Solar Water and Space Heating Components (Pumps, Tanks, Heat Exchangers, Controllers,...)

This section covers pumps, heat storage tanks, heat exchangers, differential controllers and all the other odds and ends needed to build DIY solar water heating and space heating Systems.

Page Directory

Heat Storage Tanks	Heat storage tanks for solar water and space heating systems. Several DIY designs.
Pumps	Pumps for solar systems. 120VAC, solar PV, and DC.
Fans & Blowers	Fans and blowers for solar air heating collectors.
Backdraft Dampers	Backdraft dampers prevent the reverse flow of cold air from solar collectors at night.
Heat Exchangers	Heat exchangers of all sorts. Several inexpensive DIY designs.
Controllers	Controllers for solar space and water heating systems.
Pipe Insulation	Piping insulation for underground and above ground installations.
Heat Dumps	Hardware and ideas for preventing solar system overheating.

The main Solar Water Heating Page...

The main Solar Space Heating Page...

Solar Suppliers Directory Pages...

Thermal Storage Tanks, ... Some of the options available for storing heat or "coolth".
Homemade EPDM lined plywood tanks Full Details... Similar Storage tank for $1K system... Gary Ray's similar tanks ... (including a concrete one)	Plywood tanks lined with an EPDM membrane are good to about 180F, and are reported to last 10 to 20 years or even longer before liner replacement is needed. The tank frame can be made from lumber and plywood, but the loads are high for even not so large tanks, so be careful. This is the tank I use in my "Solar Shed" house heating system Full details on design and construction.
Alan Rushforth on Building Large Heat Storage Tanks...	Detailed information from Alan Rushforth on building large solar heat storage tanks. The tanks consist of a sheet metal outer wall with a layers of insulation and an EPDM waterproof liner inside. They can be quite large -- up to 5000 gallons and more, but could also be used for small tanks typical of residnetial space and water heating applications. Alan also provides details on several types of in tank heat exchangers that work well with these tank.
EPDM Lined Cylindrical Tank with Immersed Tank Heat Exchanger Details ... Two good concepts here: - Easy to build cylindrical tank. - Immersed tank heat exchanger.	This is a very nicely done cylindrical tank design from Alan. The tank is made from sheet metal bent into a cylinder, then insulated and lined with EPDM. The design uses two small immersed tanks as heat exchangers for domestic water heating.
Polyethylene AG tanks http://www.denhartogindustries.com/gusseted-vertical.asp	These polyethylene tanks for water and chemical storage are rotary molded, fairly inexpensive, and readily available. But, they have a limited temperature capability -- from one supplier: "Our tanks are rated to spike at 140 and run a constant temp of 120. If you store the water at 150 degrees it could soften the tank. You might try finding a cross linked tank that can withstand the higher temps."
Recycled Bulk Milk Tanks for Solar Heat Storage Tanks Using bulk milk tanks for solar storage...	This is a good idea from Tom for using recycled bulk milk tanks from dairy farms for solar heat storage. The tanks are constructed from high quality stainless steel, and the prices can be quite reasonable. The tanks include some insulation. This would be a very good way to go if you live in a dairy farming area where these tanks are available.
PermaFlex Polyurethane Tank Liner for Solar Tanks Gary provides all the details on building a solar hot water storage tank using PrmaFlex paint on liner...	Gary has a promising new way to apply a water proof lining to a solar hot water storage tank. He applies a polyurethane based product (PermaFlex) to a carefully built reinforced plywood box.
Commercial Solar Storage Tanks	Commercial tanks for storing heated water. Good life, limited capacity, built in heat exchangers available, pressurized operation supported. Several suppliers. Ordinary hot water tanks with the elements disconnected can also be used.
Eric's Thermal Storage Tank	A REALLY simple thermal storage tank scheme. Dig a hole, line with insulation, and add a waterproof liner. Details...
1000 liter Homemade Thermal Storage Tank Kris's heat storage tank... Heat exchangers in tanks...	A nice DIY thermal storage tank from Kris's solar energy webstie. Aluminum frame, plywood sites, and custom made liner. And 16 heat exchanger coils!!
