Resurrecting the California Cooler

Step 5 The results

January 5, 2011
The California cooler is now just over a year old. We are now at the coldest time of the year and it's working great. One thing that has been bugging me is that I have no way of knowing how much energy the California Cooler saves. Probably the biggest savings is that we got a smaller refrigerator when we remodeled the kitchen and then the CA Cooler could be a little savings on top of that. I've decided to collect some data that may shed a little bit of light on things. I'm going to measure the energy consumption of the fridge for the entire year, and also record the outdoor, kitchen, and cooler temperature on as many days as possible. Maybe after another year I'll have a better idea of how the cooler reduces the amount of electricity used for the refrigerator.

November 8, 2010
After that heat wave in June, we had the coolest summer in at least 30 years. During that time the California Cooler worked as well as could be expected - the temperature varied from 60-65 most of the time - we still kept eggs, peanut butter, cooking oil, carrots, parsley in there, but not butter.

In August, our "indian summer" came and we had warmer weather for the next two months. We had to completely stop using the CA Cooler during that time. It wasn't much of a problem to fit all of our food in our small fridge. Maybe next year I'll get around to trying some of the ideas appearing in the comments. The two that interest me the most are: 1. evaporative cooling a la a swamp cooler and 2. A solar powered peltier cooler.

In late October, our version of fall began and now the cooler is in the low 50s in the morning, and goes up to around 60 during the day. We've started using it again and, as the weather gets colder, we should be able to add more and more items and we should be able to use it continuously until at least next June. Then we'll see what kind of summer is served up.


June 30, 2010
We had a mini heat wave and during that time the cooler didn't work well at all (went above 70 F). Fortunately, that only lasted 2-3 days. Now we are back to our typical summer pattern: 70-75 F during the day and a low of 57-59 at night. I put in the cool thermal masses in the morning before I leave for work and close the vents. The temperature swing under these conditions is about 60 F minimum and 65-67 maximum. If I watch the weather report, I could consider putting some ice in the cooler during abnormally warm days.

May, 2010
The spring has turned cool and the CA cooler is working quite well (staying below 65 F during the day).

April 4, 2010
With the warmer spring weather, I have given up keeping the temperature below 60 F and settle for a maximum of about 65 F. However, it always goes down into the 50s at night, which is why a CA cooler can work in N. California. I am using more water for thermal mass (about 3 gallons at this point) and there are certain foods that we probably won't store during the warmer months, like strawberries.


February 17, 2010
Our short Bay Area winter is coming to an end. We had a week of temperatures in the mid 60s and the CA Cooler went as high as 65 F one day. I would like to keep it below 60 F if possible, and this will become a challenge as the year progresses. I have increased the amount of cool thermal mass (bottles of water) that I put inside the cabinet every morning and remove in the evening. On a couple of days I also tried putting in 2-3 ice gel packs from our freezer and closing the vents in the morning. That worked just fine but, of course, it takes electricity to freeze those packs.

Another idea that I got from a reader's comments is to try putting a damp cloth inside, in the hopes of getting evaporative cooling. A couple of times I hung a damp cloth from one of the shelves, but, it didn't seem to have worked I will experiment some more with the location of the damp rags.

February 10, 2010
The CA Cooler is now pretty much finished. The door has built-in insulation and also weather stripping at the top and bottom edges.

January 10, 2009
We were away on vacation for 2 weeks and the CA Cooler stayed below 60 F the entire time.

December 10, 2009
We have been having unusually cold weather, with temperatures in the 30s at night. I have seen the temperature difference between the kitchen and the cooler as high as 23 degrees F. The coldest I have seen the cooler get is 39 F. I then decided to close the vents on the coldest nights, because I didn't want it to get so cold.

December 3, 2009
We have been using the CC for about three weeks and we love it! For the first two weeks, we didn't have any insulation on the door and the temperature inside the cooler was between six and ten degrees Fahrenheit colder than the kitchen temperature. Typically, the cooler has gone down to the upper forties at night and up to the high 50s or low 60s during the day.

