Using pressure and temperature to ventilate a room?

[cooljoebay]

I have converted my garage into a small studio with two rooms. Both rooms are completely airtight and isolated from one another. I am wanting to bring in fresh air and push out stale air simultaneously. I have installed a heater in the main room. Here is a basic concept that I figure could be made to work. First off, I know about HRV systems but this is much more simplistic.

The idea is to install an intake vent in the heated room that pipes in the fresh air from the attic area above by using a duct fan and possibly a filter. I figured that the room would already be somewhat pressurized and air easily "moved". So the intake vent would be low powered. Second, install a ceiling vent across the room since the heat rises and simply run an insulated duct up and over to the next room ceiling. The heat would enter the vent but I don't know if the intake fan would cause enough force to "push" the air through the ceiling duct down into the second room. Maybe I would have to install a second fan to help "pull" the heated stale air into the second room vent. Third, assuming thus far everything works, the stale out in the second room would have to go out. So, install another vent low on the wall of the second room to help keep heat from escaping badly, and to move the bad air on out back up to the attic.

Normally in a hrv system intake air is warmed before entering the room. But I figure that using a small fan and keeping the intake very gradual, this could solve the problem without caused much heat to be wasted. Maybe not even noticeable.

Two things that brought this idea to mind. Opening a front door of a house, causing the back door to push shut. Pressure? Also, when I was younger we lived in 2 story home and the only thing that heated the upstairs was open vents in the ceiling that allowed the rising heat to enter. It always worked out well.

Does anyone think this would work? Or am I clueless? lol.

 

[JaredJames]

Both rooms are completely airtight and isolated from one another.

You've hermetically sealed both rooms? I'd be curious how you achieved that with a garage, even if it does come across a bit dangerous.

I think you're over complicating things a bit.

Firstly, does the heater have enough power to heat both rooms?

Second, why are the rooms sealed so well? As above, I somehow doubt you've fully sealed them. It would be easier to install a fan connecting the heated room to the non-heated one at the top of the adjoining wall and then invert it on the bottom (giving you a circular air flow pattern - ish). Assuming the heater is powerful enough, this will solve the heating problem.

Don't worry so much about getting air in and out straight away.

 

[cooljoebay]

Thanks for the reply.

I cannot say technically how "airtight" the room is. But when I built the walls and the ceiling, I went to extra trouble to caulk all crack and seams and do everything possible to eliminate escaping or entering air. The reason is because I work with sound.

Also, I cannot install a fan into an adjoining wall because it was built to isolate the two rooms, soundwise. So, to get heat and fresh air from the main room to the second room, it would have to go up and over in a manner that would minimize the sound traveling across. My main concern though is just the air and heat. The heater is big enough to heat 500 sq ft and runs off 220v. Its all electric.

You mentioned danger. I would really like to understand why it would be dangerous. If you are referring to a 100% airtight vacuum, I doubt that the rooms are just that. But then again, I could be wrong. But I would think the use of an intake and exhaust vent would eliminate that possibility. That is why I figured if ther was only one way for air to get in, it would come in with very little effort and push out air with equal effort.

-- Joe

 

[JaredJames]

Also, I cannot install a fan into an adjoining wall because it was built to isolate the two rooms, soundwise. So, to get heat and fresh air from the main room to the second room, it would have to go up and over in a manner that would minimize the sound traveling across. My main concern though is just the air and heat. The heater is big enough to heat 500 sq ft and runs off 220v. Its all electric.

Any ducting between the rooms will allow sound to travel between them. Unless you install an attenuator, the difference between having it go 'up and over' the adjoining wall and simply straight through it will be minimal.

Personally, I'd recommend an individual heater in each room. That way you don't need to join the rooms for heating purposes - it will be far more effective.

So far as air goes, you need to make sure the fan system can swap out the air in the rooms at the required level. The required level being enough times per hour to ensure there are no build ups of dangerous gases.

You mentioned danger. I would really like to understand why it would be dangerous. If you are referring to a 100% airtight vacuum, I doubt that the rooms are just that. But then again, I could be wrong. But I would think the use of an intake and exhaust vent would eliminate that possibility. That is why I figured if ther was only one way for air to get in, it would come in with very little effort and push out air with equal effort.

There's a volume of air within the room. If that air isn't being swapped out for fresh air, and a person resides in that room for a period of time, they are subject to CO₂ levels increasingly rising. If they don't leave the room / open the door in time they would eventually die from asphyxiation. Something of a downside to hermetically sealing a room. Think astronauts and what happens if they lose the ability to get fresh oxygen.

 

[sardar]

I find your idea interesting and worth exploring. Using pressure and temperature differentials to ventilate a room is a common concept in HVAC systems, and your idea builds on that principle. However, there are a few factors that need to be considered before determining if this would work effectively in your situation.

First, it's important to understand the properties of air and how it behaves. Air naturally flows from areas of high pressure to areas of low pressure, and warm air rises while cool air sinks. In your proposed setup, the heated room would have a higher pressure due to the presence of the heater, and the cool room would have a lower pressure due to the lack of a heat source. This would create a natural flow of air from the heated room to the cool room. However, the effectiveness of this flow will depend on the size of the rooms, the size of the vents, and the fan power.

Second, the temperature differential between the two rooms will also play a role in the effectiveness of this system. The greater the temperature difference, the stronger the flow of air will be. However, if the temperature difference is too great, it can cause discomfort in the cool room or lead to energy waste in the heated room.

Third, the placement and size of the vents will also be crucial in determining the success of this system. The intake vent in the heated room should be placed in a location where it can draw in fresh air from the attic without being obstructed. The ceiling vent in the cool room should also be positioned in a way that allows for efficient air flow. Additionally, the size of the vents and the fan power should be carefully calculated to ensure an adequate flow of air.

Overall, while your idea has potential, it would require careful planning and consideration of various factors to determine its effectiveness. I would suggest consulting with an HVAC specialist to help determine the best setup for your specific situation. Additionally, conducting some experiments or simulations could also help determine the feasibility of your idea. Good luck!