Multi Drum Heat Storage System, John Canivan, www.jc-solarhomes.com All the Details... (pdf)	John Canivan discusses several heat storage schemes, and provides details on a system using multiple poly drums for space heating or DHW thermal storage. John is the inventor of the MTD collectors, and has a lot of interesting projects on his website. (Thanks very much to John for providing this material)
Tanks from Tom Details...	A new option for large heat storage tanks from Tom Gocze -- a long time friend of Build-It-Solar. Metal framed, PVC lined tanks with high insulation levels.
Softank Kit http://www.americansolartechnics.com/softank.html It would be great if we could begin to see more of these kinds of kits for tanks, collectors,... that would make it easier for DIYers to build solar water and space heating systems. Offering these kinds of kits would be a great business opportunity for someone.	Another innovative tank offering from Tom Gocze. This is a kit for DIYers to build a 120 gallon, well insulatednk for heat storage. The kit supplies all the parts including the liner and insulation. Cost is $485. The heat exchanger in the picture is not included. click on picture for full size A fun video on the durability of Tom's new lining material...
Commercial EPDM Lined Tanks STSS web site: http://www.stsscoinc.com Heat Storage Tanks www.stsscoinc.com/Products_SolarAndDHW.ASPX Hydroflex Systems http://www.hydroflexsystems.com/	These heat storage tanks use a metal cylinder with a layer of rigid insulation inside the metal and an EPDM liner inside the insulation. These tanks come pretty much assembled but folded down so they fit in a crate that will pass through an ordinary door. It looks like the installation is relatively easy and fast. Both companies also make copper pipe coil heat exchangers.
Royal Building System PVC - Concrete tanks www.praqua.com/pdf/NB/2004/N&Bjune04.pdf	An interesting tank building technique for medium to large tanks that uses PVC forms for concrete tank. Insulation can be integrated within the forms. This company uses the same type of forms for a form of ICF buildings.
Concrete Septic Tank www.solarbair.com/articles/horsecreekarticle.html	Eric describes his solar heating system. The system uses a precast concrete septic tank for heat storage.
Plans for Concrete Tanks -- Canada Plan Service http://www.cps.gov.on.ca/english/frameindex.htm The tanks are in this section...	These are plans for various types of concrete tanks from the Canada Plan Service. The tanks designs are intended for manure storage, but I don't see why they would not work for thermal storage water tanks. Several sizes of circular, rectangular, on surface, buried, ... The plans are detailed and appear to be well thought out. When working with tons and tons and tons of water its nice to have well engineered plans.
Build a 6500 gallon Concrete Water Tank for $1500, Dorothy Ainsworth, Backwoods Home Magazine www.backwoodshome.com/articles2/ainsworth101.html	Pretty detailed article from Backwoods Home Magazine on building a large concrete water tank to store water for home and irrigation. Lots of work, but it has held up for 23 years and counting. Could probably also be used as a heat storage tank in solar heating systems.
Ferro Cement Tanks http://ferrocement.com/tankBook/indici.en.html	Quite a detailed free online book on how to construct a ferro cement water tank. Plans are included for building both cylindrical and rectangular tanks.
High Temperature Polypropylene Tanks http://www.usplastic.com (see	High temperature (200F) Polypropylene tanks (and many other tanks).
ICE-X BATTERY Uses ice to store "coolth" http://www.bio-radiant.com/	A way to store cold for later use.
Western Environmental Liner http://www.westernliner.com/	Supplier of custom made tank liners. They will make a liner to fit your tank. They also sell EPDM, PVC etc. lining materials.
PlastaFlex Liners http://www.plastatech.com	Potential lining material for thermal storage tanks.
Flexi-Liner http://www.flexi-liner.com/index.htm	Supplier of custom made tank liners. They will make a liner to fit your tank/pond in various materials.
Firestone EPDM Membrane www.firestonebpe.com/roofing/rubbergard/_en/	The Firestone EPDM membrane site provides quite a bit of specification and installation material for EPDM membrane materials.
Marathon www.marathonheaters.com/consumers.html	An interesting all plastic water heating or water storage tank. Can be used for solar applications is temperature is limited to 185F or less: www.marathonheaters.com/cons_solarapps.html Warrantee is as long as you own your house.
A Sampling of Suppliers of Tanks and Tank Components
Rheem	Storage tanks for solar hot water heating applications. Hot water tanks...