We have been keeping eggs, butter, oils, peanut butter, apples, onions, tomatoes, broccoli, cilantro, parsley and strawberries inside it. It turns out that we keep so much food in the cooler that there is plenty of room in the small fridge for the rest. It's not even an issue - our old fridge was always more crowded with food than this one is.

I also keep a gallon bottle of water and two quart bottles in the top shelves to act as thermal mass in order to keep the temperature lower during the day. I can increase this effect by leaving those bottles out at night, so they get as cold as possible.

Last week, I added a layer of insulation behind the door. It's still not permanently attached to the door, so we keep it on overnight and when we're gone during the day. Now, the temperature difference between the cooler and the kitchen is between ten and seventeen degrees F, which is excellent. The weather lately has seen temperatures in the mid 40's at night and in the upper 50's during the day. The cooler goes down to around 46-50 F at night, and up to 57-62 during the day.

summer, 2009
We committed ourselves to buying a very small refrigerator at the beginning of our kitchen remodel. This refrigerator would have 10.3 cubic feet of volume, compared to the 16.6 cubic feet of our old fridge. As the kitchen remodel progressed, we sometimes got cold feet. "What will we do if the California Cooler doesn't work and we have to fit all of our food in that tiny fridge?"

Comments

[Dude567]

 try this, hang a damp towel on the outside vent, the sun evaporates the water and the air is cooled. Just keep the towel wet with a small drip from a plastic water bottle

[dlginstructables]

Thanks for the idea. I'm thinking that it would be better to have a set of hanging strips instead of a solid towel, so that air could flow through it better.

[soundmotor]

Growing up in the San Joaquin valley, one heard the term "swamp" cooler quite a bit . It may not be as effective in SF because the relative humidity needs to be low.

http://en.wikipedia.org/wiki/Evaporative_cooler

[jeanicrowe]

Use burlap or even a loosely woven mat. Rather than a plastic bottle, how about a length of tubing with small holes poked strategically along its length so the water source is continuous. Also, living in a very cold winter climate, I'm thinking of digging a 'well' that I can flood with successive layers of water, letting each freeze, with a dumb waiter type of arrangement i can lower into it to keep food cold. I know it will work in the winter, might get too cold, even. But I wonder, if the 'well' is thickly insulated, how long the ice would last into the summer? My Dad and his family cut ice blocks in the winter and stored them in a shed insulated with straw and they kept into July, sometimes longer. They cut big blocks that they stacked tightly. They also used a spring house and kept the butter and milk in a box that they lowered into the well. I don't think it was in the water, but just above it.

[zorcy]

They actually make large military ships during WWII with sawdust and water. They froze it in the shape of the hull. I think the ice lasted for years before it thawed out enough to fall apart.

[Dude567]

Put the ice in a shed and then surround it with a couple of feet of sawdust. Also living in the north west area (southern coastal British Columbia) we aren't in an extremely cold climate but some local farmers do make an outdoor ice rink on their field.

[loccomoffo]

Thanks for the great instructable! We're moving into a Californian Bungalow soon here in Perth, Western Australia and I might consider making one of these when we reno the kitchen :)

The CC from what I can see operates on the temp differential between the bottom and top vents, so you really want to have these as far apart vertically as possible. So if you'd like more cooling, try to attach an insulated aircon duct pipe to the bottom vent and drop the other end onto the ground or into your cellar. If you drop it onto the ground it will make teh use of water evaporative cooling so much easier, ie. air passing over water etc.

[dlginstructables]

That's an interesting thought. I know that the majority of these coolers were floor-to-ceiling jobs, but ours is not that tall.

[solsed]

 instead of using a towel use some cotton mosquito mesh or some muslin. 
in Australia we have what is known as a coolgardie safe that is a rectangular prism of fine muslin with mesh shelves. the bottom of the fabric is kept in a bowl of water and the evaporation cools the meat, butter, Eggs etc inside and also keeps the flies off the food. 

