Water cooled system/ High temp safety's

[OG Tree Grower]

So I'm loving this heat transfer with water but still confused on some fronts. This forum doesn't seem to have much specific info on various methods or what works and what doesn't so here I am to help/learn

So far I only have 3 heat exchangers and one res coil
One large industrial unit with 3 passes and 1/2hp fan
Next is just a heat exchanger from an engine with 1500cfm after
Next is just a cheap exchanger with a fan taped to it
The res coil is literally just a coil that runs through the res

Well water is 13c and all info is at 1.5gpm
It enters the first unit and cools 5k down to 83f no problem
The water leaves that cooler at 15.5c
It enters the next room and cools 1k to 75f
Leaving that cooler at 16.5c
Heads into the res and leaves the res at 68 deg
Water leaves the coil at 17 deg, it travels to another cooler and cools the home, finally making its way to the garden or lawn at a tempatures the plants like, everyone is very happy.

Problems/ obstacles
In the heat of Summer it is Run to waste- I tried a closed loop and tried to cool it with the well but it doesn't work, you would need a few wells to properly do that route and get back down to the 13c

Spring fall and winter you can throw a heat exchanger outside and run a closed loop

After the first pass adding more exchangers to the same room does NOTHING. I understand the concept of this but I really thought moving 1500cfm through a cooler 3 deg warmer than the primary but still 20 deg colder than ambient air temp would still have some results. It doesn't. If you want to run two you need to split the intake flow evenly across both coolers

My res heater actually kickes on from time to time.

Proper controls seem to be either not purpose built or not affordable or both, solenoid valves to open and close flow to different units need to be tied into a brain or work off simple switches. For now all I can do is control the fans with temp switches and that works fine for a small less complex system like this

Ultimately I want to be able to switch directions on a 12/12 flip so I'm heating the night room with the day rooms waste heat. I can do this with two pumps , timers and hillbilly some check valves in there somewhere but I was hoping on something a little more professional

Now all these fluid connections and fans and pumps that can fail. This bothered me so of course I had to make a safety of some sort. That's my 14" exhaust fan with scrubber and T2 enviro controller, if that room makes it to 91f that exhaust fan will kick on and hold the room at 93f, the beauty of the controller is you can program it so many different ways. This one is set to idle the fan 24/7 (neg pressure) then it Ramps up at whatever temp you program

 

[queequeg152]

After the first pass adding more exchangers to the same room does NOTHING. I understand the concept of this but I really thought moving 1500cfm through a cooler 3 deg warmer than the primary but still 20 deg colder than ambient air temp would still have some results. It doesn't. If you want to run two you need to split the intake flow evenly across both coolers

im having trouble with your lingo, by cooler you mean a simple fan coil/ liquid to air heat exchanger?

regarding your inability to extract more heat with more coils... what temp is the air after the first coil? the lower the temp differential across any heat exchanger... the less heat you can move.

also more coils will yield far far more static pressure loss, so three coils in series will probably choke your fan down to half the volume it is at with one coil.

putting the fans in parallel, with one plenum feeding all three coils is what you need to be doing here. any duct shop could build you a simple plenum like this in 5 minutes. alternativly you could build one from ductboard and take off collars.

Proper controls seem to be either not purpose built or not affordable or both, solenoid valves to open and close flow to different units need to be tied into a brain or work off simple switches. For now all I can do is control the fans with temp switches and that works fine for a small less complex system like this

i think you just are not familiar with traditional hvac controls. what you are proposing is a simple zoned hydronic radiator type system or zoned chiller... the controls are available just not at your average hardware store.

you need to split your loads into two or more zones... trying to keep the loads in each zone as close as possible for simplicity.

then you simply create a main branch of say... 1" class A pex, then take off 1/2" or 3/4" runs to your zones.

likewise your return lines are also goingto be branched out, with each room returning an identical 1/2" or 3/4" run back to a main branch of 1" or maby 3/4" idk.

1.5 gpm is nothing honestly. you cold do all this with 1/2" pvc if you wanted too.

since you are not recirculating... you cannot use bypass valving like you would in a chiller loop. what you do instead is simply valve off the zones entirely when the zone is not calling for cooling.

you can do this with simple spring return valve actuators. when you cut the the power to these acutators a strong spring and govenor mechanism pulls the valve shut slowly over a few seconds so as to not hammer your piping. these acutators are like 100 bucks new, but can be had for like 40 bucks on ebay pretty much any day of the week. most run on 24vac and only draw like 80ma when running. a tiny transformer could handle a number of them easily.


since you are not recirculating, you also need a flow regulator on each zone such that you are not running excess water to the coils. a simple adjustable watts regulator unit should suffice. they make quite a few... thoug they are like 80 bucks. after the regulator i reccomend a full flow rotameter so you can visually monitor the flow in each zone. simply turn down the regulator untill you get the flow you need as indicated on the rota meter.

each room gets its own simple thermostat, and all these thermostats connect to a simple zoning controller unit. there are 100's of zoning controllers. you only need a simple one, no BACnet modems or anything stupid like that, just a simple one meant for shitty residential jobs.

