modelling a heater in simulink

[fox]

hello,

I could use your help for a study project.
I'm trying to make a simulink model that controls the central heating for a building.
It is working for the largest part. Only in my current model the heater turn on as soon as the room temperature is lower then the required temp. And turns of again as soon as the roomtemp. is higher then the required temp.
This results into a heater that switches on and off every second trying to retain a constant temperatuur.

Somehow I have to make a system that allows the temperatuur to drop 1 degree below the required temperatuur, and then heats untill the temperatuur is 1 degree above required temp. This way the heater doesn't switch on and of that often.

Does anyone know how I could model this in simulink?

It would be a great help!!

ty. Yorick

[sany]

Post by fox
hello,
I could use your help for a study project.
I'm trying to make a simulink model that controls the central heating for a building.
It is working for the largest part. Only in my current model the heater turn on as soon as the room temperature is lower then the required temp. And turns of again as soon as the roomtemp. is higher then the required temp.
This results into a heater that switches on and off every second trying to retain a constant temperatuur.
Somehow I have to make a system that allows the temperatuur to drop 1 degree below the required temperatuur, and then heats untill the temperatuur is 1 degree above required temp. This way the heater doesn't switch on and of that often.
Does anyone know how I could model this in simulink?
It would be a great help!!
ty. Yorick

Yorick,


In this case our measurement signals are varying fast, say its high
frequency signal. find the freq of signal and estimate the desired cut-
off for for this measured signal(say through oscilloscope ) & decide
upon a cut-off freq for measured signal which wont disturb the heater
performance.

1. Industries, they have a dead-band concept for this.Say room
controlled at 27 deg C. then 27+2/27-5 deg C no change in controller
output.if changes outside this value i.e greater than 29 deg C and
less than 22 deg C.You switch on relay at 22 deg C and switch -off a
29 deg C.

If you can add more thermal sensors over different areas in the
room ,we can have more accurate control of temp around set point.

2. Put a first order delay in measurement side for the time you reqd
the controller should not respond even if temp starts falling.you can
adjust this time till you get a desiredd time period for switch on and
off.

Regards

SS