Bee Valve	Makers of a very wide variety of valves, strainers, gauges, and tank fittings. Mostly in higher temperature plastics.
Basco	Supplier of containers.
Plasti C-Mart	Polypropylene tanks good for up to 200F in a non-pressurized solar hot water storage tank. 10 gallons to 500 gallons. About $3 per gallon in the larger sizes.
WaterTanks	Wide selection of plastic, and metal tanks. They have a link that promises a tank for "Solar Water Storage" that is "Coming Soon".
Plastic Tanks	High temperature rotationally molded polypropylene tanks. Good to 220F
Tap Plastics	Supplier of containers.
HouseNeeds	Water storage tanks for solar systems -- and other solar and hydronic heating suppliec.
Pumps This section covers some of the options for pumps on solar water and space heating systems. Note that when suppliers are listed, they are just a place to start shopping -- I'm not endorsing any of them.
120 volt AC pumps -- These pumps run off regular US household 120VAC -- most are also available European etc. power.
Grundfos http://www.grundfos.com Documentation: http://www.grundfos.com HVAC Technical Guide (pdf)	Manufacturer of a wide line of pumps. Popular for radiant heating and solar applications -- solid pumps. Commonly used in open and closed solar systems. The HVAC Technical guide provides a lot of good design information on selecting the right pump for your requirements.
Taco http://www.taco-hvac.com/	Manufacturer of a wide line of pumps. Popular for radiant heating and solar applications -- solid pumps. Good technical library Commonly used in open and closed solar systems.
NEW Taco Pumps With Integrated Differential Controller Taco page... More info... Manual ... One place to buy them... And, another place... Here is a report from Sean, who is using this pump...	These are the Taco 00 series circulator pumps with an integrated differential controller for solar water and space heating systems. The 00 circulators are often used on solar water and space heating systems (including mine) -- very solid pumps. Adding the integrated differential controller makes for a bit less wiring, and you get the advantage of variable speed control on the pump, which improves the efficiency of the system a bit. Price is about the same as you would pay buying a separate pump and differential controller, but its more compact, a little bit easier to wire, and you get the variable speed feature. Downsides of the integrated control are that some of the separate differential controllers provide readouts on the system and can be mounted where they are easy to monitor, and the issues that come up if you want to change to a different pump or controller. I'd be very interested in hearing from anyone who tries these pumps ... (thanks to Jan and Sean for the heads up on these pumps)
More Beer Pump http://morebeer.com http://morebeer.com/...	An interesting pump made for making beer. Good for high temperatures. May have solar application? Magnetically driven. Too bad its not DC so that it could be powered by PV, but its might be a cheaper substitute for a bronze casing Grundfos or Taco for open systems??
March Pumps http://www.marchpump.com/	Manufacturer of a wide line of DC and AC pumps -- some suitable for solar applications. Good technical data. The 809 series seems like it has some potential for PV powered systems that require some head capability?
High Head Drainback System Pumps Laing E10 (21 ft)... Laing SM909 (up to 26ft) ... Taco and Grundfos offer some high head models (eg Taco 009, Grundfos UP 15-100, ...)	These are some possibilities for drain back systems where the storage tank is well below the collectors, and a high head at startup is needed. The Laing pumps generally come with metal or plastic cases and use brushless motors that are pretty efficient -- plastic cases typically good up to 140F. Another possibility is to hook two lower head models in series with both pumps running at startup, and the 2nd shutting down via a time delay relay after flow is established -- eg two of the Grundfos 15-58 3 speed pumps could give about 40 ft of startup head at low total cost and relatively low power consumption.
Solar PV Powered Pumps -- DC pumps made specifically to be directly driven by a PV panel.
Laing ecocirc pumps http://www.lainginc.com/ http://www.lainginc.com/pdf/LTID5solar.pdf	A line of pumps from Laing made for direct drive from a PV panel. The pumps have built in Maximum Power Point tracking for earliest startup. Suitable for high temperatures. About $200. Heads up to 12 ft. These pumps seem to be well liked by people using them.
