Tankless Water Heater
- The first part of the water heating project was to remove the old hot water tanks, which looked like they were going to break anyday. These were replaced with an undersized unit the stiebel-eltron-tempra-12, i got it from http://www.e-tankless.com. This will work for me as my showerhead is very efficient. It is even working with no preheating from the solar system. Doesn't it look much nicer?
Water Storage Tank
- The next thing i built was the water storage tank, this will hold the water before it goes into the tankless water heater. Currently this storage tank is stored in the dougout, which has some heat from the furnace preheating it from the measured 4.4C to the 12-20degrees C with no input from the solar system. This on it's own should help out the water heater.
- The Tank is a rain barrel which i had lying around. 50 US Gal. I had lined it with plastic. And is sitting on foam pad (using 2x2's to strengthen). It has a foam top, no insulation on the sides yet. - Inside the tank there is 100ft of 3/4 pex tubing carrying suply water from the city. My calculations show that this is a volume of around 10 US gal, and is almost enough for a shower. - the tank is connected into the system using flexible hoses and shutoffs in case i want to remove it from the line at anytime and connect directly up to the supply. - Update 2012-01-24 Due to a freeze somewhere in the system i added about a 12-15% antifreeze mix to the tank water.
- The solar panel is now mounted on the roof and is connected with a drain back system into the tank in the dugout. You can see it in the picture on the roof. - It was alot of work to get the pumbing installed through the foundation wall, i rented a rotorhammer to do the work much faster. - I'm using a pond pump to pump the water up into the solar panel.
Some tests i've done: running my tankless hotwater heater at 43 degrees C vs around 50 degrees C I noticed an approximate 30% savings in electricity usage, even noting more volume of water is going through the heater (as opposed to hotter water and mixing with more cold water). In other words the water coming out of the shower was the same temp. This savings seemed very high to me, i have a feeling the savings is in less loss of heat through pipes / etc. I bought the Stiebel Eltron Tempra 12 (12KW) water heater (uses a 60A 240 volt breaker) it costed me about $900 after i paid for all installation parts and the unit. This water heater is great, it is enough to run 1 shower or 1 dishwasher and will keep up. I installed it under my sink in my kitchen and works for the whole house: my calculations from using a 20 gal hot water tank i'm saving 27% on electricity My average monthly power consumption for my water heater is around 25Kwh per month measured water temperature in is about 3-5 degrees C