Using Your Lawn Sprinkling Water to Cool the House

This is a unique way of providing some free space cooling for your house.

Rick runs the water that he is using for lawn watering through a heat exchanger first and extracts some "coolth" from it before it goes out to the yard.

Rick's current test setup.

His current test setup uses a 20 by 20 inch water to air heat exchanger with a fan that blows air through the heat exchanger to cool it.  In this current test setup, it cools the airstream about 10F and provides about 5000 BTU/hr of cooling -- about a half ton of cooling.

The energy use is very low -- the COP appears to be about 29 (SEER 125!).

Side of HX with water connections.

All the details on lawn water for cooling here...

Thanks very much to Rick for sending this in.

Gary

Calling all Sunspace Owners

I think that home attached sunspaces may be the most cost effective and sensible approach to adding solar to your house -- attached sunspaces offer:

• Space heating for the house 
• Additional living space that can be very pleasant
• A place to grow plants
• A place to hang the laundry for solar drying
• A good place to locate a solar water heater

While direct gain to the house through south facing windows can be an effective solar heating scheme, the direct gain approach has the not so good feature of quite a bit of heat loss on cloudy days and at night through the large windows.  Sunspaces allow you to harvest the same heat through their large, south facing glazing, but the susnpace can be closed off from the house at night or on cloudy days to avoid the big glazing heat losss.

A nice sunspace

Compared to traditional active solar space heating (with collectors, tanks, pumps, ...) sunspaces can be better looking and more cost effective (when you consider all of the benefits).

Doug's sunspace

For space heating, low thermal mass sunspaces collect heat quite efficiently, and it is relatively easy to transfer this heat to the house.  A good writeup on the low thermal mass sunspace design...

While having a sunspace to hang laundry in bad winter weather may seem like a small thing, clothes dryers are are the largest single electricity use in many homes -- on average about 900 KWH a year!  Even more when you consider that the dryer is pulling in cold outside air as it vents its hot air outside.  The sunspace gives you a good, sheltered, efficient place to dry clothes.

Sunspaces make a good, protected enviroment to add a solar water heater to -- the water heater will be more efficient because it does not see outside temperatures, and may need less or no freeze protection.

I've got a section on Sunspaces, but it has few examples of good, attached sunspaces used as described above.

Sooooooooooooooo, I would REALLY like to hear from folks with sunspaces -- how well do they work for you?  What's good?  What's bad?  What do you consider good design features?  

A writeup on your sunspace with lots of pictures would make my whole week!

Nick's multi-story solar space heating sun space

Or, if you have some thoughts, experiences, or questions on sunspaces, how about passing them on in a Comment below.

Gary

Comparing the Performance of Two DIY Solar Water Heating Collectors -- CPVC vs Copper

Scott Davis has come up with an innovative and simple design for a solar water heating collector that uses CPVC pipes for the risers -- its easy to build and performs well.

Scott and his prototype CPVC collector.

The collector uses closely spaced CPVC riser pipes which are silicone bonded to a flat aluminum absorber sheet.    This makes for and easy and fast build.

I did a side by side performance test of Scott's design compared to the established DIY collector design that uses copper riser tubes spaced about 6 inches apart with thicker grooved aluminum fins to transfer heat into the riser tubes.  In this test, the CPVC design performed within 5% of the copper/alum collector, which I think is very good.

The side by side test of the two collectors.

There are a number of pluses and minus associated with the CPVC design compared to the copper/alum design -- things like cost, ease of build, performance, durability, and tolerance for stagnation temperatures are all important.  Which design works out best will depend on your situation -- I've tried to provide a little data on how the collectors compare in all these areas.  

I would be most interested in hearing your thoughts on the comparison and which collector you think would work out for your situation.

Full details on the performance and stagnation tests, construction, IR pictures, etc. for the two collectors...

Closer view of the test CPVC Collector.

IR image of the CPVC collector in operation

If you go ahead and build a CPVC collector, please let me know how it works out for you.

