leitmotif said:
Lawzee lawzee Mr Nachtway you sure are a demanding man - poor ole plumber runnin them pipes as fast as he can!!!!
I think he merely forgot to draw a line out of mixing tank.
Indeed, i forgot to place the pump P5 to supply hot water to the Dorm...
Ok let us be clear on each pump...
Water supply to the dorm should be both Hot and Cold.
- Therefore, pump P1 supply only cold water to the dorm.
- Pumps P2 & P4 feeds the Mixing tank,with cold and hot water respectively.
- Pump P3 is to circulate the water in the Solar Collectors.
- Pump P5 feed the dorm with hot water @ 40 c from the mixing tank.
Another point of interest which Dan raised.. that is the growth of legionella.. but still assume 24 hour stand still..
As Gil 47 stated, is it wise to do the mixing in the pipe itself, therefore removing the mixing tank..?? Or should i just increase the required temperature in the mixing tank,, most probable..
Yes, i think no one looked @ the picture which i posted together with the System layout..
The P&ID layout, whereby it gives a view of all the instrumentations equipments which i proposed to use in controlling the systems..
As far as for flow sensors i have not made provision of any, since my decision was not focussed on PID at that time, if you think it is wise to implement the flow meters make the Necessary additions in the P&ID, and i've got to check it later with my senior for approval..
See picture below Pls...
http://www.plctalk.net/qanda/uploads/P&IDLay1.JPG
One more thing, keith, the SimAPP you have posted.. looks nice
,, but i
dont quite understand these stuffs, i know you working with some mathematical formulas in order to have the right proportion of hot to cold water needed to achieve the right temp in the mixing tank.. corect me if im wrong!!!!
Pls keith i wanna understand these stuffs, look nice but will lul even better if i understand it fully. can you give me some theory and explanations on these block, you said that you are using a PI controller for both temp & level control. Pls dont mind me asking these, coz i wanna simply learn from you guys,
...You Are all too Good...
Yep, i cannot see exactly whether you are heading with a PID controller or you will be using simatic S7 for programming... coz my senior is not willing to buy a PID controller he want this to be achieved by using the simatic S7 software...
Kamenges said:
Why limit the temperature to 65oC? Why not let it get as hot as possible within safe limits? Or is 65oC your safe limit? I would think the higher the temperature the higher the energy stored (gets you through the night) and the faster the mixing tank temperature will respond.
Hmm, yep you are right about this factor, but when we will be calculating the mixing proportion, should not we know the maximum temperature of the hot water, in order to have the according proportion for the mixed water @ 40 c, but if the temperature ever achieve a high degree, then tank will need to be pressurise you think?? on top this system will be mounted on the roof of a 3 storey building... (??)
See you....