El SID Pumps -- Ivan Labs SolarDirect -- El Sid Pumps Info	Well respected small DC pumps that can be PV driven. Made by Ivan Labs -- they do not appear to have a website, but can be contacted here: Ivan Labs Inc.,305 Circle West, Jupiter, FL 33458 Telephone: 561-747-5354 Solar Direct is one of many suppliers for El SID pumps -- they list pump specs and application data. A bit more El Sid info from Thermomax (pdf)
TOPSFLO Solar DC Circulation Pump http://www.sun-pump.com/	This is a new pump that is intended for solar water heating system. It can be driven directly by a PV panel, and has a very high temperature capability. Startup head about 9 ft, flow rate about 2 gpm. Price is very attractive at $60. Kevin reports: The topsflo pump is a bit louder than TACO, Wilo and Grundfos. Just as Gary says, in an open system, like a recirculation freeze protected system, these compare to a bronze or stainless pump for 3X more $$. I measured 17 watts with my Kill-A-Watt at full load. No check valve to take apart for drainback. I have one of these pumps and have started to use it some -- so far very good. The wide range of input voltage is good for running from a PV panel. (thanks to Rodney for sending the note on this pump)
March Pumps http://www.marchpump.com/	Manufacturer of a wide line of DC and AC pumps -- some suitable for solar applications. Good technical data. Some of the March pumps can be direct PV driven.
Dankoff Solar Products http://dankoff-pumps.com/dp/	Manufacturer of pumps for solar applications including circulation pumps for solar heating, and PV driven well pumps.
Linear Current Boosters One of many potential suppliers: http://store.altenergystore.com/ ...	Linear current boosters hooked up between a PV panel and the pump it is driving match the two together more efficiently, and prevent the pump from being exposed to out of range voltages.
conergy www.conergy.us	One supplier of PV powered pumps. There are many other now -- check the "Wide Variety ..." list of suppliers at the top of this page also.
Sun Pumps http://www.sunpumps.com/	Manufacturer of solar pumping gear. Some good reference material on the site.
DC Pumps -- These pumps run off DC (mostly 12 volts)-- they may or may not be adaptable to use with PV panels. When used with PV panels, some of these pumps would likely need a battery in the system to stabilize the voltage within the pumps allowed range.
PC Cooling Pumps One potential source: www.sharkacomputers.com/waterpumps.html Notes on using the SwiftTech PC Cooling Pump...	These pumps were developed for water cooling of PCs. They appear to be high quality, have magnetic drives, and are designed for fairly high temperatures (typically 140F). Many of them have good pressure head capability. They might be a less expensive alternative for small PV powered systems -- $40 and up.
Davies Craig 12volt EBP pump daviescraig.com.au/main/display.asp?pid=27 One potential source: http://www.pegasusautoracing.com	This is a 12 volt pump with magnetic drive that is meant for pumping high temperature coolant. Solar heating is listed as one of its potential applications. Does about 3 gpm at 1.3 amps (12VDC). One user of this pump posted this message: "The Davies Craig Booster Pump is a 12 Volt DC magnetic drive pump that will handle water temps up to 120C. Draws approx 1 amp @ 12 volts, has a life in excess 10,000 hours. I have had one running on one system for over 2 years now with no problems, circulating water through 7 sq meters of panels located approx 8 meters away from HWC, connected by 15mm copper pipes. It is not suitable when in a mains pressure loop, i.e. pressures in excess of 50 psi as is constructed of a type of plastic." It is reported to have about the same pumping capability as the ELSID20 pump.
Jabsco 12V Heater Pumps http://www.jabsco.com One Supplier of Jabsco	Jabsco heater pumps, intended for circulating water or antifreeze in heater circuits up to 212F, magnetic drive, potential candidate for solar PV circulation pump? About $150. Jabsco specification Potential source: http://www.absak.com/
JATS Alternative Power Company www.jatsgreenpower.com	Manufacturer of small, high lift jack pumps that can be manual or solar powered.
LVM 12 V pumps One Supplier of LVM Pumps	LVM 12V circulation pumps -- some good to 189F. Might be a candidate for solar PV circulation pump? From about $50. LVM specification Potential source: http://www.absak.com/
Pumps Sources -- this is a not at all exhaustive list of places that sell pumps (I'm not endorsing any of them -- just some places to start shopping)
PumpBiz.com...	Pump retailer carrying a wide variety of pumps.
Real Goods...	A wide selection of pumps and other solar stuff.
PEXSupply...	Pumps, hydronic system components. ..
PEXUniverse...	Pumps, hydronic system components,...
