How to DESIGN and ANALYSE a refrigeration system
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Date: 2023-11-17
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Comments and reviews: 30
vrich
I want to ask something. I am repairing refrigerators for some time now, but I didn't solve this problem I encounter sometimes. After I recoil the evaporator of the refrigerator, I test the unit and it works fine, the pressure on both sides are normal. after 5-15 minutes the pressure in the low side begins to drop to negative and also in the high side lower to about 120 psi. I turn it off and the pressures take some time to normalize. Sometime, I just change the filter drier to solve the problem, but sometimes the problem continues even I change the filter drier. what causes the pressure to drop?
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I want to ask something. I am repairing refrigerators for some time now, but I didn't solve this problem I encounter sometimes. After I recoil the evaporator of the refrigerator, I test the unit and it works fine, the pressure on both sides are normal. after 5-15 minutes the pressure in the low side begins to drop to negative and also in the high side lower to about 120 psi. I turn it off and the pressures take some time to normalize. Sometime, I just change the filter drier to solve the problem, but sometimes the problem continues even I change the filter drier. what causes the pressure to drop?
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intellectual
I have a question please,
In our country we get ambient temperatures that reach 55 centigrade and the air temperature over the asphalt can reach 60 and inside the car if you increase the fan speed you will not get any cold air in the cabin. We use R134A refrigerant in our ac system. I was wondering if the gas will not condensate at these ambient temperatures. ? Can you help please.
Thanks a lot.
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I have a question please,
In our country we get ambient temperatures that reach 55 centigrade and the air temperature over the asphalt can reach 60 and inside the car if you increase the fan speed you will not get any cold air in the cabin. We use R134A refrigerant in our ac system. I was wondering if the gas will not condensate at these ambient temperatures. ? Can you help please.
Thanks a lot.
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movax20h
Is it possible that the exit of the evaporator (1, is further than saturation line (x=1? I. e. I understand it would create pressure extra at 1, higher than at 4, but is it possible in practice (with sufficiently thin pipes or something)
I also heard of some systems that operate above the critical pressure, could you cover these systems in separate video?
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Is it possible that the exit of the evaporator (1, is further than saturation line (x=1? I. e. I understand it would create pressure extra at 1, higher than at 4, but is it possible in practice (with sufficiently thin pipes or something)
I also heard of some systems that operate above the critical pressure, could you cover these systems in separate video?
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Gary
Fantastic video but there seems to be an error. The gas flow rate of 3kg/s is far to high for the picture in the video. Data sheets normally give this as kg/h. So I assume your data sheet said 180kg/h and you only converted to minutes instead of seconds, giving extreme kW values. The compressor looks more like a 1. 3kW rather than an 82kW. (i. e. 82/60)
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Fantastic video but there seems to be an error. The gas flow rate of 3kg/s is far to high for the picture in the video. Data sheets normally give this as kg/h. So I assume your data sheet said 180kg/h and you only converted to minutes instead of seconds, giving extreme kW values. The compressor looks more like a 1. 3kW rather than an 82kW. (i. e. 82/60)
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3D
Just wanted to ask, I am using a different table and chart that comes from a book, which has quite different values than yours. When I read the preface, it says the tables and chart are based on a 0 C where values of hf = 200 kj/kg and Sf = 1 kj/kg K. Is there a correction that I should do to get the same values that you get if I use my book. Thank you.
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Just wanted to ask, I am using a different table and chart that comes from a book, which has quite different values than yours. When I read the preface, it says the tables and chart are based on a 0 C where values of hf = 200 kj/kg and Sf = 1 kj/kg K. Is there a correction that I should do to get the same values that you get if I use my book. Thank you.
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movax20h
Just a minor correction, in your slides and in tables you use, the Enthalpy and Entropy, should be labelled Specific enthalpy and Specific entropy. Sure, it is a sortcut, but still, it is nice to be more. specific: ) Distinction is useful when then anlyzing enthalpy and mass flow and work required. Also thanks god you are using metric units.