[dlginstructables]

I am searching for the right material to put in front of the vent. Swamp coolers use "wood wool", which is made of long, thin wood shavings. It seems to be only sold in huge rolls, but I was thinking of using a plane to make a some shavings by hand.

Maybe muslin would work. It definitely has to be a material that does not block the breeze, while at the same time, puts water in the path of the breeze. Ordinary cloth will not work.

[jessandstavro]

This is such a cool idea and so neat to see it applied in modern times. I can appreciate as well, the integrity (not sure if that's the right word) that this adds to your reno project, in keeping with the history of a period home. So cool!

I also love your shots of the homes with the vents. Great instructable, very original!

[dlginstructables]

Thanks - I'm glad somebody finally commented on the photo gallery!

[Chozenwoan]

Try placing the water on the bottom shelf. This will cause the cool air coming in to pass over it and will help chill the incoming air. Having it at the top causes all of the cool air from the water to be vented outside instead of inside the cooler.

[dlginstructables]

Thanks for the idea. I do need to understand the thermal theory behind the CA cooler better. My thinking was that having the cold water at the top (when the vents are closed) would cause convection, with warm air rising up to the top, getting cooled by the bottles, and then sinking down again. However, as you pointed out, with the vents open, maybe the cooler air will just get blown out. I'll try your suggestion as an experiment. Unfortunately, if it does work, it will be inconvenient, because we need a stepping stool to access the top shelves.

[Silence]

Pull a swap of your thermal mass from bottom at night to top during day.
During the night they will catch the most cold air and during the day, the cooling they produce will 'drop' to the lower levels.
Basically what Chozenwoan said, but while the vents are closed, having it at the top is better since cold air is heavier it will more efficiently cool the contents. Having more stuff in there also helps. The more cold you can trap with product, the cooler it will remain. Works the same for fridges and freezers.

You could throw in for some modern technology as well. Some peletier coolers on a solar power supply at the top of the CC would enhance daytime cooling.

[dlginstructables]

I actually remove the thermal mass every evening and put it out on the back porch. Then I put it back in in the morning.

I'm still not clear on whether it makes more sense to have the mass at the top or bottom when the vents are open, but I'm working on it.

I also don't know if closing the vents (with thermal mass up top) does much good.

I'm actually thinking of taking temperature data with a computer logger so I can really see what's going on.

[dwosullivan]

 I commend you for doing this however you would find more increase in energy efficiency by using the vents to increase the circulation at the rear of the fridge.

While your new fridge is much smaller which is great, it needs as much room around it to allow it to get rid of the excess warmth. If it is built in and surrounded by cupboards, it cant get rid of the warmth as efficiently, meaning it uses more power.

Seeing as you were remodelling anyway, if you were able to locate the fridge on the external wall away from the equator and have plenty of space around the fridge as well as vents to the outside you would be able to make significant energy savings.

If you are lucky enough to have the kitchen on the ground floor and have suspended construction (ie not a concrete slab directly on the ground) you could have a vent at the bottom through the floor and another vent through the ext. wall at the top. this will draw cool air through the sub floor helping get rid of the heat from the rear of the fridge.

Just my 2 cents worth - hopefully of use to others doing remodelling. Perhaps it would be good to do both :-)

[dlginstructables]

Your point is well taken. In fact, we got some misinformation from the fridge company about the amount of space needed around the fridge and we then designed the space too tightly. To compensate, we put several holes in the floor behind the fridge that bring cool air up from our basement, another set of holes at the top that let warm air escape into the cabinet, and yet another set of holes on top that let warm air escape up into our attic.

I have measured the electricity consumption since those changes, and the fridge seems to average ~28-30 Watts, which isn't too bad.

[Eccles2003]

Place the damp cloth over the vent.  Not over the shelves.  You may need to experiment with the thickness of the cloth but it will work.  the breeze has to pass over it as it enters to cool the air.

[recycleking]

 I seem to remember reading about older ways of cooling food, and one way was to have a bowl of water with the food under a cloth covering both the bowl and food. The water evaporating up through the cloth could create a temperature difference of as much as 10 degrees. But this is going by memory, and I didn't re-research this info.