Show Posts
1
Everything else / Space Heating from Engine Heat
« on: October 31, 2019, 11:30:34 PM »
I have calculated that my 50 gallon solar storage tank can supply my garage with 12 hrs of heat between 160 Degf and 50 Degf if I heat it to the upper value and then draw 3500 btu/hr in the form of a fan/radiator until the lower value is reached. To help heat my garage space.
I can charge the tank to 160f by running the Listeroid for 4 hrs and transfering the coolant heat and electrical heat (via an electric heating element) to the tank fluid.
I have a fan/coil capable of 18500 btu's output which can be piped to the tank and be energized to blow heat into the space when the tank liquid reaches 160f.
Problem:
When the fan/coil is energized it will exchange far more heat (Btu's) when the water temperature is at 160f than it will when the water temp falls to, say 65f.
So I will get most of my heat transfer taking place in the first few hours of the cycle and little transfer later in the cycle becasue of the lower differential temps across the radiator as the water loses heat.
If I can pull a constant 3500 btu's from the tank, it should last 11 - 12 hours through the night.
What do you guys think of this solution....
Cycle the Fan/Coil based on tank temperature so excess heat is not expelled at the start of the cycle.
Basically cycling the fan (and circ pump) to control the release of heat over time.
As and example...
(Just for illustration, I have not calculated these values yet.)
======= FAN/COIL CYCLING==========
Tank Temp Cycle time (ON-OFF) Minutes
==================================
160 5 - 10 Short heating cycle
150 6 - 10
140 7 - 10
130 8 - 10
120 9 - 10
110 10 - 9
100 11 - 8
90 12 - 7
80 13 - 6
70 14 - 5
60 15 - 3
50 16 - 0 Long heating cycle
Does this approach make sense?
A simple Arduino program with a motor relay could run the heater fan and circ pump.
Some of you guys that are more familiar with heating and cooling systems may have an opinion as to whether I'm on the right track.?
I would use this as an initial system to prove the garage CHP model.
Later I could make the controls more intelligent by having the microcontroller measure the change in tank temperature over time (BTU's used and BTU's remaining) and dynamically adjust the fan cycle time to budget the heat over a 12 hour period.
And is an tank target temperature of 160f realistic? or should I take it higher and store more heat?
cheers,
veggie
I can charge the tank to 160f by running the Listeroid for 4 hrs and transfering the coolant heat and electrical heat (via an electric heating element) to the tank fluid.
I have a fan/coil capable of 18500 btu's output which can be piped to the tank and be energized to blow heat into the space when the tank liquid reaches 160f.
Problem:
When the fan/coil is energized it will exchange far more heat (Btu's) when the water temperature is at 160f than it will when the water temp falls to, say 65f.
So I will get most of my heat transfer taking place in the first few hours of the cycle and little transfer later in the cycle becasue of the lower differential temps across the radiator as the water loses heat.
If I can pull a constant 3500 btu's from the tank, it should last 11 - 12 hours through the night.
What do you guys think of this solution....
Cycle the Fan/Coil based on tank temperature so excess heat is not expelled at the start of the cycle.
Basically cycling the fan (and circ pump) to control the release of heat over time.
As and example...
(Just for illustration, I have not calculated these values yet.)
======= FAN/COIL CYCLING==========
Tank Temp Cycle time (ON-OFF) Minutes
==================================
160 5 - 10 Short heating cycle
150 6 - 10
140 7 - 10
130 8 - 10
120 9 - 10
110 10 - 9
100 11 - 8
90 12 - 7
80 13 - 6
70 14 - 5
60 15 - 3
50 16 - 0 Long heating cycle
Does this approach make sense?
A simple Arduino program with a motor relay could run the heater fan and circ pump.
Some of you guys that are more familiar with heating and cooling systems may have an opinion as to whether I'm on the right track.?
I would use this as an initial system to prove the garage CHP model.
Later I could make the controls more intelligent by having the microcontroller measure the change in tank temperature over time (BTU's used and BTU's remaining) and dynamically adjust the fan cycle time to budget the heat over a 12 hour period.
And is an tank target temperature of 160f realistic? or should I take it higher and store more heat?
cheers,
veggie