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Just a minor correction, in your slides and in tables you use, the Enthalpy and Entropy, should be labelled Specific enthalpy and Specific entropy. Sure, it is a sortcut, but still, it is nice to be more. specific: ) Distinction is useful when then anlyzing enthalpy and mass flow and work required. Also thanks god you are using metric units.
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Artur
Question: How do you know the pressure required for the low and high side? Is it just the pressures the compressor can generate and need for the suction side?
Also, if that's given or you find out, how do you know the mass needed in your system just use the ideal gas law at that point?
Anyone can answer, I'm just curious
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Question: How do you know the pressure required for the low and high side? Is it just the pressures the compressor can generate and need for the suction side?
Also, if that's given or you find out, how do you know the mass needed in your system just use the ideal gas law at that point?
Anyone can answer, I'm just curious
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bevara
Sir, I think according to consumer cooling load we select the evaporator to reject the heat load developed by system, in that video evaporator rejected heat load is around 408kw and compressor needs 85kw(work done on the compressor) to generate the that much capacity, what is refrigeration capacity of that compressor
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Sir, I think according to consumer cooling load we select the evaporator to reject the heat load developed by system, in that video evaporator rejected heat load is around 408kw and compressor needs 85kw(work done on the compressor) to generate the that much capacity, what is refrigeration capacity of that compressor
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u2ooberboober
Amazing! I wish to make a static evaporator for a room to produce freezing temps without air movement. How could I use this info to design the custom evaporator while utilizing a premanufactured condensing unit amd known refrigerant?
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Amazing! I wish to make a static evaporator for a room to produce freezing temps without air movement. How could I use this info to design the custom evaporator while utilizing a premanufactured condensing unit amd known refrigerant?
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Ercment
Hi Paul. Thank you so much for your videos. I'm learning a lot from your videos because I'm new at cooling world. Do you want to make a video about Pump Down Cycle of a chiller? If you do, I would be grateful to you. Best regards.
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Hi Paul. Thank you so much for your videos. I'm learning a lot from your videos because I'm new at cooling world. Do you want to make a video about Pump Down Cycle of a chiller? If you do, I would be grateful to you. Best regards.
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Babur
Thank you for this useful video, I thoroughly enjoyed watching it. There is a one thing though: on the evaporator load: it's written as m(h1-h4) but calculated as m(h1-h3. I presume is the latter. Am I correct?
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Thank you for this useful video, I thoroughly enjoyed watching it. There is a one thing though: on the evaporator load: it's written as m(h1-h4) but calculated as m(h1-h3. I presume is the latter. Am I correct?
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Kamal
If we have a cooling load then how do we start the design of the Refrigerator? Also, how to fix the evaporator pressure if we are designing a system to cool at around -70 to -80 degrees celcius?
Thank You!
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If we have a cooling load then how do we start the design of the Refrigerator? Also, how to fix the evaporator pressure if we are designing a system to cool at around -70 to -80 degrees celcius?
Thank You!
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abhinav
Hey Paul, thanks a lot for all your videos they are very resourceful. Can you please make a video for the safety devices installed in the chiller as it is a necessary devices to save chiller.
Thanks.
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Hey Paul, thanks a lot for all your videos they are very resourceful. Can you please make a video for the safety devices installed in the chiller as it is a necessary devices to save chiller.
Thanks.
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Vclav
Thank you for this video. May i ask you? How is possible to calculate dimension (ID and lenght) of capillary tube? .when I use very stron vent on condenser, how can I calculate its effect on the system?
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Thank you for this video. May i ask you? How is possible to calculate dimension (ID and lenght) of capillary tube? .when I use very stron vent on condenser, how can I calculate its effect on the system?
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Bucur
Hello, those video are great, i've learn alots of intresthing things. Can u do a video about refrigertant quantity For example: i have a condensing unit X and one evaporator N length of pipes please.
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Hello, those video are great, i've learn alots of intresthing things. Can u do a video about refrigertant quantity For example: i have a condensing unit X and one evaporator N length of pipes please.
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anant
How can the temperature at state 1 and state 4 be the same(Even in an ideal scenario)
The refrigerant after leaving the evaporator will absorb heat and there will be a rise in it's temperature.
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How can the temperature at state 1 and state 4 be the same(Even in an ideal scenario)
The refrigerant after leaving the evaporator will absorb heat and there will be a rise in it's temperature.
