Simplified Air-Conditioning Calculations

In summary, the individual is looking for guidance on how to power a concept vehicle's air conditioning system. They have found that the subject is complex and are looking for external input.
  • #1
InfernoxCJC
2
0
Hello everyone!
I am currently having some real issues estimating the power requirements for a concept vehicle's Air-Conditioning System, and I mean I've been going over this on and off for the better part of a fortnight.

At this stage I feel like I have fried my brain and have no idea if I am even on the right track, so really I am just looking for some external input.

Any guidance would be deeply appreciated <3
Conor

Homework Statement


Ideally, I need to find the energy required to lower the cabin's internal air temperature from X to Y, and subsequently find the required Mass Flow Rate and the required theoretical Heat Transfer Coefficient/Thermal Conductivity of the coolant.

Doing a fair amount of research, it seems to be a fairly complex subject, with entire Research Papers dedicated to the development of new models, so I stress that this needs to be rough, I'm not taking into account the variation of solar input due to date, time and location for instance. I've found a few sources depicting calculations for heating and cooling in Civil Engineering (Offices etc) situations but I'm not entirely sure how relevant they are, and they do not reference the coolant aspect.2. The attempt at a solution
A)
- Assume the cabin to be a cuboid
- Q = m c dT to find the total energy required to cool the cabin assuming zero losses
- Q = h A dT to find the losses due to Convection
- Grey Body Radiator equation to find losses due to Radiation
- I also tried accounting for Conduction but this gave a MASSIVE number

B)
- The equations found here: http://www.watlow.com/en/resources-a...ools/Equations [Broken]

C)
- The equations found here: http://www.arca53.dsl.pipex.com/
 
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  • #2
In the end I have tried to manipulate building models to suit my needs but I've not been able to find any examples to reference my findings against. All my research, including the Library and my University's access to the SAE Database has just brought up discussion on how systems work and possible improvements as opposed to detailed calculations

Ultimately I have found this:
- Mass Flow Rate required to maintain 16C (interior) under 50C (ambient) of 0.06 kg/s
- Mass Flow Rate required to cool the interior from 50C to 16C based on a upper power limit of 4 kW of 0.117 kg/s
- Required Fan Power based on a 10" fan of about 200 W

But as I say, I have been unable to find anything to reference my findings against so I have no idea if that is even nearly right other than finding the velocity of the Mass Flow as 0.062 m/s and thinking, well, you can't feel the air in the car moving like you do the wind (a few m/s) so maybe it is realistic? =P
 

1. What is meant by "Simplified Air-Conditioning Calculations"?

Simplified Air-Conditioning Calculations refer to a set of equations and formulas that are used to estimate the cooling load and energy consumption of an air conditioning system. These calculations are simpler and faster compared to more complex methods, making them a popular choice for initial design and sizing of air conditioning systems.

2. How are Simplified Air-Conditioning Calculations different from other methods?

Simplified Air-Conditioning Calculations are based on simplified assumptions and approximations, making them less accurate but also less time-consuming than other methods such as the heat balance method or the transfer function method. They are also more suitable for initial design and sizing, rather than detailed analysis.

3. What factors are taken into account in Simplified Air-Conditioning Calculations?

Simplified Air-Conditioning Calculations consider factors such as the size of the space to be cooled, the outdoor and indoor air temperatures, the number and type of occupants, and the heat-generating appliances and equipment in the space. They also take into account the type of cooling system and its efficiency.

4. Are Simplified Air-Conditioning Calculations accurate enough for real-life applications?

Simplified Air-Conditioning Calculations provide a good estimate of the cooling load and energy consumption of an air conditioning system, but they may not be accurate enough for detailed analysis or for systems with complex configurations. It is recommended to use more advanced methods for these cases.

5. Can Simplified Air-Conditioning Calculations be used for all types of air conditioning systems?

Simplified Air-Conditioning Calculations are suitable for most common types of air conditioning systems, such as central air conditioning, split systems, and window units. However, they may not be applicable for specialized systems, such as those using alternative refrigerants or with unique configurations.

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