Gary

A New Heliostat for an Innovative New Application

There is an interesting new heliostat being offered for a low enough price to be of interest for building home systems.  The heliostat is made by Light Manufacturing Heliostats.

The heliostat has an area of 2.3 sm (25 sqft) .  The mirror is a stretched, reflectorized film to keep the cost and weight down.  Prices from about $1300.

Details on the Light Manufacturing Heliostat here....

The same company offers a unique application that uses their heliostats to provide heat for rotational molding of plastic parts (like large water tanks).  This solar thermal rotational molding system appears to be simple and cost effective, and (to me) represents some truly innovative thinking in bringing solar to a large industrial processes in a very energy efficient and cost effective way.

Diagram of solar thermal rotational molding system.

In the system, multiple heliostats focus their beams on the mold to provide the large amount of heat needed for the process.  The heliostats can support multiple molds by simply refocusing the heliostat beams on mold as needed.

The first video on this page provides a rundown on how the heliostat heated rotational molding setup works...



Heliostats can be put to many innovative uses -- I've assembled a few of them here...

Be sure to look at this one at the link above:
"ROME (Reuters) - A village in the Italian Alps is finally basking in winter sunlight thanks to a giant mirror installed on a mountain top to reflect the sun's rays into the main square."


Gary

Making Good Use of Mountain Pine Beetle Killed Trees

This is a good and interesting video from Peter Brown about a local Bozeman, MT company that is salvaging trees killed by the Mountain Pine Beetle.

Distinctive blue coloring of beetle killed pine.

It turns out that the fungus that the beetle infects the pines with leaves a blue stain in the wood  that makes for very attractive color patterns on the boards when sawed by an experienced sawyer.

The beetle killed wood's structural properties are unaffected by the beetle infection, and the wood can be used for a wide variety of purposes.  The blue staining gives it a distinctive look that has made it popular for furniture and doors.

A great example of making good use of local materials that would otherwise go to waste.

Neil Wilbert of Beetle Kill Boards with his portable saw mill.

Makes very nice furniture.

See the story  on Peter's Video Blog...



Gary

DIY Solar Water Heating for 7 Unit Apartment

This is Micah's DIY solar water heating system for a seven unit apartment building in Iowa.

Collectors solar preheat water for apartment building.

The system is a drain back system similar to the $1K systems, but larger to accommodate the 7 units and with a few design changes to match the situation.

The solar heated water storage tank located inside the building's utility room right behind the collectors, which makes for nice direct plumbing.

The collectors.

The collectors are glazed with twinwall.  Note the very nice job of trimming and flashing the collector glazing.

The tank is a non-pressurized combination drain back and solar heat storage tank that is constructed with OSB and lined with EPDM rubber membrane.

Drain back and solar heat storage tank.  

Nice simple plumbing using PEX and SharkBite fittings.  These are the valves that allow the solar water preheat to be bypassed if desired.

Micah's day job is in Nepal, and he has some interesting comments on solar in Nepal.

Solar water heaters everywhere in Nepal

Download all the details on Micah's 7 unit apartment solar water heater...

Gary

Cooling Without Power

I know there are a few million people out there now in hot weather and without power due to the storm.

Here are a few ideas on cooling without electricity that are quick to implement and might be helpful during the hot weather power outage.

If you know people who are without power in hot weather, please pass on these ideas to them.

- Stop window solar heat gains during the day.  Windows that face south, east or west are major sources of solar heat gain that tend to cook the house.  Its critical to stop this heat gain from heating the house.

The best place to stop the solar heat gains is outside the windows with external shades -- this keeps the heat totally out of the house.  If you are working from the inside of the house, closing blinds (especially if they are reflective) is helpful.   Putting aluminium foil against the window would be much more effective in that it efficiently reflects both the visible and IR in the sunlight back out the window.

An easy and quick to install set of external shades like these can make a huge difference...

More on window shading here...


- Water the roof.  Putting a sprinkler on the roof to wet it down intermittently will cool the roof by evaporation, and therefore cool the attic.  The cooler attic will reduce the heat gain to the house.  Here is an example roof cooling system...