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Rajh
I want to build a deep freezer from scratch, what kind of expansion valve do I need using your calculation? Like what should I look for in data charts of expansion valve after doing calculations?
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I want to build a deep freezer from scratch, what kind of expansion valve do I need using your calculation? Like what should I look for in data charts of expansion valve after doing calculations?
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Honest
We can make industries but the citizens, politicians and bureaucrats are utterly corrupted in Bangladesh. So I don't dare to make and to run the business on it. Thanks from Bangladesh.
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We can make industries but the citizens, politicians and bureaucrats are utterly corrupted in Bangladesh. So I don't dare to make and to run the business on it. Thanks from Bangladesh.
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FoTeLulz
Hello, I'm looking to design my own small scale refrigeration system for educational purposes, and was wondering if there is a specific type of compressor recommended? Thanks!
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Hello, I'm looking to design my own small scale refrigeration system for educational purposes, and was wondering if there is a specific type of compressor recommended? Thanks!
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mohd
hey paul i have watched your all videos thanks for the great knowledge man.
can u suggest me any book so that i can understand steb by step about hvac and get more knowledge
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hey paul i have watched your all videos thanks for the great knowledge man.
can u suggest me any book so that i can understand steb by step about hvac and get more knowledge
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волков
The best video I've seen so far. My question is: For other gas like propane, methane and Neon? Where should I look? Tank you, I will definitely watch your other videos
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The best video I've seen so far. My question is: For other gas like propane, methane and Neon? Where should I look? Tank you, I will definitely watch your other videos
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Carlo
I am using a software and it shows hf = 200 kj/kg, hg = 400kj/kg and Sf = 1 kj/kg K, Sg = 1. 72 kj/kg. The table that you have does not match with software for U, H and S.
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I am using a software and it shows hf = 200 kj/kg, hg = 400kj/kg and Sf = 1 kj/kg K, Sg = 1. 72 kj/kg. The table that you have does not match with software for U, H and S.
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Rahul
how to design according to the application?
For example I want to design 50 ltr water cooler which cools water from 20 degree Celsius to 10 degree Celsius.
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how to design according to the application?
For example I want to design 50 ltr water cooler which cools water from 20 degree Celsius to 10 degree Celsius.
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Sam
This might be not so smart question, but may I know what chemical modelling is usually used for the saturation table? What I mean, is it Peng-Robinson, or etc?
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This might be not so smart question, but may I know what chemical modelling is usually used for the saturation table? What I mean, is it Peng-Robinson, or etc?
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education
compressor on the video shows m: 3kg/s and not 7kg/s as you mentioned. I can't find any compressor that show's its mass flow rate specifications.
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compressor on the video shows m: 3kg/s and not 7kg/s as you mentioned. I can't find any compressor that show's its mass flow rate specifications.
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education
12: 30 How can the temperature at state 4 (refrigerant entering the evaporator) equal temperature at state 1 (refrigerant exiting the evaporator?
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12: 30 How can the temperature at state 4 (refrigerant entering the evaporator) equal temperature at state 1 (refrigerant exiting the evaporator?
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elham
thanks for your video and useful information. how can we design a refrigeration system according to the heat that we want to rejected from building?
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thanks for your video and useful information. how can we design a refrigeration system according to the heat that we want to rejected from building?
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Jorge
137/5000
Hello Paul. Your videos are great. I'm just curious to know in which part of the system is located the plate heat exchanger? Thank you.
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137/5000
Hello Paul. Your videos are great. I'm just curious to know in which part of the system is located the plate heat exchanger? Thank you.
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Mahmoud
thank u so much for ur efforts but can u please upload how to calculate refregiation system using out and TEC peltier with water cooled system
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thank u so much for ur efforts but can u please upload how to calculate refregiation system using out and TEC peltier with water cooled system
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Johnny
Can someone help me out with entropy? What is it and what does it mean when its increasing and decreasing in the refrigerant cycle.
Thanks
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Can someone help me out with entropy? What is it and what does it mean when its increasing and decreasing in the refrigerant cycle.
Thanks
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