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Hello hope all is fine Please, I have to realize a calculation for a Nitrogen cooler. Nonetheless I have available the sole properties of air. My question is: my I realize an approximation and consider nitrogen as dry air (that is , relative humidity = 0)? Many thanks

Hello there I am facing to following topic. Very specific, and old post can't help me, unfortunately. I am dealing with a cooling coil, and volumetric air flow at OUTLET is given to me. Known data are: - air inlet temperature - air inlet relative humidity - coil capacity It is a strange...

Hi there hope somebody could help me in following topic. Usually fan curves are provided @ 68F. In this case, with the system pressure curve, I can get a certain volumetric air flow. I am wondering if somebody could explain me what happens when ambient temperature changes. In a first...

Hi there, hope all is fine. Please I would have to calculate an heat exchanger in free cooling. This means that in this case there is no forced convection but only natural convection with one of the two fluids. The heat exchange is driven by the temperature difference. I suppose that...

Hi there, hope somebody could help me. I have found and red several old posts concerning pressure drop and friction factors. As a matter of fact, I am not able to find the difference between friction factors of following materials - copper - iron - carbon steel - stainless steel AISI 304 -...

Hello there I am dealing with a plate fin and tube heat exchanger. From classic thermodynamics I know that if the counterflow is perfect, I would have following equation Q = UA*LMTD In case of not perfect counterflow, I shall multiply for the F factor Q = UA*F*LMTD Let's consider a case...

Dear All, I am trying to find an equation to fit the data of oil viscosity properties. As I suppose many of you know, the main problem is due to the large excursion of values in function of temperature. I have found this interesting post thread391-287467. I have then tried to utilize the...

Hi there, hope everything is fine. Please, I would be grateful if somebody could help me in following topic. I have red following topic thread338-273391 but I am afraid it doesn't answer completely my question. Following is the topic: Ammonia is not corrosive for stainless steel without...

Hi there. please don't hate or kid me, but I am here to ask your help since I have received a more than odd question from a Customer. Following is the question. The subject is an air conditioning unit with an axial fan. My customer is asking me which is the maximum level of vibration the unit...

Hello there, I am currently designing a NH3 pump evaporator. I would have following questions. 1 - Which correlation may I utilize for calculating NH3 pressure drop ? 2 - Is there a suggested value for the pressure drop to keep ? Ex, is equivalent temperature loss similar to the one adopted...

Hi there apologizes for the banal question, but I am new to Matlab and unfortunately I have to require a kind, but quick help. I'd like to understand following topic. I have a main function in matlab, let's call it main.m Into this function there is a call to other functions, let call them...

Hi there, Hope somebody can help me in this topic. I have to calculate three different heat exchagers - put in bank in the air flow direction - to cool water coming from a glass furnace. Following is the topic: I have the fan curve of the producer given according to standard conditions, but...

Hello, I don't want to make you an odd question but I am facing to the concept of pump evaporator. I'd like to understand a little more concerning the way of working of the system. In detail, I would understand how to determine the enthalpic way to determine the capacity. I would suppose...

HI there I've searched in the past posts but with no specific answer. I am dealing with some AHU and I am facing to standard air. Please, is there anybody who knows the exact definition ? Is it referring to a specific density value ? Should it be the case, according to standard psychometric...

Hello there, I am focusing in a new design and I found a very strange issue: I have to dimension an heat exchanger. What really puzzles me is that not both inlet temperatures are provided, but one inlet temperature and the max value for the outlet temperature of hot fluid. Capacity is...

Hi there, wish you a great Year for everybody. Hope that somebody could clarify me following issue. When dealing with surface overdesing in an heat exchanger sizing, I understand as follows. If I suppose to have, x% overdesign, it means as follows: I will realize the calculation of the heat...

Hello there, hope somebody could help me since I am dealing with an issue not faced to the forum up to now, - according to a research I have made a search in past posts - Indeed the topic is quite crossing different forums. I hope to be correct posting it here. I have to design an heat...

Hi there ! This time I've got a odd question. Seems banal, but I can't work it out. Issue: A sealed tank is completely filled with water @ 72.5 PSI and a known outside temperature, (ex 77 F). The tank is not insulated with respect of outside temperature Let's suppose that, after one day...

Hi there, made a research on past posts but I haven't found this piece of information. Even in google I can find several correlations, but for plate heat exchanger This time I am searching for some suitable correlations for tube internal boiling in case of flooded systems. I am trying to...

Hello there, I'd need an help from you concerning pressure, volumes and time. I tried to find something in past post, but with poor success. Following is the issue. I have got a compressor, and I now that for increasing pressure of a volume of 50 l of air from 1 to 120 bar it takes 100...