There are more examples in this section of the Cooling page on Build-It-Solar...

Example of a fancy roof cooler, but a sprinkler or two will do.

- Shade the house.  This may not be that easy to do on short notice, but anything that shades the exterior of the house will reduce heat gain.  Maybe a jury rigged set of Shade Sails?...

- Using cool basement air.  Some people have reported that circulating cool basement air to the living area can be quite helpful.  This is a simple example of Fran's system...  While this system uses a small fan, if you open a window in the basement and a window as high as possible in the house, the stack effect will tend to circulate the air even without a fan.  Or, I guess, you cold just move down to the basement?

- Ventilation.  In these days of Air Conditioning and powered everything, people tend to forget how effective night time open window ventilation can be.  Opening windows on opposite sides of the house in the direction of the wind is helpful.  In multi-story homes, opening windows low and high makes use of the stack or chimney effect to circulate more air.
If it cools off enough at night, using as much might ventilation as possible to cool the thermal mass of the house will make it more comfortable on  the following day...

If you can rig up a fan that is solar powered or car battery powered, this can help a lot with the ventilation.  Solar powered attic ventilation fans are available at a lot of hardware stores...

- Evaporative Cooling.  One simple form of evaporative cooling that has been reported to work pretty well if you have a concrete patio and a window above the patio where air is flowing into the house.  You wet the patio area down with a hose, and try to keep it wet.  The evaporation of the water cools the air before it enters the window.  The evaporation also adds humidity, so this will not be as effective if the humidity is already high.
Conventional evaporative (swamp) coolers require some power, but much less that conventional AC units for the same output, but, again, are less effective in high humidity areas...
Some evaporative coolers are solar powered -- an example...

Edit July8: Note the DIY solar powered evaporative coolers here...  This is something one might be able to make on short notice for cooling during an extended power outage.  It could be run directly off solar or a solar charged car battery.


Mist Cooling.  Mist cooling can be very effective for even fairly large outdoor areas.   Here is one DIY outdoor mist cooler...   Dripworks sells an inexpensive mist cooling kit...

- Cooling just your immediate area.  This section gives two simple schemes in which only your immediate sleeping area is cooled...  Very little power required.
If you can get ice, the water bed scheme might work with ice cooling?  Insulate around the outside to keep the coolth in the waterbed.

- Reflective roofs.  This is perhaps a bit extreme, but you could change your roof color to white...

There are dozens more cooling ideas on the Build-It-Solar Passive Cooling page -- many of these require no or minimal electricity to implement ...

If you know of any additional good cooling ideas for emergency power outage situations, please add them in the comments, or email me -- Gary...

If you try any of these methods, I'd like to hear how they worked out for you.

Gary

A New DIY Solar Water Heater That Goes Together Like LEGO's

I'm taking a cut at a new solar water heating system that is an easier and quicker DIY project than our current $1K system.

While our current $1K solar water heating system has been popular and lots of people have built it with good success, it does require the building both the collectors and the solar storage tank yourself, and that takes a bit of time.

The aim of the new system is to make the job of doing your own solar water heating system quicker and easier by using all off the shelf components that just need to be mounted and hooked up together.

A prototype system is in the works using these components:

• Collectors are 80 sq ft of plastic matt style pool heating collectors 
• The tank is the 175 gallon Softank 
• The controller is a standard differential controller from sun-pump
• The pump is a Grundfos HVAC circulation pump

The prototype is very much a work in progress, and I'm looking for ideas and comments.  Please look over the design and build, and if you have any thoughts on the system please leave comments on that page.

The system design is very much like the existing $1K system in that it is a drain back system that uses a large, non-pressurized tank for both the drain back tank and for heat storage.  It also uses the one pass large coil of pipe heat exchanger to preheat cold water before it gets to your hot water heater.

Overview of the Components

Collectors:

The 80 sf of pool heating collector in place.

The collectors are lightweight and easy to handle and install.  You can put 40 sf of collector under one arm and easily climb a ladder.  The three season performance of these collectors is good in a solar water heating application, and there are some ideas on how to improve the not so good winter performance -- maybe you have more ideas?

