Tom Jenkins
What you need is, I think, called optimized start/stop.
. You could replace the existing thermostat with another RTD and include night setback functions and so on as well.
. You could even use decreasing temperature trend in conjunction with the outside temperature to get a dead nuts pre-start.
… I think you can hae some fun and give the guy a system that works.
Sliver =>>The RTD is painted flat black. (talking ‘bout this bird house)
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Pierre =>> The bird house will act as a Dead Leg, like in heat tracing difficult pipe systems. Its cheap but works great.
Substitute 10 watt light bulb for the bird, and you have a single analog input that can be tweaked to give you a reasonable, if not elegant predictor of heating load.
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Pierre =>> The bird house is also a "Black body".
Peter Nachtwey
I think the situation can be made better but it can't really be fixed.
… your problem. The heat is NOT being removed radiated from the floor
…. You must find a way to remove the heat from the floor and get it into the rest of the house
… insulated the time constant of the floor may be on the order of hours instead of minutes.
First fix the heat exchanger problem
Pierre =>> Even his wife tought of that one. The design does not permit it.
...We have a problem like this in reverse where I work. When it gets really hot the air conditioner cools the air but the fan is not big enough to blow enough air over the cooling coils. Parts in the air condition unit start to freeze but that doesn't help get cool air to the working spaces. We need a bigger fan or bigger heat exchanger. So does your friend.
Pierre =>> I've done my fare share of systems like yours. Just to give you a hint. RELATIVE HUMIDITY. The fact that the coil freeze tells us that your fans are big enough. Push more water into this system and it will only freeze faster.
Bitmore =>> Peter brought up a good point, it seems the system is not sized wrong, just the method for BTU exchange.
Pierre =>> The fact of the mather is that it is perfectly sized. It was only installed in the wrong part of the globe
Elevmike =>> I don't think any amout of control can ever make up for a poorly designed mechanical system.
… With that in mind, I still see the problem as a delay in the rate of transfer from the heat source to the living space,
Pierre =>> We have tryed to increase the airflow but it was creating a disconfort to the people sitting under it.
Ricdel =>> I think I'd try putting a sensor right on the floor's surface.
Use the floor sensor to turn the heat in the basement on.
Pierre =>> We eventually will have something like this.
Rod =>> And I would set one ceiling fan to blow upwards and the second to blow downwards to add to the convection currents.
Pierre =>> This we did not try. Tanks.
So here it goes. I will soon install a "ACR Smart Reader Plus" 6 channel temp. recorder around his house. Its battery operated and will record a full month of variations.
In the mean time we will connect the BUH heaters to a small control panel with PLC and HMI. And yes Tom we will be having fun ... and MGD.
I will keep you posted on this one but the real cold weather is still a few months away.