Passive Home Cooling

Because you leave your windows at least partial open all day. The two most important things that come to mind are shading and internal thermal mass. Given you climate you could there might be possibilities of using water or solar chimneys. If you wanted to pm me with images/ location I might be able to give you more specific advice. Also rotating what rooms are used for what functions per season can help dependant upon the house/inhabitants.

 

Fix or replace the Sump cooler?
Use it in the early AM to cool the home
Monitor your elec usage

 

We did a couple of things about 18 months back: replaced all windows with double panes having infrared blocking, and put another foot of insulation in the attic. Really stabilized our interior temps.

 

Seems you really want to maximise what you get out of what you have. So I would concentrate on plantings and shading. Horizontal exterior shades on south windows and vertical shades on e/w windows. Since you have a two story house are there any two story spots, if so an operable opening at the top could help draw out heat.

 

If your graph is accurate, it looks like your house is heating up between 8 and 8:45-9 even though the inside temp is higher than outside.
Do you have graphing of the temps before 8am?

I would repeat the suggestion from others that you are getting unwanted passive solar heating. If you can lessen that impact it should help quite a bit.

What interior thermal mass do you have? If it never gets down to ambient temperature, there may be a way to correct for that?

 

A little comedy. Ice masks. Keeps you cool and makes you younger looking.

 

What color is the roof gravel? Perhaps you can hang some shading mesh, like used for plants, on the roof to shade the gravel. The less heat the gravel picks up during the day, the less that it can radiate into the house.

 

Use nature to your advantage. Since you are in a dry climate it is much easier in the net. In the middle east they have been using "wind towers" for centuries. After shading the glass, open vents at the top of the house, and near the base. Add a mist of water (tiny little bits) at the lower opening. The evap of water will cool the incoming air, and the top vents (windows) will create a natural draft. Ideally a Coupola or omni directional vent structure on the roof, as high as possible helps.

We spend so much energy (and money) air conditioning our buildings, when some simple but well tested design systems work nearly as well with almost zero energy input. If we allow the natural rules of convection and evaporation in our design, we could reduce our cooling loads considerably.

The great irony, in much of the Middle east, they are building buildings with fake wind towers as a homage to tradition, but instead of actually using them, they simply use conventional A/C. go figure!

Do a google search for Arab Wind towers and you might be impressed.

http://www.ijens.org/105403-6868%20ijcee-ijens.pdf

Solaripedia | Green Architecture & Building | Projects in Green Architecture & Building

Among a couple,

Icarus

PS. If you d go with A\C, mini splits are far and away the most efficient and comparatively inexpensive. Small window shakers for single rooms are not too bad for small spaces, but portables, like the one pictured above are far and away the least efficient units you can possibly use! (not to mention, they are very much more expensive to buy on a BTU/BTU basis.)

 

Solar panels on the roof could shade the gravel, and give you enough extra power to run the furnace fan.

One other low-tech wild and crazy idea is to build a wind tunnel. No, not one big enough to put your car in, but one that will bring cool air into your house. If you were to dig a trench in your yard, line it with big rocks in such a way to leave large air gaps, and then cover it over, you could have a steady flow of naturally-cooled air. A few screens in the right places should keep out the critters.

 

I hope that isn't the only roof insulation. Evaporative roof cooling could work, especially if you don't have any roof insulation. I have see people hook up a sprinkler system on their roof, could be an easy thing to test out. Hopeful you are not in a drought area.

 

I designed my house per Passive Solar House of James Kachadorian. Biggest change is 25% of south-facing walls are windows that are shaded in summer and let in sunlight in winter (with no adjustment needed). I open a vent from my HVAC ductwork in summer, and open two windows at night. Close up the house in morning. Never need artificial cooling and my heat bills are tiny.

 

Thread revival yay. New guy makes a plug for what appears to be a solid text on this subject. Might as well give the standard plug:

Or the TL;DR free summary/subset link

https://people.wou.edu/~mcgladm/Geography%20470%20Energy/some%20required%20material/passive%20solar%20house/Passive%20Solar%20House.pdf

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Having been to Taos NM I can say that anyone there with tiny heating bills is doing something right. It is not the most challenging place for cooling in summer Generally regarded as a ski resort for Texas. Who call it tay-os (rhymes with chaos). But I digress.

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New home construction in US (by commercial builders) has never been linked to thermal efficiency AFAIK. Interfering with free marketplace is bad yes? But an open niche may exist for companies offering efficiency and lower long operating costs, in exchange for (not that much higher) construction costs. Rational governments* might offer incentives for that. The existence of Prius Chat (as a consequence of existence of Prius) suggests that this consumer market exists.

Rational governments* I am not implying that any such exist but still...

 

I once saw an option where long pipes are laid underground and connected to the house, they provide cold during the day and heat during the night.