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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 commentary applies to the density argument: yes, but the effect is small. The fact that the outlet air is at 43 C represents the 8% efficiency loss of your furnace. ...


3

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, but there are a few things with respect to the RO that must be addressed. If you have sand in the feedwater to your RO, you have much bigger issues than heat ...


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you should look into district heating solutions. For your application the lengths are quite small so you probably can get away with using an air duct and a fan to push the air through. However, a better way is (probably optimal) to actually use a air/liquid heat pump which extracts the heat (cools down the air in one building), and heats up water which is ...


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If this is a student design problem to see whether you understand the principles, make it as easy as you can, use steam and cooling water. Calculating all the pressure drops on the weird pipe systems and valves you need when using one stream to cool/heat the others will drive you insane. Not to mention what it can do to your choice of materials of ...


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Photons either pass through a given material or they don't. If they pass through, it's as if the material isn't there as far as they're concerned (ignoring refraction). If they get absorbed, then they dump all their energy into the material. This might excite the incident atom such that it then re-emits the photon with the same or different wavelength, such ...


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Outside air is colder. Does this decrease the maximum temperature of the flames? Your furnace will always need air for combustion. This combustion air must ultimately come from the outside. Combustion air can either come directly from outside (say it's 30F outside) or it can leak into your house, go through the heater and be warmed up from 30F to 70F, and ...


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Cost is not usually the deciding factor. Usually we need to keep the fluids separate for a reason: one fluid needs treating the other doesn’t Or the systems are at different pressures Or the fluids need to be different due to later use.


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In order to calculate geothermal pumps, the best place to start is from ASHRAE Technical Committee 6.8. Having gone through the ropes myself, and since you already know the heating loads, I'll provide you with what is -in IMHO- a very useful shortcut. (Keep in mind that this should not be a substitute for a proper geothermal study following the guidelines ...


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You need to consult a phase diagram for nitrogen to answer this. Yes, it could be done, but nitrogen is a terrible refrigerant, and you'll have trouble finding somewhere to discharge heat to at the extreme low temps. https://www.engineeringtoolbox.com/nitrogen-d_1421.html shows the properties. In the graph, you want the area where pressure and temperature ...


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Background Total energy lost from fluid The heat transfer rate $\dot{Q} $ if you know for a pipe with fluid $f$ (where f: Red, Yellow, Blue) the temperature at input and output, the mass rate, and the heat capacity of the material is given by: $$\dot{Q}_f = \dot{m}_f\cdot C_{p,f}(T_{f,o}- T_{f,i}) $$ So for the Red-yellow pipe you have: $$\dot{Q}_{ry} = -\...


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Edit to add: The OP states the applicaiton is a heat pipe, so this answer assumed the yellow fluid is a liquid and moves by free convection. It turns out the yellow fluid will undergo a phase change, which changes a lot. This is an outline for a solution that should get you going: Step one - find an equation describing the convection of the yellow medium. $\...


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