heat pipe good or not???

[moideen]

the wrap around heat pipe, as per the catalogued claim it will reheat and reduce the capacity or rows of cooling coil. I have not checked this in field. Have anybody real field experience on this? Has it claimed potential power to do that job?

 

[IRstuff]

datasheet?

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[chicopee]

Could you list the manufacturer and its catalog.

 

[moideen]

i will post the data sheet later, but what is your opinions about heat pipe technology?? some says that it is just a snake oil.

 

[IRstuff]

If you are talking about a heat pipe as in a sealed liquid heat transfer device, they'd better work, since they're in a huge number of computers, satellites, etc.

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[moideen]

IRstuff: i cannot catch your mind. what you intended sir

 

[MintJulep]

Snake oil should be ok as the working fluid.

But a mix of water and glycol is more common.

 

[LittleInch]

Is this what you mean?

https://en.m.wikipedia.org/wiki/Heat_pipe

As it says the it's a heart conduction device but only works within a certain range and needs cooling at one end and some sort of circulation.

Works when the hot surface boils the liquid which then condensest at the Cold end

So like a lot of things, used properly it works. Used badly it won't.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IRstuff]

A conventional heat pipe essentially operates by evaporating fluid at one end and condensing at the other, as shown in the LI's Wiki cite. We've used heat pipes very successfully in highly packed processor boards; no heat pipe, processor overheats, with heat pipe processor is hot, but functioning.

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[moideen]

Why I concerned on performance of heat pipe that my builing’s FAHU, some FAHU are above 230 ton, in our buildings most of which equipped with heat pipe. The cooling coil are trapped with heat pipe and is very difficult to service the coil. The annual maintenance contractors were reluctant to service the unit because of the difficult to remove the heat pipe which rivetted around the coil and very congested between the walls. But all buildings are experiencing serious fresh air issues and humidity, so we decided to remove the heat pipes, some cut the pipe and some removed from the housing. Some FAHU was totally dismantled and took out the coil. It was totally blocked the coil. Now some local contractors proposed heat pipes of easy removal type and they submitted the data sheet. The manufacturer mainly claimed that the heat pipe will reduce the rows, in design, of cooling coil and will maintain relative humidity. So, I put in psychometric, I found very small changes in humidity content 0.1 g/kg only. this same digit is aligning with other manufactures also when comparing.

 

[moideen]

please look at the yeloow color column,

 

[SAK9]

I am assuming you use heatpipes so that you can precool the fresh air coming into the FAHU and once the air is cooled and dehumidified reheat it to required room temperature.If you decide not to reheat the air there are better energy systems out there such as a plate heat exchanger or energy recovery wheels that work far more efficiently than a heat pipe

 

[IRstuff]

If you're referring to something like

https://www.1-act.com/hvac/products/

there seems to be SOME hyperbole. While a heat pipe could be ostensibly better than solid copper; it's unlikely to be "thousands" of times, and it probably doesn't work that well over extremely long distances as the pictures sort of imply. Moreover, horizontal heat pipes are further limited in performance, since most heat pipes depend on gravity to get the internal convection to work correctly.

Nevertheless, someone intimately familiar with the operating values for a heat pipe would need to do a detailed analysis.

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[moideen]

SAK9: already FAHU has energy recovery wheel, it does amazing job.

 

[moideen]

IRstuff: the above psychometric value was accounted from the selection sheet which manufacture provided me. it clearly shows 0.1g/kg moisture content removed by heat pipe. but relative humidity changed to 94% to 70%. apart these passive benefit(i have not conducted any field test to prove the performance)what the benefit of heat pipe especially is in FAHU operation.

 

[SAK9]

Moideen,

It is clear from your table that heat pipe's primary function is to reheat the air not to dehumidify.Without the heat pipe you would have required a few hundred kw of electrical reheat to heat it from 14C to 22C.

However if this is an office or retail space I would question the need for the reheat as supplying air at 14C into the space will take a substantial burden off your cooling AHUs/FCUs or whaterver you are using to handle the room load

 

[moideen]

SAK9: you raised same thought what i was thinking that the reheat will be helpful if the application is 100% fresh air, but these FAHUS are supplied the air to terminal unit.then the fresh air mixing with return air from conditioned space and treated back to the room. the terminal unit's design is based to maintain comfort RH level at conditioned area.

 

[moideen]

i am not against heat pipe, it may work well in electronic ,computers,satellite etc.also consider the two side pressure loss impacts on sizing the fan. added static will increase the size of ahu fan.anyway, i am planning to make a field test to know actual performance...thank you