Hello!
I hope it’s clear to everyone considering an answer that radiant heating is a different matter than heating intended to raise the overall room temperature.
Plan: Make a workshop shed usable in winter, which will be used occasionally and then spontaneously for just a few hours.
Problem: Not possible to heat the space, and a chimney is not an option, also not allowed from a building regulation / planning permission perspective.
Approach: Electric heating. Not as room heating, but as mentioned, large-area radiant heating. The room temperature can be as low as 10-15°C (50-59°F) or less. Possibly add solar air heating, but the roof is in an unfavorable position.
Advantages: Very fast response, affordable, simple.
My idea: Use an electric underfloor heating mat and convert a few square meters into radiant panels to hang overhead. I know the radiation angle isn’t ideal for me this way, but otherwise I don’t have enough surface area.
They have about 160 W/m (approximately 49 W/ft), which isn’t much, but the goal is just to prevent freezing.
If I make two strips of 0.5 x 4m (1.6 x 13 ft), that’s 640 W total, which would cost roughly 1 EUR for 6 hours of use. Just as a reference. I could increase the width a bit with an aluminum sheet as a carrier.
What I don’t know is whether this surface area and power output will be sufficient in the right order of magnitude? For now, I would skip any control system; it would be simple enough with a resistive load.
Does anyone have experience with this?
Best regards,
Dirk
I hope it’s clear to everyone considering an answer that radiant heating is a different matter than heating intended to raise the overall room temperature.
Plan: Make a workshop shed usable in winter, which will be used occasionally and then spontaneously for just a few hours.
Problem: Not possible to heat the space, and a chimney is not an option, also not allowed from a building regulation / planning permission perspective.
Approach: Electric heating. Not as room heating, but as mentioned, large-area radiant heating. The room temperature can be as low as 10-15°C (50-59°F) or less. Possibly add solar air heating, but the roof is in an unfavorable position.
Advantages: Very fast response, affordable, simple.
My idea: Use an electric underfloor heating mat and convert a few square meters into radiant panels to hang overhead. I know the radiation angle isn’t ideal for me this way, but otherwise I don’t have enough surface area.
They have about 160 W/m (approximately 49 W/ft), which isn’t much, but the goal is just to prevent freezing.
If I make two strips of 0.5 x 4m (1.6 x 13 ft), that’s 640 W total, which would cost roughly 1 EUR for 6 hours of use. Just as a reference. I could increase the width a bit with an aluminum sheet as a carrier.
What I don’t know is whether this surface area and power output will be sufficient in the right order of magnitude? For now, I would skip any control system; it would be simple enough with a resistive load.
Does anyone have experience with this?
Best regards,
Dirk
First test with a 150W/m² (14 W/sq ft) mat: underwhelming... it gets a little warm, but hardly any radiant heat can be felt. I’ll probably move the test piece soon to under my desk next to the exterior wall.
This kind of product only works well with properly insulated walls; it’s not enough as a radiant heater on its own.
There are also mats with 250W/m² (23 W/sq ft)... maybe those could achieve more.
Or I could run it on 400V, then the power increases by a factor of 1.7... so a maximum of 434W/m² (40 W/sq ft) would be possible, which is almost three times the tested value above. That should have some effect, but you’d likely have to dissipate the heat and securely bond the mat over its entire surface to prevent deformation. For example, sticking it to an aluminum plate with heat-resistant adhesive or similar.
I can already hear the objections, but stay calm: 400V is just electricity (ouch...). It’s all about the duty cycle and the actual temperature increase. The conductors just must not overheat, that’s all.
Any simple hairdryer would burn out in seconds if it weren’t for the strong airflow cooling the heating elements.
Best regards,
Dirk
This kind of product only works well with properly insulated walls; it’s not enough as a radiant heater on its own.
There are also mats with 250W/m² (23 W/sq ft)... maybe those could achieve more.
Or I could run it on 400V, then the power increases by a factor of 1.7... so a maximum of 434W/m² (40 W/sq ft) would be possible, which is almost three times the tested value above. That should have some effect, but you’d likely have to dissipate the heat and securely bond the mat over its entire surface to prevent deformation. For example, sticking it to an aluminum plate with heat-resistant adhesive or similar.
I can already hear the objections, but stay calm: 400V is just electricity (ouch...). It’s all about the duty cycle and the actual temperature increase. The conductors just must not overheat, that’s all.
Any simple hairdryer would burn out in seconds if it weren’t for the strong airflow cooling the heating elements.
Best regards,
Dirk
Dirk16 schrieb:
First test with a 150 W/m² mat: underwhelming... it gets a bit warm, but you can hardly call it radiant heat.Musketier schrieb:
The workshop probably needs more than 120 watts per square meter. ...... But with 650 watts for 35 m² (375 sq ft), I hardly think you'll even notice the heating.That was somehow to be expected
Dirk16 schrieb:
I can already hear the outcry, but calm down: 400 V is just electricity (ouch...). It’s all a matter of duty cycle and actual heating. The conductors just must not overheat, that’s all.
Any simple hairdryer would burn out within seconds if a strong airflow didn’t cool the heating coils.If your Horst wouldn’t keep obstructing, then the large power lines could be built to the south. Then you could certainly tap more than 400 V. You’d just need an extremely large fan so the small mats don’t overheat.
I feel like giving Horst a good kick where the sun never shines every time I see him… especially if Drehofer ends up routing the line over our house—you never know with that guy. But then I’ll just install a receiving coil under the roof and heat using the alternating field.
For a moment, I actually considered just putting modules on the roof to generate electricity for heating… well, I abandoned that idea after about 1.5 seconds because those things don’t produce any power at night or in bad weather, and anyway, it’s clearly uneconomical.
You learn by trying. Let’s see when I take the next step; for now, other priorities dominate.
For a moment, I actually considered just putting modules on the roof to generate electricity for heating… well, I abandoned that idea after about 1.5 seconds because those things don’t produce any power at night or in bad weather, and anyway, it’s clearly uneconomical.
You learn by trying. Let’s see when I take the next step; for now, other priorities dominate.
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