Now
all these fluid connections and fans and pumps that can fail. This bothered me so of course I had to make a safety of some sort. That's my 14" exhaust fan with scrubber and T2 enviro controller, if that room makes it to 91f that exhaust fan will kick on and hold the room at 93f, the beauty of the controller is you can program it so many different ways. This one is set to idle the fan 24/7 (neg pressure) then it Ramps up at whatever temp you program

honeywell also makes a number of multistage temperature controllers. up to 4 stages i believe. they go from 100-300 bucks i think. they are quite popular in greenhouses. with first stage being lovers opening, second fans powering on, 3rd evaporative cooler... 4th alarm or something like that.

 

[OG Tree Grower]

Thanks for the reply,

Yes they are all heat exchangers. Depending on where I put them they are heaters or coolers, sorry.

The industrial unit with 3 passes is manufactured that way with a fan to match, it's actually an outdoor heat exchanger that went with my last cooling system, the compressor blew so I scavenged this and now just use it as a heat exchanger

Ok I should have given More info. I want to cool and heat the rooms and house in both seasons without a compressor or heat pump. Cooling isn't a problem at all but the reason I don't use manifolds is because you waste water by volume and temp. I need 2 gpm to cool this system if I split the flow, also my final discharge temp is 15c. Still lots of cooling available when it goes out to the lawn or garden. Running everything daily chained I can put the best cooling where it's needed most and continue down the line , when I'm done the final discharge temp is 19c. At this point it's cooling abilites are spent and it can now be easily heated without a heat pump and continue to other heat exchangers for home heating

Now like I said I'm only run to waste in June July August, the rest of the year I throw a heat exchanger outside and run a closed loop, nighttime temps keep me well within ranges so any system I incorporate will have to accept flow in both from directions so I can run a flip 12/12 using all my waste heat to heat the home 24/7 and keep the rooms warm at night and cool in the day.

With the system controls you speak of I will only be able to heat or cool , it would be very efficient for larger places with 4-5 rooms and a system that needs to retain its cooling capibilites to jump over and cool a different heat source but with my system where the waste heat is wanted and cooling abilitea are not very limited I don't have a need to bypass any exchangers, as long as the fan trips off it retains its temp. I spent some time today thinking about controls and I'm really just overthink king it. Fans on temp sensors are all I need for this application.

I really appreciate your input.

 

[queequeg152]

the reason you want to zone shit out is to save on pumping costs and increase the effective capacity of the equipment.

if you system is so small that pumping costs are already small, it may not matter, but most well systems use a 3hp+ submersible well pump and maby a secondary pressure boosting pump so costs are rather high.

running equipment in serial is very lossy with respect to pressure drops. by bypassing a radiator with 3/8" copper and like 4 passes and like 24 u bends... you can save lots of energy over the long run.

there is nothing you can do with a serial configuration that you cannot do better with a proper parallel zoned configuration. its just more cost in equipment and complexity. its up to you do determine if the extra cost and hassle of going with a proper zoning system is worth it.

with regard to your desired temp delta across the zone... this is controlled with the regulator i mentioned. you simply regulate the zone by slowly closing a needle valve or regulator or what ever untill your rota meter indicates what ever GPM your coil needs.
alternativly you could just turn down this regulator untill you get the TEMPERATURE delta you desire.

there is a VERY simple relationship between the temp delta and and mass flow rate of water that governs how much energy water flows have.

its... specific energy x mass flow rate x temp delta = energy per unit of time.

its a linear relationship. very simple. just plug it into a graphing calculator and you will see what im talking about here. to get the same energy into or out of water with a lesser temp delta with an identical heat exchanger will require more mass flow.

in other words you can get more energy into or out of the water with a greater temp delta with less work.

also the lower temp water should be better at extracting humidity from the air, though 15c is still warm as fuck.

with respect to your winter arrangemetns with the outdoor heat exchanger, there is no reason why the same arrangement cannot be made with my proposal.

 

[OG Tree Grower]

Ok that makes a lot more sense. And yes the well pump is 3 hp I think so I hear ya there.ill get some more gate valves and fab up a few manifolds to test this,but with my exchangers being so oversized and the whole setup is so small I don't know if it will make a huge differance. the well pump runs pretty steady at 1.5 gpm. I was actually gonna get a holding tank and a smaller pump for the place but that creates problems with the water absorbing heat before it ever hits the exchanger

 

[queequeg152]

Ok that makes a lot more sense. And yes the well pump is 3 hp I think so I hear ya there.ill get some more gate valves and fab up a few manifolds to test this,but with my exchangers being so oversized and the whole setup is so small I don't know if it will make a huge differance. the well pump runs pretty steady at 1.5 gpm. I was actually gonna get a holding tank and a smaller pump for the place but that creates problems with the water absorbing heat before it ever hits the exchanger

i think you should spend some time researching and learning about these types of systems before you buy anything.