A nice side benefit of using these collectors is that they are SRCC OG100 certified, and therefore the whole system qualifies for the federal tax credit, and maybe state rebates depending on where you live.


The prototype collectors are Fafco SunGrabbers bought on ebay.

Solar Storage Tank:
The tank is the Softank kit offered by American Solartechnics.  The kit goes together easily and the tank holds about 180 gallons of solar heated water.  

The Softank with 175 gallons of water.
The top of the tank looks like a mess because I've not finished the lid
and not trimmed things back and tucked things in.
The controller and pump are visible at the left.
The insulation bulges on the pipes are covering temperature logging sensors.

Controller:
The controller is an off the shelf differential controller from sun-pump that has all the advanced features at a not so advanced price.

The controller -- the wiring showing here is
most of the wiring for the whole system.

Pump:
The pump is a Grundfos 15-58 three speed HVAC circulation pump.  These pumps are relatively efficient and very rugged with a reasonable price.  

The Grundfos pump -- this is the rest of the wiring.

Heat Exchanger:
The heat exchanger is a large coil of PEX pipe that is immersed in the tank.  Cold water from the street takes one pass through this coil to be preheated on its way to your hot water tank.  It is the same one that is used in the $1K system and is explained in detail there.


Plumbing and Electrical:
The system is plumbed together with easy to use CPVC pipe.  This is the easiest system for people new to plumbing.  You cut it with a scissors like device and the joints are just glued together.  Goofs are easy to fix.  There is a  little bit of electrical wiring is that is easy and safe to do.


The target cost for the system is around $1300 before rebates.  Depending on your rebate situation, payback may inside one year.


All the details on the Off-The-Shelf DIY Solar Water Heating System...

The "going together like LEGO's" title is no doubt an exaggeration, but the system is designed from the bottom up to be easy to put together.


Let me know what you think.


Gary

Solar Hot Water and Space Heating System With Integrated Boiler

This is Norm's very nicely done solar space and water heating system.

The system uses a large, unpressurized tank that serves as both the solar heat storage tank and the drain back tank for the collectors.  The solar heat is used both to preheat domestic water and also for space heating, which is integrated with a propane fired boiler.

The solar storage tank with the copper coil heat exchangers.

Heat is extracted from the tank using one heat exchanger for space heating and a 2nd for domestic water heating.  Both heat exchangers are made from two coils of copper pipe with parallel flow and are very nicely done.  Norm provides good detail on making these heat exchangers.

The system uses four Sun Earth flat plate collectors.

The four 4 by 10 ft Sun Earth Collectors.

In Norm's system the boiler is integrated with the solar system such that the boiler only provides heat when the solar collectors cannot.

Boiler is at upper left -- solar components are mounted on the tank wall.

Heat distribution is to PEX runs in concrete and to the radiant floor done with Warm Board shown just below.

Warm Board hydronic radiant flooring distributes solar heat.

All the details on Norm's olar Hot Water and Space Heating System With Integrated Boiler...

Gary

Energy Fair Season!

Its the Energy Fair season!

Energy Fairs provide a great way to learn about renewable energy and sustainable practices.  They typically include workshops, seminars, demonstrations and exhibitors -- everything you need to get started on that next project.

From the point of view of Do-It-Yourselfers, the MREA Energy Fair in Wisconsin is probably the best of the best.  June 15-17, Custer, WI.

MREA

MREA Workshops

The MREA workshops alone are amazing in their scope and the level of expertise of the workshop hosts...
More than 200 workshops...

Or, find an Energy Fair near you.

A list of the Energy Fairs I know about in the US is here:...
Its hard to keep this list up to date and websites, dates, ... change each year -- so, if you find an Energy Fair on the list, but the link is broken, just Google for it.
There are also MANY fairs that are not on the list, so check around and see what you can find in your area.

If you are putting on an Energy Fair, let me know the date and place and I'll add it to the list -- contact Gary...


Gary