Running 5000 BTU air conditioner solar

[nomadh]

On a night here that you would like a/C there is no wind to power a windmill. It's summer so fridge and freezer are working hard at using up battery storage.

We are acclimatised and prefer not to have A/ C if we can. There are some uncomfortable nights but we are ok as is.

A/C in cars is never turned off.

Water can be a good store of energy. Maybe double the PV panels so you can freeze or chill lots of water during the day then sleep on or in it at night. I'll do anything to not have to deal with or pay for batteries

[nomadh]

So do this: Run the cars all night w/the vehicle A/C running full blast and duct it out of the vehicle and into a bedroom. Then return from the bedroom to the vehicle. Classic redneck engineering.

Or just sleep in the car. Not out of the question if it only happens a few days a year and you have an important meeting in the morn.

[nomadh]

A buried heat pipe will need some way to move the cooler (and thus more dense) air from a lower elevation (underground) to a higher elevation (above ground). That will take some power, therefore not passive. On the whole, to be effective at all, such ground source methods of heating/cooling require careful design and in addition are usually more costly to build and maintain than most folks realize, not to mention the safety considerations with respect to air quality that need to be addressed. Maybe not a bad idea on paper or in the mind, but the devil is in the details.

My thinking was the chimney, where the hot air would naturally gravitate, would rise as it is inclined to do. As it rises it would pull air from below to fill the vacuum.
Now the practical part depends on the math I suppose. Maybe to be functional enough to matter maybe the chimney and pipe need to be 10" or 5 ft across. OR if the chimney needs to be 5 ft or 90ft and corrugated steel or 4" thick concrete to absorb the heat of the day I know not. Just wondering if its been done.

[jflorey2]

So do this: Run the cars all night w/the vehicle A/C running full blast and duct it out of the vehicle and into a bedroom. Then return from the bedroom to the vehicle. Classic redneck engineering.

You'll need some good insulation around that duct to make it all the way to the bedroom. Time to order some fast food in to-go containers!

[J.P.M.]

There are some uncomfortable nights but we are ok as is. A/C in cars is never turned off.

So do this: Run the cars all night w/the vehicle A/C running full blast and duct it out of the vehicle and into a bedroom. Then return from the bedroom to the vehicle. Classic redneck engineering.

[Sunking]

If we were real serious about minimizing the sweat we would move to a cot or hammock. I here there are new bed topping devices that help shed heat and wick moisture. Anyone tried them?

You can sure the the age of some posters from their questions and answers. None of them have ever heard of a Water Bed us ole Hippies use to make waves rocking the boat.

[Bala]

Even at night a passive heat pipe could work. A fan would help and even run off battery would still be miles ahead energywise compared to any AC. I suppose a small windmill could power the fan somewhat but then it gets all swiss family robinson looking.

On a night here that you would like a/C there is no wind to power a windmill. It's summer so fridge and freezer are working hard at using up battery storage.

We are acclimatised and prefer not to have A/ C if we can. There are some uncomfortable nights but we are ok as is.

A/C in cars is never turned off.

[jflorey2]

If we were real serious about minimizing the sweat we would move to a cot or hammock. I here there are new bed topping devices that help shed heat and wick moisture. Anyone tried them?

I used a tiny chiller (called Chillpad I think) that just cooled the mattress. It's active cooling of course, but since it's only trying to cool you and not the room you use much less energy. (80 watt draw when the compressor is on.) Seemed to work OK.

[J.P.M.]

Even at night a passive heat pipe could work. A fan would help and even run off battery would still be miles ahead energywise compared to any AC. I suppose a small windmill could power the fan somewhat but then it gets all swiss family robinson looking.

A buried heat pipe will need some way to move the cooler (and thus more dense) air from a lower elevation (underground) to a higher elevation (above ground). That will take some power, therefore not passive. On the whole, to be effective at all, such ground source methods of heating/cooling require careful design and in addition are usually more costly to build and maintain than most folks realize, not to mention the safety considerations with respect to air quality that need to be addressed. Maybe not a bad idea on paper or in the mind, but the devil is in the details.

[nomadh]

The worst time here when you would really need cooling is night time, very high humidity. So if I were to put in a pipe I would need a decent fan, so it would be a drain on my existing system. A lot of continuous watts of a long time. There is no way I could close up the house, it would be to stuffy.

I could sleep by the creek but the mozzies would be horrendous.

This house was built for no A/C, if it gets to a point where we cant stand it any longer I will sell up and move to a house with mains power and then have all the A/C I want.

Even at night a passive heat pipe could work. A fan would help and even run off battery would still be miles ahead energywise compared to any AC. I suppose a small windmill could power the fan somewhat but then it gets all swiss family robinson looking.

[nomadh]

There's been plenty of those lately.

I've always thought, there's something very wrong with laying in bed, doing nothing at all, and still sweating.

If we were real serious about minimizing the sweat we would move to a cot or hammock. I here there are new bed topping devices that help shed heat and wick moisture. Anyone tried them?

[littleharbor]

On a good hot humid night get out of a cold shower,

There's been plenty of those lately.

I've always thought, there's something very wrong with laying in bed, doing nothing at all, and still sweating.

[Bala]

Down in Baja, some nights we prefer a pedestal fan aimed right at us to the AC with windows closed up. The fans evaporative cooling on otherwise sweating, hot skin works pretty well. I'm laughing, thinking of the mental picture this explanation may cause, but from experience I can say, the fan really works. Ceiling fans look nice but are just about useless in this scenario.

I know what your talking about. Pedestal preferred to the ceiling fan. On a good hot humid night get out of a cold shower, dont dry yourself and hope you get to sleep before you do dry off.

[J.P.M.]

The ACDC12C is in the mini split class, so I believe the (very respectable) mid 3s COPs include all
parasitic losses. Bruce Roe

Yes, in cooling mode, but lower in heating mode and that COP will get lower still as the outside amb. air temp. drops. That's just the way the 2d law of Thermodynamics works, and what all the heat pump/refrigeration system rating methods sidestep.

Have you measured the COP to confirm your beliefs ?

Dirty little secret that's related to heating and heat pump efficiency (COP):

A well insulated and sealed dwelling will not need heat until a lower outside temp. is reached than an identical dwelling that's not as well sealed, mostly because of uncontrolled or unintentional internal heat gain or solar gain. As the heat load goes down, the internal/solar gain represents a greater percentage of the (now smaller) heating load. That effectively lowers something called the balance temp. - the outside temp. below which the building requires heat to maintain comfort. Example: When I bought my first house in Buffalo, the balance temp. was about 60 F. That is, when the ave. outside temp. dropped to 60 F or less and stayed there for ~ 8 hrs. or so, the house needed heat to maintain an indoor temp. of 68 F. Once I got done remodeling and some serious conservation efforts of the variety that some neighbors and friends called extreme, the balance temp. dropped to about 43 F and, not specific to this conversation, but with some implications to HSPF, the building time constant increased to ~ 23 hours.

Now, a heat pump operating with the original load and heating profile and balance temp. would have been operating more often when it was warmer outside (warmer than 43 F), meaning it would be operating more efficiently due to operation in warmer weather, but operating more. Point is, the COP would have been higher ("better") working to a higher balance temp. ,but operating more and as a result using more electricity for heating on an annual basis. After conservation efforts, a heat pump would not have operated as much in warmer weather and with a higher percentage of the operation happening when outside temps. were lower, meaning the COP would have been lower, even though the use of electricity would have been less due to the much lower heating load.

[bcroe]

The ACDC12C is in the mini split class, so I believe the (very respectable) mid 3s COPs include all
parasitic losses. Bruce Roe