[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[TRNSYS-users] Water Heater - Water Draw Forcing Function (variable)
I created a model for a water heating system and I currently use a Type14b forcing function to set my water draws. This forcing function takes the variable water mains temperature from the weather input and forces the mains water (tap water) into the water heater at a set schedule and rate. The problem I have with this is that now the water exiting the water heater is fixed at the 120 degrees F from the water storage tank, and I want to use a tempering valve and set the flow rate of the water to the mixture of hot and cold water instead of just the hot water.
I'd like to use a Type11b tempering valve to mix the 120F hot water from the tank with water from the mains (which varies in temperature) and output water at a fixed 105F. This means that the flow rate exiting the hot water tank is less than the flow rate after the tempering valve, since some cold water is added. (water from the mains comes in both to the storage tank and again to mix with the hot water exiting the storage tank)
Is there a way where I can use a forcing function to set the mixed hot/cold water coming OUT of the tempering valve instead of using it to push water into the storage tank from the mains. The water temperature of the hot water (in the tank) will be fixed at 120F, but the cold water from the mains that mixes with the hot water from the tank will have a variable temperature. So, while the overall flow rate after the tempering valve will be constant, the flow rate from each the hot water tank and the mains will be variable since the mains temperatures change throughout the year.
The Type14b forcing function only allows me to 'push' water into the storage tank, not 'pull' water out of the tempering valve after it has been mixed with both hot and cold water. Can you please suggest what forcing function to use and in what order?
Thank you,
Tom