down.
When the TRVs are all off the flow switch cuts out the burner
The Smart pump opens the auto by-pass and circulation through the boiler. When a TRV opens the Smart pump detects a low pressure resistance and revs up.
The flow switch closes and brings in the burner.

With the above scheme the over-run is sort of provided by the pump running constantly on a timer - except for when the timer goes off. I could always get round this by timing-out the boiler a few minutes before the pump - which is what you've got in your second suggestion...

(BTW Why do you suggest the Grundfos Alpha Smart pump for this? It's an awful lot more expensive than the Wilo Smart Pump!)

Smart pumps use less electricity and are far quieter when TRVs are nearly all closed up.

I'm already sold on this!

Or:
Keep the fixed speed pump.
Insert a by-pass and have a 2-port zone valve in it. After the tee to the by-pass on the flow, install a flow switch. The flow switch switches the burner (boiler) out using the room stat circuitry. The pump is switched on and off by a remote time clock (not integral to the boiler).
You have a simple timer.
When the flow switch switches off it activates the timer that opens the zone valve for 2 to 5 minutes.. The end switch on the zone valve energises the pump too, if a pump over-run is needed.

Cost?
a timer, a cheap 2-port zone valve, flow switch and a TRV.

When all TRVs are closed the flow switch switches out the burner.
The timer operates and opens the zone valve
If the pump is switched via the boiler (needs pump over-run) leave it as it is.
If the pump is not switched via the boiler and by the time clock, also switch the pump via the z0ne valve end switch too.

With this you get fill flow through the zone valve to dissipate heat.

What makes this more suitable for a fixed-speed pump? I want to use a smart pump.

I understand that the main issues are the boiler over run, and bypass. You have provided some very useful suggestions that address these. With some external timing, a smart pump that slows down when flow is reduced (actually sounds a bit like magic to me ) coupled with an intelligent bypass might just do it!

 

[simond]

Sounds like you should have selected a boiler without pump over run. Like mine!

Whatever way you look at it, heat is being intentionally given up with an 'overrun boiler'.

Personally, I think a thermal store with some optimisation would be best. The store is run just below temp so that the overrun completes the job. It would really be down to a boiler manufacturer to design their unvented/thermal store software to intentionally capture the wasted heat.

For all I know, the Vaillant/Viessmann/Bosch gear marketed in Germany with their internal HW divertor valves already do this in software. Over here our antiquated G3 regs make the incorporation of such measures difficult.

 

[tabs]

I've got stats in each room on a 2-wire network linked to a manifold with actuators for each rad, all controlled by a tablet pc and bespoke written java progam.

 

[JohnD]

Whatever way you look at it, heat is being intentionally given up with an 'overrun boiler'.

On mine, the overrun transfers excess heat remaining in the boiler after it stops firing, into the radiators. It does not require a bypass.

Since the purpose of the heating system is to warm the house, I don't see this as a problem.

Mine has a lightweight stainless tube exchanger and low water content, and modulates down as it approaches temp, so far less heat than an old iron boiler would hold.

 

[BigBurner]

I understand that the main issues are the boiler over run, and bypass. You have provided some very useful suggestions that address these. With some external timing, a smart pump that slows down when flow is reduced (actually sounds a bit like magic to me ) coupled with an intelligent bypass might just do it!

Smart pumps are magic. They should be the norm. I would like one that I could by-pass the smart side and ramp up to full speed when needed.

OK. The boiler energises the pump. Make it a make it a Smart pump. When the flow switches off (no flow), after being "on", the timer kicks in and opens the zone valve by-pass. Set to say 5 minutes would ensure that the boiler kept the pump running to keep the boiler cool. Then it closes. If it closed just a little too early the pump would just wind down and no harm caused.

So,

Zone valve Have the pipes to the zone valve at 15mm
Smart pump
flow switch
TRV

 

[D_Hailsham]

On mine, the overrun transfers excess heat remaining in the boiler after it stops firing, into the radiators. It does not require a bypass.

So you don't have any motorized valves which shut the path to your rads when the room is up to temp?

 

[JohnD]

If CH was satisfied and HW was still calling, then yes, it would turn the valve to HW. Or vice versa.

the makers tech dept told me that, when both calls are satisfied, it stops firing, and leaves the pump on the timed overrun with the valves at whatever position they were previously at.

Next time there is a call for heat, it opens the valve to suit, starts the pump, then fires again.

I phoned them because I wanted to know why it did not need a bypass.

 

[BigBurner]

If CH was satisfied and HW was still calling, then yes, it would turn the valve to HW. Or vice versa.

the makers tech dept told me that, when both calls are satisfied, it stops firing, and leaves the pump on the timed overrun with the valves at whatever position they were previously at.

Next time there is a call for heat, it opens the valve to suit, starts the pump, then fires again.

I phoned them because I wanted to know why it did not need a bypass.

What boiler do you have?

 

[JohnD]

Vitodens 100 Compact