Browse Forums Eco Living 1 Jan 13, 2011 10:35 am I am trying to add a storage tank to my existing Solar HWS but not sure the best way to do it. I have an evacuated tube low pressure type with an incorporated storage tank on the roof, the tank on the roof only holds 160 Lt. so I thought I could purchase a second hand electric boosted hot water cylinder, put it where the original electric HWS used to be (on the ground) and pipe the two together to increase my total storage. Can anyone help with a connection diagram or explain the correct positions for the pipes to connect into the tank ect. or at least give me an idea of the hydralic principles involved in the interconnection of the existing tubes and tank on the roof and the new tank on the ground. Cheers Re: Adding a storage tank to existing solar hot water system 2Jan 13, 2011 5:35 pm Not an easy question to answer, and I have big concerns about how well it would operate, but here are some thoughts: To get the hot water to the lower tank you will need to install a pump. The pump will probably need to pump the water from the existing solar system outlet to the new tank lower fitting below the point where the connection to the taps takes off. Between the pump and the tank the cold water feed will be connected.If the pump hasn't got a one way valve to stop the cold water feeding back up to the taps you will need to fit one. The hot water tank top fitting will now connect to the solar inlet pipe. The pump should probably be controlled by the temperature in the existing solar tank The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Adding a storage tank to existing solar hot water system 3Jan 14, 2011 7:20 pm Hot water will flow uphill provided he pipe is a slope up for the length of a pipe, so if you can connect the new ground level tank so that the insulated pipe from the top of the new tank goes to the top of the existing tank, in a constant uphill slope, then you can continue to take your hot water feed to your outlets from the existing point on the existing tank. A similar system is used for wetbacks in combusion stoves. If not then things get tricky. If yes then all you need to do is have the bottom outlet of the new tank connected to the cold inlet on the existing tank with a pump to circulate from the new tank to the existing tank. Control this pump with a simple thermostat set to turn on the pump when the temperature at the outlet of the existing tank is above your required outlet temperature. This would be about 50-55 degrees. Hot water reaches the preset temperature, the pump turns on and by pumping cold water from the bottom of the ground tank will force hot water from the top of the top tank to the top of the bottom tank.This means that when the pump is off the thermosyphon effect will allow hot water to return to the top tank if it is colder than the top of the bottom tank. Pipe insulation is important in this setup. Search for retrofit solar hot water controllers for a more technical description of possible solutions. Normally it is retrofitting the EV tube units to existing HW units on the ground but the controllers used could do what you want. The time to heat is purely a function of the distance between the hws and the faucet. There are many options for hot water, you can also have a circulating circuit of hot… 1 8672 18 74798 From what I know about water tanks (I've been working with a client on them for a few years now) is this - The concrete can last a lifetime if they don't crack for some… 2 6485 |