hi m a final year be student in electrical stream help me and my group in our project....?

Question

our project is to obtain temperature control by mixing cold water to hot water in a proper proportion , so that the water coming out from shower is at a safe and at a temperature required by the user. There are two separate containers for hot water and cold water. User will input the temperature limit by keyboard, LCD will display the choice of user. There will be 4 choices given to the user cold, moderate, hot, very hot. The temperature of the water in the hot water container is assumed that it is more than the temperature of very hot water condition. The whole process is controlled by PIC microcontroller. For the controlled flow of water we are using solenoid valves. to obtain this v r using a logic of giving opening time to the solenoid valve.. so v hav to find out exactly how much time the valves should be kept open? so plz give us a sollution?

Answer 1

The final temperature will be an average between the hot and cold water temperatures AND the amount of flow of each source. It is a mixing problem.



Heat = specific_heat_water_c x temperature_T x flow_Q



H1 - H2 = c (T1 x Q1) - (T2 x Q2) = c Tout (Q1 + Q2 )



Tout = (T1 Q1 - T2 Q2) / (Q1 + Q2)



It is not time the valves should be kept open, but how much. There are no time lags in this problem, since the mixing and the output temperature is practically instantaneous.



What you need to do is to setup a calc block in the PIC, with flowmeter and temperature signals.



questions???

Answer 2

Hi so the use of a reservoir chamber is required where the water is mixed before being pumped to the shower head and the reservoir chamber is a tank which has thermistors which are heat resistance devices which give information back to a micro chip so the inputs can be varied. simple really so no one gets either cold water or scolded by hot water.

you will have to write the program to control valves and use the input temperature resistances to monitor temperature and switch the pump on and off.

Answer 3

You can find different projects and ideas for many departments

projects ideas ( http://projectabstracts.com/ )