BlueRidge Company...	Lots O' pumps and hydronic heating supplies
Harbor Frieght...	Source for cheap utility pumps.
Pump Packages -- These are packages that integrate all of the pumps, heat exchangers, valves, and controller needed to implement a solar heating system. Using one of these packages simplifies the plumbing, and makes for a more compact arrangement. There are a number of these packages out there -- and growing.
Heliodyne http://www.heliodyne.com	Supplier of solar collectors and full packages for water heating, space heating, and pool heating. Good technical information.
Solarhot USA -- Solar hot water http://www.solarhotusa.com	The SolVelox packages everything needed for a solar water heating system into one unit, including pumps, heat exchanger, and valves. Add collectors and some connecting plumbing, and you have the full system. The system can be used to add solar water heating to your existing hot water tank, or can utilize a separate solar water storage tank -- the first option saves the cost of a solar storage tank, and the 2nd offers more efficiency.
Fans and Blowers This section covers fans and blowers for solar air heating system.
Axial flow fans for solar air heating systems Dayton 10 inch diameter...	This is one example of a good sized axial flow fan that can handle collector systems with pressure drops up to 0.1 inches of water or abit more. 665 cfm at no pressure drop, and about 375 cfm at 0.1 inches of water. This is the fan curve for this model...
Inline blowers Fantech... Data... Elicent... Data... Hydrofarm, Vortex, and more	Several companies make this kind of inline fan that installs in a duct and provides flow rates from less than 100 cfm up to 700 cfm with pressure drops up to about 1.5 inches of water. Diameters range from 4 inches up to 12 inches. Data on the Fantech FG line... There are a number of companies that make a line of these fans. One source is stores that sell plant growing supplies, also available on ebay.
Sunon Fans www.sunon.com/pro.php	This is a pretty good page to start on for small to moderate size fans for collectors with low to moderate pressure drops. The page offers good data including fan curves and noise levels on several lines of fans.
Backdraft Dampers Backdraft dampers prevent the flow of cold air from the solar air heating collector into the house when the sun is not shining on the collector.
DIY Poly film style rectangular back draft damper	Good instructions for building a poly film type backdraft damper for a rectangular duct or vent. The damper uses Tedlar film backed up by a screen.
DIY poly filme style backdraft damper Some additional views...	This is a poly film backdraft damper similar to the one just above, but simpler. I have used this on several collectors including my larger thermosyphon shop collector. The damper film on mine is just two layers of Costco kitchen garbage bags. It works very well and is quite sensitive to even small reverse flows. The film lasts about 4 years (the Tedlar film used in the damper above would probably have a much longer life). This damper and the one just above are probably the only ones shown here that would work on a thermosyphon collector -- the others are for fan driven collectors.
DIY cloth sleeve style backdraft damper for round ducts	Plans for a nice DIY cloth sleeve style backdraft damper from the SimplySolar forum. In operation, the lightweight cloth sleeve is opened by the collector airflow when the fan is on, but collapses to prevent back flow when the fan is off.
Tamarack Backdraft Dampers...	This is a commercial cloth sleeve style backdraft damper similar to the DIY one just above. Their website provides some comparitive test results for several styles of backdraft dampers.
Butterfly dampers	In the this damper, the airflow from the fan blows the butterfly vanes open when the fan is running. When the fan stops, a spring pulls the vanes shut. There are several companies that make these dampers for a range of duct sizes. I have one of these on my sunspace, and it works fairly well, but it tends not to fully open when the fan is on (causing some flow resistance), and it leaks a little when the fan is off.
Bag Damper	Another option when the collector outlet is a duct that is not in a place that is visible is to simple cut the bottom out of a plastic bag and secure the top of the bag to the outlet duct or vent. When the fan is on, the bag is blown open and allows air to flow freely. When the fan is off, the bag collapses and prevents backflow.
Locating vents to reduce backflow	Another strategy to prevent reverse flow through the collector is to locate the inside inlet and outlet vents at about the same elevation. The idea is that the cold air in the collector is more dense and is stable just sitting in the collector. I don't have any experience with this approach -- if you do, please let me know how well it works.
Motor driven dampers	Another option would be to have a motorized damper that drives the damper open when the fan goes on and drives the damper closed when the fan goes off. There are several makers of these damper driver actuator -- search for HVAC Actuator -- around $50.
