solar

Derheatmeister

Bob do you have some feed back ? So we can help!

bob eck

solar

last year one of my customers installed a oventrop solar unit for domestic hot water.
the solar tubes are facing directly south.
they have a 80 gallon sotrage tank with one coil in the tank.
the trouble is even with one or two sunny days in a row the water temp will not go above 85*F in the storage tank.
they are not using more hot water. only three people and only wife home during the day.
what angle should the tubes be at? what could be wrong with this system?
job near allentown pennsylvania.

Derheatmeister

there are Lot's of factors that go into a Proper design.i.e.Angle of tube's are they pitched at the right angel? Are they pointing due south?.Shading?how Many tubes? what kind of Tank/exchanger? Pump station? piping to/from Collectors to tank. Insulation?.GPM on circ pump? what is the load(GPD per Person) ???

Metro Man

delta's

If everything is set up right.... facing south, 25 + psi in solar loop, etc.... Check collector temp vrs. storage temp. Then actually verify at both. Depending on controller settings your collectors will need to be XX degrees above storage tank temp to turn on and XX degrees above before turning off. Usually around 12 and 5 respectively. If that checks out look at high limit setting on control. Also depending on controller setting you may be hitting a too high collector temp and controller is protecting pump by shutting down.

Watch system run in direct sun.... check delta T between feed and return for collectors. When running (in full sun) 10 - 15 is good.

Hope this helps..

Metro Man

PS It's been about 40 years since I been to Allentown..... Tony Dorsett's hometown. Isn't there a horseshoe bend or am I thinking of Hershey?

hothead

horseshoe curve on PRR

It's near Altoona. Must see

Unknown

Is their pump AC or DC ? If it's AC does their temp sensor work ?
If it's DC is the pump running ? Those panels should be facing south. How many PV panels do they have on the roof ?

scott markle_2

oops

scott markle_2

85 deg.

That doesn't sound so bad for this time of year, If this is families usage is consistent with average americans. I assume this is a two tank arrangement. If the solar is raising well water from 48 to 85 that equals some real energy, and fuel savings. Seem like people want to see solar doing the whole thing, supplemental heating can have a very real impact, and actualy operates at a much higher utilization efficiency than a large array that could meet the whole load.

I do think it's important to have some verification of performance. Some controllers will monitor supply and return temps and based on flow rate, performance can be measured.

mark schofield

solar

Are the sensors reversed? is the pump running at night doing a veverse heat exchange (this happened to me when a sensor failed)? do you have a check valve in the system to prevent thermosyphon when the pump isn't running? please post what you find the problem to be. good luck. mark s