I haven’t read every word of the 200+ comments across all the posts about this, but has anyone considered how active heat sources in the room could confound / interact with efficiency measurements that are based only on air temperatures? Or be used to make more accurate measurements, using a different (perhaps nonstandard) criterion for efficiency?
Maybe from the perspective of how comfortable you feel, the only thing that matters is air temperature.
But consider an air conditioner that cools a room with a bunch of servers or space heaters in it to an equilibrium temperature of 70° F in a dual-hose setup vs. 72° in a single-hose setup, assuming the power consumption of the air conditioner and heaters is fixed in both cases. Depending on how much energy the heaters themselves are consuming, a small difference in temperature could represent a pretty big difference in the amount of heat energy the air conditioner is actually removing from the room in the different setups.
A related point / consideration: if there are enough active heat sources, I would expect their effect on cooling to dominate the effects from indoor / outdoor temperature difference, infiltration, etc. But even in a well-insulated room with few or no active heat sources, there’s still all the furniture and other non-air stuff in the room that has to equilibrate to the air temperature before it stops dissipating some amount of heat into the air. I suspect that this can go on happening for a while after the air temperature has (initially / apparently) equilibrated, but I’ve never tested it by sticking a giant meat thermometer into my couch cushions or anything like that.
Anecdotally, I’ve noticed that when I come back from a long absence (e.g. vacation) and turn on my window unit air conditioner for the first time, the air temperature seems to initially drop almost as quickly as it always does, but if I then turn the air conditioner off after a short while, the temperature seems to bounce back to a warmer temperature noticeably more quickly than if I’ve been home all day, running the air conditioner such that the long-term average air temperature (and thus the core temperature of all my furniture, flooring, etc.) is much lower.
I haven’t read every word of the 200+ comments across all the posts about this, but has anyone considered how active heat sources in the room could confound / interact with efficiency measurements that are based only on air temperatures? Or be used to make more accurate measurements, using a different (perhaps nonstandard) criterion for efficiency?
Maybe from the perspective of how comfortable you feel, the only thing that matters is air temperature.
But consider an air conditioner that cools a room with a bunch of servers or space heaters in it to an equilibrium temperature of 70° F in a dual-hose setup vs. 72° in a single-hose setup, assuming the power consumption of the air conditioner and heaters is fixed in both cases. Depending on how much energy the heaters themselves are consuming, a small difference in temperature could represent a pretty big difference in the amount of heat energy the air conditioner is actually removing from the room in the different setups.
A related point / consideration: if there are enough active heat sources, I would expect their effect on cooling to dominate the effects from indoor / outdoor temperature difference, infiltration, etc. But even in a well-insulated room with few or no active heat sources, there’s still all the furniture and other non-air stuff in the room that has to equilibrate to the air temperature before it stops dissipating some amount of heat into the air. I suspect that this can go on happening for a while after the air temperature has (initially / apparently) equilibrated, but I’ve never tested it by sticking a giant meat thermometer into my couch cushions or anything like that.
Anecdotally, I’ve noticed that when I come back from a long absence (e.g. vacation) and turn on my window unit air conditioner for the first time, the air temperature seems to initially drop almost as quickly as it always does, but if I then turn the air conditioner off after a short while, the temperature seems to bounce back to a warmer temperature noticeably more quickly than if I’ve been home all day, running the air conditioner such that the long-term average air temperature (and thus the core temperature of all my furniture, flooring, etc.) is much lower.