CHE the economical way

[Anyfoot]

Hi

I've just spent half an hour joining and trying to post on an electrical forum, failed, need to post at least 10 posts about something I don't know anything about before starting a thread. Tried answering some ones post and it came up with some computer cobbledigoop. So falling short of throwing my computer through my window I came back here for some calm and sanity. deep breath.
I'm hoping there is an electrical expert amongst us.
Right, If I decided to heat an enclosure up with a number CHE's connected to thermostats controlled to 25/30degc. What would be the most economical. 150w CHE's or 250w CHE's.
I'm under the impression that when the 250w CHE kicks in at 25degc it will get to 30degc faster. So it will use more power but in a shorter time than the 150w CHE. This in theory means my torts would be at the ideal 30deg more often, rather than waiting for a 150w CHE to get there for a longer period.
Does anyone know what the formula is to work out the power consumption used in both scenarios.
Thank you

Craig

 

[jaizei]

Where would the thermostat probe be located? To compare the power usage, you need to know how long each would need to be on to reach the desired temperature.

Assuming that the 250 got to the desired temp faster, it would then turn off until the temperature dropped below the lower threshold. And then start again. Meaning it would be cycling faster/more often which could shorten the lifespan of the element.

Have you thought about proportional thermostats?

 

[WithLisa]

Theoretically it makes no difference in energy consumption, you just need a certain amount of energy to heat the enclosure. But depending on where you put the CHE and the thermostat the 150w might take a little less energy, because the warm air has more time to spread evenly.

The 150w will take longer to reach 30°, but that also means your torts have a longer time with 28 and 29° and a more constant temperature.

 

[Anyfoot]

Where would the thermostat probe be located? To compare the power usage, you need to know how long each would need to be on to reach the desired temperature.

Assuming that the 250 got to the desired temp faster, it would then turn off until the temperature dropped below the lower threshold. And then start again. Meaning it would be cycling faster/more often which could shorten the lifespan of the element.

Have you thought about proportional thermostats?

Hi Jaizei

The temperature drop from lets say 30 down to 25 I thought was dependent on how well the enclosure was insulated(and air mass). So the better I insulate it the longer it takes for the drop limit which means for that period of time (lets say 10 minutes) I am not using electricity. Then Its a case of what's the most economical to get back to 30deg. So for example to make the maths easy if a 150watt took 5mins and a 250watt took 3mins I am on par with both methods. But is it that simple?

The probes I thought need to be fairly close to each block of 2 or 3 CHE's. So I can create a gradient down the enclosure. This way I've a better chance of keeping a gradient. I wanted from 1 end of enclose to the other ideally to taper from 30/27 down to 25/22deg. over 7meters long. It will be 4 meter wide.
I'm thinking I would get more control over temp gradients with more lower wattage CHE's. for example taking it to the extreme 20x 100watts controlled would give you more control than 1 x 2000watts because you can space them out into each area.
I contacted some heating companies to find out what was the most economical way to heat a room up is using electricity, all they want to do is sell you what's to there benefit. I asked this question on electrical open website a few weeks ago and all that happened was a few electricians started arguing amongst themselves about how much power was needed to heat up a room. Which was not my question. The amount of power it takes to get the room heated in the first place is irrelevant, its power consumption it takes to maintain that will cost me going forward. Hope that made sense. lol

I'm not familiar with proportional thermostats, could you explain this to me please. I was thinking of day/night thermostats so I could simply set the night time temps to 3 to 5 deg lower.


If you or Withlisa have any better ideas I would greatly appreciate it.

 

[keepergale]

Proportional thermostats don't just shut off the heat at a set temperature.
In effect they lower the wattage at your set temperature to hold a very consistent temperature. A lot less up and down. Not really nessicary for our tortoises but good for our incubators. They are also more pricey.
I have no idea if they would use more or less electricity in regards to your original question.

 

[Anyfoot]

Proportional thermostats don't just shut off the heat at a set temperature.
In effect they lower the wattage at your set temperature to hold a very consistent temperature. A lot less up and down. Not really nessicary for our tortoises but good for our incubators. They are also more pricey.
I have no idea if they would use more or less electricity in regards to your original question.

Thanks keepergale. I now understand that. I use furnaces at work regular at about 1050deg c. Once they get to that temp after a wacking 45kw/hr usage they simply blip electricity pulses on and off to maintain that temp within a 1 deg tolerance. I think this is the exact same thing but on an industrial level. I left our furnace on over night once to test if it was cheaper to leave it on at weekends instead of turning it back on every Monday morning. There was a vast saving. Cost about £7 to leave on for every 24hrs. As oppose to cold upto 1050c over 4 hrs at 45kw/hr and loss of 4hrs of production. Just a little useless info that helps me relate to what you just said. lol

Thank you again

 

[Tidgy's Dad]

You came to Tortoise Forum for calm and sanity?
Questionable decision.

 

[Anyfoot]

You came to Tortoise Forum for calm and sanity?
Questionable decision.

Ha Ha Ha that's funny. Have you not yet realised it could be you that causes chaos and insanity. lol

 

[Tidgy's Dad]

Ha Ha Ha that's funny. Have you not yet realised it could be you that causes chaos and insanity. lol

Guilty as charged.
But I'm not alone.