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Attacking My Landlord's Boiler

blog.videah.net

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Re: Attacking My Landlord's Boiler

#91

Post by frereubu »

leoedin wrote: post #74
frereubu wrote: post #54

Earlier quoted context omitted.

I've read that it's always more efficient to turn heating off when you're not home and then turn it back on when you return. Is the reason for it being on 22-24 hours here that it takes a very long time to get back to the desired temperature, meaning you'd actually be cold for quite a while as it returned to the desired temperature?

The hidden factor here is that condensing boilers and heat pumps have non-linear efficiency vs flow temperature curves. Heat pumps in particular show high increase in coefficient of performance (CoP) as flow temperature drops. The other variable is how well controlled your heating is. A lower flow temperature means less overshoot of the target set point - and as losses scale linearly with temperature delta, that can…

Thanks for the explanation.

Re: Attacking My Landlord's Boiler

#92

Post by frereubu »

sokoloff wrote: post #60
frereubu wrote: post #54

Earlier quoted context omitted.

I've read that it's always more efficient to turn heating off when you're not home and then turn it back on when you return. Is the reason for it being on 22-24 hours here that it takes a very long time to get back to the desired temperature, meaning you'd actually be cold for quite a while as it returned to the desired temperature?

I work entirely remote so, other than travel, there are not many long periods when the house is unoccupied. I target the long run time to maximize efficiency. A 160°F pipe will lose more heat to the part of the building that I don’t want to heat as well as more heat to the wall right behind the radiators. It also results in the house going micro too-hot, too-cold, too-hot, too-cold as it cycles. Mine is constantly tr…

Thanks for the explanation.

Re: Attacking My Landlord's Boiler

#93

Post by paulkrush »

gcanyon wrote: post #90

It's an awesome hack! It seems like the easier hack would be to put a peltier heater/cooler under the thermostat then control that remotely to assume control over what temperature the thermostat sees. The link to the exact model of thermostat isn't working, so I don't know how amenable its design is to this approach, but the thermostats I've used are generally wall-mounted and putting a heat/cool source under them wo…

Cool idea! It's ironic that this is such an efficient use case for device that is so inefficient.

Re: Attacking My Landlord's Boiler

#94

Post by cameronh90 »

sz4kerto wrote: post #58

We've moved to an new apartment (house) and we had to do a full renovation. It doesn't have modern insulation and I calculated that for the time being the ROI on insulation isn't worth it. It's a multi-floor semi-detached house and I wanted the best comfort and the most economical heating possible. In particular: stable and individually adjustable temperatures for bedrooms and living rooms; underfloor heating in some…

Off the shelf systems aren't only optimised solely for efficiency. They're made to be simple enough that an installer with half a day's training can do a few multiplications and additions to set the parameters that'll give you a tolerable percentage of optimal in the situations that equipment is specified for -- while still being understandable by the next guy. This nearly always means things are a bit oversized and inefficient to account for the things that the simple models are missing.

Almost everything in engineering is like this, not just heating. It's pretty rare that something is fully optimised.

Re: Attacking My Landlord's Boiler

#96

Post by gwbas1c »

> The only thing I'm not happy with is needing to use a very powerful and versatile radio like the HackRF for something as simple as a boiler on/off switch. But I'd rather use something overkill and have it work than spend ages trying to force smaller radios to do my bidding.

All the apartments I lived in had basic thermostats; and I even rewired and replaced one of them.

What was blocking Videah from buying an off-the-shelf thermostat?

Re: Attacking My Landlord's Boiler

#97

Post by simooooo »

gwbas1c wrote: post #96

> The only thing I'm not happy with is needing to use a very powerful and versatile radio like the HackRF for something as simple as a boiler on/off switch. But I'd rather use something overkill and have it work than spend ages trying to force smaller radios to do my bidding. All the apartments I lived in had basic thermostats; and I even rewired and replaced one of them. What was blocking Videah from buying an off-t…

I’ve got a similar problem, and plan to replace the thermostat with a Shelly relay which can be toggled by home assistant’s events based on the TRVs in each room.

Then the boiler is basically controlled by the relay.

Re: Attacking My Landlord's Boiler

#98

Post by eru »

sokoloff wrote: post #60
frereubu wrote: post #54

Earlier quoted context omitted.

I've read that it's always more efficient to turn heating off when you're not home and then turn it back on when you return. Is the reason for it being on 22-24 hours here that it takes a very long time to get back to the desired temperature, meaning you'd actually be cold for quite a while as it returned to the desired temperature?

I work entirely remote so, other than travel, there are not many long periods when the house is unoccupied. I target the long run time to maximize efficiency. A 160°F pipe will lose more heat to the part of the building that I don’t want to heat as well as more heat to the wall right behind the radiators. It also results in the house going micro too-hot, too-cold, too-hot, too-cold as it cycles. Mine is constantly tr…

Btw, a heated blanket would be a lot more efficient, as it warms just your butt.

Re: Attacking My Landlord's Boiler

#99

Post by eru »

alistairSH wrote: post #40
vladms wrote: post #39

Earlier quoted context omitted.

I think in real life there are more constraints. For example there are people that sleep better at a lower temperature than the daily one (so leaving the thermostat at the same temperature it's a minus for them). Regarding "what is better" from energy efficiency, I would prefer a system that "check it" because my guess is that it depends a lot based on the individual situation. I mean everybody is going crazy over "I…

In slightly cooler climates, the answer for sleep is to open windows. This works in much of Europe, even through summer. But of course, not really feasible in Atlanta or Phoenix. Nighttime temps are too warm.

We are talking about places that need heating here.

In general, you should either run the heater or have your window open. Both at the same time is bad news for your energy bill.

Re: Attacking My Landlord's Boiler

#100

Post by eru »

sz4kerto wrote: post #61
wickedsight wrote: post #45

Earlier quoted context omitted.

> the theory being that warming up a cold house in the morning costs more energy than maintaining a stable temperature I've heard this theory a lot too, but it doesn't match with physics. A warm house loses more energy than a cold house, due to a higher temperature difference allowing easier heat transfer. So in most homes, with radiators and high temperature CV, it's way more efficient to just turn it off when you g…

It does match physics if you consider other factors. Apart from the heat pump scenario, this statement can also be true when you have condensing boilers (and okay-ish insulation) The reasoning: when you heat up the house, then your boiler needs to produce constant high-temperature water. When you keep the house at the same temperature, then the boiler produces much lower temp water and it is more efficient. Insulatio…

> The reasoning: when you heat up the house, then your boiler needs to produce constant high-temperature water. When you keep the house at the same temperature, then the boiler produces much lower temp water and it is more efficient.

How does your boiler produce heat for your water in your scenario?

> Therefore it is better to heat the whole house than heating just a couple of rooms because if you do the latter then you'll end up heating the whole house anyway but you're using less surface area (meaning you need higher flow temperatures, meaning less efficiency).

Just model the other rooms as very weird wall to the outside.

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