- Joined
- Aug 8, 2004
This post is a bit of a brainstorm inspired by an excellent idea by Como in another thread HERE (sorry for the thread theft maze).
In a discussion about fitting multiple heater cores in a case, Como mentioned that he is going to attempt to cool his radiator by mounting it without fans or a shroud and allowing the case fans to build pressure inside the case that consequently force air to be exhausted through the fins of the core. This would be achieved by sealing off all the exhausts save the hole in the case that is occupied by the rad. The case fans will all be used as intakes and as pressure builds inside the case, air flows through the radiator fins and into the room. The implications of such a configuration are profound. Consider that without a shroud and mounted fans one is now at liberty to mount a heater core/rad in many different configurations due to the reduced bulk of the assembly. Also consider the cooling potential presented by not being limited by the standard 1 or 2 fans. The more fans your case can accommodate the greater the pressure inside the case and the faster air exhausts through the fins.
This entire concept is based on the principals of entropy which is also the second law of thermodynamics. Essentially all matter tends to move towards a state of disorganization. That is why hot air cools, glass breaks, and your house gets messy. In this case the pressure inside your case is creating a state of highly ordered air molecules with a considerable amount of potential energy. This energy is then converted to kinetic energy that carries the air through the fins of the radiator to the less ordered, more entropic environment out side your case. At the risk of over explanation, we are essentially creating a positive pressure gradient down which the air moves into a less ordered state.
After some thought and debate with Como, I considered another very important entropic gradient in a water cooling system. When we pass water through a heater core we expose the water to a thermodynamic gradient between itself and the walls of the radiator. The heat in the water is moves along the gradient to the radiator, then moves once more into the even cooler air. And their within lies one hang up with a positive pressure gradient. As we all hopefully know, the effectiveness of a radiator is restricted by the temperature of the air passing over it. The warmer the air the more shallow the gradient will be between the radiator and the air, and the less efficient the radiator will be. So in a positive pressure environment the radiators performance would be hindered by the higher temps of case air exhausting through its fins. So I proposed reversing the gradient and inducing negative pressure by creating a vacuum inside the case. In practice all you would do is reverse all the case fans so they exhausted, if all things remain the same you’ve created an inverse of the entropic scenario illustrated above. Now the air outside the case is more highly ordered than the air inside the case so as a surrender to thermodynamics the cooler air outside your case travels down the pressure gradient through the radiator and into your case. Once there, the hot air is expelled by the exhausting fans.
Como and I have been in a bit of a pragmatic debate about positive pressure vs. negative pressure. Como’s argument is that negative pressure exposes passively cooled components inside the case to hot radiator air. My argument is that positive pressure significantly degrades the efficiency of the radiator for the reasons explained above. I think this is an excellent topic for the community to explore both academically and in practice. I’m working on a negative gradient system now utilizing 2x 2-342 heater cores I’ll let you know what my experiments find. Until then give us your feedback and criticism of the proposal.
BTW: I’m not a physicist so be at liberty to criticize my science if it’s misleading.
In a discussion about fitting multiple heater cores in a case, Como mentioned that he is going to attempt to cool his radiator by mounting it without fans or a shroud and allowing the case fans to build pressure inside the case that consequently force air to be exhausted through the fins of the core. This would be achieved by sealing off all the exhausts save the hole in the case that is occupied by the rad. The case fans will all be used as intakes and as pressure builds inside the case, air flows through the radiator fins and into the room. The implications of such a configuration are profound. Consider that without a shroud and mounted fans one is now at liberty to mount a heater core/rad in many different configurations due to the reduced bulk of the assembly. Also consider the cooling potential presented by not being limited by the standard 1 or 2 fans. The more fans your case can accommodate the greater the pressure inside the case and the faster air exhausts through the fins.
This entire concept is based on the principals of entropy which is also the second law of thermodynamics. Essentially all matter tends to move towards a state of disorganization. That is why hot air cools, glass breaks, and your house gets messy. In this case the pressure inside your case is creating a state of highly ordered air molecules with a considerable amount of potential energy. This energy is then converted to kinetic energy that carries the air through the fins of the radiator to the less ordered, more entropic environment out side your case. At the risk of over explanation, we are essentially creating a positive pressure gradient down which the air moves into a less ordered state.
After some thought and debate with Como, I considered another very important entropic gradient in a water cooling system. When we pass water through a heater core we expose the water to a thermodynamic gradient between itself and the walls of the radiator. The heat in the water is moves along the gradient to the radiator, then moves once more into the even cooler air. And their within lies one hang up with a positive pressure gradient. As we all hopefully know, the effectiveness of a radiator is restricted by the temperature of the air passing over it. The warmer the air the more shallow the gradient will be between the radiator and the air, and the less efficient the radiator will be. So in a positive pressure environment the radiators performance would be hindered by the higher temps of case air exhausting through its fins. So I proposed reversing the gradient and inducing negative pressure by creating a vacuum inside the case. In practice all you would do is reverse all the case fans so they exhausted, if all things remain the same you’ve created an inverse of the entropic scenario illustrated above. Now the air outside the case is more highly ordered than the air inside the case so as a surrender to thermodynamics the cooler air outside your case travels down the pressure gradient through the radiator and into your case. Once there, the hot air is expelled by the exhausting fans.
Como and I have been in a bit of a pragmatic debate about positive pressure vs. negative pressure. Como’s argument is that negative pressure exposes passively cooled components inside the case to hot radiator air. My argument is that positive pressure significantly degrades the efficiency of the radiator for the reasons explained above. I think this is an excellent topic for the community to explore both academically and in practice. I’m working on a negative gradient system now utilizing 2x 2-342 heater cores I’ll let you know what my experiments find. Until then give us your feedback and criticism of the proposal.
BTW: I’m not a physicist so be at liberty to criticize my science if it’s misleading.
