Optimizing Airflow for Efficient Fridge Cooling: A Scientific Approach

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Discussion Overview

The discussion revolves around optimizing airflow for a fridge that utilizes cold air from outside instead of relying on an electrical compressor. Participants explore variables affecting the cooling process, including pipe dimensions, fan speed, and temperature dynamics, with a focus on calculating the necessary fan operation to achieve desired internal temperatures.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant outlines the variables involved in designing a fridge that uses outside air for cooling and seeks to calculate the fan operation needed to reach a specific internal temperature.
  • Another participant questions the necessity of measuring fan run time, suggesting that a thermostat could manage the cooling process more effectively.
  • A different participant expresses a desire for finer control over the cooling process, proposing the use of a computer model to simulate energy requirements for maintaining fridge temperature.
  • Some participants challenge the assumption that outside temperatures will always be below the desired internal temperature, arguing that this may not be realistic in many locations.
  • One participant shares their experience of living in a very cold climate, noting that outside temperatures can drop significantly, which could impact the feasibility of the proposed system.
  • Another suggestion is made to relocate the fridge to a colder part of the house to minimize energy use during colder months.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of using outside air for cooling, with some questioning the assumptions made about outside temperatures. There is no consensus on the practicality of the proposed design or the necessity of measuring fan run time.

Contextual Notes

Participants highlight the importance of considering local climate conditions and the variability of outside temperatures, which may affect the proposed cooling strategy. The discussion also reflects differing perspectives on the control mechanisms for the cooling process.

Who May Find This Useful

Individuals interested in energy-efficient cooling solutions, DIY fridge design, or those exploring alternative refrigeration methods may find this discussion relevant.

cxo
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The problem is as follows, my friend and I want to make a fridge that uses cold air from outside, instead of an electrical compressor. We plan to simply use a fan, and pipe to bring cold air from outside into the fridge.

So if our variables are:

- Pipe length / Diameter
- Fan speed / CFM
- Wind temperature outside
- Temperature inside the fridge
- Desired temperature to reach inside the fridge
- Heat capacity of fridge contents
- Volume of fridge / Volume of contents

How do we calculate, how long the fan needs to run, at what CFM to bring the temperature in the fridge from its current temperature down to the desired temperature in a particular amount of time?

Assuming the outside temperature is always below the desired temperature.

Thanks.
 
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Welcome to PF. I'm not sure why you would care to measure how long the fan has to run. Why does it matter? You use a thermostat to control the temp and the fan goes on and off as necessary.
 
Yes, the end result would eventually be something like that. Moreover we'd like to have finer grained control over the cooling process, than just ON|OFF of the fan, ie adjust the RPM etc..

We would like to model the system on a computer before implementing it. Basically to determine the amount of energy needed to maintain the fridge temperature. It's meant to be an energy efficient solution, and I'd like to prove it using a computer model.
 
""Assuming the outside temperature is always below the desired temperature.""

It won't be. If you do live in a very cold place it is going to be too cold a lot of the time. Bit of a.. daft idea..sorry to say.
 
Pumblechook said:
""Assuming the outside temperature is always below the desired temperature.""

It won't be. If you do live in a very cold place it is going to be too cold a lot of the time. Bit of a.. daft idea..sorry to say.

How does this help the thread?

And actually the city I live in, the temperature outside is below -20degC over 5months in a year.
 
Just move the fridge to a cold part of the house then.. Outbuilding. Zero electricity use for a good part of the year.
 

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