9 votes

Energy required to raise temperature of water flowing through a heater

You just need to convert the volumetric flow rate to a mass flow rate by multiplying by its density. This is easy for water: $$10\ \mathrm{l/hr} \cdot 1\ \mathrm{kg/l} = 10\ \mathrm{kg/hr} = 10^4\ \...
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  • 6,749
8 votes

Can I use a pipe of any material other than copper in a counter-flow heat exchanger?

What we usually care about when selecting a material for a heat exchanger is its thermal conductivity. The higher the thermal conductivity, the easier it'll be to transfer heat between the two fluids. ...
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7 votes
Accepted

Radiators in series or parallel?

The efficiency of any radiator (heat exchanger) is a function of the temperature difference between the two fluids in question. All else being equal, a heat exchanger with a greater temperature ...
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  • 6,749
7 votes

Can I use a pipe of any material other than copper in a counter-flow heat exchanger?

If your question means, "for a given surface area and wall thickness, is there anything that performs better than Copper", then the answer is - "Unless you are prepared to make your ...
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7 votes
Accepted

In a diesel engine, does more heat leave the engine through the tailpipe or the radiator?

They are very nearly equal for typical four-stroke non-turbo diesels under load. A turbo diesel under load should have slightly more radiator loss than exhaust loss. At the bottom is a link to the ...
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  • 3,425
5 votes
Accepted

Furnace Combustion Air Properties

the outside air is colder, but the flame temperature is still much much hotter than that so the difference cold inlet air makes on the outlet temperature of the furnace will be small. The same ...
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4 votes

Heat Exchanger Design - finding necessary variables

I found the average of the inlet and outlet pressure and temperature in the hydrocarbon stream and then used those values in the ideal gas equation to find the densities of each hydrocarbon Why would ...
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  • 2,149
4 votes

Energy required to raise temperature of water flowing through a heater

$$P = \dot m \cdot C_p \cdot \Delta T $$ Where $P$ is the power required in Watts ($Joules/sec$) $\dot m$ is the mass flow rate ($kg/sec$) (you'll have to convert the volumetric flow given to a mass ...
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  • 2,135
4 votes

estimating the surface area of a steam coil immersed in a tank

One thing to consider is that pipes used for heating like this are normally « finned » to increase the surface area - fins can be small discs fitted to the pipe or even wire loops - both increase the ...
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  • 13.9k
3 votes

Energy required to raise temperature of water flowing through a heater

10 litres per hour 10 kg per hour 10,000 g per hour 166.66 g per minute 2.77 g per second Every second, you need to raise the temperature of 2.77 g of water by 30 °C. 2.77 g of water 4.18 J/g ...
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  • 131
3 votes
Accepted

Log Mean Temperature Difference of a Counterflow Heat Exchanger

$\triangle max$ and $\triangle min$ are not defined as maximum and minimum temperature differences in a heat exchanger. Quoting from Wikipedia: The LMTD is a logarithmic average of the temperature ...
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  • 2,149
3 votes

Most efficient heat exchanger for dirty air/water medium?

I'm going to have to make this an answer. If someone feels it's inappropriate I can delete it, what follows is the start of my comment. Grin, I bought my house with an outdoor wood stove, we have ...
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3 votes

Valve first,then heat exchanger OR heat exchanger first then valve

I think the key information is that the liquid is saturated. This means any reduction in pressure will lead to partial vaporization and two phase flow. For heat tranfer best overall heat transfer ...
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3 votes

why not put the compressor right next to the evaporator?

The evaporator is usually in the area to be cooled ie where the people work, read etc As the compressor takes space and tends to be noisy it is located away from that area. That makes the system in ...
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  • 13.9k
3 votes

What is the fouling effect (in rate, foulant thickness) of sand inside tube side of a shell and tube heat exchanger?

There is quite a bit to unpack here, so I may need to deconstruct your question a bit. Your question is surrounding the fouling rate of a Shell & Tube (S&T) heat exchanger which I will get to, ...
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3 votes

In a shell and tube heat exchanger, does reducing flowrate affect the outlet temperatures?

I assume you are referring to a exchanger like the following: If : the external dimensions of the heat exchanger remain the same. the tubing diameter remains the same. the number of tubes changes (...
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  • 22.6k
3 votes

Why does thermal conductivity of a pipe matter in a double pipe heat exchanger?

In the steady-state case you describe, the thermal conductivity determines how much heat (kW) a material will trasnmit per unit surface for a given temperature difference (K). In heat exchanger ...
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  • 4,618
3 votes

Cooling system to maintain 0.5 °C at 95% humidity

At near-freezing temperatures, the amount of water vapor in the air to get 95% relative humidity is tiny, this is no problem. I recommend filling 55 gallon poly drums on pallets with water, park them ...
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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 ...
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  • 13.9k
2 votes
Accepted

Most efficient heat exchanger for dirty air/water medium?

I can't speak from real (=hands on with my own hands) experience, but in industrial applications I see mostly shell and tube type HX. Exhaust is in the tubes, the shell has the water. Pros: lots of ...
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  • 4,618
2 votes

Optimizing return temperature in a brazed plate heat exchanger

As stated the problem is probably not well enough constrained. Given the specification, the way you get minimum temperature out is to pump as much volume as you can through the primary and then ...
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2 votes
Accepted

How to size a heat exchanger for a shear thinning fluid?

First, as Arthur notes, even the best Nusselt number correlations are often as much as 20% off, so don't expect any analytical method to give results that are much better than approximate. With that ...
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  • 1,167
2 votes

Can I use a pipe of any material other than copper in a counter-flow heat exchanger?

No, not any material. Only materials with a higher thermal conductivity than copper will increase the rate of heat transfer. In some cases, you may get better heat transfer by using a stronger ...
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  • 2,989
2 votes

Automotive Radiator Simulation

Either your definition of "completely" is a bit unusual, or there's something wrong with those charts, because in those charts, 1.6 x the model does not completely match any of the six observations ...
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  • 3,701
2 votes

Heat Exchanger Design - finding necessary variables

Between 135 F and 100 F I don't think the heat capacity or density would vary much so using average properties should be fine. If you want to be more conservative you can use the higher Cp between ...
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2 votes

Fluid allocation for shell and tube heat exchanger

This is a good start for your decision and you can probably get away with it however you should factor in everything that influences that decision. Cleaning Corrosion Fouling Temperature Viscosity ...
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  • 1,704
2 votes

Radiators in series or parallel?

Assumptions: "Radiator" means a forced-air air-to-fluid heat exchanger. Radiators in either setup will pull from their own fresh air source (not from the exhaust of another radiator). Ignoring ...
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  • 7,469
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 ...
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  • 479
2 votes

Modelling reactor jacket with or without insulation, how to proceed?

Full Analysis Perfectly Insulated System The best case is to analyze this system in both the time and position domains. The time domain considers the variation of the reactor temperature $T_r(t)$ ...
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2 votes

How to control precisely the wall temperature of a tubular reactor?

I've had this problem before, albeit not with such a tight temperature range. I would recommend immersing the reactor in a fluid with high thermal mass, then I would circulate and temperature control ...
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