Adding to new setup need help

Joebif

Here is a drawing of my setup with the existing propane heater on the right, except for the mixing valve and ball valve B and everything on the left of the variable speed circulator that is using a DELTA T that is not there yet. Everything works great and was tested from the past 2 days of colder weather.



I want to add the 500 gallon open storage tank for the wood fired boiler and future solar panels. In doing that I added a ball valve B and ball valve C and a mixing valve to my existing system and need help on a problem I see.



If I want to force the return of my radiant system to go through the storage tank heat exchanger I close ball valve A and open ball valves B & C.  The mixing valve then will not have a source for the cold side to mix with and need help on where that should come from. When ball valve A is open and B & C are closed then the water will just pass through the mixing valve and not be used.



I was thinking that I could always keep ball valve A open but was wondering if my return would for sure still go to the storage tank and get used or not.



I could have the cold side of the mixing valve get cold at a T underneath the mixing valve between the ball valve from the cold from the source and put on a backflow preventer so if I wanted to put in glycol I could but was not sure if that was correct or not.  Or is there another way?



I am learning a lot here.

Thanks

hot_rod

two valves

one is a 3 way zone valve. It selects which heat source to use. If the 500 tank is 120F or warmer the flow is through that coil. Once that tank drops to a lower temperature the valve shuts off that coil and allows flow thru the water heater tank. The water heater runs 130F or so.



A simple differential control, or solar control runs that valve.



The other 3 way valve is a thermostatic valve, it mixes down the temperature from the coil in the 500 tank, as you do not want 190F temperature going to your slab.



If the water heater is a standard tank be carefull not to run it continously at low temperatures or you could condense and cause the HX to rust and the flue to soot up. If you hear water dripping on the burner in the water heater you are running too cold.



Depending what type of wood boiler you have, it may also require a thermostatic valve to protect against extended condensing mode.



hr

Joebif

New drawing

This is based on yours so I make sure I am doing it correctly.



I am looking at the TACO 560 series 3 way zone valves.



Also becasue I want to do Solar down the road is there a differential or solar controller that you recommend that will help me with this and the solar panels in the future? Maybe a few names or links to what I might get. Also what type of temp gauges do I need to read the temps in the storage tank? Or do I just get pipe sensors.



Thanks for all of your help.

hot_rod

solar controllers

plenty to chose from. You can buy a single zone, or multiple. Just like a zone controller.



I like the Caleffi BX or equivelent. It allows you to control 4 different outputs. Each relay has two sensors assigned to it.



So S1 would go at the solar collector

S2 at the bottom of the storage tank. Relay 1 responds to a temperature difference between S1 and S2.



S3 and S4 might go on the water heater and the tank to switch the zone valve for that load.



S5 and S6 might watch the tank temperature and the load and decide when it is time to switch from one source to another.



Wherever you install a sensor you have the ability to "know" that temperature by scrolling across the view screen. Sensors can be strapped on a pipe or inserted into a well in the tank.



This same control can do some energy monitoring. If you install a flowmeter to determine the flowrate the control knows the delta T and then calculates the energy that has moved thru that loop. Then if you know the cost of your fuel you can determine operating cost, or solar harvest.



A multiple zone, multiple temperature, multiple heat source system takes a bit of head scratching to build a control logic. Once you decide what has to happen and when, the piping and the control logic need to be built to work with one another.



You might consider hiring a nearby hydronic guru with experience in designing a system like this for a consultation. You really need to know all the pieces, application and your needs and budget to build a custom system like yours.



Energy is pretty expensive to be building trial and error systems. If in fact you are running a standard water heater as your heat source you might be operating at a 60% efficiency, it is on the low end of fuel burning appliances.



hr

Joebif

Looking into the controllers

I will look at that brand of controllers. 



We are using the propane heater for the heat source only becasue the BTU's needed to heat the water in the Fish tanks, plant troughs and Utility room is very low.  A tank-less would not go low enough and would not work at all, it would not be able to get the small btu's needed for the smaller tanks.



A Wood burning stove will be used with a 500 gallon storage tank and should eliminate the use of the propane heater and then the propane heater will just be used as a backup. The propane heater can be used all the time and if I am not able to get a big burn going it will be enough until I get back and get the wood stove going. The wood burning stove will give us a much higher efficiency. Then when we add several solar panels we will gain even more efficiency.



We only have one heat temperature needed.  The heat source at the propane heater is set at 120 degrees. We hope the wood will be able to keep the storage tank at above that temperature if not we will add the solar panels in the daytime. Or we may find that the solar panels are all we need for the heating requirements and the wood stove will just give us the heat we need at night. Or if they both do really good we may use the extra heat in the storage tanks and put fan coils in the greenhouse just to keep it above freezing or higher.



The TACO zone controller turns on the circulator when any zone needs heat. It is a variable speed pump and will be able to take care of all of the zones so we do not have multiple temperature requirements. The circulator takes care of what btu's are needed with all of the zones becasue it is a variable speed pump set at a DELTA T of about 5 degrees. 



My first cold day was Saturday and it worked great. It kept the output at 120 and the return at 115 all day Saturday and the propane heater went on 3 times in the 5 hours I was working in the Utility room. It was on for very short periods once the floor got to temp. When it first stated up it ran for a longer period but the heater was never on at that point.



We do have multiple heat sources and that was why I was asking about the mixing valves and controllers.  I thank you for these ideas and will look at the Caleffi BX.

Joebif

Caleffi Controler

This is an nice controller. I had not heard of this model. Also the flowmeter and Grundfos Direct Sensors working with the controller makes it really an excellent controller. WOW!



Now I understand more of what you are saying in how to control everything. Excellent job and I appreciate all of you help hot rod.



I wonder is it possible to use the flowmeter or the Grundfos Direct Sensors to monitor the other test idea I have in the other post?