DIY Solar Water Heater
DIY Solar Water Heater Field Performance Results
It's true that a diy solar water heater costs a lot less than a commercial one for the homeowner but what isn't as clear is how much the performance suffers due to the fact that the system is homemade.
Does cheaper necessarily mean worse in terms of performance?
Is it possible to build a system yourself that can heat water as well as the professionally designed, built and installed units costing thousands more?
The measured efficiency results listed below specifically from diy solar water heaters already installed in homes worldwide hold the answers.
They were measured by the system builders themselves using a variety of different temperature and energy monitors.
If you've built and installed your own diy solar water heater, please consider making a planet saving difference by measuring the efficiency of your system and sharing the results with me here.
DIY Solar Water Heater Efficiency Results
Insolation: 3.75 kW/m2 per day
Performance Indicator: Electricity Saved (kwh)
DIY Builder: Matt
Tank Size: 378 l (100 gal.)
Collector Size: 5.01 m2 (54 ft2)
Configuration: Flat Plate, Active, Indirect
Cost: $1513 US
Matt was kind enough to send me the figures of his household electricity bill before and after the installation of the system he built in August 2009.
This allowed me to work out how much the system was saving him every month and the expected payback time...
Matt's diy solar collector and system performance.
Insolation: 3.73 kW/m2 per day
Performance Indicator: Tank, Collector Temperature
DIY Builder: Gary Resa
Tank Size: 620 l (164 gal.)
Collector Size: 4.83 m2 (52 ft2)
Configuration: Flat Plate, Active, Indirect
Hot Water Demand: 90 l (24 gal.) per day, 2 people
Cost: Under $1000 US
He made use of an Onset U12, 4 channel data logger with four temperature sensors connected to measure the efficiency of the diy solar collector and tank.
It's a testament to the quality of the design and construction that it does so well, along with a few other factors which Gary mentions, as well as discussing at length how he went about building the system.
This is 'must read' material if you have any interest at all in building your own solar hot water system...
Gary's diy solar water heater performance and build.
Insolation: 3.23 kW/m2 per day
Performance Indicator: Tank, Collector Temperature
DIY Builder: Kevin Sharman
Tank Size: 620 l (164 gal.)
Collector Size: 6.41 m2 (69 ft2)
Configuration: Flat Plate, Active, Indirect
Hot Water Demand: 215 l (57 gal.) per day
Cost: Approximately $1600 US
Kevin started measuring the efficiency of his homemade solar water heater in May 2009 until March 2010 using a PICAXE 18X 4 channel datalogger.
He rigged his own temperature probes by taking a piece of steel antenna from the dump, wiring up a DS18B20 temperature sensor, and then encasing the sensor in epoxy inside the piece of antenna.
The results of his efficiency measurements was a solar fraction of 84%, not bad if you take into account temperatures drop to minus 40° C (minus 40° F ) in Tumbler Ridge BC on occasion.
Kevin's system performance and construction.
Insolation: 2.77 kW/m2 per day
Performance Indicator: Tank Temperature
DIY Builder: Niel
Tank Size: 800 l (211 gal.)
Collector Size: 11.52 m2 (124 ft2)
Configuration: Flat Plate, Active, Indirect
Cost: Approximately £1700 Sterling
Niel hasn't been measuring the efficiency of his diy solar hot water heater system long enough to be able to determine the solar fraction yet but initial results in May 2010 showed the top tank temperature fluctuating between 45° C (113° F ) and 68° C (154° F ).
Hopefully Niel will provide more comprehensive figures in future but there is a lot to be learnt from the way in which he designed and constructed the diy solar water panel and tank.
Chart of the performance results and full description of the system.
Insolation: 3.66 kW/m2 per day
Performance Indicator: Tank, Collector Temperature
DIY Builder: Eric
Tank Size: 757 l (200 gal.)
Collector Size: 3.71 m2 (40 ft2)
Configuration: Flat Plate, Active, Indirect
Real time measurement is first prize when it comes to performance results and Eric makes use of the IO-204 module from IoBridge to display the live temperature readings of the tank, collector and outdoor temperature.
He didn't build the components of the system himself but bought them from various places and then installed them all, so it does still qualify as a diy solar water heater.
See the live performance results of Eric's system.
Conclusions Based on Measured Performance Results
Looking at the results that the DIY solar water heaters are achieving the conclusion can be drawn that given the correct design and construction it definitely is possible for a home made and installed system to perform as well as its commercial counterparts.
As long as you take the following ten factors into account when you design and build your homemade solar water heater, as I did for my own DIY flat plate solar collector.
Solar thermal diy is still not cheap, as the systems above cost from just under US$1000 up to US$2800 to build, but in comparison to the professional systems that is very affordable. So if you are willing to put in the work yourself and build a diy solar water heater, you can save a lot of money and still get very good hot water performance.
Top 3 Commercial Solar Water Heaters
These are the top three solar water heaters manufactured and installed commercially in various areas of the world, ranked by efficiency results.