Recent content by Sorade

I know the initial outer wall temperature yes. But eventually the cooling will reach the outer wall and then the outer wall's temperature is starting to drop. When that happens I need to figure out both the temperature drop of the outer wall, and the outflow temperature, as function of time...

Hi anorlunda, Thank you for your response. You are absolutely correct, and in my case the pipe is surrounded by perfect insulation...(in practice I actually have a network of pipes evenly spaced together, so half way between the pipes the heat transfer is equal but in opposite direction). Does...

Hi everyone, I'm trying to solve the following problem but can't quite get my head around it. I have a pipe of length, L (m), diameter, d (m), the pipe walls are thick (multiple meters). I know the inflow temperature of the pipe, say, Tin (K), and the pipe's external wall temperature, Tw. I...

Hello all, I am not sure my question will totally make sense for those of you who now this topic well but as I am new to it I hope I can be forgiven. My problem is to work out how much water will condensate as a stream of moist air is expanded through a turbine. So far I was using Antoine's...

Hello, I am currently trying to get my head around the concept of entropy. One way to understand it is that it can be related to the amount of available energy levels in a system. From what I read, the availability of energy levels in a system: 1) increase with an increase in the system...

Does anybody know if the efficiency listed for compressors include the energy losses due to the inter-coolers. For example say a one stage system with no cooling consumes 500 kJ/kg. and that one with two stages with an inter-cooler and an after cooler consumes 250 kJ/kg for compression + 100...

Thank you Nidum, Apologies if it sounds a bit academic, I'm not a mechanical or electrical engineer, so I had to start from scratch. Do you have any example of good starting points to look at maximum inlet pressures of gas turbines ? I am looking at a system where the compression of the gas is...

Thanks. I suspected it would be okay with high temperatures, but I wasn't sure that the high pressure wouldn't counter act that. Nidium, I am not sure I used the correct outlet temperature, it is not needed for the equation and I usually work it out separately once I worked out the amount of...

Hi all, I need to estimate the mechanical work I can recover from expanding hot air through a gas turbine. So far I am using the equation below, where Wrev is my ideal isentropic work, s the number of stages, n = k = ratio of specific heats, R gas constant, T1 is the inlet Temperature, Pin the...

But isn't that conversion of electrical energy to chemical energy (in a battery) rather than storing electricity itself ?

I am working on "electrical energy" storage and I want to know why exactly can't we store "electricity" from a power plant. My understanding is that "electrical energy" storage actually refers to the conversion of electricity to other forms of potential energy (such as mechanical eg: dam, or...

Hi all, I am looking at a air compressor train design which looks like this: I know how to work the compressor work needed for a two stage compressor, and hence how much work I can save using 2 instead of 1 stage. The question I have is: How much energy does it require to operate an...

Hello, I am currently looking at a way to calculate brine density using temperature, pressure and salinity. I found the following page which describes the change in fluid density with pressure and temperature : http://www.engineeringtoolbox.com/fluid-density-temperature-pressure-d_309.html...

@Ketch22 as @Rx7man says, the air is pre-compressed (say at night time) and then, re-heated by adding gas and combusting the mixture, before being expanded. I do agree that me using the term "gas turbine" is misleading, since usually the compressor is part of it. I guess you could see it as...

Thank you both for your replies. @Ketch22 , so do you suggest adding a compressor just before the turbine ? Wouldn't that defeat the purpose of decoupling the air compression and expansion ? At the moment I have ~100% of my power output which can be sent to the grid ... if I was to add a...