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Questions tagged [heating-systems]

126 questions
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Heating circuit: Galvanized steel with press fitting vs welded steel pipes

What are the downsides for galvanized steel pipes + press fittings vs. welded steel pipes in a heating application? Diameter would be DN25/1". Background: The customer specifies only steel, only welded connections for heating pipes starting at this…
mart
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Calculation of the stored energy for a heat storage tank

There is a heat storage tank that is directly loaded from the top and the heat is also taken from the top. The colder water from the heating circuit return flow enters the heat storage tank at the bottom. This creates a layered water temperature in…
Emma
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Is it a problem to have two heat sources controlled for different temperatures on the same heating circuit?

This is the situation - I have three heat sources, called CHP, burner 1 and burner 2 on the same circuit. All three feed to the same heating manifold, with various heat demands. Preferably I want to heat with the CHP; if that is not sufficient,…
mart
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What is the most common control method in Underfloor heating?

I am trying to research the common methods on an underfloor heating system that are available in the market. I know there are usually, On/Off control to control the flow of water into the pipe Outdoor reset control to control the supply water…
Tanay Rastogi
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Calculation of the specific CO2 emission of a cogeneration plant for the produced electricity

Suppose I have a cogeneration plant that runs on natural gas and produces heat and electricity. The heat effeicieny is $\eta_{th} = 0.4$ and the electricity efficiency is $\eta_{el} = 0.4$. The burning of natural gas produces 215 g/kWh of CO2. For…
Emma
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Heat transfer coefficient of a cylindrical hot water storage tank depending on its size

I have a simulation model of a cylindrical hot water storage tank. The heat loss is determined by the surface area and the heat transfer coefficient. A configuration of the storage tank with 900 liters was validated with a real scenario. Now I…
MerklT
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Controlling the temperature with high precision

I need to control the temperature with high precision, and for this task would be good a temperature controller with pt-100 sensor, something like this one PID Temperature Controller ITC-100. As I see that, it can be very simple: there is an input…
Antonio
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Heat pump driven by a Stirling engine that requires no external work

I was considering some theoretical limits on transferring heat from one system at to another to another. It is well known that if you have two systems at temperatures $T_1$ and $T_2$, respectively, with $T_2> T_1$ then you need to provide work to…
Count Iblis
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What surface temperature (rise) is required to (dis)qualify a combustion appliance from obtaining a "zero clearance to combustibles" rating?

How far must the surface temperature of a UL-listed combustion appliance rise to prohibit the manufacturer from specifying it for a zero clearance to combustibles installation? (I looked in UL 127 but was unable to find a straightforward answer…
ThreePhaseEel
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Analog PID controller - settings wrt $V_{err}$ - setpoint always higher than room temp

I designed from scratch an analog PID controller to mantain a temperature selected in the range of 60 to 80ºC with a room temp say = 20ºC. The "plant" is a simple 4R7 5 W resistor heated by a PWM-controlled current (100% to 0% range). For any given…
atferrari
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Winding a wire heating element after a few uses

I bought recently 10 meters of Kanthal A1 AWG18 wire, which is a type of heating element (FeCrAl alloy). I intend to make a coil out of it, but it's no use doing that right now, I need more of it for my project (electric furnace), have ordered more…
camurgo
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How to deal with thermal expansion in a city wide heating system?

How to deal with thermal expansion in a city wide heating system? Background: As part of the program to combat pollution in and around Beijing, my adopted city of Zhuozhou (population, over half million, about 90 minutes Southwest of central…
Astor Florida
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At what (outside) temperatures is it efficient to run my windowbox heat pump?

I am an electrical engineer that took two semesters of Thermodynamics about 4 decades ago. I am aware of the theory behind the Carnot cycle and such. I live in a condo in the Boston area that is all-electric (except for a fireplace I am not using…
robert bristow-johnson
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Yellow/Purple Flue gas in the stack

I was informed today by one of the on-site operators that they saw the colour of the stack flue gas change from colourless to a yellow/purple gas for a short period (~5mins) before returning back to colourless It's a heavy-fuel oil steam boiler…
SimpleJack
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Simulation of temperature in insulated box

I have a box outside that I want to insulate such that the temperature inside the box doesn't drop below 10°C given outside temperatures of (in the most extreme case - at night) -10°C. Inside the box I have a "heater" of 5 W. The box is in direct…
Daniel Jour
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