# Questions tagged [heating-systems]

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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 ...
• 213
264 views

### 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 ...
• 4,781
238 views

### 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 ...
• 4,781
339 views

### 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 ...
• 197
543 views

### 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 ...
• 213
215 views

### 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 ...
342 views

### 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 ...
• 53
190 views

### 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 ...
• 143
261 views

### 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 ...
1k views

### 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, ...
• 141
122 views

### 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 ...
109 views

### 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-...
137 views

### A humidifier before a heater and after a heater

What is the difference between installing a humidifier before a heater and after a heater?
46 views

### Question about flow temperature and storage temperature in a cogeneration plant

Let's assume I have a cogeneration plant that produces heat with a nominal output. The heat is given into a heat storage tank, which is filled from above. The maximum flow temperature of the ...
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209 views

### 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-...
57 views

### How to periodically shut down a recirculating hot water solar thermal system

I am posed with a scenario where a hot water solar thermal system has been setup. The system comprises of a cold water tank, heating arrays and then a hot water tank. The system is closed loop and ...
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2k views

### 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 ...
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101 views

### Nickel Chromium Wire for high temperatures

I've been trying for months to find a way to heat moving air inside a tube to high temperatures. The closest to success I ever had was using an element from a heat gun. It would achieve the desired ...
• 205
88 views

### Is it better to heat a heat pump evaporator or the load directly?

I have a heat pump which moves heat from outside to inside. I also have a solar heating array that collects radiant heat from the sun. Given that my goal is to heat the inside (with minimal energy ...
• 133
54 views

### 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 ...
• 145
309 views

### What is the minimum height of a chimney needed in a camper?

Like a lot of people nowadays, I'm fitting a log fire into the back of a camper van but can't find the minimum height above the roof for the chimney. Ideally, it should be as low as possible for ...
• 171
119 views

### Why does a radiator valve require more torque after a few turns?

I'm automating a non-thermostatic household radiator valve, by replacing the knob with a DC motor and adding some support structure. You can see the system at work here: https://www.instagram.com/p/...
84 views

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

Geothermal systems are used in regions across the U.S. for home use, but industrial geothermal plants are only used in areas where subteranian temperatures are very high. Why is this? https://en....
2k views

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

In split air conditioners, there are two tubes connecting the indoor unit and the outdoor unit. According to the generic schematics I find online (like this one), they are part of the closed circuit ...
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164 views

### Why isn't heat pump used for heating for most case

Heat pump cost 2-4 times lesser of energy to heat than non-heat pump heater, then why are non-heat pump heater still very common ? (1) At home, boiler and water radiator is used. (2) For district ...
• 163
695 views

### Do infrared heaters have a special blackbody radiation specturm?

There are many infrared heaters on the market, that I would put in 3 categories, filament in quartz tube, filament in ceramic, and carbon film (for flat panel heaters). They all claim to be "...
654 views

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

Theses are my thoughts on the question. I can't find an answer to "why not?". It there something I am missing, or are auto manufacturers simply too focussed on cars only? The automotive industry has ...
• 121
158 views

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

Referring to the pasted in ductwork diagram, if an inline ventilation fan with a high CFM airflow was used to circulate air within a sealed ductwork system, would the fast moving airflow result in a ...
60 views

### Designing for a specific flowrate

I have a simple, practical engineering question. I'm trying to design a hot water circulation system with a constant flow rate of 1.3 L/min. I'm having trouble finding any pumps that will do the job ...
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### Storage losses of a heat storage tank

Suppose I have a heat generator with a connected heat storage tank. If the heat generator remains the same and the heat storage tank is dimensioned larger, the running time of the heat generator ...
• 197
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### Placement of supporting boiler in heating circuit

In my thesis, I deal with heating circuits, where several heat generators are present, e.g. a combined heat and power unit and a supporting boiler. Usually, the boiler is placed in front of the heat ...
• 197
700 views

### Hydraulic switch vs heat exchanger

In a heating circuit, there's two (known to me) ways to decouple primary flow (through heat source) and the secondary flows (to consumers): a hydraulic switch in the heating manifold complete ...
• 4,781
50 views