Heat Exchangers This section covers heat exchangers with an emphasis on ones that can be DIY projects.
Heat Exchangers for Solar Water Heating Chuck Marken How to get articles from Home Power ...	Home Power magazine article, issue 92 Good overview of the various types of heat exchangers. Pro and cons of each. Not a lot of sizing information.
Homebrew Heat Exchanger, Bert Echt How to get articles from Home Power ... Some good examples of this kind of HX on Fieldlines Forum...	Home Power magazine, issue 97. Article describing how to build a single wall, pipe-in-pipe heat exchanger from regular copper pipe and fittings.
STSS Pipe Coil Heat Exchangers www.stsscoinc.com/Products_SolarAndDHW.aspx Copper Coil Heat Exchanger Performance: www.stsscoinc.com/Products_HeatExchangerCoil.aspx	Copper coil heat exchangers. These heat exchangers are immersed in a heat storage tank. Similar to what can be constructed at home. Some performance on these heat exchangers here: www.stsscoinc.com/Products_HeatExchangerCoil.aspx this is the only published data I have seen on the popular copper coil heat exchangers -- if you find more, please let me know ...
Heat Exchanger Designs Used in the $1K Solar Water Heater The PEX coil heat exchanger... Examples of the $1K Solar Water Heater showing several heat exchanger designs...	The section on the $1K Solar Water Heater has several examples of water to water heat exchangers. This includes the large PEX coil heat exchanger, as well as some copper and copper/PEX hybrid heat exchangers developed by others who have built the system.
EPDM Lined Cylindrical Tank with Immersed Tank Heat Exchanger Details ... Two good concepts here: - Easy to build cylindrical tank. - Immersed tank heat exchanger.	This is a very nicely done cylindrical tank design from Alan. The tank is made from sheet metal bent into a cylinder, then insulated and lined with EPDM. The design uses two small immersed tanks as heat exchangers for domestic water heating.
Commercial Heat Exchangers http://www.heatexchangersonline.com/index.htm	The links above point to homemade heat exchangers, but there are many many makes of commercial heat exchangers. The cost of these is not so high, and they might be a good choice for some cases as they tend to be compact and efficient. The sample suppler listed to the left is one of many.
Outdoor Furnace Supply http://stores.ebay.com/Outdoor-Furnace-Supply	Outdoor Furnace Supply An ebay supplier of a wide variety of heat exchangers, pumps, ... for outdoor furnaces, but also useful for solar heating systems. Prices seem good.
Solar Hot Water and Space Heating System With Integrated Boiler All the details on Norm's space and water heating system...	Norm's system solar space and water heating system uses a set of four copper coil heat exchangers, and he provides quite a bit of detail on how they are made and sized.
Heat Exchangers Built for $1K Systems	The people who have built the $1K and other solar water and space heating systems have used a number of approaches to implementing heat exchangers -- its worth browsing through these projects on the Solar Water Heating and Solar Space Heating Pages to see if one of these heat exchangers fits your needs. Examples of the $1K systems...
Soft Copper Coil Heat Exchangers From Kris's website Kris's DIY heat exchanger designs...	Some good pictures on Kris's website showing how to make heat exchanger coils from soft copper tubing.
DIY Heat Exchanger http://www.bio-power.co.uk/exchanger.htm	Build it yourself heat exchangers. Not all double wall-- be careful.
Wood Stove Hot Water Coils http://www.hilkoil.com/	Stainless steel coils to extract heat from a wood stove firebox for heating water. Be EXTREMELY careful how you plumb these to avoid steam expolosions.
More Beer Heat Exchanger http://morebeer.com	This is a heat exchanger made for making beer, but might be of use in some solar applications. Its a copper tube inside a copper tube -- the price is reasonable $109. If it does not work out you can always try your hand a making beer. It is NOT a double wall heat exchanger, so don't use it where a double wall is needed for code or health reasons.
Magic Aire -- Water to Air http://www.magicaire.com/productd.htm	Supplier of water to air heat exchangers and air handlers.
Heat Exchangers Online http://www.heatexchangersonline.com/index.htm	A variety of types of heat exchangers with some design information.
