Brazed Heat Exchangers

Justin Topel

I have an existing system that has a brazed flat plate heat exchanger. It has four arrays of solar panels going into one side and the other side with have an injection loop off of it to storage, boiler, domestic, etc. The problem is the guys who mounted the solar panels placed some on the roof, some on a wall, and some on another wall that will be shaded part of the day. So I am going to use differential controllers for each array. My question is what is the best in regards to efficiency concerning pump speeds. I cannot simply place a flow setter on the injection loop to keep it at a fixed GPM since the other side will vary on GPM output depending on which panels are running at the time. So I am thinking of using a Taco Delta T pump to vary the GPMs based on a 10 degree delta T. Does this seem right going with 10 degrees. I have looked at fixing this system for so long I am beginning to cross a few wires upstairs. I cannot remember at this time what the rules are anymore. Is there an optimum delta T for the heat exchangers? Any imput is appreciated.

Mister T

Joe Mattiello

yes, the Delta T pump will work nicely in your application. Because the system dynamics are constantly changing when zoning with zonevalves, it makes perfect sense to use a circulator that can adjust with the system changes. Another alternative is a Differential by-pass valve, and a constant speed circulator.

hot_rod

are the arrays

all piped separately into the a side of the HX?

You could use two controllers that have the east/ west function built in. Most of the new solar controllers have that function. Some brands have variable speed function for those dual pumps, also. It may simplify the controls for you, but you will need a pump for each array.

Yes, good idea to use a delta t circ on the B side to adjust that side as the a side changes.

Justin Topel

They all return..

back to a main header. I spoke with GEA today and had them help with the design a bit. They recommended that we keep a 15 delta T for the flat plate that is already installed. The east/west function sounds like a good idea for the controllers. The only thing that I would like to have for the system is an inline air separator that will work on 1" pipe. HR can you talk to the guys at work to make me a custom one :-). I will post system drawings if you would like to see what is going on.
Thanks

Mister T

nugs

The variable speed circulators are going to revolutionize the industry within a short time. That is precisely how I would solve your problem.