7 votes
Accepted

Why are home geothermal systems usable anywhere in the U.S. but industrial geothermal plants limited in geographical use?

Because they're two completely different systems that have, in some circles, accidentally been given the same names. The things that are sometimes (particularly in the USA) called home geothermal ...
  • 3,701
5 votes

Where water goes in split air conditioner system in "dry" mode?

Split system air conditions (heat pumps) are refrigerator based systems. The two tubes you mention transport refrigerant from the compressor in the outdoor to unit to the indoor unit & return it ...
  • 9,527
4 votes

A humidifier before a heater and after a heater

warm air can hold more moisture than cold air so the amount of water you can suspend in the air will change depending on where you install the humidifier. Mounting the humidifier before the heater ...
  • 4,651
4 votes

Designing for a specific flowrate

Many commercial hot water recirculation pumps will do that. Just grabbed one at random - Grundfoss Alpha1 15 40 130. I couldn't fetch the page after I ran their calculator. I used temp of 99C and ...
  • 3,755
4 votes
Accepted

Does a house heating system affect perceived and true indoor air humidity?

Your last statement is basically correct: Another possible explanation is that the higher air temperature increases the air's water carrying capacity, which in the absence of an abundant water ...
  • 1,723
4 votes
Accepted

Question about flow temperature and storage temperature in a cogeneration plant

when the cogeneration plant switches of upon reaching 85°C flow and without another heat source, there's no way to reach 95°C. Are you sure the switch-off happens at 85°C flow, and not at 75°C return ...
  • 4,651
4 votes
Accepted

Do infrared heaters have a special blackbody radiation specturm?

The heater is often so hot that it glows red, so it also radiates some visible light. And with fine enough instruments one could also detect some emitted microwave noise. But the main part of the ...
3 votes

is it possible to achieve 1000C temperature in a cabin?

If the heating element is constantly at 100°C, there is no way it can cause the room can get warmer than 100°C. Otherwise, perpetual motion machines would be possible. If you meant the heating ...
  • 31
3 votes

What is the cost of heating of a 60k sqm building to 27 degrees celsius vs 20 degrees celsius?

This is a heat transfer problem You can get a first order estimate by considering only conductive heat transfer, neglecting radiative and convective. Simplifying it even more, (again we don't know ...
3 votes
Accepted

Storage losses of a heat storage tank

Heat loss due to conductivity of the walls of your container assuming the ambient outside temperature, $$ \frac{\Delta Q}{\Delta t*A}=-k \frac{\Delta T}{\Delta x} =C_{constant}$$ In the above ...
  • 21.2k
3 votes
Accepted

Heat transfer coefficient of a cylindrical hot water storage tank depending on its size

In a tank with no fluid movement and no heat source with steady ambient temperature, the temperature of fluid are layered strata roughly in onion layers but favoring the top of the tank, meaning the ...
  • 21.2k
3 votes
Accepted

Heating tape that has leads like picture below

When searching for 1100 watt heating tape, a number of returns match almost exactly the image you've provided. A few of the manufacturers provide NEMA separable molded plugs and also offer bare leads. ...
  • 6,427
3 votes
Accepted

Why materials with preferably a negative temperature coefficient for heating elements?

(I am putting this forward as a opinion to be validated by others more knowledgeable than myself). I am not certain that the resistance will have the effect the original OP expected. i.e. I assume ...
  • 22.9k
3 votes

Why materials with preferably a negative temperature coefficient for heating elements?

Hence, I wonder why one would preferably use materials with a negative temperature coefficient? Most metals will have a positive temperature coefficient. Platinum, for example, is commonly used as a ...
  • 8,834
3 votes

Why materials with preferably a negative temperature coefficient for heating elements?

It really depends. If you have multiple heating elements (or areas within a single element), in parallel, they will end up at slightly different temperatures. If the application is temperature limited,...
  • 1,367
3 votes
Accepted

Does it make sense to increase the thermal "dead weight" of a wood stove?

Several high performance houses with lots of insulation have been designed with wood stoves that are surrounded by lots of stone to give the thermal mass. Some are still giving out heat 24 hours after ...
  • 14.2k
2 votes

Is it a problem to have two heat sources controlled for different temperatures on the same heating circuit?

Your control logic appears to be sound. And with that logic, they could each be on separate simple thermostats if necessary. Just make sure all of your temperature sensors are sensing at the same ...
  • 7,499
2 votes
Accepted

Calculate efficiency of water heating

You are confusing units, which is making your question difficult to understand. Electrical energy is measured in kW-hours (or Joules), not kW. If your heater consumed 500 W of power for 610 s, then ...
  • 6,759
2 votes

When heating a house, does the water flow slowly decrease as the difference in temperatures approaches 0?

A hot water based central heating system is fed by a pump and the only signal from the thermostat is heat/don't heat. The temperature regulation is done by duty cycling the pump so that when the ...
2 votes

Hydraulic switch vs heat exchanger

Hydraulic separation in hydronic systems is generally more important with high flow resistance heat sources such as condensing boilers. If you don't hydraulically separate the heat source from the ...
  • 561
2 votes

At what (outside) temperatures is it efficient to run my windowbox heat pump?

Recently I reviewed the technical specifications for a number of heat pumps (reverse cycle air conditioners) with a view to recommending one for purchase. The lowest outside temperature for a heat ...
  • 9,527
2 votes

Control power to a tungsten filament?

We have a test rig that works something like this, to heat up small objects (typically cubes of material with sides a few mm long) to about 1000C fairly quickly. The heat source is a "tube" of ...
  • 12.5k
2 votes

Natural gas boiler Vs. Electric Heater efficiency

I answered a similar question on SE Sustainable Living recently. Before anyone (including yourself) can answer your question you need to supply some more information. The first thing you need to ...
  • 9,527
2 votes
Accepted

The air conditioner mechanism

An air conditioning system is basically a refrigerator, it passes air over a heat exchanger to cool it ie it injects cold air into a space, it doesn't 'suck' anything out'. The water which comes ...
  • 15.1k
2 votes
Accepted

Winding a wire heating element after a few uses

I have not used Kanthal, but I imagine it has similar properties to nicrome. Basically when you heat the wire up and cool it quickly, it quenches the wire. To reverse this process (or avoid it all ...
  • 7,499
2 votes

is it possible to achieve 1000C temperature in a cabin?

To answer the question the way it's asked heating element of sort which is providing 100°C constantly but because room is totally insulated and shut can the temperature goes upto 1000°C or not ? ...
  • 1,045
2 votes

Process fluid flow in a fired heater

It is just getting as much heat as possible. Heat flows from hot to cold. The convection section is a much lower temperature. The convection section is basically waste heat in flue gas. The cold ...
  • 479
2 votes

Why not drive an air source heat pump domestic heating system with an auto engine?

Automotive engines have their own inefficiencies. If the engine runs at its optimum speed, expect to convert ~30% of the energy in the fuel to motive power, 30% to heat in the cooling system and 30% ...
  • 736
2 votes

Will circulating air within a sealed ductwork system cause it to implode?

Would the pressures be the same with the fan On/Off? No. The pressure in front of the fan would be higher than that behind it - that is to say, the pressure would be highest at A, and then drop ...

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