Outdoor Furnace Supply www.outdoorfurnacesupply.com/index.php	A variety of heat exchangers -- water to air, water to water. Some suitable for solar applications, hot tub heating, ...
Several Air to Water Suppliers http://www.brazetek.com/products (good prices?) http://www.siliconsolar.com/... And, similar ones, with more data: http://www.heatexchangersonline.com/airtowater.htm http://www.outdoorfurnacesupply.com/water-to-air-heat-exchangers.htm	Air to water heat exchangers. One of the advantages of this kind of unit is that a single heat exchanger with a nice quiet fan can deliver quite a bit of heat -- of the order of 24,000 BTU/hr for a 17 inch wide exchanger with 120F water. This is enough to handle a fairly large array of collectors.
Solar Wand -- Hot Water Assist for Cold Climates Barry Butler How to get articles from Home Power ... Butler website -- good installation and design info: http://www.butlersunsolutions.com/index.html	Home Power magazine, issue 104 Describes a solar water heating system that uses only one conventional water tank. The innovative heat exchanger fits through one of the water tank plumbing connections. This system sacrifices some efficiency for a more compact system with fewer components -- this might well be a good trade depending on your situation. The article covers another innovative Butler product that prevents solar collectors from overheating. The Butler web site has pictures of several DIY installations, and the Documentation tab has full install and maintenance manuals for download.
http://www.amazon.com/The-Solar-Sidewinder-Exchanging-Element/,,, If the link above does not work, search for "Spectrum Solar Sidewinder"	A heat exchanger that replaces the lower heating element in a conventional electric water heater to transfer heat from solar collectors (or maybe a wood stove?) into the hot water tank. Relatively low capacity --they recommend one of these per 13 sqft of collector area.
http://www.consolar.co.uk	A unique design solar thermal heat storage tank. Some of the features might be incorporated into a tank you build.
Differential Controllers (and other Controls) Differential controllers compare the temperature of the collector and the storage tank, and turn the collector circulation pump on when the collector is hotter than the tank by a set amount. The prices have always seemed very high to me this very simple function.
Caleffi http://www.caleffi.us/... (see the iSolar entries) Manual for iSolar 1...http://www.caleffi.us/en_US/caleffi/Details/News/files/iSolar_1.pdf	A line of differential controllers -- some include advanced features such as logging. Some models not for US. $200 and up. I have been using one of these on my $2K system for several years and it has provided good service.
Steca http://www.stecasolar.com/... Manual for 301 model...	A line of differential controller -- some with advanced features. Some models not for US. $175 and up.
Goldline GL30 www.goldlinecontrols.com/Products/Solar.aspx One sample suppler...	A solid and reliable differential controller with all the required features for most applications. About $140.
Import Differential Controller http://www.sun-pump.com/controller.htm and, www.solarheatexchangemanufacturing.com/...	A less expensive, imported option with similar functionality to the ones above at a lower price. About $100. I have two of these and have had good service from them.
ART-TEC Controllers for PV powered systems http://www.arttecsolar.com/index.htm	ART TEC Solar offers a line of affordable Differential Temperature Controllers that are designed specifically for solar thermal systems in which the pump is powered from a PV (solar) panel or 12 V DC batteries. I have heard from people who use these controllers and have had good service from them.
Differential Controller Kits from John Canivan http://www.jc-solarhomes.com/...	John offers some kit and assembled differential controllers. Starting at $55.
myDTC Differential Temperature Controller www.mydtcstore.com Videos describing the controllers, programming, ...	This is an interesting controller for the person who is comfortable with working with electronics and software. It has quite a bit of flexibility and also does data logging. Brian has expanded the myDTC offering into a whole family of controllers from a very simple $50 one that does the basics up to a just added offering that controls up to 8 devices, has a 2 line LCD display, and does much longer term logging. A low cost sun tracker is also offered. I have heard from a couple people who have used these controllers and have been satisfied with them.
Open source temperature differential controller based on the Arduino prototyping platform http://nateful.com/?p=102 or, www.Nateful.com	This is an Open Source differential controller project from Nathan that uses the very popular Arduino micro processor board as a base. Be sure that you know what you are getting into before going down this road: its perfect if you have been looking for a good Arduino project or want to learn more about it micro processors, but if you just want a differential controller that you can plug in a few sensor wires to and go, this is not the one. One nice feature of the controller is that it can be equipped with an Ethernet shield and log data to the pachube.com free online logging service by just connecting it to your router -- no need for a PC to be running 24/7.
