Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [heat-exchanger]

89 questions
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Energy required to raise temperature of water flowing through a heater

I am trying to work out how much energy (ideally electrical heating) I need to put into a heater to raise the temperature of water from say 10 degrees C to 40 degrees C, if the water is flowing at 10 litres per hour. Assume that the heater is 80%…
Richard
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Can I use a pipe of any material other than copper in a counter-flow heat exchanger?

Why are copper pipes used in counter-flow heat exchangers? Could I enhance heat transfer by using a pipe made of any other material?
Ramnaresh Prajapati
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Radiators in series or parallel?

So let's say I have some heat generating machine be it a combustion engine or a fridge cooled by a fluid. I don't have a single radiator that is big enough for the amount of heat being generated but I do have a couple of smaller ones so I guess I…
Cathier
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6
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2 answers

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

To size a heat exchanger, I need to know (among other things) the Reynolds number (Re) as an indication of the flow conditions. The Re number depends on the viscosity. In a shear thinning fluid, I can't assume a constant viscosity, instead it will…
mart
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In a diesel engine, does more heat leave the engine through the tailpipe or the radiator?

Diesel exhaust is hot, and there's a lot of it. Diesel radiators also get pretty hot. In a typical diesel engine, which one is dissipating more heat? EDIT: In response to a request for specificity below, I am specifically interested in heat losses…
Diogenes Creosote
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4
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Viscosity of select species at atmospheric pressure for very large temperatures?

I'm dealing with hot combustion products flowing through heat exchangers and I'd like to perform some calculations regarding the flow properties (velocity, temperature, pressure and density) as it passes trough the heat exchanger. I've a 1D model…
André Almeida
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2 answers

Cooling system to maintain 0.5 °C at 95% humidity

I am looking for some guidance on a redneck cooling system. I need to store seeding trees at a temperature just above freezing, and at a humidity of close to saturation. I only need the system for about 2 months of the year. At present I use…
Sherwood Botsford
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Why Nusselt number for laminar flow in a pipe is independent of Reynolds number

I understand that for fully developed flow inside a tube (with constant properties), Nusselt number doesn’t change in axial direction but it is surprising that it is also independent of Reynolds number which means that the rate of heat transfer (for…
moeinSj
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Automotive Radiator Simulation

I'm developing a code to simulate thermal performance of automotive radiators. My results are 40% under-predicted. But when I multiply them to 1.6, they match completely. This is the graph that compares the results of program and experimental…
Naghi
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Furnace Combustion Air Properties

My house is heated by a condensing natural gas furnace that is rated as 92% efficient. It has the option to draw combustion air directly from outside. I know the main advantage of this is avoiding negative pressure within the house to reduce drafts.…
obligong36
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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 water always keeps recirculating. The system uses…
NoumanQ
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estimating the surface area of a steam coil immersed in a tank

I've been tasked to design a steam coil that will be immersed into a tank in order to maintain the fluid temperature above 25C (but not to exceed 40C), and I need to calculate its surface area & length. The fluid is a highly viscous oil additive and…
dnc123
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Heat exchanger design guidance

I need to design a water to air heat exchanger with a blower for a small greenhouse as an engineering project. There aren't much design specifications - only that it must maintain a temperature of between 15 and 25 degrees celsius during winter…
N. Burger
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Fluid allocation for shell and tube heat exchanger

I'm designing a shell and tube heat exchanger with a hydrocarbon stream (31.6% propane and 60.4% propylene) entering at 135F and 321psi, and leaving at 100F being cooled by water at 85F and 74.7 psi. As of now I have the hydrocarbon stream on tube…
user4785
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Optimizing return temperature in a brazed plate heat exchanger

I have a brazed plate heat exchanger similar to these. I can regulate flow and temperature of water on the primary side of the exchanger to achieve the desired temperature of water on secondary side. The desired temperature and flow on the secondary…
user2116182
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