I'd like something that does a better job of the controlling the central heating than the "intelligent thermostats" that we have.
I think this may be to complex for the controllers I am currently working with and I can see potential problems with the fact that anything I made would not be CE approved and you would be plugging it into your mains...
But that doesn't mean that we cannot think abut the problem and come up with at least a theoretical solution.
But I am a little puzzled as to what you want other than to be able to come on earlier than it has been doing and to have a better boost facility.
Do you necessarily want the whole house brought up to temperature if you are going to be mainly in the office?
How about a system that first takes the chill off the house and properly warms the office, and then works on warming the rest of the house properly?
Re: Microcontrollers.But I am a little puzzled as to what you want other than to be able to come on earlier than it has been doing and to have a better boost facility.
Half a dozen years ago we replaced our, ageing, oil boiler with a log batch-boiler (logs rather than chip/pellet) and a decent sized accumulator. This isn't anything like as convenient as the type of boilers that a Corgi fitter bungs in, and which are well known and understood; some lifestyle changes are required, but I think it would help enormously to have some controllers that would accommodate what I want - unless the problem is ME rather than the kit?!!
Here's what we do / how I envisage the solution:
I put logs in boiler and light. It will burn for some hours (maybe as much as 8 ). Accumulator has capacity to store some, but not all, of the heat from the burn so I need to also dump heat into house Rads.
Depending on the weather I load the burner between 50% and 100%, and the accumulator might be as low as 40C (no point running the Rads when it falls below that, pumping lukewarm water around the circuit doesn't achieve much), or it might be up around 60C (above that and I don't need to light the boiler, its Autumn or Spring and mild, and a Burn will last two days at least.
The aim is to have the accumulator at 90C just as the fire goes out - that gives us maximum storage over night and thus heat for the following day, until the next Burn. If the accumulator gets past 90C the fir damps down, so we waste fire wood just smouldering away. Its a bit of a balancing act. (Chip/Pellet would be much easier in this regard, of course)
Our house has good thermal mass so (I think & have convinced myself) overheating the house, somewhat, just "charges" the thermal mass. In practice we only manage to over heat the house by a degree or so. We're happy if the house is 18C - 20C, and never get it much above 21C (short of deliberately firing the burner more often).
My wish list:
Input how big a fire I am lighting - 50%, 75%, 100%
Sense what the accumulator temperature is
Sense what the current house temperature is
Download?? what the weather will be - overnight MIN and morning temperature tomorrow
Option to set "Family at home" or "Entertaining" to force higher temperature
In fact better to do all that first and then controller can tell me how big a fire I should light That to be "predicted" based on historical performance.
So we heat the house from 3pm (lighting up time) until the fire goes out. Following morning there is a target temperature of 19C (not always reached by the set time, but 18C will do).
During the day if I, or others in the house, feel cold we sh/ould use the Boost button to bring the Rads on for, say, and hour. I think this is more efficient than just maintaining a set temperature by thermostat - probably something to do with numerous cycles, where the Rads cool inbetween, causing a large slug of cold water to be returned to the accumulator, when the pump first comes on, which probably disrupts the stratification of the heat in the tank. A longer burst of heating (I think ) increases the temperature of the overall mass of the building, and then the room temperature decays slowly over a period of time - when we feel cold again we can press Boost again. In practice, apart from Arctic Blasts, a boost once a day in late morning has generally been enough, and in Autumn / Spring it is not needed at all. There are also days in winter with strong sunshine where the solar gain is enough too, regardless of outdoor temperaature. Overcast / windy days require more heating.
If we aren't in the house, or are in a room that is warmer, then we delay pressing the Boost button, so we conserve more heat.
Sounds like a project for a Microchip dev board, some add-on sensors, and a C compiler
Does a bigger fire burn hotter or longer or both?
Does a bigger fire burn hotter or longer or both? |
I doubt it burns hotter, but there is a "getting going" period, which presumably makes a smaller fire less efficient, over all.
The boiler has a Laddomat blending valve, so adjusts the temperature of the water jacket as the fire heat increases; with the accumulator I expect that it is also able to provide "cool enough" water to be most efficient until the end of the burn when the accumulator is getting hot top-to-bottom.
Supposedly the boiler is 98% efficient, or somesuch. The gases are taken downwards and burn in a separate chamber - the spy-glass looks like a furnace
Bigger fire definitely burns longer.
What programmer is it?
It's a "Picstart Plus", but since posting I have found the software archive with the older versions so I should be able to get it to work...
Except the firmware is obsolete and the upgrade kit costs more than a new PicKit3.
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