A DIY Arduino based solar water heater controller with many features http://house4u.com.ua/solar/en/	This DIY solar water heating controller is based on the Arduino. It provides overheat protection, frost protection, SD card logging and more. The instructions are pretty complete, but it is not a small project. It may make more sense if you are 1) already pretty familiar with the Arduino, or 2) want a project to learn about the Arduino on.
ThermokLogger http://www.aprsworld.com/thermoklogger/	This is an interesting controller that includes data logging to a built in SD memory card. I have heard from one satisfied user.
NEW Taco Pumps With Integrated Differential Controller Taco page... More info... Manual ... One place to buy them... And, another place...	These are the Taco 00 series circulator pumps with an integrated differential controller for solar water and space heating systems. The 00 circulators are often used on solar water and space heating systems (including mine) -- very solid pumps. Adding the integrated differential controller makes for a bit less wiring, and you get the advantage of variable speed control on the pump, which improves the efficiency of the system a bit. Price is about the same as you would pay buying a separate pump and differential controller, but its more compact, a little bit easier to wire, and you get the variable speed feature. Downsides of the integrated control are that some of the separate differential controllers provide readouts on the system and can be mounted where they are easy to monitor, and the issues that come up if you want to change to a different pump or controller. I'd be very interested in hearing from anyone who tries these pumps ... (thanks to Jan and Sean for the heads up on these pumps)
Thermo Technologies www.thermotechs.com/Solar_Controllers_Menu.php	Differential controllers and other solar system components.
Sorel http://www.sorel.de/en/...	A line of differential controllers. A bit unclear to me how you order one in the US?
RESOL http://www.resol.de/en/index.html	The manufacturer of a line of controllers for solar thermal systems.
In-line Electric Thermostat http://www.infraredheaters.com/kt-121.htm	Electric in-line thermostat. Allows you to turn an electrical device on/off at a set temperature. Temperature can be set from -10F to 100F. Switches up to 12 amps.
Snap Disc Switches www.pexsupply.com/...	These simple, less than $10 thermal snap switches can be used to control solar air heating collectors. They come in versions that turn on at a set temp, and ones that turn off at a set temp. White Rodgers makes a full line of them. PEX Supply carries a lot of them.
Insulating Pipes -- Underground and Above Ground If you locate your collectors away from your house, you will need to run the supply and return pipes underground. This section provides a few schemes for doing this without losing too much heat.
Underground Pipe Insulation
Encase pipes in extruded polystyrene sheet Details...	This method encases the pipes in extruded polystyrene. Its the method I used on my Solar Shed project. Details...
Bead-Foam-Crete Details...	This is a method used by Don Stephens of Greener Shelter. Basically, the pipes are enclosed in an insulating concrete made from Styrofoam beads and cement. The resulting product is similar to Rastra. Details...
MAXX-R Pipe Insulation System http://www.heatall.com/maxx-r/index.html	An insulating scheme for buried pipes. The claimed R values seem reasonable for the the thickness of the insulation (in contrast to some of the products in this area). I think that you may want more R value than this scheme provides for long runs. Beware of some of the commercial products that make very large R value claims -- if they are claiming more than R 5 or 6 per inch of insulation they are "exaggerating".
Pipe Insulation
Drillspot -- Pipe Insualtion www.drillspot.com/...	One source for thick wall, closed cell pipe insulation.
Heat Dump Solar water and space heating systems can be kept from overheating in the summer using various techniques. In most cases, no explicit overheat protection is required, but in cases where it is, some options are listed below. One of the most basic and effective options is just to use a steep tilt angle so the high summer sun shines less directly on the collector.
Overheat Protection for Solar Systems www.radiantcompany.com/system/heatdump.shtml	Article on various methods of protecting solar systems from overheating when the solar heat supply exceeds the heat demand.
Heat Dissipater http://www.apricus-solar.com/html/solar_heat_dissipator.htm	This Heat Dissipater by Apricus prevents overheating of collectors under summer conditions of high solar incidence and low demand. There are homemade versions of dissipaters, including ones that look like this, loops of pipe in the ground, hot tubs, ...

Gary June 24, 2010