i always say never put your hands somewhere you mind has not been days earlier...

and maby you could post some pics so i can get a better idea of what you are proposing?

im curious about your setup because you are apparently cooling your entire gig with just well water which is rather difficult in my mind... i live in texas though where heat loads and latent heat gain is insane... im guessing you are in a very moderate climate with very shallow well water?

i only took one physical geology class in my entire life... but it was enough to get aquainted with the problems associated with pumping ground water. generally speaking, ground water is easy to get at... but getting it to the surface in any appreciable quantity is very often impossible, or so costly that it might as well be impossible.

hell i recall following an architects blog about some fancy arizona mountain side estate with pool and all sorts of shit , way out 100 miles form nowhere. i believe the well was something like 1600 feet deep and cost like 60 grand.

i cant imagine ever cooling my house with well water.... mainly due to the cost of installing such a large well. here in houston our aquifer is a confined non surface type aquafer that goes down to like 300 feet in some places. it costs lots to pump that water up. and the recharge rate can be poor in some places so you need like 80 feet of well screen which costs shit loads.


im guessing you have a shallower alluvial type aquifer with a higher recharge rate? how deep is your well? is your pump a submerged bore hole type pump or is this an above ground pump?

 

[OG Tree Grower]

Climate is 30c average in the summer and peaks at 36c night time ops are a must. Winter average is -5 and drops to -20c at times, high humidity

I live beside a river and the well is 45 feet deep and has 4" casing with a 2-3 hp sump pump. I've never ran it dry even in the worst dry spells, I assume it connects to the river bed somehow it was flow tested at 8 gpm in 1978 lol.

Cooling the whole house is probably not possible but it blows cool air in the living area and maintains a nice temp while its blistering hot outside. But I've never turned it up or ran it on a manifold so I don't know how good it "could" work. It's my last exchanger in series so it gets 17 deg water and the exchange isnt that great the fan runs 24-7 on that one.

Picts. Hum. I'm just an old farmer learning the Internet. I'll talk to my tech friend and see what he thinks about me posting any Picts, although I do want to. I have some good ones for the vert guys. Maybe under a different account from a coffe shop or something.

Your clearly very smart and know your stuff about chillers but we take very different approaches on things. I like the quote you made about not putting your hands where your mind hasn't been days before. But one thing I have learned over the years doing different rooms in different climates is what works for you probably won't work for me. So I kinda just fly by the seat of my pants, I love experiments and testing shit and have enough old gear laying around I can do this stuff pretty cheap and dirty. My whole water cooled system is old grow gear , truck parts and pvc.. I'm no havoc guy by any means but I can hook up a 5 ton ac for you and create an environment with even temps, windflow and no hotspots.

 

[queequeg152]

Climate is 30c average in the summer and peaks at 36c night time ops are a must. Winter average is -5 and drops to -20c at times, high humidity

I live beside a river and the well is 45 feet deep and has 4" casing with a 2-3 hp sump pump. I've never ran it dry even in the worst dry spells, I assume it connects to the river bed somehow it was flow tested at 8 gpm in 1978 lol.

Cooling the whole house is probably not possible but it blows cool air in the living area and maintains a nice temp while its blistering hot outside. But I've never turned it up or ran it on a manifold so I don't know how good it "could" work. It's my last exchanger in series so it gets 17 deg water and the exchange isnt that great the fan runs 24-7 on that one.

Picts. Hum. I'm just an old farmer learning the Internet. I'll talk to my tech friend and see what he thinks about me posting any Picts, although I do want to. I have some good ones for the vert guys. Maybe under a different account from a coffe shop or something.

Your clearly very smart and know your stuff about chillers but we take very different approaches on things. I like the quote you made about not putting your hands where your mind hasn't been days before. But one thing I have learned over the years doing different rooms in different climates is what works for you probably won't work for me. So I kinda just fly by the seat of my pants, I love experiments and testing shit and have enough old gear laying around I can do this stuff pretty cheap and dirty. My whole water cooled system is old grow gear , truck parts and pvc.. I'm no havoc guy by any means but I can hook up a 5 ton ac for you and create an environment with even temps, windflow and no hotspots.

ok so you have an alluvial aquifer. that explains how you can get so much water. its basically an aquifer made up of river bed material... silt sand and rock. if you are super lucky, the alluvial material is sitting on top of something like a layer of clay... so the aquifer has nowhere to go so it never dries out and you get very good recharge rates. very few folks have aquifers like that. im not an hvac guy either really... i just have the section 608 universal license to work on hvac equipment and handle refrigerants. i dont have a state journeyman lisence or anything... they require 3 years apprentice ship unfortunately. i got it because some of my pursuits require fabrication of small water chillers or plate chillers.