### Does a photon impart energy on a surface (to raise its temp) if it goes THROUGH that surface?

Hi so I have this senior design project involving cooling human skin as it is irradiated by an infrared LED. Human skin not only is super absorbent to IR, but that IR goes THROUGH the thickness of it ...
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42 views

### Comparing EPA emission limits between wood stoves and wood furnaces

Emission limits set by the EPA were updated in 2020. Currently, "Wood-burning stoves" are allowed 2.5 grams/hour of smoke emission [1]. On the other hand, "Wood-burning forced-air ...
• 121
74 views

### Heat loss calculation and Energy Balance

The image shows the CAD model of the annealing zone in a galvanization simulator. The zone is electrically heated with a AC current of 5597A at 2.09V. This whole zone is surrounded by insulating ...
431 views

### Best way to create separate heating zone for basement

I have 2 heating zone in the house: one for the upper floor and one for main and basement. Both zones split from the main duct into their own ducts and use a damper to close/open. Now I want to ...
• 121
50 views

### Increase in target emission rate (TER) when using a air source heat pump (ASHP) in standard assessment procedure (SAP) calculation

I am running a SAP calculation on a proposed building which will be utilising a 8.5 kW ASHP for space and water heating. I am also running a comparative analysis against a mains gas boiler to show the ...
24 views

### Alternative to heater cartridge for 10mm deep hole?

In a design for a heated block I am working on I only have the space for a 6mm X 10mm hole for my heating element to be inserted into. Originally I had planned to use a 40W heater cartridge but the ...
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1 vote
174 views

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

Does a house heating system affect indoor air humidity? Or to be more precise, does it affect your perception of how dry the air in the house feels (for instance dry is your mouth waking up)? (I ...
• 113
1 vote
62 views

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

It is general practice to put a bucket of water on top of a wood stove to keep air humidity under control during the burning of the stove. But, such a bucket is also bound to keep some more thermal ...
• 140
1 vote
272 views

### Layman's thermal storage device

I am a software engineer and have hobbyist understanding about electronics, so this is something completely out of my scope. Just need to understand if my idea of thermal storage is practical at all. ...
1 vote
1k views

### How can Geothermal heat a home using the ~55 degree heat source of underground to a more usual 72 degree inside temperature?

It has bugged me for a while. If the earth is a constant 50-60-odd degrees several tens of feet beneath ground, and houses (I assume; ours at least does) don't drop down to lower than those ...
• 111
1 vote
148 views

### Control power to a tungsten filament?

I'm afraid I'm completely out of my depth here. I would like to use a tungsten filament to radiatively heat something near to it (in vacuum). My issue is I cannot figure out the easiest and/or ...
• 126
1 vote
392 views

### Heat Exchanger Design (Log Mean Temp Difference or Epsilon NTU Method)

I am trying to design two heat exchanger interfaces (shell and tube) that transfers heat to and from an intermediate heat pipe. The picture below gives a general idea of the problem I am trying to ...
• 111
1 vote
172 views

### Are these oscillations normal in a boiler?

I recently helped upgrade an old (±20years) 4ton boiler (heavy fuel oil) with some monitoring instrumentation. I decided to have a look at the data and I'm not sure if these kind of oscillations are ...
• 145
1 vote
122 views

### Cheap low-temperature oven

I'd like to make an oven for curing adhesives that require an elevated temperature for a proper cure. I'd like for the temperature to be settable from 60 degrees C to 75 C plus or minus 5 degrees over ...
• 111
1 vote
71 views

### What is the efficiency of direct electric heating versus water heated via electricity?

I am attempting to keep plants warm in a greenhouse. Therefore, I assume that heating the soil should be most efficient, as that's what plants seem to care about the most (i.e. the temperature of the ...
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1 vote
116 views

### Why do heat pumps take more time to heat up a space than resistive heaters?

I was wondering why do heat pumps heat a place so slowly as compared to the resistive heaters? (This thought just came to my mind when upon ironing my shirt the iron became hot quickly which is a ...
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1 vote