- #1
Blank_Stare
- 111
- 66
First time here. I browsed around a bit, but did not see a topic quite like what I am about to write, so I started a new topic. If I missed an existing topic, please point me to it, and I will thank you for doing so.
Please select a prefix? I seem to remember some of this from High School and/or first year College Physics, but that was about 35 years ago, and I haven't had occasion to use much of what I studied...so I am going to guess that it would be High School level stuff
Simple scenario: I want to move water from my hot water heater, up to the roof, where it will run through a solar collector, and then drop back into the water heater. I will do this using a very low (possibly solar) powered pump, during daylight hours only.
The questions that come to mind are as follows:
1.
When selecting a pump, do I have to account for the pressure of the water in the loop, in addition to the pressure created by the elevation change between the tank and the solar collector, or, because it is a closed loop, does that pressure cancel itself out, coming down the return side of the loop?
2. Since I will have a closed loop, would it make sense to place the pump at the highest elevation, thus requiring less power to operate? (I think this is a "no", but I am not a Mathematician, Engineer, or Physicist...) Does it make more sense to have it at the bottom of the return side? (push-me, pull-me, probably makes no difference, right?) My gut tells me anywhere on a closed loop is going to require virtually the same energy, but I have to ask...
3.
I'm sure there must be an online calculator, somewhere, but I can not find one for the layman. Can anyone tell me how many PSI (sorry for old school standards,) at the bottom of a 20 foot column of standing water.
In the end what I have envisioned is moving a gallon (or so) of water an hour - just enough to replace heat that is leaching off the tank, and into the atmosphere of the utility room where the tank resides. I will probably use 1/4" copper tubing for the loop, wrapped in some sort of insulation, most likely fiberglass, on the feed and return, and an enclosed reflection box as the collector.
I give the information about application so that you can envision what I am setting up. I have seen proof of concept, and I know that a collector like this does a very good job of heating water to scalding temperatures, in under a minute on a clear day, if collector volumes, and other details of the collector itself are properly constructed. However, incorporating a storage tank, and recirculating the hot water in an elevated loop through the tank are not something I have good information about.
Any and all suggestions and raw information are very much appreciated, and should this mental exercise actually become a project that I build, I will be more than happy to share the results.
Thank you in advance,
Blank_Stare
Please select a prefix? I seem to remember some of this from High School and/or first year College Physics, but that was about 35 years ago, and I haven't had occasion to use much of what I studied...so I am going to guess that it would be High School level stuff
Simple scenario: I want to move water from my hot water heater, up to the roof, where it will run through a solar collector, and then drop back into the water heater. I will do this using a very low (possibly solar) powered pump, during daylight hours only.
The questions that come to mind are as follows:
1.
When selecting a pump, do I have to account for the pressure of the water in the loop, in addition to the pressure created by the elevation change between the tank and the solar collector, or, because it is a closed loop, does that pressure cancel itself out, coming down the return side of the loop?
2. Since I will have a closed loop, would it make sense to place the pump at the highest elevation, thus requiring less power to operate? (I think this is a "no", but I am not a Mathematician, Engineer, or Physicist...) Does it make more sense to have it at the bottom of the return side? (push-me, pull-me, probably makes no difference, right?) My gut tells me anywhere on a closed loop is going to require virtually the same energy, but I have to ask...
3.
I'm sure there must be an online calculator, somewhere, but I can not find one for the layman. Can anyone tell me how many PSI (sorry for old school standards,) at the bottom of a 20 foot column of standing water.
In the end what I have envisioned is moving a gallon (or so) of water an hour - just enough to replace heat that is leaching off the tank, and into the atmosphere of the utility room where the tank resides. I will probably use 1/4" copper tubing for the loop, wrapped in some sort of insulation, most likely fiberglass, on the feed and return, and an enclosed reflection box as the collector.
I give the information about application so that you can envision what I am setting up. I have seen proof of concept, and I know that a collector like this does a very good job of heating water to scalding temperatures, in under a minute on a clear day, if collector volumes, and other details of the collector itself are properly constructed. However, incorporating a storage tank, and recirculating the hot water in an elevated loop through the tank are not something I have good information about.
Any and all suggestions and raw information are very much appreciated, and should this mental exercise actually become a project that I build, I will be more than happy to share the results.
Thank you in advance,
Blank_Stare